2015 FSAE Rules [Archive] - FSAE.com Forums

mdavis

07-12-2014, 04:48 PM

The Triumph 675 3 cylinder engine might be pretty interesting to run. Also there are some interesting 650 twins around. I think the justification for the larger engines was to increase secondhand availability of engines to teams. It is no secret that the 600s are more expensive secondhand due to FSAE, and the singles aren't exactly cheap. Given the restrictor these larger engines shouldn't give too much more (if any).

It is nice to see a rule change that might help decrease costs for teams.

Kev

Kevin,

There was a team that showed up with a Triumph 675 sleeved down to 609 or something like that at Lincoln 2013. I do not think the car got through tech, I remember them complaining about design judges not liking the idea (they were in paddock right next to us), and one of the team members was ranting/raving about a simple car after Endurance, primarily dragging his team members to look at our car, which was entertaining. If they hadn't had to go through all of the engine redesign/customization stuff, I can only imagine what the results would have been. The only thing I can think would have happened was a lot of glorious glorious noise from that car.

It still annoys me that the DbC noise check is being brought about after the committee was notified that teams were cheating the noise test. As I've said before, I do not care that they cheated if they think it gives them an advantage: If you think you gain hp or whatever by running loud, then run loud. It's when the rules committee members think they are legal on track as they passed the test (which they are not!) and then try to make rules changes around these perceptions. If that change goes through, purchasing an OTS muffler will no longer pass on a single cylinder, and we will likely see more teams running plugs to get through noise test and then pulling them after the test is passed.

-Matt

BeunMan

07-12-2014, 05:03 PM

...
If that change goes through, purchasing an OTS muffler will no longer pass on a single cylinder, and we will likely see more teams running plugs to get through noise test and then pulling them after the test is passed.

-Matt

As with any rule, you can be request to show compliance at any point during the competition. I think in case of engine noise they should do that, at the fines which the track gets are directly charged to the organizers (e.g. FSAE) which is not in the interest of ALL teams.

Kevin Hayward

07-12-2014, 06:32 PM

Matt,

Looks like they could run the engine now without having to re-sleeve. Should offer similar advantages to the four, but with a narrower package (and maybe lower vibrations). I would love to know the base weight of one of the triumph engines. I am sure the judges probably disliked the idea of heavy customization to end up with an engine not much better than a standard 4 pot.

Definitely not as radical as building a powertrain around something like a BMW R65 engine. An aircooled boxer engine could make for an interesting change.

Opening up the options here doesn't hurt anyone, and definitely means more of the engines sitting around a wrecker will be suitable.

Kev

Yessamgerg

07-14-2014, 03:55 PM

Very interesting set of proposals, Overall they are much much better than the stuff proposed in the aero rules survey...

I like the rear wing limit as it makes for a more interesting design challenge to promote clean airflow around the open cockpit. If you don't do a good job of managing the airflow around the cockpit your wing will have to be extremely tall which will ruin the handling of the car due to the CG penalty. I think its an interesting change that should promote some new concepts.

I agree that the plenum size would be very difficult to regulate, especially for teams with active runners who wouldn't be super excited about flooding their electronics with water. The real issue here though is if the plenum volume restriction is applied to NA cars or just turbo ones? Possibly a different size could be applied to different cars (1L for FI 3L for NA, just random numbers)

mdavis

07-14-2014, 06:44 PM

As with any rule, you can be request to show compliance at any point during the competition. I think in case of engine noise they should do that, at the fines which the track gets are directly charged to the organizers (e.g. FSAE) which is not in the interest of ALL teams.

I do not know if that is the case with the US venues, as the MIS event regularly hosts NASCAR testing, which is incredibly loud, and the Lincoln event is held on an active airpark. There were several planes taking off, landing, practicing various maneuvers while we were competing. Even the loudest single cylinder cars were quiet in comparison.

The way I would like to see noise checked is where it matters most: on track with the car loaded up. This is the way that the SCCA (Sports Car Club of America) does their noise testing at the Solo Nationals event that is held in the same location as FSAE-West. From my understanding (I've never run a National event) they find a spot on the course where all cars are most likely to be at full throttle under the highest load and set up a mic 50' from the racing line. They then measure noise for all cars that go past. If a car is close (within ~5db), I believe they are warned after the run. This would make sense for the autocross event, where teams have 4 total runs with a slight break in between. If a team is close on a given run, then they are warned and they have a chance to talk with the driver/make changes to the car before the next run. If they go over, the run would be DNF'ed. IMO, for the endurance event, it would be best to provide some tolerance, and then anything above the tolerance results in a DNF (either for the lap or for the entire endurance event). 2 laps over noise and you're black flagged for Mechanical and done for the event. If you want cars to be quiet on track, this is a good way to do it. It's harsh, but it accomplishes the goal of quieting down cars. It would only take 1 event where teams DNF for noise before the word gets out and teams quit cheating the test by adding plugs to their exhaust for the current test then pulling them and running the competition loud.

Matt,

Looks like they could run the engine now without having to re-sleeve. Should offer similar advantages to the four, but with a narrower package (and maybe lower vibrations). I would love to know the base weight of one of the triumph engines. I am sure the judges probably disliked the idea of heavy customization to end up with an engine not much better than a standard 4 pot.

Definitely not as radical as building a powertrain around something like a BMW R65 engine. An aircooled boxer engine could make for an interesting change.

Opening up the options here doesn't hurt anyone, and definitely means more of the engines sitting around a wrecker will be suitable.

Kev

Kevin,

If this rule goes through, that would seem to be the case. I do not remember if their sleeves could be removed, but if they were able to (or have easy access for more engines) this would definitely seem to be the case. I think this is a good change for the competition. Singles are incredibly expensive, but something like a Suzuki SV650 can be had for 1/3 the price of a single cylinder, and you get the whole rest of the bike to scrap out as part of that deal.

I always thought something like the Honda Goldwing would make for an interesting engine for an A-Modified (SCCA class which is basically big FSAE car with almost no rules). Flat 4 (or 6 in the later versions), shaft drive right out the back of the gearbox, etc. There are a lot of unknowns in terms of aftermarket support, transmission strength, actual power capability (I've heard the top A-Mods are near 300hp) etc. etc. etc. Either way, still fun to think about.

-Matt

Kevin Hayward

07-14-2014, 07:35 PM

While I dont think the particular change to the aero is a good one it is great to see a change to the rules that actually opens up possibilities, and forces teams to consider more trade-offs. New turbo trade-offs, rear wing / rear track trade-off, more available engines, powerful 2wd electric vs more control of the less powerful 4wd. It is amazing that changes like this require very few textual changes to the rules, especially compared to something like the alternate frame rules. From the look of it most teams will be affected which should cause a little bit of a shake-up. Some concepts will win, some will lose, and now that I am over my initial shock I am excited to see how it will all pan out.

As much as I have liked seeing the performance of the big winged cars (my team included) it was a bad rule change in the sense that it made aero devices compulsory if you wanted to do well. This definitely increases the cost of performing at the front (although not nearly as much as people complain about).

Kev

07-14-2014, 10:49 PM

... new rule set ...
According to Racecar Engineering...

- Smaller Wings (inside of the wheels instead of outside)
- Probably ban of unsprung aero?

FSAE Rules Committee Members to students;

"FSAE is NOT a Mini-F1 contest!!!
Now, you students know that FSAE is supposed to be about challenging your, err..., "Creativity and Imagination" to, umm..., build some sort of, err..., C&I car ..., or something...
So STOP THINKING OF MINI-F1!"
~o0o~

Meanwhile, FSAE Rules Committee Members amongst themselves;

Senior RC Member, "Well, looks like we are going to have to make some big changes to the aero Rules now..."

Junior RC Member, "Why?"

S-RCM, "Geez, haven't you seen this year's F1 cars!!! They've all got those narrow rear wing packages! Now that's because the narrow wings are much, much better at, umm..., well, something. It doesn't really matter why. But obviously it's something really important, innit?! I mean, they wouldn't have 'em in F1 otherwise, would they?"

J-RCM, "Yeeahhh... I guess so. They've got to be a good idea, ... 'cos they're in F1..."

S-RCM, "Yes, and we must get rid of that "unsprung aero" nonsense too. MADNESS!!! You never see any of that in F1, do you?!!!"

J-RCM, "Ok...
So I guess we should probably also include some definitions of what "aero", and "suspension", and "bodywork" are, so that there will be no confusion about what is unsprung..."

S-RCM (interjecting), "NO, no, no, no, no!
That'll allow some troublesome C&I students to come up with a really fast car that doesn't look at all like an F1 car. No way!!! Oh no, no, no. We have to leave ourselves a means of, err..., "discouraging" that sort of disrespectful heathenism!
Better to keep the Rules as vague as possible..."
~o0o~

- Larger engines (700cc)

J-RCM, "Now, about this engine capacity limit. Given that we already restrict engine power with the "restrictor", I don't think we need ANY capacity limit AT ALL..."

S-RCM, "What!!! Are you MAD!? What if a team comes with a 8 litre big-block V-8??? It's too frightening to even imagine..."

J-RCM, "Well, a big-block like that will have so much internal friction that, together with the restrictor, it'll be lucky to make as much power as a Baja-Briggs."

S-RCM, "No, no, no, you just don't get it.
F1 has all sorts of specifications that very tightly control the type of engine they use. So we have to do the same. Simple as that!"
~o0o~

- 2WD eCars with 80kW; 4WD eCars with only 50-60kW

J-RCM, "I've been doing some research, and it seems that the 20 mm restrictor is good for about 90 kW on the Combustion-cars. So no current disadvantage to them. And I was talking to some toothless hillbillies at the local drag strip, very nice guys BTW, and they say that a RWD-only C-car should be able to blow the 4WD E-cars away in the Acceleration event. So I'm not sure about this idea of lowering E-car performance?"

S-RCM, "Geez, you still don't get it!
This competition is about breeding an army of witless drones that will design the next generation of production cars. And we have already decided that the next-gen cars must be E-cars.
So we DO NOT want the students learning how to make the current C-cars faster, or more efficient. Instead, we want them
believing that E-cars are far superior to C-cars. So much so that the E-cars have to be severely nobbled just to get some equivalency in performance.
(And God help us all if anyone ever suggests that Enduro be lengthened, to show up the piss-poor real-life range of the E-cars. That must NEVER be allowed to happen!)"
~o0o~

The downward spiral continues...

Z

Kevin Hayward

07-15-2014, 12:54 AM

Z,

The changes to aero I think are a performance restriction to counteract some of the performance added when they changed a few years ago. There are many ways to do this, and limiting the size of aerodynamic elements is a good one. I don't agree with the unsprung mounting restrictions, but it hasn't been clearly communicated that it is amongst these rule changes (maybe by implication only).

I'm not sure what your complaint about the bigger engines is ... as you state the restrictor already provides a limit. It might be a bad idea for students to use the bigger and heavier engines,b ut I like that it will be there mistake to make.

Lastly the big difference between the electric motors and petrol is not the peak power, but the sustained power. An electric car limited to 80kw will be able to do this through-out their rev range by the rules, meaning incredibly torque down low. An IC motor only touches it peak power for a small rev range (which is much smaller than the range you need to use in the acceleration). A CVT could make things better, but introduces issues of its own. However as I have stated previously keeping the classes separate is the only sensible approach. The electric cars are faster partly because the petrol cars are held back (especially by the restrictor, turbo location etc). It does not represent accurately the differences between IC and EV cars in the real world.

Kev

Dunk Mckay

07-15-2014, 05:23 AM

Z,

The 2WD vs 4WD thing is a bit strange. But I would dispute the idea that the combustion cars have the potential to blow the e-cars our of the water in acceleration. Maybe a car designed purely for acceleration could keep up with the standard e-cars, i.e. a dragster that meet the regulations. But that car would suffer in every other event, and would not beat a electric dragster. The issue being toqrue curves, dropping power to shift gear 2 or 3 times costs as much a half a second, that yes, as Kev said a CVT would get back and even improve the torque performance. But ultimately it's not going to match the full-power-all-the-time of an electric motor.

If dramatically changing the power allowances for electric cars causes them to be at a disadvantage against combustion cars then great, all the more reason to separate out the classes at FSUK. if they're competing against each other it doesn't matter what their rules are as long as it's safe and cost effective for all universities that run them.

BeunMan

07-15-2014, 06:02 AM

Note that most FSE cars run at much lower power ranges when driving the Endurance due to 'fuel' issues. E.g. taking enough power to driver at 85kW the entire course would make you car heavy... really heavy. So wins for electrics at Accel and AutoX, they are even at Skidpad and possibly in a disadvantage in Endurance but at an advantage in Economy when done properly. I think it will probably even out quite a lot.

Swiftus

07-15-2014, 08:39 AM

I was thinking about this on my flight today. If the goal of the new rules is to encourage the use of turbos (which is the obvious choice when the order of turbo > throttle becomes the industry standard), then I hope there are additional fire safety rules added. Here is my line of thought, and I am kind of think out loud here.

Under the current rules set, turbo teams have a chore in keeping their systems well oiled under vacuum. Because their oiling systems, and therefore cooling systems, for the turbos are in non-ideal conditions, these teams are forced to either go for max performance and risk overheating and fire or minimize their risk and have an 'underperforming' turbo.

With the proposed rules, if the throttle / turbo order is rearranged to that of the industry standard, teams will no longer have such a tough choice in turbo reliability vs performance. I think this is the goal (because turbos are on every engine everywhere now). However, I think that making the decision to use a turbo (obviously you HAVE to turbo your car) a given will cause many teams who do not have the resources to develop a turbo car to dive in. And this is where I forsee many half-built turbo cars catching fire.

With the old rules set, a team would see a turbo as an option, think about it for a minute and then come to a conclusion like "unless (insert industry engine manufacturer) helped us develop a custom turbo, there is no way we have the ability to make a turbo car. Better use a NA 1-2-4 cylinder because of x,y, and z."

The new rules set would allow turbo cars to make more power for the same economy, or the same power for better economy (its what they do), without the drawback of having to completely design your own turbo system. I fear the ease of entry into the turbo FSAE car market creates an atmosphere around turbos and their "industry standard reliablity" which is unsafe in the FSAE environment. I have personally witnessed a number of FSAE cars catch fire at multiple competitions, and more often than not they were carrying turbochargers.

When the rules are changed to match the "industry standard" I think the details get lost in the obvious. Real life example. When the automotive industry started putting catalytic converters on cars to improve the exhaust emissions, there industry managed to make the cars just as reliable and drivable as they had been before. So they started selling a bunch of these better emissions cars to the public. What they didn't realize is that the public was not going to think about what having a catalytic converter on your car actually meant. So people kept driving and parking their cars just like they always had. People would park their cars in front of their house on a nice and brisk fall day, walk inside and soon look out the window to see their car completely engulfed in flames.

Auto manufacturers made sure to keep the heat from the new catalytic converters out of the passenger compartment, but they completely missed the whole 'do not set fire to the leaves on the ground' part. And they got paid to implement a catalytic converter.

The problem was the benefits were obvious and the potential flaws were not. And any flaw within a volatile system meant for a lot of destruction.

I realize I am rambling but hopefully my point does get across.

TLDR: Changing the current turbo rules to 'industry standard' type rules will cause there to be many more half-attempts at turbocharging and result in many more fires.

Mbirt

07-15-2014, 12:55 PM

TLDR: Changing the current turbo rules to 'industry standard' type rules will cause there to be many more half-attempts at turbocharging and result in many more fires.Jay, we see this often as the price of admission is lowered. Carbon fiber becomes increasingly more available: more suspension points pull out of tubs during the brake test. Giant wings become almost mandatory to win under wide-open aero rules: more wings fall off during endurance, more cars crash due to aero balance issues that weren't sorted in design or testing. And so on.

The SAE CDS has experience dealing with students and insurers to allow electronic throttle control in the Clean Snowmobile Challenge and Supermileage, in addition to piping hot turbochargers and catalysts under full bodywork at the CSC. In 2013, as a 4-man CSC team, we undertook turbocharging and ETC on a naturally asiprated, manual throttle snowmobile with no major issues other than a cracked exhaust manifold weld after the 100 mile endurance. It was quite a successful vehicle despite our inexperience with turbocharging and ETC and a TINY team. I don't think the pre-2015 rules stopped underqualified teams from running turbochargers, they just weren't highly visible like the one thermal event-prone example of late you're probably thinking of. There are easier/lower-risk ways to manage the oil system.

Let teams focus more intently on their powertrains if they choose to do so--it's still no substitute for good vehicle dynamics, aero, test time, driver training/recruitment, and so on. Overall these proposed changes are very good for increasing the quality of the engineering experience.

Question--Is the intake plenum volume limit only for turbo engines with post-compressor throttle?

bob.paasch

07-15-2014, 04:23 PM

Question--Is the intake plenum volume limit only for turbo engines with post-compressor throttle?

That is my understanding. NA engine would have no plenum limit, but also would still be required to have the throttle body upstream of the restrictor with the resultant plenum volume verses throttle response tradeoffs. Only supercharged/turbocharged engines get to move the throttle body downstream.

In my opinion, this change will have a similar effect as the aero rule changes 4 years ago: teams will have to super or turbo-charge to be competitive. The advantages to the throttle body move will be too great to ignore.

apalrd

07-15-2014, 06:40 PM

In my opinion, this change will have a similar effect as the aero rule changes 4 years ago: teams will have to super or turbo-charge to be competitive. The advantages to the throttle body move will be too great to ignore.

We would still be limited to the same power limit due to the restrictor, and there are already many common FSAE engines which choke the restrictor naturally aspirated as is. The turbo still has a tradeoff of transient response, complexity, packaging, intercooling, calibration and controls, vs a larger displacement or otherwise higher power engine which is heavier.

Anyone aside from mbirt have opinions on ETC? No opposition?

Alumni

07-15-2014, 08:09 PM

Someone throw Z the life preserver. He's really gone off the deep end this time!

As far as the turbo discussion I do have to agree with Jay that there will be an increase in thermal events, but probably not by much. There will be, as MBirt eludes to, a number of teams undertaking a turbo attempt that have no business doing so, simply to jump on board. And at early September planning meetings, a turbo now makes a lot of sense. This will result in one or two turbos or engines spitting bearings and connecting rods out through previously non-existent holes in their engines, which almost always leads to an oil fire.

With that said, Bob, I agree that in order to be a top five team such as yourself a turbo will be practically a necessity (sidenote: it'll be interesting to see how the Europeans fair at MIS this year with these and the aero changes...) As you drop below the top few teams, reliability is increasingly driving factor between, and a turbo adds a lot of complexity and weight to a car. I do not see them as being necessary to compete with "the best of the rest" such as at FSAE West or smaller competitions.

As far as ETC, it should have been implemented years ago. Unfortunately, the rules committee and their fear of unknowns at that time can be better explained via Simpsons meme than another mindless forum rant.
283

Luckily things seem to be changing. Slowly.

Charles Kaneb

07-15-2014, 09:44 PM

I'm fine with most of these rules, but I'd REALLY rather not see unsprung aero go away for three reasons.

1) Banning it eliminates your most difficult first-day design decision. There are very few half-measures - either unsprung aero is a primary feature of your car and other systems were designed around it, or it isn't and you don't have it. Can you get enough additional performance out of an unsprung system to justify the rest of the compromises to the car?

2) Unsprung aero is only legal here. There's no "canned" design solution available. You cannot modify an IndyCar, F1, LeMans wing and mounting type to suit the scale and use of the car if you go unsprung. Therefore, if it's on the car and it works, you designed it, or you reverse-engineered it from another FSAE car with nothing to go on but photos.

3) The cars aren't fast enough yet. Unsprung aero gives an avenue for making one a lot (multiple seconds/lap) faster if you can make practice match initial calculations. The SCCA Solo PAX index for FSAE is 0.989, for a K-mod it's 0.957, for an A-Modified it's 1.000 A 2013 FSAE car is expected to be 1.1% slower (one second per lap or so) than an A-Modified car and 3% faster (2 1/2 seconds per lap) faster than an SCCA-legal kart. If we do something that slows FSAE cars down by 3% between 2013 and 2015, they will be slower than a kart that is 1) Ballasted way up to 385 lbs 2) Not first-line equipment (CRG Bad Boy, TonyKart Racer EVK, or equivalent, powered by a Swedetech CR125 or a 2010-homogolation KZ2 shifter engine and 3) Driven by someone who won't win SuperNationals. These cars are expensive ($25,000+) and take a lot of student effort (5000+ hours) to design and build. What they get in return should be able to beat throwing a dart at the eKartingNews classifieds.

07-15-2014, 10:50 PM

I'm not sure what your complaint about the bigger engines is ... as you state the restrictor already provides a limit.

Kev,

And that is exactly my point. Why bother with any engine-capacity limit at all? Just scrap it. Make the Rule book thinner. Save some trees...

But for reasons to do with low self-esteem, the RC Members only ever want to make the Rule Book longer. This is a bit like blokes with small, err, "members", wanting to drive high-powered cars with long bonnets. (I will retract that last statement when any RC Member provides any reason at all why a RESTRICTED big-block V8 might have any advantage in FSAE, or otherwise be too dangerous because of its "awesome" power.)
~o0o~

Also by Kev.
... the big difference between the electric motors and petrol is not the peak power, but the sustained power. An electric car limited to 80kw will be able to do this through-out their rev range by the rules, meaning incredible torque down low...

Technically correct, but IRRELEVANT to the Acceleration event. So WRONG, WRONG, WRONG!!!

Sorry Kev, but I have spent the last decade+++ bashing my head against a wall in frustration over this. Please do not take personal offence, be patient, and read on...
~~~~~o0o~~~~~

Head-banging rage building... Internal pressures reaching critical... Stand back, boys and girls...

(I have selectively rearranged the following quotes to better make the point. What follows is not directed soley at Dunk, but at ALL OF YOU, because you are all making the same STUPID MISTAKES!)

Originally posted by Dunk on this thread, and also the FSUK Comp thread:

... I don't agree that 2wd is better than 4wd for accel. ... if the cars are breaking traction, and the coefficient of friction cannot be increased (short of cu$tom tyre compounds), then the only way to accelerate off the line faster is to drive all 4 wheels.

... biasing all the mass to the rear of the car to maximise traction on the rear tyres, will not only make the cars impossible to control but also just darn terrible in every other event.

Maybe a [combustion] car designed purely for acceleration could keep up with the standard e-cars, i.e. a dragster that meet the regulations. But that car would suffer in every other event, and would not beat a electric dragster. The issue being torque curves, dropping power to shift gear 2 or 3 times [blah, blah...]...

Copying last years car is an industry standard, because well it works. It means ... the problems [are] easy to solve.

But starting from the ground up with students who don't really know what they are doing and haven't got a clue ... is just going to [fail]...

Is it possible for the best combustion car to outperform the best electric car in acceleration under the current rules? ... doubtful ... a insurmountable amount of work for a bunch of inexperienced students to have to do in the space of 10 months.

The above sentiments, shared by almost all FSAEers, are proof positive of just how far down the S-bend the Education system has flushed the lot of you.

The emboldened sections are PURE, UNADULTERATED, CODSWALLOP!!! The fact that the vast majority of you FSAEers BLINDLY accept such BRAIN-DEAD "explanations-cum-excuses" is a DISGRACE.

I accept that a small part of the blame for YOUR STUPIDITY can be laid at the feet of your current teachers. When your current University teachers refuse to teach you the most basic elements of Mechanics, then, yes, there is a skerrick of an excuse for you to keep making the same STUPID MISTAKES.

But you have been doing it non-stop, over and over, for 30 years! By contrast, the Toothless-Hillbillies don't have any teachers at all, other than each other. And they keep going faster and faster, non-stop, year after year.

Your generation call yourselves the "interconnected" (or "networked", or whatever...) generation. You have Google. But have any of you ever used it, for this particular problem? CLEARLY NOT! Otherwise you would not make the STUPID sort of comments above. INCREDIBLY, BLEEDING, STOOOPID!!! And BONE-IDLE LAZY, too! You cannot blame your current teachers for your own laziness.

So, what is the root cause of all this STUPIDITY?

It is ALL THE TEACHERS you have had since Kindergarten. They have brainwashed you into believing that "There are no wrong answers. All opinions are equally valid. Yes! That way every one of you darling little kiddies can get a Gold Star!"

The end result of a decade and a half of such CLAPTRAP is that none of you have to think about anything. None of you have to learn anything. None of you will ever question the emboldened quotes above (which, I repeat, are pure BULLDUST, and obviously so!). And all of you can be content just "copying last year's car", because that way the "problems are easy to solve", and you are assured of getting that Gold Star. (And here the GS is simply having "FSAE" on your CV - "Sure, the car never turned a wheel, but I are an FSAEer!".)

There are a few students who question the above stupidity, and are prepared to put in the hard work seeking the correct answers. Unfortunately for them, they are vastly outnumbered by the zombie hordes of IMBECILES who are chasing their bonus Gold Star by shouting out "Look at me! I have an opinion! I think we should keep doing the same STUPID things we did last year. And I won't give a single good reason why...".

Even more unfortunately, the philosophy of mindlessly "copying last year's" whatever ultimately takes you all down the crapper. Very rarely there might be some small, random, improvement. Much, much, more often there is degeneration in the "copying" process (look up entropy).

The degenerative changes that result from this "mindless copying" of society's accumulated knowledge are now so bad that I know of legions of Emeritus Professors who are nowadays metaphorically teaching Flat-Earth Theory - "Oh yes, it's supported by four huge elephants, all standing on an even bigger turtle. All done in 6 days back in 4004 BC. And I can prove it. Look, its in these books!"

I feel very sorry for all your children, and the world they will inherit.
~~~~~o0o~~~~~

Should any of you want to show that you are NOT as STUPID as I say, then here is a quick quiz. All the answers are available on these pages (I have been spelling them out since 2005). So a Pass mark requires a perfect score.

Q1. Explain how the car's "power" and "grip" influence the Acceleration event. Specifically, which is more important at different stages of the event.

Q2. For a car with a given maximum power, why is the "launch" phase the most important for low times? (The THs know this, and call it "hooking up", or some such...)

Q3. Why is RWD-ONLY better than 4WD for a good launch? (The Mechanics of this are simple, but since they require knowledge of "rotational quantities" I am confident you will all fail.)

Q4. Explain the differences between Formula-5000 and Formula-Ford racecars in terms of their power, mass-distribution, and tyre-sizes, and how these differences affect the two cars' relative performances on the circuits they race on. (Note that neither of these cars is a "dragster", and their type of racing demands that they go around corners as fast as possible. Like in FSAE S-P, AutoX, and Enduro.)

Q5. Explain why the vast majority of FSAEers have more closely copied the general layout of F-Ford, rather than F-5000. (There is only one correct answer here, and that is that said FSAEers are LAZY IMBECILES).

Z

(PS. Dunk, again, not directed soley at you, but at ALL of you...)

(PPS. Pressure still near critical. Better go for a walk... :))

Swiftus

07-15-2014, 11:28 PM

We would still be limited to the same power limit due to the restrictor

I disagree. A supercharger or electrically driven turbocharger would allow an engine to continue to compress air into the plenum further down the line during any part throttle event (most likely more than 50% of an FSAE course). That mass which is stored is then used during the full throttle events. If the course is transient enough and the plenum large enough, then power is effectively unlimited.

The engine only needs to last for ~45 minutes, so turn the boost up to 11 and, partnered with Electronics throttles, auto-drive your 600hp FSAE around the track. I'm sure that car would win every event by enough of a margin that the economy wouldn't matter.

Swiftus

07-15-2014, 11:39 PM

(1)Jay, we see this often as the price of admission is lowered. Carbon fiber becomes increasingly more available: more suspension points pull out of tubs during the brake test. Giant wings become almost mandatory to win under wide-open aero rules: more wings fall off during endurance, more cars crash due to aero balance issues that weren't sorted in design or testing. And so on.

(2)...no major issues other than a cracked exhaust manifold weld after the 100 mile endurance....(3)they just weren't highly visible like the one thermal event-prone example of late you're probably thinking of.

Cool! I like this discussion! How about a couple of counterpoints?

(1) I agree that as tech becomes cheaper, it becomes more common which means more mistakes can be seen. However, unlike all of the failures you mention, a failure in a turbocharged system means unpredictability with moving parts and explosive fluids at 1100C.

(2) Pre or post turbo? And does a snowmobile in CSC compete in the snow during winter?

(3) I have seen two very thermal events in the last three competitions I have attended, plus additional minor thermal events in the previous four events. I would not consider it uncommon and to see how common failures are with the big teams, imagine the catastrophe of the smaller teams joining in. Who wants to work all year to end up with a smoldering pile of tubing?

Kevin Hayward

07-16-2014, 12:33 AM

Z,

Both power and grip are important in the acceleration event, no one disagrees with you that the launch phase is the most important. It does not mean that increased power does not contribute to the overall time. This is true in the very powerful drag cars that are traction limited for around the first half of a pass. I am also aware that good times can still be had from drag cars even getting off the throttle at the half track mark. The other important thing to note is the more we improve grip, the more important power becomes for decreasing accel time.

We have a number of drag racing guys as students. One of whom is the crew chief for one of Australia's top teams. I also agree that we have a lot to learn from the drag racing guys.

Likewise I agree with your points about rear mass distribution. When we made the move in 2003 (UWA) to much more rear weight it was seen as the wrong path with just about every other team eschewing a 50-50 weight balance. In fact calcs support quite a lot more rear weight even with the same size tyres front and rear (60-65% with appropriate suspension changes). Changing relative tyres sizes and you could go much further, making RWD the way to go, with a car able to do well in all circumstances.

In this case power still matters, more so than before, because grip has improved.

The big problem with going down that path is getting all the weight to the rear. If we say that a top level FSAE car is 140-150kg. On average a driver will weigh about 80kg with all gear. Of that weight 50% will be below the navel. Lower body weighs significantly more than upper due to lungs and dense leg bones. This means the drivers legs will push the weight forward a lot. This has been made worse with the chassis length rules.

We want the engine and driver as close together and as rearwards as possible. You would probably agree that this means not having double wishbones at the rear. It also probably means hanging the engine out the back 911 style. Achievable, but has some packaging considerations. The newest ECU car tries push the weight further rearwards than before, including a live rear end. Unfortunately for the weight balance a lot of weight was saved out of the powertrain, but very little from the driver. So despite the wheel centreline and the driver being a lot closer together than in the past the rear weight (with driver) is still only 56%. Without the driver the rear weight percentage is huge. A rear hanging engine was considered, but wasn't implemented at this time, for a number of reasons. A lot of which could be revised later.

One of the big issues for these cars is having enough yaw acceleration. To this end close to minimum wheelbase was chosen. Extending the wheelbase out to 1700mm would take the rear weight bias to around 60%. Which is better but still far from making your case work.

Getting a larger car such as a F5000 to have a much more rearwards weight bias is a lot easier mainly due to the fact that the powertrain is much heavier than the driver and the cars are longer. The driver is a small proportion of length and weight.

There are car configurations that make your assumptions work reasonably well, but they almost defintiely involve powertrains currently unused in FSAE, as well as a vastly different car architecture. Not implementing these is not just a case of laziness. These students have only a starting knowledge in maybe a couple of areas. Teams consist of a large number of students that didn't grasp a lot of the engineering mechanics. Maybe somewhat because of bad teaching, but also because they didn't go to all classes, or work hard on their knowledge. In designing a car they are finally finding out why that knowledge was important.

The pace of improvement in FSAE is slow, with high student turnover, poor knowledge retention, and conservative design being the primary cause. But overall the cars are moving towards more go-karts. In 2003 (reference year for the UWA car mentioned above) the norm for top cars was:

- Weigh ~230kg
- 4 cylinders (with around 60hp)
- 50% rear weight
- 1750mm wheelbase
- 1200mm track
- No downforce
- 13" wheels and tyres
- Almost universal double a-arms and rockers
- Mountain bike shocks

Now the picture is signifcantly different
- ~160kg
- Single cylinder (around 60hp - fours with around 85hp)
- 55-57% rear weight
- 1530mm wheelbase
- 1100mm track
- ~100kg at 70km/h downforce
- 10" wheels and tires
- Much reduced unsprung and rotating mass
- Purpose built shocks

The typical Formula ford design of the rear suspension mounting significantly rearwards of the powertrain is almost unseen near the top. A lot of focus of teams has moved away from mid-corner ultimate grip towards initial turn in and increasing yaw acceleration. Understanding of the physics behind the cars is slowly improving. The questions asked now in design are significantly harder and more involved than 10 years ago. Any student that goes into a design event now with a 2d understanding of 4 bar linkages, a lack of data analysis, and no effective team management structure will be crucified. The loop is being closed as ex-top students start to fill the judging roles. Nothing bores them more than seeing the same stuff being done now as what was done 10 years ago.

More importantly we are seeing more teams playing around with different powertrains, and drive methods. More teams looking at alternative suspension mechanisms. More teams playing with smaller different tyres and so on. We are heading towards the go-kart slowly but surely. This work isn't being done by the majority of the teams, but I think that just mirrors the wider engineering community. One of the big issues here is that it is difficult for teams to look past the short term pain for long term gain (especially considering they will not be the students benefiting from the work). For example the ECU car this year was a massive re-design of all systems, with some pretty large conceptual changes. Some you will like, some you wont. Things did not go smoothly at the recent UK comp. Some of the new systems had some teething problems, and students were doing a lot of different types of work that they had very little experience with. An unlucky problem right after the team arrived in the UK, ended up causing problems that dogged the team the whole way through.

By making a lot of changes at once there was increased risk. The question is was it acceptable risk? The previous car would have outperformed the newer car at the same competition, purely by being a more developed machine (a polished turd compared to a rough-cut diamond). But the new car has much more potential. A lot of the people that took that risk, will not be there if it comes good. Was that a good strategy? The points on the board say no, only future development might reverse that.

Lastly when looking at simulated evolution we see some funny things:

- Improvement is almost never purely linear
- Evolution is slow and fast. There are spikes of improvement, but there can also be long periods of stagnation
- Ultimately it is mutation, not combination that moves the performance of a population (these random improvements that you mention)
- There is a difference between genotypes and phenotypes. The outward display of the genes does not necessarily represent their inward design. With respect to FSAE that could mean that the future "best" FSAE team at the moment does not look like it could be the best, likewise the teams currently winning, might have deep structural flaws. Same goes with the cars.
- Selection is based largely on Phenotype. Teams try to copy another, but do not replicate the underlying ideas (genotype) causing a flawed copy. Similarly less judgement is made on the inner properties. It is not difficult to imagine people ignoring the good designs of an otherwise poor vehicle.
- A population average can improve without the best solution improving. For example given enough time the seemingly worse solutions may overtake the current best.
- Changes to the environment will change the population. We cannot underestimate the effect that rule changes have on disrupting the improvement in performance.

I would say we could very clearly see this process occuring in FSAE, in both the teams and cars we see. When you see entropy, I see evolution. It is an inefficient method of utilising all of the resources of all of the teams to move towards a global optimum, but it is probably better than the alternative.

To avoid getting stuck in local minima it is important to increase variability (mutation). Commenters like you can help with that (although it would be nice if it was with less acid), overly strong selective pressure (i.e. too much focus on final performance) will encourage local minima. Given that the greatest pressure comes from the score-line and prizes and reputation rewarded accordingly there is a great pressure to stay in the local minima. For example when we see the reports of the events, almost all of the focus is on the winning teams, and almost no focus on the innovative concepts.

I think the best way to help teams move towards the global minima is to encourage a population that is more focused on genotype than phenotype. What is the make-up of the car, not the final result. To call them lazy is wrong, teams are just organisms responding to external pressures encouraging local optimisation.

Kev

Tim.Wright

07-16-2014, 12:52 AM

http://imgs.xkcd.com/comics/people_are_stupid.png

Dunk Mckay

07-16-2014, 09:35 AM

I'm hurt, Z, very hurt. Just kidding, I fully agree with you on the education side of things. I skipped most of my lectures in my final 2 years of uni, preferring to educate myself on the relevant subjects. Yet somehow I still got a 1st class degree. Just a shame I had to pay a lot of money for it, and that a load of other people I wouldn't want to work with in a million years also got the same qualification. The issue for me, I guess, was that I was still reading from the same books as everyone else, more or less, as that's all there is to read.

Due to this, I don't expect to do very well, but I'll play your game, for now...

Q1. Explain how the car's "power" and "grip" influence the Acceleration event. Specifically, which is more important at different stages of the event.
Based on my observations of wheel spin on launching I have to say that cars are low on grip in the early stages, so this is the limiting factor, not power.
Further down the course the rate of acceleration is dropping so the engine is struggling to overcome the drag and inertia, i.e. it is lacking in power.

Q2. For a car with a given maximum power, why is the "launch" phase the most important for low times? (The THs know this, and call it "hooking up", or some such...)
For a given maximum power there is a given top speed. Reducing the overall time along a straight means increasing the average speed, this means reducing the time it takes to get to top speed. (an oversimplification FSAE cars rarely reach "top speed" over 75m, but they start to plateau and the overall principal applies).
I'm getting my thoughts muddled, not being a powertrain guy. But power and torque curves probably come into it. The quicker you can get the car up to a speed where the engine speeds being used are such that maximum power/torque are being sent to the wheels the better. So the more efficient the launch, the quicker you can get some real power down.

Q3. Why is RWD-ONLY better than 4WD for a good launch? (The Mechanics of this are simple, but since they require knowledge of "rotational quantities" I am confident you will all fail.)
I'm still going to say that F=ma, and that force is the product of normal load and the coefficient of friction. and the best way to maximise that force is by spreading your traction across 4 wheels. The only downside to this being that it invariably increases m, but probably not by as much as it increases F.
There is also load transfer to the rear wheels, dictated by numerous factors, susp geometry, CoG height, etc. Which will increase the normal load on the rear contact patches. Shifting the mass of the car rearwards in it's design will also do this.
But assuming that a 4wd system weighs the same as a 2wd system, all else being equal, unless you car is doing a wheely of the line (i.e. dragster) then there is still more traction to be had from the front wheels. In fact I would hope that there is still some traction on the front wheels otherwise you driver will have no control, and with uneven driveshafts and imperfect components a guarantee, torque steer is going to spin the car into a wall, like this guy: http://www.youtube.com/watch?v=kh1uE4jdxh4 (still no excuses for ruining a perfectly good helmet though).

Q4. Explain the differences between Formula-5000 and Formula-Ford racecars in terms of their power, mass-distribution, and tyre-sizes, and how these differences affect the two cars' relative performances on the circuits they race on. (Note that neither of these cars is a "dragster", and their type of racing demands that they go around corners as fast as possible. Like in FSAE S-P, AutoX, and Enduro.)
I'm going to skip this because it has been covered by someone more knowledgeable on the subject that I.

Q5. Explain why the vast majority of FSAEers have more closely copied the general layout of F-Ford, rather than F-5000. (There is only one correct answer here, and that is that said FSAEers are LAZY IMBECILES).
Rhetorical?
Lazy? No, well some of them maybe. Some are scared or lack confidence in their own abilities. Others know the limits of their own abilities which aren't great. Others have the ability but don't have the time. Others have the ability and the time but no one to support them. Some even have the abilities and the support, but that support completely lacks in ability and one man can't design and build a racecar all on their own, not in the allocated time anyway. (I use the term ability here to encompass experience, knowledge, skills, or the capability to acquire said qualities.

So to some extent yes, you're right people in FSAE are what you call 'stupid', some of them, a significant portion of them perhaps. I've helped manage a team of 30-40 "engineers" and as I said above there is a good portion of them that I would not want to work with in future. And of the hundred or so people that I met doing FSAE at my university during my time there, there are probably only 20-odd that I would ask for help if I was given the task of recruiting a team to design and build a really good FSAE car.

Mbirt

07-16-2014, 02:32 PM

Cool! I like this discussion! How about a couple of counterpoints?

(1) I agree that as tech becomes cheaper, it becomes more common which means more mistakes can be seen. However, unlike all of the failures you mention, a failure in a turbocharged system means unpredictability with moving parts and explosive fluids at 1100C.

(2) Pre or post turbo? And does a snowmobile in CSC compete in the snow during winter?

(3) I have seen two very thermal events in the last three competitions I have attended, plus additional minor thermal events in the previous four events. I would not consider it uncommon and to see how common failures are with the big teams, imagine the catastrophe of the smaller teams joining in. Who wants to work all year to end up with a smoldering pile of tubing?
1. An 1100 C EGT would be a sign that that team should not be running a turbocharger: "I can just keep retarding the timing and adding fuel, right?" Custom dry systems have been allowed for years and have dumped plenty of oil on tracks and exhaust systems. Student-built fuel systems are almost always in close proximity to the exhaust system. I don't think you can say that turbo oil plumbing is an order of magnitude more dangerous than student-built dry sump systems and fuel systems.

2. Pre-turbo, at the turbine inlet flange. We finished the endurance and the crack could have been repaired without penalty under FSAE rules. At CSC there is a 100 point no maintenance "bonus" that you lose when you break a serial-coded hood seal to make a repair to the vehicle. We had to fix the crack/leak to comply with the rules of the lab emissions test.

Snowmobiles at CSC do in fact operate on snow, on public trails, in a dyno lab at peak power speed WOT for 2 minutes, and are even ridden by competition judges for a subjective handling event. That should make FSAE safety folks cringe considering the fully enclosed bodywork, turbochargers, and catalysts, but SAE manages to get the event insured (the same organizers handle FSAE) and no one debates whether or not students should be allowed to innovate with boosting concepts.

3. Big team does not equal good powertrain sub-team. Small teams that venture into turbocharging without a thorough points analysis or thorough development of the rest of the car have probably already done so. I often tried to stay abreast with what these teams were doing in previous years, became excited to see them at competition, and was eventually let down when they arrived naturally aspirated.

Contrary to what Dr. Paasch and you believe, turbocharging will not become mandatory to win the competition. Well-tested and well-driven cars will continue to win. A second-tier team might crash the party with solid design, acceleration, and fuel economy scores, but it's no reason for teams at the top to be concerned.

I disagree. A supercharger or electrically driven turbocharger would allow an engine to continue to compress air into the plenum further down the line during any part throttle event (most likely more than 50% of an FSAE course). That mass which is stored is then used during the full throttle events. If the course is transient enough and the plenum large enough, then power is effectively unlimited.Your capacitive overboost/compressor surge theory giving any team a huge advantage is a bit ridiculous and the plenum size limit will attempt to keep this in check if anyone does attempt it. If a team does figure this out, more power to them (pun intended)! It would still not be able to achieve the same average power of an 80 kW e-car.

Swiftus

07-16-2014, 04:04 PM

1. 1100C in a turbocharged system is precisely my point. EGTs that high should not exist around turbochargers, but it is very easy to do. Maybe a team cuts spark for their rev limiter. Maybe a team placed the turbo too close to the cylinder head so it takes just a very small amount of unburned fuel to greatly increase the EGTs. Maybe the team did everything right except they have poorly atomized fuel? Without a huge amount of testing and knowledge, it can be very difficult to make all of the mistakes and design a good solution. The current rules set helps a team make that effort distinction right away.

2. The failure at a weld next to the large bending load makes sense for why it failed there.

How enclosed are the snowmobiles? If they are anything like I've see in the mountains, than the engine exposure is a little less than an ATV.

My point, as you correctly inferred, is that snowmobile engines are in front of the rider and are somewhat exposed. Formula engines are behind the driver (typically) and are enclosed. Which is partly why it can be so difficult to cool Formula cars with the 'stock' cooling system from the bike.

...to be continued...Boarding an airplane.

apalrd

07-16-2014, 06:18 PM

1100C EGTs shouldn't exist on any engine, not just turbo engines.

I don't think that allowing the throttle to move for forced induction engines is a sudden reason for teams to turbocharge. As is, you can build a very good turbocharged powertrain with the throttle upstream of the restrictor. It's not a huge thing turning the vast majority of teams away from turbochargers, you can get over the transient issues with good controls. Moving the throttle helps teams get over the compressor vacuum and some transient issues that turbos see, and lets teams put the throttle in the industry-standard location for turbocharged engines.

Moving the throttle is a little help to turbo teams but in no way requires that a good team turbocharges to stay competitive.

Alumni

07-16-2014, 06:38 PM

Snowmobile engines are far more enclosed than any ATV or formula car i've ever seen. Particularly at CSC where there is dynamat and other sound deadening materials lining the engine bay several layers thick.

I'd bet that the total inlet area on a snowmobile for air passing through the engine bay is not much more than 1sqft.

Bemo

07-17-2014, 01:09 AM

Is there anywhere an official document available or are these just rumors. Before starting to make an opinion I'd like to see the real wording ;-)

mech5496

07-17-2014, 04:38 AM

No Bemo, there is not. Those were discussed in the 2015 rules briefing during FSUK and are just thoughts for the moment, some of them to be implemented much later than 2015.

Dunk Mckay

07-17-2014, 06:21 AM

I'd like to add that I find it very strange that having made the progression to a 2 year rules cycle that now no draft rules are being released and the final rules are coming out later than previously... Surely one of the reasons for doing a 2 year cycle is to get the rules out to teams earlier in their development cycle. Which for most European teams at least should really already have started for the 2015 competition.

GXP_Matt

07-17-2014, 10:29 AM

I was thinking about this on my flight today. If the goal of the new rules is to encourage the use of turbos (which is the obvious choice when the order of turbo > throttle becomes the industry standard), then I hope there are additional fire safety rules added. Here is my line of thought, and I am kind of think out loud here.

Under the current rules set, turbo teams have a chore in keeping their systems well oiled under vacuum. Because their oiling systems, and therefore cooling systems, for the turbos are in non-ideal conditions, these teams are forced to either go for max performance and risk overheating and fire or minimize their risk and have an 'underperforming' turbo.

TLDR: Changing the current turbo rules to 'industry standard' type rules will cause there to be many more half-attempts at turbocharging and result in many more fires.

I'll have to disagree with you here. Under the current rule set, it isn't a problem keeping the turbo well oiled, it's that the turbo is TOO well-oiled! With the throttle in front of the compressor, whenever the plate is closed you have a large vacuum in front of the compressor wheel, which pulls oil through the piston rings that seal the turbo shaft. So at idle or under braking for a corner you are just pulling oil through the comp seals and burning it, unless you can pull significant vacuum on the turbo oil drain at all times.

Now if FSAE was to switch to restrictor-> turbo-> throttle, you would greatly reduce the situations where you are pulling oil through the turbo seals since the compressor stage wouldn't see nearly the vacuum at idle or on the overrun. I would say that this arrangement actually reduces the chances of a thermal event since you don't have big pools of oil sitting in your compressor housing or intake plenum. It actually makes it easier for someone to make a half-attempt at turbocharging since you don't need to scavenge the turbo's oil drain, you can just run a high pressure oil line to the top and a normal drain to the bottom. You'd still want to scavenge the turbo if you mounted it below the oil level in the sump since it wouldn't drain very well that way, but you wouldn't need as much vacuum.

I'd be happy to dispel any other fears you have about turbocharging an FSAE car- I think if these rules go through it would make way more sense for a lot of teams. I would urge people to not try and skimp on weight savings on the turbo manifold, especially if you are using the manifold to fully support the turbo. Mount the turbo close to the cylinder head for good usage of exhaust pulse energy, make the manifold out of thick stainless, run a nice oil drain, and then all you have to figure out is a boost control strategy and how much boost your engine will take :) Oh, and the GT12 is too big for FSAE engines.

Mumpitz

07-17-2014, 10:32 AM

Swiftus, why the portrayal of turbochargers as grenades with the pin pulled? You know what spins fast, is filled with flammable liquids, and spews extremely hot gasses? An engine, yet the turbo is being portrayed as the evil monster that is certain incinerate any car it comes near. Don't want to run one for the perceived risk? OK don't, but don't tell others that they shouldn't be allowed to either. Almost all thermal events that I have witnessed at competition or heard about have been attributed to either oil or fuel leaks as the root cause. What's the difference between the inexperienced team running 1100C EGTs on a turbo car or the inexperienced team running 900C EGTs N/A? What does it matter when it's already glowing red? If anything an N/A exhaust typically has more hot exhaust surface area exposed since the turbo is capturing that thermal energy early on in the system.
1100C may not make your exhaust bridge very happy and may lead to very premature seat damage but it's not apocalyptic. Current production turbos are designed to operate at 1050C sustained to reduce the need for boost enrichment.
If you don't want to keep the flames on the paint job and off the car build a robust fuel and oiling system.
*I should mention I have 0.000 stake for or against the use of turbos. I am an alumni of a team (Oakland Univ.) that doesn't run a turbo and, as far as I know, doesn't have plans to run one in the near future. I am just a proponent of freedom and racecars though. You do like freedom and racecars don't you? :P
This is also why I don't support the talk of banning unsprung aero. No one is proposing banning unsprung corners of the car yet which has more mass? More effect on vehicle control? Potential danger to course workers and spectators?

Suspension/wheel failure: corner flies off, brakes and steering lost, wheel assembly goes for a long journey until it hits something or eventually dissipates all it's energy.

Wing failure (sprung or not): Wing flops over or falls off. Massive surface area and low mass bring it to an abrupt halt. The arguments about car stability are irrelevant. Wing falls off there is no concern about vehicle handling, the black flag flies.

Are we more concerned with safety or perceived safety? It seems like someone wrote a FMEA for the comp and had their grandma read it. "Won't you crash like a plane if your wing falls off!!!" "A turbo spins how fast???" "1100C! no more racecar for you, I'll heat up some tea for us and we can watch my soaps" (proceeds to light her Virginia Slim off the blue flame of the gas burner).

Mbirt

07-17-2014, 05:50 PM

Haha thanks for the great lunchtime read, John. It's good to hear some more voices of reason here. I too was afraid of turbos before I got a chance to implement one on the Clean Snowmobile project. I'm glad I did because I got to travel to Taiwan to present the SETC paper born from it and that got us on the cover of Momentum.

Jay, here's the extent of the bodywork openings of a typical Clean Snowmobile:
http://www.mtukrc.org/csc2014pix/Saturday/images/ETS-Hand-IMG_5895.jpg

Here's what lies under that bodywork:
http://www.mtukrc.org/csc2014pix/Monday/images/05-ETS-IMG_3539.JPG
http://www.mtukrc.org/csc2014pix/Monday/images/01-Madison-IMG_3235.JPG
http://www.mtukrc.org/csc2014pix/Monday/images/14-Kettering-IMG_3492.JPG

Pass-by WOT noise is worth 300 points at the competition, so you might imagine how much foam/dynamat/etc also gets shoved in and around the engine compartment. The competition still gets insured to have the sleds held at peak power speed WOT for 2 minutes in a lab test and to have volunteer judges climb abord them and bomb around a handling course (with JUMPS!).

I'm surprised that GFR's points simulations show that a particular powertrain will be so dominating under more restrictive aero rules. Let's call this the Wisconsin-Madison car. With a very well developed turbocharged single cylinder powertrain, has this car ever had a distinct advantage due to that particular subsystem? I think history has shown that teams with great powertrain capabilities haven't ever been a threat to teams with more important project management/vehicle dynamics/driver capabilities.

07-17-2014, 10:05 PM

Kev and Dunk,

Thank you both for your thoughtful replies.

My (mildly? :)) heated last post was a by-product of some recent discussions with some academics at the local Uni, where it dawned on me that they really do believe that the world is flat (metaphorically speaking, in a non-FSAE field). The derisory snorts they made when I suggested that the world is round (again, metaphorically) didn't help. But even worse was their complete disinterest in any sort of rational discussion of flat-earth vs round-earth theories.

I have now found this to be the case in several different fields. The Emeritus Professors honestly believe that they can teach anything they want, without ever having to give a rational justification of their teachings. The Education system is now a free-for-all with no quality control system to catch mistakes (and the above Professors are making some atrocious mistakes!).

That is why I like competitions like FSAE, because the stop-watch provides the error-checking procedure that decides which answers are more, or less, correct. I stand by my comments (on another tread) that in the most objective FSAE events, namely Acceleration and Skid-Pad, the "(in)correctness" of the answers has hardly changed in ~30 years. The bell-curve has got higher and wider, but its centre has not shifted.

This implies a lack of "learning" by the overall FSAE community. Or at a more local level, a lack of an effective "education process" from older team members (and supervisors) to the newbies. There are, of course, exceptions, such as yourselves and the other successful teams (eg. Monash, GFR, Stuttgart, Delft, Zurich, etc.). But the global bell-curve seems to be stuck in the 1980s.

By contrast, it is interesting to note that the global community of Toothless-Hillbillies (wonderful people, and perhaps "Toothless-Bogans" in Oz :)) must have a great education process going, because their times have been dropping steadily, year after year, for the last 50+ years!
~~~~~~~~~~o0o~~~~~~~~~~

So, in the interests of some sort of global FSAE education process, I requote some of your above posts, with some added emphasis and brief comments.

From Kevin.

... I agree with your points about rear mass distribution. When we made the move in 2003 (UWA) to much more rear weight it was seen as the wrong path with just about every other team eschewing a 50-50 weight balance. In fact calcs support quite a lot more rear weight even with the same size tyres front and rear (60-65% with appropriate suspension changes).

Yes. With all equal-sized tyres and ~F35:R65 you simply carry most of your LLTD at the front, and lift the inner-front-wheel during cornering. This has the beneficial side-effect of allowing you to use an open-diff without spinning your inner-rear-tyre.
~o0o~

Changing relative tyres sizes [ie. bigger rears, smaller fronts] and you could go much further, making RWD the way to go, with a car able to do well IN ALL CIRCUMSTANCES. (My ADDED emphasis.)

This is the way the vast majority of circuit racecars have done it for the last 50+ years. Some historical notes here.

Pre-WWII, racing was mainly about top-speeds (and reliability, as always). Cars would get up to top-speed and travel long distances on (quite rough) country roads. Then heavy braking as they entered a small village, four-wheel drift around the fountain in the middle of the town-square, then back up to top-speed to the next village. Roughly 50:50 weight and equal tyre sizes worked well here.

Immediately post-WWII there was less money, more amateurs in motorsport, and lots of now unused airstrips. So the new airstrip-racetracks were shorter, with many corners connected by short straights. Initially, with low-powered cars (like the Lotus 7) the 50:50 weight and equal tyres sizes still worked OK. But as power increased, and still with RWD-only, the rear tyres couldn't take it anymore!. They kept melting! So, the simple fix was bigger rear tyres and more rear weight!

By the time of turboed 1,000+ hp F1 cars, the rears were monstrous ~20" wide slicks, still with relatively small fronts. Similarly in Sportscar racing (see turboed 1500 hp Porsche 917, much earlier than the F1s). Weight distributions of ~F30:R70 were common. These cars could use all their horses to accelerate very hard, AND they could also go around corners fast.

With interweb+++, all this should be BLEEDING COMMON KNOWLEDGE (:)), and is why I get annoyed when FSAEers say "Oh, but we CAAAN'T be good at BOTH Acceleration AND AutoX...".

In the 1990s Max Mosely decided that for PURELY AESTHETIC REASONS he liked the equal-sized tyre look. So he MANDATED it in F1! (Well, almost equal sizes, with fronts very slightly smaller than rears). This had NOTHING to do with performance. In fact, the cars became notably slower accelerating off the start-line and out of slow speed corners, but nobody was allowed to mention that.

Much more interesting history here, but briefly F1 cars DO NOT have their tyre sizes based on performance. It is just the (BRAIN-DEAD :)) Rules!
~o0o~

WE WANT THE ENGINE AND DRIVER AS CLOSE TOGETHER AND AS REARWARDS AS POSSIBLE. You would probably agree that this means not having double wishbones at the rear. It also probably means hanging the engine out the back 911 style. Achievable, but has some packaging considerations. The newest ECU car tries push the weight further rearwards than before, including a live rear end. (My ADDED emphasis.)

Agreed on the first sentence. From a "big-picture" approach to car design, the overall size of the car comes first (ie. L/W/H, and WB), and the overall mass-distribution is a very close second (ie. CG height, F:R weight, and Yaw-inertia mainly).

But I think you could get those right even with Double-Wishbones. However, the suspension type is of very low importance, and DWs are the most complicated type there is, so they should be the last choice. Also I reckon the right F:R mass distribution can be achieved with engine inside the wheelbase (just squashed up a lot), which then gives a lower Yaw-MoI.
~o0o~

There are car configurations that make your assumptions work reasonably well, but they almost definitely involve powertrains currently unused in FSAE, as well as a vastly different car architecture. Not implementing these is not just a case of laziness...

Agreed that the standard powertrain layout needs changing, but I do not think it is a "vastly different car architecture". Just a simplified and squashed-up one. Like yours, but a bit more so!

It is in this area that I believe that the students are, by and large, really being lazy. It is the laziness of not wanting to break away from the rest of the flock.
So,
"Everyone else uses an off-the-shelf BIKE-ENGINE, which pushes the driver way too far forward, which then makes the rears light up with the slightest opening of the throttle. But we'll do that too, because doing anything else requires, err..., original thinking..."

There is a herd mentality that says that it is OK to spend ages designing and building a ridiculously complicated suspension system, and electronic-paddle-shifter, and carbonfibre-tub-and-everything-else, and other junk, but for some reason YOU MUST NEVER CHANGE THE POWERTRAIN LAYOUT! (Well, some do, but a tiny minority.)

Laziness? Stupidity? Whatever you call it, it is causing the performance of the cars to be stuck where they were 30 years ago. Namely, with the rear tyres on fire, while the car is all but stationary as it tries to accelerate hard out of a slow corner.
~o0o~

The pace of improvement in FSAE is slow, with high student turnover, poor knowledge retention, and conservative design being the primary cause. But ... We are heading towards the go-kart slowly but surely...
...
- Evolution is slow and fast...

Yes, and lots of other things I would like to add. But better stay on message.

IMPORTANT POINTS for students.
1. GET THE BIG THINGS RIGHT FIRST.
2. Until you do, DO NOT WASTE TIME ON TRIVIALITIES (eg. push/pullrods&rockers, electro-pneumatic-shifters, drive-by-wire, and really STUPID things like traction-control to stop your rear-wheels spinning, simply because you did not put enough weight on them!).
3. Re-read Kevin's post above. Several times.
4. Take a close look at ECUs car. A good evolutionary change. See if you can evolve it simpler and better. (Hint: I might tilt the cylinders back by ~45 degrees, and only have ONE of them (though still ~600cc).)
~~~~~o0o~~~~~

More following ... (10k char limit!).

Z

07-17-2014, 10:06 PM

From Dunk.

"Q1. Explain how the car's "power" and "grip" influence the Acceleration event..."

Based on my observations of wheel spin on launching I have to say that cars are low on grip in the early stages, so this is the limiting factor, not power. Further down the course the rate of acceleration is dropping so the engine is struggling to overcome the drag and inertia, i.e. it is lacking in power.

Yes, that is the gist of it. But I will wait a few more days before giving some numbers that show how grip-at-launch is significantly more important than maximum power later on. Meanwhile, if anyone else would like to take a crack at answering the questions...? (The F-5000 vs F-Ford issue is hinted at above.)
~o0o~

Bottom line, IMO, is that the current E-cars do NOT have a significant advantage over the C-cars. The classes DO NOT have to be split.

The main reason the E-cars benefit from 4WD is via better regenerative braking, which allows them to carry a lighter and less expen$$$ive battery pack. But the E-cars' current ~half-second advantage in Acceleration is merely a by-product of this. Their main advantage in Accel is that the C-cars have locked themselves into a very ineffective ~50:50 weight distribution, simply because they don't want to (or are too lazy to?) mess with the off-the-shelf powertrain layouts.

I note that quite a few of the C-cars in the recent FSUK were within 50 points of First Place outright, but they lost more than 50 points to the E-cars in the Acceleration event (Edit: See PS). So they were overall LOSERS!

Must try harder! :)

Z

(PS. Edit: FSUK results,
# Team O/A Acc.
1. Delft(E) 856 73
2. Stutt(C) 837 38
3. KIT(C) 828 37
4. Zurich(E) 827 75
5. Monash(C) 821 21
If better C-car Acceleration, then no E-cars on podium! :))

stever95

07-17-2014, 10:33 PM

Z,

You think the main reason that 4WD is better is that it yields more regenerative braking?

I.....I......I......

Disagree.

Swiftus

07-18-2014, 07:03 AM

As is, you can build a very good turbocharged powertrain with the throttle upstream of the restrictor. It's not a huge thing turning the vast majority of teams away from turbochargers, you can get over the transient issues with good controls. Moving the throttle helps teams get over the compressor vacuum and some transient issues that turbos see, and lets teams put the throttle in the industry-standard location for turbocharged engines.

Moving the throttle is a little help to turbo teams but in no way requires that a good team turbocharges to stay competitive.

Those transient issues which hurt turbo performance also hurt NA performance. The engine is doing the same job, so why treat the peripherals differently? If the rules were to place the throttle body after the resitrictor for all types of induction, then turbocharging would be a more difficult choice. The current proposed rumor highly biases a turbo choice for powertrain in the future.

Is there anywhere an official document available or are these just rumors. Before starting to make an opinion I'd like to see the real wording ;-)

No, Bemo. But that is kind of the point of creating a dialogue on the forum, correct? The unofficial FSG rules were removed after they were leaked onto the forums and the community was able to respond, both on the forums and in formal letters of complaint.

I'd like to add that I find it very strange that having made the progression to a 2 year rules cycle that now no draft rules are being released and the final rules are coming out later than previously... Surely one of the reasons for doing a 2 year cycle is to get the rules out to teams earlier in their development cycle. Which for most European teams at least should really already have started for the 2015 competition.

I agree. But the Americans are who suffer more than the Europeans with the late rules. If you are an American team wishing to compete in Europe and at Michigan or Lincoln, your car needs to be running 1 to 2 months earlier than the Europeans. That is a lot of time, which is why we are well into our development for the 2015 season. We are also involved in providing feedback for some of the proposed rules.

I'll have to disagree with you here. Under the current rule set, it isn't a problem keeping the turbo well oiled, it's that the turbo is TOO well-oiled!

Yup. And what happens when the oil supply runs out? Like in a high-G situation on an engine originally developed with a wet sump? If the turbo is always removing the oil from itself with vacuum by dumping it into the intake, if it isn't supplied with oil it will overheat.

I'd be happy to dispel any other fears you have about turbocharging an FSAE car- I think if these rules go through it would make way more sense for a lot of teams.

I am not worried about turbocharging an FSAE car. I have access to resources which makes it possible for me to try different things and brake a few engines getting to a good turbocharged system. For a smaller team, however, creating a good working turbo system becomes yet another barrier preventing upward motion in the FSAE classes.

Are we more concerned with safety or perceived safety? It seems like someone wrote a FMEA for the comp and had their grandma read it. "Won't you crash like a plane if your wing falls off!!!" "A turbo spins how fast???" "1100C! no more racecar for you, I'll heat up some tea for us and we can watch my soaps" (proceeds to light her Virginia Slim off the blue flame of the gas burner).

I like the risk in racing. Go to the pits of any circletrack race and you will quickly get run over by a 3500# car driving 20mph with no clutch. The organisers of the event are worried that fresh people to racing won't know how to operate dangerous devices like race cars in a safe manner. Guess what FSAE is full of? Thousands of 20 year olds who have never gone to a race track and built their first car. If you are concerned with litigation than you have to cover your ass. Safety rules and other preventative measures make sense when you stand in the organizer's shoes.

I'm surprised that GFR's points simulations show that a particular powertrain will be so dominating under more restrictive aero rules.
Thanks for the photos Matt. Everything looks pretty wedged in. Do you have any data about the ambient temps in the engine compartment? We put peak temperature stickers everywhere to track the hotspots for cheap.

GFR's simulations give us a lot of guidance. I have been speaking for myself and not for the team. If turbos happen, it just means that I get a bigger budget and new toys and more people dedicated engine development and engine sponsor resourcing. I have had potential sponsors turn me down for sponsorship because I was not running a turbocharger.

I think that changing up the turbo rules would need to be couple with a rule creating separate classes. A small and underfunded team working against their university is never going to be able to compete against turbo-charged hyper-aero cars. But as an organiser you can't simply remove all of the fun and learning possibilities surrounding aero developement and engine development. It would turn FSAE into Baja, which is just a parade of the same car driving around the track testing to see who has the higher quality construction.

apalrd

07-18-2014, 08:41 AM

Those transient issues which hurt turbo performance also hurt NA performance. The engine is doing the same job, so why treat the peripherals differently? If the rules were to place the throttle body after the resitrictor for all types of induction, then turbocharging would be a more difficult choice. The current proposed rumor highly biases a turbo choice for powertrain in the future.

It could, depending on the wording of the rules. I think that's what the plenum volume limit tries to fix. But I don't like how difficult plenum volume is to measure. A turbo also doesn't just have the time delays of filling the manifold (which can be helped with transient controls and ETC, NA or turbo), they also have time delays of spooling the turbo, and building boost to whatever high pressure the team wants to run. A supercharger does not usually have this issue as it can build boost without significant exhaust mass flow.

Maybe the rules should allow the throttle to be downstream of the restrictor and compressor but require it to be close to the compressor? Or the plenum volume restriction should only apply to the space between the compressor and throttle (allow additional, unmeasured plenum volume between the throttle and engine?)

We currently run software/calibration changes to help with the filling delays of a 4.5L plenum (on a 450cc engine).

GXP_Matt

07-18-2014, 12:21 PM

Yup. And what happens when the oil supply runs out? Like in a high-G situation on an engine originally developed with a wet sump? If the turbo is always removing the oil from itself with vacuum by dumping it into the intake, if it isn't supplied with oil it will overheat.

I am not worried about turbocharging an FSAE car. I have access to resources which makes it possible for me to try different things and brake a few engines getting to a good turbocharged system. For a smaller team, however, creating a good working turbo system becomes yet another barrier preventing upward motion in the FSAE classes.

Uh, if you can't supply pressurized oil to the turbo then you'll have bigger problems on your hands very quickly, like a spun rod bearing and after that some unintended engine block ventilation...

I don't think you understood my point that the proposed turbo rules make it EASIER on smaller teams, since the installation is simplified. A small team could slap a turbo running a few lbs of boost on an un-optimized engine package (maybe even intentionally compromise the engine for weight savings) and be making more torque than a fully built and CFD optimized NA engine of a well-funded larger team.

Swiftus

07-18-2014, 12:48 PM

Maybe the rules should allow the throttle to be downstream of the restrictor and compressor but require it to be close to the compressor? Or the plenum volume restriction should only apply to the space between the compressor and throttle (allow additional, unmeasured plenum volume between the throttle and engine?)

Wherever a volume is set for the plenum, it is going to add a step and therefore more time to tech inspection. At every competition without a dedicated scrutineering day, it will be adding more time onto a process which already cannot be completed within the allotted amount.

Uh, if you can't supply pressurized oil to the turbo then you'll have bigger problems on your hands very quickly, like a spun rod bearing and after that some unintended engine block ventilation...
...which happens quite often in FSAE?... How many cars complete Endurance? Autocross? Skidpad?

I don't think you understood my point that the proposed turbo rules make it EASIER on smaller teams, since the installation is simplified. A small team could slap a turbo running a few lbs of boost on an un-optimized engine package (maybe even intentionally compromise the engine for weight savings) and be making more torque than a fully built and CFD optimized NA engine of a well-funded larger team.

I did understand what you said. And for a no more effort or time but a lot more money, a well funded team could make more power for less weight without any compromises in safety or performance. Turbo manufacturers would be having a field day because of the huge demand for tiny turbos! 'Custom turbo sized for a 250-610cc engine you say? How much are you willing to spend?'

This point's intent was to show that making turbos easy will simply widen the gap. If it is currently a lot of effort for small gains, than imagine the same amount of effort for huge gains? Does the small team have the resources to try and keep up with the big teams?

I am all for making the competition more interesting with the easier implementation of complex technologies like E-throttles and turbochargers.

BTW, what do you do at BorgWarner Turbo Systems?

tromoly

07-18-2014, 01:00 PM

Z,

You think the main reason that 4WD is better is that it yields better more regenerative braking?

I.....I......I......

Disagree.

My thoughts exactly. For someone who comes on here and calls all current Formula students, and I quote,

FSAEers are LAZY IMBECILES

Mr. Z would understand the simple Dynamics problem comparing the traction loads available for FWD, RWD, and 4WD configurations on a given vehicle.

Thinking out loud, with the electric cars I've seen running a Motor-on-Hub arrangement, wouldn't the inertia losses on a 4WD Electric car be lower than on a 2WD Combustion car? In the electric car there's another set of wheel/tire/hub to turn in addition to the four electric motors, however that is offset by not having to operate an engine/transmission/drive chain/differential/driveshafts, intuition would suggest that combining lower inertia losses and a higher tractive potential for an equivalent power level would give higher acceleration, all other things being equal, no? Someone please correct me if I'm wrong.

Thijs

07-20-2014, 09:44 AM

Z,

We've gone down this road before a while ago on a different thread, discussing drag strip methods for the FSAE acceleration event.

Considering your third question, you may be 'confident [we] will all fail', but I remember your explanation concerning inertial resistance to pitch motions about the rear-wheel.
However, in order for resistance to pitch motions to come in to play, there must be pitch motions. In other words, there must be enough grip off the line to lift your front wheels in the first place.
You basically agreed to that, by saying we should assume a start line acceleration of 2.5g.

Like I said before, I don't see that happening with 'normal' tires on a 'normal' track. 1.5g might be doable.
You still haven't told me where you do your tire shopping.

I'm sure there are things we can learn from drag racing, but I feel you're a bit overeager to draw parallels.

This is how sticky a drag strip is:
https://www.youtube.com/watch?v=x5wQajhGaeI
so this:
http://bit.ly/Uj6YRP
comes as no suprise.

On the other hand, I don't remember seeing cars in a circuit race class lifting their front wheels.
Again, no surprise, they'll just have their rear wheels spinning instead.

If you want to make a point about how slow and boring current FSAE car designs are, and how stupid 4WD is, please point out a single race car that can go around corners (i.e. one that doesn't do its runs on a duct tape track, using tires with 9.5" walls at <0.5 bar that last 3km at most), and that accelerates quicker to 60km/h than the fastest 4WD electric FSAE cars.

DMuusers

07-20-2014, 11:29 AM

Regarding the weight distribution on 2WD (combustion) cars. If you only look at acceleration then yes, you want to design a static weight distribution as close to the driven axle (usually rear). That's why dragracers look the way they do. However, there are 4 dynamic events in formula student, where 3 out of 4 require some sort of lateral force creation. With minimal load on the front axle, minimal total lateral force is created needed for cornering. I guess every team that has some sort of lap simulation will agree that the average speed during these 3 dynamic events is significantly increased by increasing cornering speed. I won't mention F1, ok maybe I did. Therefore increasing points obtained significantly. So yes, you take a slight hit on 75 points from acceleration, but you gain a lot more on 50+150+300=500 points. Hmm... hard decision.

Then you have the issue of balancing the car for these 3 dynamic events. Even if you can get close to a good setup, a slighty hickup will cause the car to oversteer with a very rearward CoG (ask the people from the DUT11 for example). Yes drifting is a lot of fun, but it's also not very quick around a corner. As added bonus you'll wear out your tires quite rapidly, which is costly at ~150 dollars a pop.

And then I haven't even mentioned tire load sensitivity yet...

Note: if anyone has 2.5G tires I will trade them for ours :)

StevenWebb

07-20-2014, 07:23 PM

Rear weight bias in fsae has definateley been done quite well by maryland
https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-xaf1/t1.0-9/298415_121963357912886_681080726_n.jpg

as far as lateral force generation goes, if I remember correctly, there weren't many SAE cars faster around a skid pad, or scca autocross. (even though it was heavier than most)
transient response and the length required to get the weight distribution could be improved with a custom, short engine/driveline as discussed by other in this thread.

One problem with the rear weight distribution which will be getting worse with the proposed rules is trying to get the aero balance to where it should be. In my non-aero-person opinion, with current packaging "maximum" downforce on a minimum length car would likely occur with an aero balance pretty close to 50:50. With these new rules who knows? Maybe some low-powered aero teams might show up with 65% front weight distribution and skinny rear tires to maximise total balanced downforce? (i am choosing to keep the questionable claims of creating massive underbody downforce in their other threads)

It will interesting to see if any of the top teams come up with something radically different in these new rules

Jay Lawrence

07-21-2014, 12:11 AM

Daniel,

If your theory on axle loading held true, there would be no point to reducing mass. Minimal axle loading may create minimal lateral force, but there is less mass to move. See the Deltawing concept.

Having done quite a bit on turbo tuning with the UoW cars, I agree with GXP_Matt that turbo implementation would be easier. Drainage was a frustrating problem and on some cars resulted in much victory smoke. Also, the amount of work required to make the turbo provide a gain was huge. This doesn't seem to be appreciated by many, who think it's just a matter of whacking on a turbo and boosting like hectic. With the proposed intake path, it would be possible to do just that. I don't see this as a problem, because it forces teams who go down that path to realise the other requirements for successful turbo implementation (assuming the oiling and some lag issues have been resolved by the new layout). I can go through my take on these requirements if anyone is interested, but suffice to say they are applicable to real world situations.

07-22-2014, 10:04 PM

To reiterate my main point here, there is a strong suggestion in the proposed Rules changes, and in many students comments here, that E-cars have an "unfair advantage" over the C-cars. This is supposed to be particularly so with the 4WD E-cars in the Acceleration event, and the recent FSUK-14 results might (!?) be used to support this view.

FSUK-14 results:
#. Team ......... O/A ... Acc.
===================
1. Delft(E) .... 856 ... 73
2. Stutt(C) .... 837 ... 38
3. KIT(C) ..... 828 ... 37
4. Zurich(E) . 827 ... 75
5. Monash(C) 821 ... 21

My argument is that if the above C-car teams learn how to do Acceleration properly, then there would be NO E-cars on the podium!

I will spell out how to do this in more detail in a few days, but meanwhile...
~~~~~o0o~~~~~

Stever95,

"I.....I......I...... Disagree."

The appropriate saying here is that "Opinions are like a...holes. Everyone has one."

Would you care to support your opinion with some quantifiable reasoning?
~~~~~o0o~~~~~

Troy,

"... intuition would suggest that combining lower inertia losses and a higher tractive potential for an equivalent power level would give higher acceleration, all other things being equal, no?"

Your intuition is wrong because your premisses are wrong. Your main mistake above is the second one. I'll give the numbers later.
~~~o0o~~~

Thijs,

"In other words, there must be enough grip off the line to lift your front wheels in the first place.
You basically agreed to that, by saying we should assume a start line acceleration of 2.5g."

Yes, as all the Toothless-Hillbillies know! And the "front-wheels lifting" kind of makes your front-motors redundant, doesn't it? (Except, as noted before, for regen-braking, and also good for very low grip conditions where there is little rear weight transfer.)

"You still haven't told me where you do your tire shopping."

I buy whatever is readily available, but then use it correctly. I note that Delft has some rather special looking Apollos? They look good. :)

"This is how sticky a drag strip is:
https://www.youtube.com/watch?v=x5wQajhGaeI"

And on that sort of drag strip (which is only like that near the start) a Top Fueler takes ~3.8 seconds for ~400m (Edit: STUPID Z!!! See later post). That is an AVERAGE of more that 5.5 Gs, over the full distance! I am asking you to aim for LESS THAN HALF that number, and only for a very brief period at launch (numbers later....).

"I don't remember seeing cars in a circuit race class lifting their front wheels.
...
If you want to make a point about how slow and boring current FSAE car designs are, and how stupid 4WD is, please point out a single race car that can go around corners ..., and that accelerates quicker to 60km/h than the fastest 4WD electric FSAE cars."

You really should get out more. Or use Google?

Last time we had this discussion all the student "experts" were saying that no racecar engine could ever make the 30 kW/sq.cm of restrictor area that I said was a reasonable upper limit. I then had to spend five minutes on Google to find the countless engines that do, in fact, make close to that number, with some claiming quite a bit higher.

You are being LAZY. Please do your own research.
~~~~~o0o~~~~~

Daniel,

"Regarding the weight distribution ...
[Premisses ->]
If you only look at acceleration then yes, you want to design a static weight distribution as close to the driven [rear] axle ...
However, there are 4 dynamic events in formula student, where 3 out of 4 require some sort of lateral force creation. ...
With minimal load on the front axle, minimal total lateral force is created needed for cornering. ...
Then you have the issue of balancing the car for these 3 dynamic events. ... slight hickup ... oversteer ...
[Conclusion ->]
So yes, [with 50:50 WD] you take a slight hit on 75 points from acceleration, but you gain a lot more on 50+150+300=500 points."

Try not to take this personally, because the majority of your fellow students also think the same way, but the above reasoning is really STUPID.

Firstly, your "theoretical" reasoning is based on vague, qualitative, hunches. There are NO NUMBERS! If you do your calculations/simulations correctly, with NUMBERS, then you will see how wrong the above reasoning is.

Secondly, you have clearly not done any "empirical" research (ie. checking the "prior art", aka "benchmarking"). If you did, then you would be aware of the countless racecars that have a significant rear weight bias, with larger rear-tyres than fronts, and can BOTH accelerate hard, AND go around corners fast. See below for examples.

Sadly, your sort of reasoning is all too common amongst people who like to call themselves "Engineers" (I have heard it too many times in the past). NO correct use of theory, and NO checking of the empiricism. But worse yet, NO shortage of arrogance along the lines of "I are an Engineer, so I know all about these things. And if I can't do it, then it can't be done!".
~~~~~o0o~~~~~

Steven,

"[Maryland car]... as far as lateral force generation goes, if I remember correctly, there weren't many SAE cars faster around a skid pad, or scca autocross.
... transient response and the length required to get the weight distribution could be improved with a custom, short engine/driveline ..."

Yep. It works well, and squashing it all up and making it a bit lighter would work even better...
~~~~~o0o~~~~~

Jay,

"Minimal axle loading may create minimal lateral force, but there is less mass to move. See the Deltawing concept."

Again, yes.

Ben Bowlby's DeltaWing concept is driven primarily by the goal of half-mass + half-power = half-fuel-consumption + same-laptimes. To a large degree this is achieved via better aerodynamics. But along with the aero (or as a result of it?) the DW has ~28F:72R weight-distribution (with 75% rear aero), and it goes around corners just fine!

Interestingly, before it ran all the Engineering experts said "IT WILL NEVER WORK!!!". They said this even though the earlier 1980's AAR Eagles (http://www.motorsportmagazine.com/race/sports-cars/the-secrets-behing-the-delta-wing/) that inspired the DW worked really well! Ah, ... experts! :)
~~~~~o0o~~~~~

Bottom line for now, next year's FSUK C-cars should aim to win Acceleration outright, and push the E-cars off the Overall podium. So stop carrying on like sooky little girly-boys and wingeing that the E-cars are not playing fair... :)

The empirical evidence is out there, and numbers coming soon...

Z

JurrienK

07-23-2014, 07:27 AM

Mumpitz

07-23-2014, 08:47 AM

I can't get this image out of my head when visualizing Z's weight distribution concept
http://images.thesamba.com/vw/gallery/pix/1025010.jpg
Low CG (boxer motor)
High rear weight dist.
No unnecessary technology

Don't take that as an insult to the idea by any means either. As an FSAE alumni with a few rotary motors laying around and an adapter kit for a VW bug box... craigslist is a dangerous place for the post FSAE junkie.

tromoly

07-23-2014, 03:43 PM

Z,

May I suggest spending more time around the drag strip when the track is being prepared. I have worked at a multiple-time record-holding (both ET and MPH) drag racing facility for 8 years, the track surface is sprayed the entire quarter mile in PJ1 Trackbite, per NHRA guidelines.

I'm not buying the Top Fuel comparison. I am personally interested in seeing your math that says an FSAE car on an unprepared surface can accelerate at half the rate of a Top Fuel dragster with a power/weight ratio >5200 hp/ton on a much higher bite track surface.

ADDED: Also, the quarter mile record is 4.58 seconds in a wheel-drive car as seen here (*Language Warning* http://youtu.be/57-DDGblOJw), you are most likely thinking of the 1,000-foot record of 3.7 seconds (http://www.nhra.com/points/national-records.aspx). Unless you're thinking of the 3.58 quarter mile set by a Hydrogen-Peroxide rocket car at Santa Pod a number of years ago (http://youtu.be/0lnEjOuQGBc), that really isn't relevant 'cause rockets aren't FSAE-legal.

Dylan Edmiston

07-23-2014, 04:13 PM

FSUK-14 results:
#. Team ......... O/A ... Acc.
===================
1. Delft(E) .... 856 ... 73
2. Stutt(C) .... 837 ... 38
3. KIT(C) ..... 828 ... 37
4. Zurich(E) . 827 ... 75
5. Monash(C) 821 ... 21

My argument is that if the above C-car teams learn how to do Acceleration properly, then there would be NO E-cars on the podium!

To quote someone I highly regard on these forums:

Would you care to support your opinion with some quantifiable reasoning?

I would like to see support from your statement that the combustion cars are NOT doing accel "properly". On top of that, support that the electric cars ARE doing accel "properly".

MCoach

07-23-2014, 05:47 PM

For the people that are not swinging their lower members around here....

With reference to the proposed rules I don't think anyone has bothered to reference to the 2014 rules. Throttle only seems to affect forced induction applications.
Check page 66: http://students.sae.org/cds/formulaseries/rules/2014_fsae_rules.pdf

T15.9 Throttle Body – The committee is considering changing the position of the throttle body to place it
downstream of the compressor on turbocharged and centrifugally supercharged engines. The restrictor would
remain upstream from the compressor. Naturally aspirated engines would not be impacted by the change.

Drive by wire includes switch (hopefully not, because we already have a driver kill switch)
T15.7 Drive by Wire Throttle – The Committee is considering that drive by wire throttles can be used on
Formula SAE cars if they include a form of the brake plausibility device which is currently required for
EVs. Feedback on this topic and whether you would like to adopt a throttle by wire throttle would be
appreciated.

As a student from Kettering, and having by far the most cost efficient car, this is in my interest.
T15.10 Design Event – The committee is considering including the objective of value in the design event
objectives. This is to make it clear to all participants that a cost effective car which is well executed should be
able to score well in the design event. This will result in the design event being judged on the three main
objectives of Design for Performance, Design for Value and the knowledge of the team members. The
committee hopes that this will change the perception of the design event so that it is clear that a large budget is
not a prerequisite to winning the design event.
T15.11 Cost Event – The committee is considering a major revamp of the cost event such that it addresses
product / component engineering issues including design for cost, design for manufacturing, design for
sustainability and the life cycle of the product. Students will be expected to have an appreciation of all areas of
relating to product / component engineering which will be important in their engineering careers. The
committee would appreciate feedback and prop

Swiftus

07-23-2014, 06:05 PM

I'll bite on on this one MCoach.

Would a kind person please explain why engines with different types of induction should be treated differently with regards to how their power is being limited?

"T15.9 Throttle Body – The committee is considering changing the position of the throttle body to place it
downstream of the compressor on turbocharged and centrifugally supercharged engines. The restrictor would
remain upstream from the compressor. Naturally aspirated engines would not be impacted by the change."

MCoach

07-23-2014, 08:59 PM

Jay, glad you've asked. I went looking and dug up another relevant document.

From this 2013 document, this is the exact reasoning from the rules committee:

http://www.fsaeonline.com/content/Change%20restrictor%20placement%20location%20web.p df

"B8.6.1:
Moving the throttle body downstream of the centrifugal boosting devices will avoid
creating a vacuum in the compressor housing when the throttle is closed which draws oil
past the seal resulting in visual engine smoking and potential plug fouling. No
performance benefit will be gained by centrifugally boosted engines as any air leaks in
the throttle body will reduce the amount of air going into the engine at wide open throttle.
The restrictor will continue to choke the flow through the compressor limiting power as
with the current configuration.Placing the throttle body downstream from the turbocharger will put it in the normal
position used in current production vehicles thus making the turbo a realistic design
option for the teams. Turbocharging of production vehicles is widely expected to grow
significantly worldwide in the near future so providing an opportunity to incorporate this
technology into FSAE performs an important part of the educational purpose of the
competition.
Naturally aspirated engines would keep the same layout (sequence) as currently
required because of concerns that a leaky throttle body downstream could allow
unregulated extra airflow to the engine if it was placed downstream of the restrictor.
Positive displacement boosted engines would continue to use this layout because oil
seal leakage is not an issue and there is no motivation to change the design."

Swiftus

07-24-2014, 05:57 AM

Thanks MCoach.

I don't see how a 'leaky throttle' is a defense though. At FSG the scrutineers will put their hand over the intake to physically plug the engine. If the engine doesn't immediately die, they will ask you to go full throttle as they plug the intake. This should make the engine stop faster... unless there is a 'leak'.

This same process could be performed no matter where the throttle body is located within the system and no matter what kind of induction the engine has equipped.

Why not simply place the restrictor after the throttle body and the turbo?

Pat Clarke

07-24-2014, 08:11 AM

Oh Jay, think about it :-)
You want 300 horsepower turbo FSAE cars?

On second thoughts, sounds good to me :-) :-)

Pat

MCoach

07-24-2014, 08:48 AM

The restrictor functions on a difference in pressure differential. Usually it is referenced to atmospheric pressure, which then defines your maximum flow rate compared to the vacuum drawn by your engine. If you move that downstream of the turbo, you then end up in a situation where the restrictor no longer is limited by the vacuum, but by how pressurized you can get the air to force it through that tiny restriction. Not regarding efficiency and eventually melting turbos, power becomes unlimited. Essentially, your mass flow rate is no longer limited, which makes it an easy decision to run a turbo in that configuration over NA.

Turbo-609.9cc here I come. ;)

To circle back to the placement of the throttle, a leaky throttle in an naturally aspirated application allows more air to flow by circumventing the throttle while in a boosted application it would leak down presssure, decreasing mass flow rate, decreasing power. It actually seems pretty practical.

PS...
Please, don't go and prove what the downstream restrictor would practically restrict the engines to. I've had enough lower member swinging contests this week. Also, couldn't pass up a Powerthirst reference.

Swiftus

07-24-2014, 05:06 PM

Oh Jay, think about it :-)
You want 300 horsepower turbo FSAE cars?

On second thoughts, sounds good to me :-) :-)

Pat

Could you imagine the top speeds in the straights? They would be hilarious! 5G braking into hairpins, all sorts of oversteer in slaloms. I would bet you could more than double the attendance at a Formula Student event if the cars all had 1hp per pound.

MCoach - My point about the throttle body placement was more to show that it can be trivial to prove a 'leaky' throttle in either case. Differential pressure sure is exciting, but I don't think the sarcasm came across in my post.

Start here for large differential pressures through restrictors:

http://en.wikipedia.org/wiki/Rocket_engine_nozzle

P.S. Please keep your member to yourself.

MCoach

07-24-2014, 06:36 PM

Well, now. If I understood there was sarcasm in that post my response would have looked something like this:

downstream, eh? You mean we get to make formula cars with this much power:
http://www.youtube.com/watch?v=qRuNxHqwazs

1hp/pound would be very exciting.

07-24-2014, 09:30 PM

JurrienK,

"... both the electrical cars in the top 5 had problems getting a good time in endurance."

Ok, the results pages didn't mention that. I thought the E-cars might have been conserving their batteries, hence both having very similar (but slowish) times.
~~~~~o0o~~~~~

Mumpitz,

Yep. More below...
~~~~~o0o~~~~~

Troy,

"May I suggest spending more time around the drag strip...
... the quarter mile record is 4.58 seconds in a wheel-drive car as seen here"

Yes indeed, I should get out more often. You are right, and I WAS WRONG!!! (And you have just brought eternal joy to legions of FSAEers! :))

Last time I attended a dragstrip the racing was ONLY 1/4 mile, and they only stickied-up the first 60' or so. I do recall the fastest times in the low 5s and headed for the high 4s, with sustained ~4-ish Gs.

I found a 1/4 mile (402 m) "record" of 4.42 sec which gives average 4.2 G, and your 1,000' (305 m) of 3.73 sec giving ~4.5 G. Given that the cars are travelling at half the speed of sound at the end of the runs, their Gs should be dropping off there, so must be higher earlier in the runs.

[Nevertheless, note to STUPID self: Z, do NOT trust Google! Must try harder... :)]
~~~~~o0o~~~~~

Dylan,

"I would like to see support from your statement that the combustion cars are NOT doing accel "properly". On top of that, support that the electric cars ARE doing accel "properly"."

Right and wrong ways:

C-cars.
======
1. The fact that times have been static for ~30 years strongly suggests that something is very wrong. In open competitions of almost any type, the times always steadily drop.

2. Watching FSAE Acceleration first in 2002, and again last year, ALL the cars smoke their rear tyres at the start-line, keep them smoking for the next 5 to 10 metres, but NEVER make a great deal of forward progress. Having seen lots of other cars accelerating hard, it is blindingly obvious that the FSAE "wrongness" is a lack of rear grip, due to lack of rear weight.

When I question a team about this the response is usually something like:
"Well, this year we turboed the engine, so of course the tyres are going to be spinning more than last year..."

Then another team member adds,
"Yeah, but next year we're going to add Traction Control, so that should fix it..."

To spell out the multi-level-wrongness here.
1. Start with nowhere near enough grip from the driving wheels, for a MEDIUM powered FSAE engine.
2. $pend re$ources to add even more power...
3. $pend even more re$ources to SWITCH OFF the power you added in step 2!

E-Cars.
======
1. They must be doing something right because they are a half-second, and half of the 75 points, faster than the C-cars.

2. On the other hand, this thrashing of the opposition might be quite "wrong". The general rule in motorsport is that as soon as you start winning too easily, all the other teams start whingeing and moaning to the Organisers, who then change the Rules to ban whatever advantage you have. Yes, FSAE is not supposed to be "motorsport", but this nobbling of the E-cars is (part of) the topic of this thread.

I would much rather see both C- and E-cars competing on their merits. Restrict both to the current 85-90 kW for safety reasons. Let the E-cars have their perceived advantage of 4WD, because IMO they have a possible (?) disadvantage of heavy batteries. Certainly, if the Enduro is made much longer, then the E-car battery mass will become a problem.

The two areas in the Rules where the E-cars really do seem to have an "unfair advantage" is Cost, which doesn't seem to reflect their expensive batteries (? corrections welcome), and Fuel, which reads like a fairytale!

Given that the E-car energy is likely coming from a coal-fired steam-engine, with umpteen transmission/conversion losses between there and the car, I honestly can not see how they can be rated as using less than half the CO2 of the C-cars. You can grow ethanol (E85) in the back paddock. Fully sustainable, closed-loop carbon-cycle, etc. But perhaps best to leave that argument for another time. :)
~~~~~o0o~~~~~

I'll give my Acceleration numbers tomorrow, promise...

Z

07-24-2014, 09:31 PM

Meanwhile, here are some pics to go with Mumpitz's.

Typical F-5000 car (late 1960s to early 1980s). This was a low-cost, entry level Formula series, using inexpensive stock-block, but ~500hp, 5 litre V8s. Highish power + heavyish engine = more rear weight, => so also needs bigger rear tyres => so accelerated faster off the start-line and out of slow corners than contemporary F1 cars.
http://www.sportscardigest.com/wp-content/uploads/MSC11Rnd3R3JayEsterer1.jpg
~o0o~

Typical F1 Turbo era car. Renault started it, but this first 1977(?) car wasn't too successful (took them a few more years...), and had nowhere near the 1,000++ hp of the later turbo cars.
http://autoinjected.files.wordpress.com/2012/03/jean-pierre-jabouille-renault77.jpg
~o0o~

Not really relevant, but interesting. F1 Tyrell P-34 "six-wheeler" (1976/7). Design was mainly to reduce aero-drag by tucking front wheels into bodywork. Only moderately successful (1 win, several other podiums...) because Goodyear (?) didn't do enough development of the front tyres. Avon now make tyres for these 10" front-wheels which has led to these cars winning many "Old-F1" races. I think (?) Avon also make these ~40 cm diameter tyres in the sticky hillclimb compound, possibly very suitable for FSAE?
http://media.crash.net/original/AU1091067.jpg

Williams and March also made 4R(tandem):2F-wheeled experimental cars, and Ferrari experimentally fitted 2 x tyres on each rear corner, similar to the rear-engined (~600 hp) Auto Unions of the 1930s.
~o0o~

IMPORTANTLY, all the above cars were designed when the Rules were much more open than now, and the goal was to build cars that go as fast as possible in a straight line, AND AROUND CORNERS. Most modern Formulae have the tyre-sizes, and hence also the weight-distribution, tightly specified by the Rules. Modern racecars do NOT look like they do because "it works better".

Z

Dylan Edmiston

07-25-2014, 03:04 PM

Dylan,

"I would like to see support from your statement that the combustion cars are NOT doing accel "properly". On top of that, support that the electric cars ARE doing accel "properly"."

Right and wrong ways:

C-cars.
======
1. The fact that times have been static for ~30 years strongly suggests that something is very wrong. In open competitions of almost any type, the times always steadily drop.

2. Watching FSAE Acceleration first in 2002, and again last year, ALL the cars smoke their rear tyres at the start-line, keep them smoking for the next 5 to 10 metres, but NEVER make a great deal of forward progress. Having seen lots of other cars accelerating hard, it is blindingly obvious that the FSAE "wrongness" is a lack of rear grip, due to lack of rear weight.

When I question a team about this the response is usually something like:
"Well, this year we turboed the engine, so of course the tyres are going to be spinning more than last year..."

Then another team member adds,
"Yeah, but next year we're going to add Traction Control, so that should fix it..."

To spell out the multi-level-wrongness here.
1. Start with nowhere near enough grip from the driving wheels, for a MEDIUM powered FSAE engine.
2. $pend re$ources to add even more power...
3. $pend even more re$ources to SWITCH OFF the power you added in step 2!

E-Cars.
======
1. They must be doing something right because they are a half-second, and half of the 75 points, faster than the C-cars.

2. On the other hand, this thrashing of the opposition might be quite "wrong". The general rule in motorsport is that as soon as you start winning too easily, all the other teams start whingeing and moaning to the Organisers, who then change the Rules to ban whatever advantage you have. Yes, FSAE is not supposed to be "motorsport", but this nobbling of the E-cars is (part of) the topic of this thread.

I would much rather see both C- and E-cars competing on their merits. Restrict both to the current 85-90 kW for safety reasons. Let the E-cars have their perceived advantage of 4WD, because IMO they have a possible (?) disadvantage of heavy batteries. Certainly, if the Enduro is made much longer, then the E-car battery mass will become a problem.

The two areas in the Rules where the E-cars really do seem to have an "unfair advantage" is Cost, which doesn't seem to reflect their expensive batteries (? corrections welcome), and Fuel, which reads like a fairytale!

Given that the E-car energy is likely coming from a coal-fired steam-engine, with umpteen transmission/conversion losses between there and the car, I honestly can not see how they can be rated as using less than half the CO2 of the C-cars. You can grow ethanol (E85) in the back paddock. Fully sustainable, closed-loop carbon-cycle, etc. But perhaps best to leave that argument for another time. :)

If an open class will always have times steadily drop, you are implying that an FSAE car will eventually have a 0.000 second accel run. At some point it does begin to level off. There's a good chance we are already at that point (note, I am not saying we are, otherwise I would use data to back that up).

From my experince with accel tuning, it has proven to be advantageous to slip the rear wheels since the "hook up" RPM (for a 600cc motor) is ~mid way through the RPM range. Otherwise the car has a good chance of getting bogged down in a low RPM area that is strongly suffering from lack of power. Of course, this is operating on my team's car that does not have a huge rear static rear weight distribution like you think would be better (of course better for accel, but how will it affect the rest of the events?). For accel, my team does take measures to increase rear weight distribution and increase rear load transfer. Our poor results in accel this year were a cause of timing issues that caused us to lose a faster run (the rerun was then on cold tyres because we were notified after the driver got out) and hold us up in line which forced us to forefit our final two runs (with an improved LC tune). I do not have numbers on our accel setup (weight distribution and CG compared to our autocross setup), but it would be interesting to get those written down to discuss.

As far as Ecars being faster, what if the complaints are actually true? :). And you are right, the general rule in motorsports is if one team is winning, they must have an unfair advantage so they should get some sort of restriction. The issue is, especially for student designed and built cars, what levels the playing field in regards to performance? When you look at some levels of motorsports, it is absolutely ridiculous. Being that some teams may be the only ones running a certain car, if they are doing poorly, regardless of the level of their engineers and drivers, they can convince the rules to decrease their weight restriction or power output to "level" them.

07-26-2014, 12:58 AM

FSAE ACCELERATION - INTO THE LOW 3s.
===================================

Below is a Velocity-Time graph that shows why the first few metres of the Acceleration event, the "Launch phase", is most important for fast times.

BTW, V-T diagrams are good for this sort of thing because the rate of Acceleration is given by the slope of the curve, and Distance travelled is area under the curve. The curve, of course, represents Velocity of the car at any given Time. So most of what you want to know (ie. A, V, D, and T) are all on the same diagram.

Some simplifying assumptions.
* "G" is conveniently rounded off to 10 m/s.s.
* The total mass of car and driver, including equivalent rotating inertias, is 200 kg. Why would anyone want more?
* There is an artificial Vmax "speed-limit" of 30 m/s (= 108 kph), perhaps set by the gearing of the car (or by the Rulemakers?).
* Maximum "drawbar" power of the car is 60 kW (~80 hp). This is the net power available to increase the Kinetic Energy of the car's mass, after driveline-friction (including tyre-slip) and aero-drag are overcome.
* Maximum distance required, from the FSAE Rules, is 75 m.

Four different "runs" are shown.

A - dashed line at left.
=================
This (unrealistic) run minimises the Time required for the 75 m, given the above constraint of Vmax. Perhaps the car got a "flying start", or else you parked it out on the main road, and a large truck travelling at 108.1 kph hit it from behind. Anyway, with the constraint of Vmax, the Time is minimised by squashing the given area of D = 75 m into a RECTANGLE, which gives an Elapsed Time of 75/30 = 2.5 seconds.

C - dot-dashed line at right.
====================
This run has a constant acceleration Ac = 1 G (= 10 m/s.s). Perhaps the car has tyres with Mu = 2 (ie. quite sticky), but because only HALF THE STATIC WEIGHT of the car is on the driven rear-wheels (so that, despite some rear-weight-transfer, the tyres are furiously spinning and losing that extra grip), the car can only accelerate at 1/2 x Mu = 1 G!

At time T = 1 second the car has travelled distance Dc = 5 m (... yaaawwwn ...), and requires power Pc = 20 kW to maintain this rate of acceleration (see graph for all these numbers). Much, much later ("... are we there yet ..."), at T = 3 seconds and Dc = 45 m, the car eventually becomes power-limited, with Pc = 60 kW. It has also just hit the Vmax speed-limiter, so then continues at 30 m/s to the finish line in an even ET = 4 seconds.

C' - dot-dashed extension to C at top-right.
==============================
Team Testosterone want to go faster, and they figure it is all about MORE POWER, ... and SPEEEEED! So they hyper-mega-turbo-boost their engine, and ... ahem, "fix" the speed-limiter. The grip stays the same (probably less, given tyres are now molten puddles), so with the same A = 1 G all the way they hit the finish-line at V = 139 kph, and ET = 3.87 seconds (= sqrt(15), from "distance = half-Aye-Tee-squared").

Despite needing almost 30% more peak-power, and having almost 30% more top-speed, the Elapsed Time drops by ONLY ~3%!

https://lh5.googleusercontent.com/-hwj2i2rl3-I/U9MEUYJs9HI/AAAAAAAAAQw/mklPsKXMcEM/s800/LaunchVTGraph.jpg

B - solid line around cross-hatched area.
==========================
Meanwhile, Team Toothless concentrate on the "launch" (see below for details). Doing so, they manage a very brief, but also very rewarding, initial acceleration of Ab = 2.5 G. This only lasts for T = 0.4 seconds, and covers a distance Db = 2 m (ie. less than the length of the car!), but it is where they win.

At the end of this 2 metre launch-phase the car is at V = 10 m/s (36 kph), and requires Pb = 50 kW to maintain this rate of acceleration. So the Gs drop off to only Ab = 1.5 G. At T = 1 seconds the car is at V = 20 m/s, has covered Db = 11 metres (I fudged the curve a bit here to keep the calcs simple), and has again hit peak power = 60 kW.

So the driver changes up a gear, and the reduced wheel torque means the car only accelerates at Ab = 1 G, requiring Pb = 40 kW (ie. engine is away from peak power). By T = 2 seconds the engine is again at its peak Pb = 60 kW, Db = 36 metres, and the car has hit the Vmax = 30 m/s speed-limiter. So the car coasts at constant speed to the Db = 75 metre finish-line with an ET = 3.3 seconds.

This time would be a World Record for C-cars and would win most comps. I believe that an E-car once did a T ~3.2 s (memory???). Continuing the above "B" curve above V = 30 m/s, but still keeping the power limit below 60 kW, would reduce the ET to below 3.2 seconds, for an outright WR. More engine power, and a transmission that keeps the engine near that peak power, should allow an ET in the high 2's.

But I stress again that the initial ACCELERATION AT LAUNCH is most important for good times (ie. it squashes the D = 75 m area towards the left). And mega-power is NOT necessary for good points in the other FSAE events (ie. SP, AX, E), nor does it make a big difference here.
~~~~~o0o~~~~~

LAUNCH TECHNIQUE.
===================
So, how do you get those high Gs at the start-line?

Let's start by dismissing the idea of putting only half the car weight on the driving wheels, and then hoping to find some magical Mu = 5 tyres. That is just wishful thinking, so STUPID. :)

The obvious first step is to have the driving wheels carry as much of the gravitational downward Fz force of the car as possible. Assuming RWD, and depending on CG-height and tyre-Mu, this might ONLY require about 60% static-rear-weight. Any forward acceleration causes "weight" to be transferred to the rear, which gives the rear-wheels a greater capability for forward acceleration, so more rear-weight transfer, etc. Generally, the higher your CG, and/or the higher the tyre-road-Mu, then the less R% you need, and vice versa.

(Note that with a 50F:50R Electric-4WD car, with typical CG-height, wheelbase, and tyre-Mu, during acceleration the rear-wheels might carry about 75% of the Fz loads, so require about 75% of power sent to them. Conversely, during hard braking the front-wheels might have to do about 75% of the "regenerative-braking". So the front-motors are 75% for "regen", but only 25% for "acceleration".)

But the BIG STEP to better launches (as all the THs know), is to have the CG of the car LIFT as it comes off the start-line. The only way the CG can move upwards is by INCREASING the road-to-wheel Fz forces. This Fz+ increase, which is above the static gravitational "weight", gives the car a greater forwards tractive Fx force capability.

Here are some ways to increase rear-wheel Fz forces:

1. Pop a "wheelie". Obvious really! Here the rear-wheels necessarily carry ALL the gravitational Fz loads (because fronts in air), and the UPWARD acceleration of the CG adds even more Fz loads. So much greater Fx forces, and more forward Gs. To maintain control you can let the front-wheels droop down so they stay on the road, while the rest of the car lifts. But remember that this launch-phase "wheelie" only has to last about 2 metres. Also, differential choice is quite important (and NOT so obvious...).

2. Set-up the rear-suspension with >100% anti-squat (ie. longitudinal n-lines sloping steeply up-to-front). This forces the rear-wheels down as the CG LIFTS. More grip = more forward Gs.

3. Do both of above. Basically, the higher the CG LIFTS, the more forward G capability. 4WD cars could have lots of anti-squat at both F&R suspensions, but eventually they run out of suspension travel, or all the weight is transferred to the rear anyway. Easier just with RWD.

4. DO NOT have a car with very high Pitch MoI. Dragsters are very long to increase their Yaw MoI, which slows down any Yaw motions. But they have frames that are flexible in bending so that the front of the car does NOT prevent the heavy engine and centre section from LIFTING upward. Fortunately, FSAE cars come standard with lowish Pitch MoI, but try not to let your "wheelie" go the full 180 degrees...

5. On the aero front, have a large undertray that, together with the lifting car, generates UNSTEADY aero forces that suck the car down. Note that your magical "Crayons For Drawing" are unlikely to help you understand these unsteady flows (which, BTW, can generate BIG forces!). Instead, quickly lift a large sheet of plywood up off the floor, and note how it "sucks" down. Also note that by the end of launch (ie. 2 metres!) the car is going fast enough to generate significant aero-downforce.

And a bunch of other stuff...

But as a last suggestion, look at the sprint races at the current Commonwealth Games. The runners squat down low at the start-line, then push DOWN and back as they come up and out of the blocks. Similarly with startled horses or antelopes, who always lift their front legs off the ground when accelerating hard.

Enough for now...

Z

stever95

07-26-2014, 01:35 PM

Z,

I look forward to going through your post in more detail.

That being said, there are a couple things I notice:

1. I think your total inertia is quite off: 200 kg means a sub 300 lb car. Including rotational inertia in that figure is even more false, especially considering that your examples require a 4 cyl from what I can tell (>80hp).
2. For a typical CG, wheelbase, and 2.5G of accel, I'm not finding that there's a whole lot of weight transfer to the rears, 5% at best. Maybe I'm doing something wrong here..
But that would mean you'd need a larger % of the weight on the rear wheels statically. Or to raise the CG under accel pretty dramatically. Or have super sticky tires.

So I agree with your physics, but I don't think the realities are there to make this possible. Unfortunately I can't comment on the aero or CG raising techniques, I just don't know much about plausibility there. From what I can see... there's still a good case for 4WD in a straight line.

DMuusers

07-26-2014, 02:45 PM

So I've ran your numbers Z. From the simulation the 130kg(!) car with 70kg driver with a mu of 1.5 (which is according to our tests quite viable) and a 60% CoG at 300mm above the ground. Without any drag but also no aero forces and driving constantly on the tire limit (like only electric cars can, since shifting and power and torque curves and such). With load transfer. No tire load sensitivity. The 2WD car completes the 75 meters in 3.705 seconds (stuttgart did 4.04 at FSUK2014, the fastest combustion).
Now, when maximizing the load on the rear tires without the car flipping over, for the same CoG height, we need 70% static weight distribution. Then the 2WD car completes the 75 meters in 3.545 seconds.
For it to get near the 3 second mark, the mu should be at least 3. And in that case you'd have to shift the CoG down or forward to prevent the car flipping.

I'm sorry if I missed something. But I don't think it's physically possible. The lightest car ever built was (I think, correct me if I'm wrong) the DUT06 at 120kg with a single cylinder (45bhp). I'm not sure what the lightest 4 cylinder (which has more power) was, but I'm guessing it's not less than 175kg.

On topic of the proposed rule changes, I guess this monday they are releasing the draft version which I think is quite exciting. I wonder how they will implement the rules for the rear wheel steering aswell, besides all the aero, power, etc. changes.

Kevin Hayward

07-26-2014, 06:56 PM

There are another couple of things to consider, some of which can be rectified by design, but which are not there today namely:

- It takes time to perform a gear change, during this time there is a period of no acceleration. This also occurs quite early in the run, which has a large effect.

- Secondly even though only modest power is required for the early acceleration it does mean that there needs to be an rpm differential between the rear wheels and the engine for the given gear.

The first and second can be solved by a CVT, the second also by using a clutch controlled launch phase rather than rpm based. I am assuming that most teams have a simple acceleration sim to run these sims.

I'm not sure I have been convinced that we have tyres that can produce a mu of 2.5-3 for a period of 0.4s at low speeds.

The line that is missing here is one for the electric AWD cars. In that case lets assume fairly normal tyres that can produce 1.5g accel throughout the 75m, although I have heard figures of constant 1.7g. The cars have sufficient power throughout the run, and have no need for gear changes this means 2.58s. The only problem with that is that it takes 90kW at the 30m/s barrier. That is not too much more than the mandated limit. So the car accelerates at 1.5g up to a little lower than 30m/s then continues with a lower acceleration. Not in a place to do the calcs, but it ends up with low 3s.

Kev

Kevin Hayward

07-26-2014, 07:25 PM

Just did the calcs ... around 3.1s (obviously close to accel times of the electric cars now). The big point here is that for these 4wd electric cars the tyres only need to provide a mu of 1.5 in all conditions, which is pretty reasonable. The power is controlled through the motor controller, which is the ultimate traction control. No gear changes to sap power. No need to play around with weight balance or COG height.

The power limit comes into effect after the first 1.8s (42% of the run).

This was done for a 200kg car. Change it to a 300kg car the time drops a whole 0.1s to 3.2 seconds (getting closer to where we are now) and the power limit comes into effect after 1.2s (62.5% of the run). The power limit for electric cars is effectively limiting how long you can have the extreme acceleration.

I have heard of 1.7g accel from the electric AWD drive cars, and obviously believable. In this case the run would be improved (with a 300kg car) to 3.1s, with the power limit coming into effect after 0.9s. (71% of the run)

So the AWD electric cars can do the ultimate times that Z suggests, but with a lot less effort, and on the power limit nearly the whole time. All the calcs here (Z's as well) are not including the effect of drag, which obviously slows things down, and will almost completely account between the difference of 3.1s to what the electric cars are currently doing. Also allow for a margin teams will be running to ensure they do not cross the 80kW limit.

Please note that I didn't crack open my proper sim code, and just did this roughly on excel. But I think the results are fairly clear, and close to expectations.

Of concern is that if the AWD electric cars are dropped to only 50kW of power they will do the run in about 3.45s, allow a couple of tenths for drag and we are still at 3.65s and they only need to worry about grip for less than 0.6s. Even with a big drop in EV power we will not be seeing the petrol cars faster than the EV's without doing a lot of work.

Kev

tromoly

07-27-2014, 02:38 PM

I'm sorry if I missed something. But I don't think it's physically possible. The lightest car ever built was (I think, correct me if I'm wrong) the DUT06 at 120kg with a single cylinder (45bhp). I'm not sure what the lightest 4 cylinder (which has more power) was, but I'm guessing it's not less than 175kg.

Lightest US car was UC Berkley, last year their car weighed 275 pounds/~125kg with a Swissauto 250 karting engine that put out 35hp.

BeunMan

07-28-2014, 09:53 AM

Lightest US car was UC Berkley, last year their car weighed 275 pounds/~125kg with a Swissauto 250 karting engine that put out 35hp.

That is (with the current rules) more what you can expect. The lightest GFR/DUT singles were around the 138-145 kg with about 45-50bhp if I remember correctly. I know there are some more teams running the (W/Y)R450 and in the 140-150kg range which gives around 0.30 - 0.36hp/kg in terms of power/weight ratios. The value DMuusers mentioned for the DUT06 was at the time when side impact structures were there just for rules sake and not there to protect the driver. Which is lighter of course. The lightest 4cyl stuttgart cars (both quite light and powerfull) generate about 85hp at 185 kg according to their specs on the website, which amounts to 0.45 hp/kg which is even better. So the 60kW option would be more near the 170kg without driver than the 130s mentioned.

Or you just do the 75 yard accel like some years back at FSUK. That way you should be able to get in the low 3s on accel.

Dylan Edmiston

07-28-2014, 11:02 PM

The 2015 rules are expected to release late August.

From a Facebook post:

Menisk

07-29-2014, 08:24 AM

A big thing I found surprising in my messing around with acceleration of a 4 cylinder was how little gears and wheelspin really affected times. We seemed to gear taller than most teams at FSAE-A with a 1st gear that ended at 78km/h and 2nd at 105km/h. The majority of our acceleration runs were between 3.95 and 4.00 seconds as we messed around with winding the launch control from being restrictive to barely doing anything at all. The fastest runs we put down were when we were dropping the clutch at 10,000 and holding a 10,000 rev limit until 35km/h. Hardly a well calculated map. We ended up somehow posting a freak run of 3.82 amongst all the 3.95 - 4.00 runs, but I'm not convinced it wasn't a timing error or just pure dumb luck that we parked on the oddly sticky part of the strip.

There were a few people that mentioned our fast gearshift times as helping a lot. We were running a 45ms cut on full throttle upshifts and only shifting once on the accel run. For the heck of it I did 2 runs at comp with no launch control and no gears. I started in 2nd, dropped the clutch at 14,200 and fishtailed my way to the end. We posted a time of 4 seconds flat. At best our "launch control" and use of another gear may have gained us 0.05 but I imagine you could get more by fitting a billet headrest to your car, which if you do the calcs still does jack all compared to static rear weight bias. Also by the time we get to ~70km/h, we're nearly at the end of the run. At that point even 300ms with no torque to the wheels is going to do bugger all to the time after we just spent a second or two clawing at asphalt trying to get our lump of a car moving.

As far as I'm concerned, so long as you have some sweet anti-squat, static rear weight, low driveline inertia and enough power to keep the wheels spinning for the first half of the run you'll win. Every bit of testing I've done with the R25B 13x7 Hoosiers tells me that for the most part more slip is more grip. I'd be inclined to guess at somewhere in the order of 30%-40% slip is where you'll make your max longitudinal.

Also for those that feel you need a light car to win accel, we weighed in at 240kg with a 50/50 weight bias. We simply aim to get the weight as rearward as we can, that's where we ended up with a "conventional" layout SAE car. Also we have a dyno printout that says 59.6hp.

Jonny Rochester

07-30-2014, 07:24 AM

That is an enjoyable read Menisk, and I tend to agree with the spirit of what you are saying. One should understand gear charts and spreadsheets, but just as valuable is to understand the weighting of that info, especially as tyres are spinning as you say.

"More slip is more grip" will ruffle a few feathers on this forums, and I love it!

I believe UTAS did well in acceleration in 2001/2002 with a very heavy car, but a pro had dyno tuned the 4cyl engine several times to get the most from it.

Shuff

07-30-2014, 08:05 AM

I believe UTAS did well in acceleration in 2001/2002 with a very heavy car, but a pro had dyno tuned the 4cyl engine several times to get the most from it.
Dyno tuning for acceleration times... Hmmm, I get where your coming from, but, you tune some things on the dyne, the things that get the times are done on the track, not talking about launch/trac control either.
Just something to think about:)

AxelRipper

08-02-2014, 11:17 AM

I've just been trying to figure out why none of the "Acceleration Specialist" teams have just said the hell with it and gotten some Jr Dragster tires.

Dunk Mckay

08-02-2014, 04:45 PM

I've just been trying to figure out why none of the "Acceleration Specialist" teams have just said the hell with it and gotten some Jr Dragster tires.

Cos they still need to finish Endurance on them? Also do they not need a reasonable amount of heat in them first? (they may not, but if they do....) That's something that will be difficult in series where tyre warmers are banned.

mech5496

08-02-2014, 04:59 PM

Regarding heat, I found this:

http://www.mickeythompsontires.com/strip.php?item=ETDragJr

"Requires little or no burnout". Plus they come in a FSAE-friendly 19/8-10 size. Finishing endurance (and takcling corners) is a whole different issue, and definitely a more serious one though...

MCoach

08-02-2014, 04:59 PM

The Jr. Dragster tires are meant to be used burn-out free because they are attached to Briggs and Stratton engines that have trouble doing a burn-out in the first place and they come in a 8.5" wide model. I don't think they would have a problem finishing endurance, honestly.

The 8.5" wides are 8" wheels if anyone decides they need to go even smaller.

Alex and I have had serious conversations about Jr. Dragster tires but never had the funds to buy a set to test.

Big Bird

08-02-2014, 05:21 PM

I have never really prioritized the acceleration event – rather I always assumed that one point earned in acceleration was worth half of two points earned in Cost. Or maybe that one point in acceleration was worth ten times as much as a tenth of a point in skid pad. Once I had satisfied myself that one point was in fact equal to a point, and that our overall score would not be adjusted because acceleration points have greater awesomeness than presentation points, I just put them all together into an overall event sim to see what concept worked out best over the whole event.

Some quick observations having skimmed through the above fairly quickly:

The reward for the Accel Event is in points. Points then sum to an overall score, which determines the overall event winner. The times above are interesting – but I didn’t notice anyone taking the next step to convert them to points. It is then you begin to see whether the changes required to bring about these times are feasible.

I would love to see a 300hp FSAE car. I would love to see how fast it was along straights. How much faster it would be around corners. How fast it would be under braking. How cheap it would be to run. How cheap it would be to build. How little fuel it would use. I would love to meet the powertrain leader and the traction control programmer. I would love to give the two of them a teacup, and call the teacup “grip limit”, and fill it to within 5mm of a line drawn just below the rim. At the sound of an academic wringing his hands and quietly sobbing the word “sub-optimal” I’d set them the challenge of filling the cup to the line using nothing but:
a metropolitan firetruck driven by banjo wielding bogans wearing Chev v8 t-shirts, and
a small bailing bucket with a traction control brochure in it.
I’d offer the two of them $50 to finish filling the cup to the line, and in plain view but without telling them I’d debit their credit card $25 for every litre of water that was wasted, and every minute spent on the task. Upon completion of the task, I’d get them to write a cost benefit analysis on cost benefit analyses until someone cried the word “futility”.

It is a constant amusement to me to see the way that the first reaction to Z’s input is one of antagonism - more often than not to identify some detail that is wrong, or difficult, or uncomfortable, or unfashionable, or just plain different – ridicule it – and then dismiss it. It is almost a sport. Z pokes his head up – and the masses quickly rally to shoot him down. Irrespective of his message.

Quick lads, better shut him up. How can we all agree on what it takes to be novel and creative while this guy keeps throwing up different ideas…

Now I do not agree with everything he says. But I enjoy hearing it. He challenges me. I learn from the challenge. I look for aspects that I might refute, and I look for gems that might help me.

Z and I chatted about acceleration event at Oz comp last year. He mentioned the concept of the 100% rear axle load acceleration vehicle. That was enough for me. I took the idea home. I wrote a simulation. I found that raising a c of g 30cm gave the same gain as 15 extra kW for the vehicle spec I analysed. I started thinking of ways to design a device that could jack up 30cm through reversible brackets, etc. I didn’t think of FSAE car, I thought of “self propelled jacking seat”. I had an original thought. I had fun.

It seems that others prefer to pick the eyes out of z’s words, in order to dismiss them and shield themself from a different way of thinking. I personally see that as exerting yourself in order to stand still. Seems a bit pointless really. Probably get you a good middle management job in Australian manufacturing, though…

Our society only celebrates critical analysis of what is wrong. Creativity often comes from recognizing and toying with what is good. The former is confining and narrows down the solution space. The latter is generative and expands it.

Z is the only guy here who takes the time to draw diagrams. Bloody good ones. Do any of his detractors bother to expend as much effort?
Should we dismiss his ideas just because he is not “one of us”? Does dismissing the different make us more creative thinkers?

Z is not here to teach detail. When he screams BROWN GO KART, he couldn’t give a ship about BROWN. Or GO. Or KART. The message is THINK OUTSIDE THE SQUARE. LOOK FOR INSPIRATION ANYWHERE. BE ORIGINAL. DON’T FOLLOW THE CROWD. The response? Duh….why brown????

Z is the guy here to stand up and make a call on the emporer’s new clothes. If you want to reject all he says without looking into his intent, then you are the one at the risk of smugly shouting in your underpants.

mech5496

08-02-2014, 05:57 PM

Geoff, you still keep amazing me with your posts! 10000% agreed with you!

Big Bird

08-02-2014, 06:10 PM

thanks Harry! Hope you are doing well, mate

Big Bird

08-02-2014, 06:32 PM

p.s. how to win FSAE
1. learn rules
2. build car to suit

how to win ten times:
Repeat above ten times

Kevin Hayward

08-02-2014, 07:20 PM

Geoff, sorry that I spewed times not points, but since the discussion was about massively improving acceleration times and EVs vs ICVs we can see the results from the UK.

Fastest Electric car: 75 points (3.439s)
Fastest IC car: 38.39 points (4.147s)

I would say in anyone's language or point sim that 36.61 points is quite a lot!! It is more than the difference between the highest performing IC car and EV car in the comp (around 19 points). In fact that points difference covers the top 5 cars in the field. It was the only event in which the EV cars showed a big points advantage (efficiency also gave a 20 point advantage). In this case the IC car is slower what we normally see as the fastest (closer to 3.9s to 4.0s). That would have still been a deficit of around 25 points.

If Z is right and an IC car can equal these times it is a worthy exercise to investigate the claims. From a rules perspective if you want to run EVs against ICs and Z is wrong then the rules absolutely need to change. Handing a 35-55 points advantage (efficiency & accel) to the EV cars with no apparent detrimental event (except cost event appears to be a 10-15 point loss) is not something you can overcome by fiddling the concept. Remembering that an IC brown go-kart can be met with an EV brown go-kart. There is no weight penalty for the top EV cars in powertrain anymore.

Does that satisfy your points requirement Geoff?

Sorry that I used results rather than a simulation, but the calcs performed earlier back up these sorts of times, and hence points.

Kev

Big Bird

08-02-2014, 07:37 PM

Kev, I'd respond promptly but as you know the internet here in Cockatoo is delivered by horse, and deliveries stop whenever it starts raini.. damn

Big Bird

08-03-2014, 08:07 AM

Hi Kev,
The point I was making was that a fair analysis would cover the whole breadth of the competition. I.e. the two options should be analyzed across all events, cost, energy used, etc. For each of these factors, relative points allocations should be compared.

I'm sure there is not much new to you there kev.

Cheers

Geoff

Kevin Hayward

08-03-2014, 09:21 AM

I will try to avoid a two person conversation happening ... especially one between to self-acknowledged gasbags.

What I am not sure is blatantly obvious is how well a small handful of EV teams have exploited rules that favour EV performance over IC cars. They should be commended for it, and not have their toys taken away. Z is spot on in saying that there is a lot more to look at in the IC cars, but I think way off base in any assumption that would claim parity between EV and IC in the current ruleset.

Once there is a powertrain performance advantage (power, efficiency, handling) with no noticeable detriment (with cost as the exception) then the solution is clear. It is definitely not an option for all because there is a very large monetary cost associated with the high level EV powertrains.

I am a big supporter of all teams running points analysis over the full comp. However with some issues there is a clear technical winner. High grip vs low grip tyres for instance, no need to run the points sim on that one. It just so happens that for competitions between EV and IC cars there is a clear winner in the powertrain department. A well executed IC team will not be able to beat a well executed EV team. The points just aren't there. I would also add that people need to chuck the crazy into their points sims even if they don't think it will happen. No one expected the high powered EVs to weigh what they do now, and have enough energy to do the endurance at full tilt. Has everyone considered what an IC car could do if it was 120kg with aero? What would happen if a team had custom made slicks capable of sustained mechanical grip of 2.5g?

My take is that if your concept is within 10 (maybe 20 points) then you can call it about equal and in with a chance. Anymore and you carry a deficit that is unlikely to be overcome in a large competition (i.e. ~100 teams) The reason for doing the overall comp points analysis is not to show that all concepts have an equal opportunity, it is to try and find if there is a clear winner (or an alternative strategy that differs from the leaders, but close enough to give you a chance). Or to plot out the best value in terms of points per dollar or points per hour. In that equation the IC cars still come out on top.

I do worry that without careful consideration of where the competition is heading that we will lose something special. Now having been involved with a team building a custom engine I have seen first hand how difficult it is to build a better engine than what you can buy off the shelf. Any team can access (for $2-5k) an engine good enough to build a comp winning IC car around. Build a simple vehicle around that out of fibreglass, glue and balsa, a couple of steel suspension members and you can have an innovative high performance vehicle. With the right skills a team can legitimately build a top level IC car for $20k. ECU's most recent car with carbon folded tub, carbon wings, plenty of spare wheels and tyres, and a custom engine cost around $40-50k. Monash's probably a lot less for more performance. The higher spends on these cars don't translate well to improved performance. Mainly because the nearly all components can be built by students at a very high quality, and there aren't too many of them.

For the EV programs these amounts of money do not even start to pay the bills.

Just don't run them against each other. The points sims validate this ... but don't trust me ... do the calcs, and please post the results if they say something different.

I'm sure there is not much new to you there Geoff.

Kev

08-03-2014, 09:58 PM

I REST MY CASE.
=============

Firstly, thanks Geoff for the supportive words.

I gave the "points argument" for faster Acceleration at the top of page 6 (and some more words later regarding E-Car-bias in Fuel Efficiency). The ~50 points that are on offer from doing Acceleration properly, and the self-evident fact that better straight-line acceleration out of slow speed corners (ie. NO fish-tailing!) also means more points in AutoX and Enduro, are my main reasons for pushing this point.

(And to repeat "my point", it is that Teams (other than Maryland+) should, for the first time in 30 years, start thinking about weight-distribution and tyre sizes, given FSAE's particular power levels and track layouts. The answer is only "50:50 with equal-sized tyres" when you have a sub-~30kW engine.)

But I have all but given up trying to help anyone from the "University" system.

LONG MAY THE DENTALLY-VENTILATED LIVE, for they are the only hope humanity has left...
~~~o0o~~~

PROOF POSITIVE OF MY PREVIOUS POST - The fastest Acceleration time at the just run FSG was ET = 3.36 seconds with Vmax = 115 kph = ~32 m/s (this taken off the web, so I shouldn't trust it, but anyway...).

This was a 4WD E-Car, but note that,
* It has LESS POWER than the maximum available to a C-Car (and as noted many times, MAX POWER IS NOT VERY IMPORTANT!!!)
* It uses the SAME TYRES as those available to ALL other FSAE cars (NOT magical "super-sticky" drag racing hoops). So same Mu, and same Fx/Fz.
* It set the time on the SAME TRACK as that used by all the other FSAE cars (NOT a specially prepared dragstrip).
* Its ET and Vmax are remarkably similar to that of Team Toothless's in my last post, so its V-T graph should be very similar to curve B.

So, to anyone who has a skerrick of understanding of the simplest 1-D Mechanics (ie. as spelt-out in my last post), A SIMILAR TIME IS POSSIBLE FROM A RWD C-CAR! (In fact, see below to see why RWD can be faster.)
~~~o0o~~~

But, in the SAME competition, on the SAME track, with the SAME weather conditions, ALL the C-Cars had the SAME SLOW TIMES that they have been getting for the last 30 years!

Here, from some earlier posts, are paraphrased the LAME EXCUSES for this PERENNIAL UNDERACHIEVEMENT.

* "A 200 kg total mass is IMPOSSIBLE because the driver MUST weigh at least 70 kg." - Just really, really stupid!

* "A lightweight car with a reasonably powerful engine is IMPOSSIBLE... because NO ONE HAS DONE IT YET." - So, you best go back to living in caves.

* "It is IMPOSSIBLE to go faster, because if the times keep dropping we'll suddenly be at 0.0 seconds..., which is IMPOSSIBLE" - Groaaannnn... How about just taking a few percent off the times each year (which you can do FOREVER!!!)?

* "It is IMPOSSIBLE to go faster..., err ... unless we spin the tyres impossibly fast..." - Jonny, a lot of the 4.5+ second teams where doing just that.

* "It is IMPOSSIBLE to go around a corner with a Junior-Dragster tyre. Just IMPOSSIBLE! And even if you could, they'd wear-out INSTANTLY!" - So, you may as well QUIT RIGHT NOW. Go home to Mummy... Or spend 2 x $150 (RRP on link) and have some fun.

(For the record, I DO NOT think any sort of special tyres are needed for a RWD C-Car to get into the low 3s. But, sadly, I do know of a team of PERENNIAL LOSERS who are planning to spend ~$8,000 on totally inappropriate tyres this year, simply because their $chool gives them a huge wad of cash each year. I say "sadly", because it is my tax dollars they are pissing away!)
~~~o0o~~~

The above are just some examples of the FSAE world's STUPIDITY and LAZINESS. To some degree you can pass the blame for that onto the Education System, for it is they who have fostered your belief that "Going faster is IMPOSSIBLE, just IMPOSSIBLE... But if we keep optimising our ridiculously ornate rockers, then WE DAMN WELL DESERVE OUR GOLD STARS!".

But you CANNOT BLAME OTHERS FOR YOUR COMPLETE LACK OF WILL TO WIN. All of the knowledge of how to do well in FSAE, both generally and in Acceleration specifically, has been spelled out on this Forum for years. Yet, year after year after year, you all seem oh-so happy to just STAND STILL, DO NOTHING, and GO NOWHERE.

I pity your children...

Z

(PS. I don't know why I bother, but one more time.
* To get really fast Acceleration times, THE CAR'S CG MUST LIFT as it comes "out of the hole"!
* This puts MORE THAN 100% of the car's weight on the driving wheels (so faster than 4WD with constant CG height).
* This "launch" lasts a split-second, and covers ~2 metres.
* Measure that 2 m time, and get it right.)

08-03-2014, 10:22 PM

Kevin,

Z is spot on in saying that there is a lot more to look at in the IC cars, but I think way off base in any assumption that would claim parity between EV and IC in the current ruleset.

(Almost) ALL the current C-Cars handicap themselves by using off-the-shelf powertrains (ie. "gearboxes", usually from motorbikes). Bad idea because;
1. These totally mess up the overall mass distribution of the cars. It is hard to get much more than 50%R, and gives too high a Yaw inertia.
2. These gearboxes, typically with rather weak clutches, are not very good at converting the constant and high level of power available from the IC engines (which is on par with E-cars), into the most appropriate torque at the wheels. Especially so at the lower speeds. (Note that for the E-cars, this "power-to-torque-gearing" is really just a software problem (PWM?), albeit reliant on expensive electrical hardware.)

But the typical FSAE aversion to solving these problems really boils down to LAZINESS. There is NOTHING NEW to be "invented", and the cost of using the "right answer" is NOT high.

I remember a long thread (possibly several threads) covering these issues back in 2005. There was huge negativity back then, just as there is now. Very, very few Teams have tried to solve these problems. Usually they are very small Teams, typically with only one highly motivated member. After some limited success, the new team members decide it is MUCH EASIER to simply jump back into the middle of the FSAE flock. "Hey, sooo much easier, and we still get our Gold Stars!"

Your Team is one of the very few who are now addressing this problem. PLEASE KEEP DOING WHAT YOU ARE DOING. Burn it into ECU's DNA.

IMO the path to E-Car-like drivetrain performance is only a few steps away. I hope you come to Oz-14, so we can talk about stuff. Like tractor IVTs, or the typical drag-car drivetrain, which at the lower power levels use mildly modified auto-boxes (hint, hint..., very simple FSAE system, suitable for your engine... :)).
~o0o~

IMO the only pro-E-Car BIAS in the current Rules is that they pretend that energy supplied from coal-fired steam-engines, that then suffers countless transmission and conversion losses, is somehow GREENER than a fuel you can grow in your own back paddock (= ethanol). I also like propane...

Discussion, anyone...? :)

Z

mech5496

08-04-2014, 03:08 AM

* To get really fast Acceleration times, THE CAR'S CG MUST LIFT as it comes "out of the hole"!
* This puts MORE THAN 100% of the car's weight on the driving wheels (so faster than 4WD with constant CG height).
* This "launch" lasts a split-second, and covers ~2 metres.
* Measure that 2 m time, and get it right.)

Too much time in a dragstrip? :P Drag racers really know their game when it comes into (usually 4-link) suspension geometry and "anti's", without using nothing more than paper and pencil. In fact, some of them could ballpack your rear suspension setup based on the available grip (slippery or super sticky track) and available power. Plus all of them seem to realize that the "launch phase" and Fz on tires is a highly dynamic phenomenon, an that you could (and in fact do have) more than 100% of car's weight on the rears, just because of that. You could find examples of people running really exreme values of antisquat, albeit I have heard from people that very powerful cars tend to start spinning their tires after the initial launch phase, because the Fz drops after a few milliseconds... Oh, and there is nothing forbidding having "special" suspesion pickups for the acceleration event only... ;)

EDIT: By the looks of it, ECU was doing something right in the launch phase of accel. at FSUK

* "It is IMPOSSIBLE to go around a corner with a Junior-Dragster tyre. Just IMPOSSIBLE! And even if you could, they'd wear-out INSTANTLY!" - So, you may as well QUIT RIGHT NOW. Go home to Mummy... Or spend 2 x $150 (RRP on link) and have some fun!

I like that! And as said, the M/Ts I have linked come in a FSAE-friendly size...

Kevin Hayward

08-04-2014, 09:59 AM

Z,

I should be at Oz 2014. The team has plans for moving away from the current style of clutch. A clutch is really only important getting going and there are much better ways of doing that than a multi-plate wet clutch. The clutch was probably the hardest thing to work around in the whole custom engine deal, and the first engine subsystem in line for a change in the next design. Next gen wont be around for another couple of years for the team though.

I was surprised to find out how what is done with clutches in drag racing and how much they are the first port of call for tuning the early stages of the run. I had incorrectly written off drag racing when I was younger, only to realise as the amateurs go the local guys at the drag strip are practicing better vehicle dynamics and data analysis than the guys at the circuit. It is almost impossible to find someone with a decent drag car that doesn't go through data, and almost impossible to find a similar circuit racer that does.

I am still not sure that you could keep enough load on the rears long enough to generate the sustained g's in the early launch phase, but I know what you are proposing teams exploit. The M/Ts might have a low enough torsional stiffness to make better use of the spike in unsprung vertical load. When I was a student we were running the older Goodyears that were very torsionally stiff and even tuning springs and dampers to try and improve the temporary vertical load (with reasonable CoG lifting) we could only get about a tenth. Additionally you could only go so low with the tyre pressures before you were running on very stiff sidewalls that screwed things up. The 10" LCO's would probably be a lot better.

The other issue we dealt with is that a lot of the dampers available had high inherent damping even without the valves. The first versions of the kinetics cars would have been able to run reasonably well around a track without the adjustable valves in at all. Later versions pulled out a lot of the damping due to path restrictions. The MTB shocks were garbage and hard to get in the range we would have needed to improve the launch. I have tested the current crop of Ohlins twin barrel dampers with one of my classes. They suffer from similar inherent damping to the early Kinetics cylinders we made at UWA. Not really a problem for track work and the adjustability is great, but they limit what you can do in the acceleration. Frankly I think they are not the best choice for dampers. The ECU guys switched to Penske non-adjustabe (but rebuildable) single barrel dampers. They weight exactly the same, and you can buy 2 for less than the price of one Ohlins. A much better unit to be working with to make the most out of Accel.

By the way for the teams that haven't done back to back testing of different style dampers, please do. Pull a couple apart and get an idea of what is happening to that oil squirting through little holes. If you don't have a damper dyno then build one. We built one in 2003/2004 and the required parts, control systems and DAQ, are much cheaper today. There is almost no reason for any decent FSAE team not to have one.

Most of the point sims I have seen in use don't have the fidelity to model the acceleration event properly, and should be used with caution when making tuning decisions on the basis of the results. The code I was running for my Thesis (focused on evolutionary optimisation algorithms) used a vehicle dynamics model designed for fast computation. As per most models of this type it was quasi-static. One area this lacks considerable accuracy is in launch zones, where transient behaviour dominates. We did some work with a much more accurate transient model of the acceleration event, but I would need to try and find the code for that, and change a few assumptions. Casting my memory back though I still don't see think magnitude of transient rear load you would need for 0.4 seconds of 2.5g accel being possible (in an FSAE event). It would be great if someone currently running a decent transient sim could post some numbers to confirm or deny this. Also out of curiosity how many teams are running good search algorithms on the solution space for their points sims? I would love to hear about any improvements on that front. Most of the approaches I hear about are 1 variable at a time style searches, or incredibly coarse searches with only a couple of variables each time. How are teams going about determining whether they are close to the global optimum, rather than local optima for their given sims?

On the face of it I would think that some of the newer cars would be in a better place to be tuned for the accel event than the older UWA cars. Weights, tyre construction, and basic design (i.e. wheelbase, available dampers, weight distribution, and even power) have gone in the right direction when compared to the mid 2000s. It is a little surprising that the times haven't dropped a tenth or two from back then.

I think you are right in that there is a lot of time that can be had by designing a car that can be tuned for accel (while still working well for the other events). I just disagree on the magnitude of the improvement possible. But I am proved wrong on a daily basis.

Kev

mech5496

08-04-2014, 03:12 PM

Kevin,

really a pity we did not catch a word or two in FSUK, I am pretty sure it would be massively interesting! Any plans to get back to Europe soon? Anyway, back to topic!

tromoly

08-04-2014, 05:31 PM

Z,

Would you mind running your numbers again using a 50:50 weight distribution and 681 pounds / ~310kg? I'm curious what it would come out to, these numbers are mostly from this year's University of Kansas car, which runs a 4cyl engine and full aero package.

https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-xfp1/t1.0-9/10302640_10154113385450648_1869054565980730692_n.j pg

I'm also curious on the numbers because I'm writing my own acceleration code and would like to compare numbers with what your simulation gives. On a similar note, could you possibly share what numbers and assumptions were used for your initial simulations, I would be grateful to use those for comparison as well.

Thinking on your weight transfer comments, I ran some numbers last night and found that a 441 pound car with 60% static rear weight on a 60-inch wheelbase accelerating at 1.5g only needs a CG height of 16-inches to get 100% rear weight transfer, that's pretty remarkable as it's far lower than I would have thought. I ran the same numbers under braking (with a tire Mu of 1.5) just to see what would happen and it gave a front weight transfer of 80% at peak load, that's pretty remarkable.

Now, I don't have enough of a grasp on cornering performance to run numbers in cornering, so anything hereafter is just speculating. If the CG is causing such massive weight transfer front-to-back, wouldn't that have a dramatic effect on cornering performance as well? This is what's tripping me up, something is telling me the lateral weight transfer would be an issue.

AxelRipper

08-04-2014, 09:49 PM

A 16" CG height seems excessively high in a FSAE car. Maybe if you had a way to change your suspension to get the "gasser" style suspension for accel, possibly with some accel ballast to help with weight transfer.

Maybe it was just the points analyses that I always ran, but acceleration always seemed to be one of the easier places to not worry about a few tenths of trade off due to the weighting relative to every other event. If you dropped a few tenths there you could pick up in cost and efficiency (then again that is just the justification for not running a 4 cylinder, right?)

08-05-2014, 02:13 AM

Harry,

"Plus all [drag racers] realize that the "launch phase" and Fz on tires is a highly dynamic phenomenon, and that you could (and in fact do have) more than 100% of car's weight on the rears, [...but...] the Fz drops after a few milliseconds...
Oh, and there is nothing forbidding having "special" suspesion pickups for the acceleration event only..."

Yes and Yes. More below...
~~~~~o0o~~~~~

Kevin,

"The team has plans for moving away from the current style of clutch. A clutch is really only important getting going and there are much better ways of doing that than a multi-plate wet clutch..."

Yes. And especially so the smallish motorcycle clutches that are designed for the lesser duty of getting a light-ish bike going.

Given that an IC engine does not work well at low revs (~or AT ALL), the choice at launch is to, 1 - slip the clutch, or 2 - slip the tyres. The Top Fuel dragsters have only one gear, and they slip their BIG multi-plate sintered-iron clutches for most of the run. (Interestingly, electronic control is banned, so they have to use a carefully set-up pneumatic-mechanical system.)

So, once again the standard FSAE approach of using an off-the-shelf motorcycle engine is a handicap, because fitting a bigger, better, clutch can be a major hassle. I reckon better is to start with an engine-sans-gearbox (there are lots of options), and then build your own custom (but simple!) drivetrain, probably integrated with the diff. A bit like you are doing!

"... I still don't see magnitude of transient rear load you would need for 0.4 seconds of 2.5g accel being possible (in an FSAE event). It would be great if someone currently running a decent transient sim could post some numbers to confirm or deny this."

I would definitely be doing "transient sims" for all the Dynamic Event analyses. (Very briefly, ~10 ms time-stepping, "F = P-dot" each step, and DRIVER-IN-THE-LOOP! So run it like a video-game.)

But above is NOT necessary to "confirm or deny" this particular case. See next...
~~~~~o0o~~~~~

Troy,

"Z ... I'm writing my own acceleration code and would like to compare numbers with what your simulation gives..."

Ahh..., Old-School vs New-School... :)

The SUM-TOTAL of my "simulation code" is ...
... the graph I drew. NOTHING MORE! I repost it here so that the next lot of words make more sense.

Stuttgart's #26 E-car did FSG Acceleration (of presumably 75 metres?) in 3.36 seconds, with a final speed (?) of 115 kph = ~32 m/s.

The car apparently weighed ~166 kg (on FSG website, though ~178kg on Team page?). With lightweight driver the total mass should have been not too much over 200 kg. (Given assumed computerised-everything-control, I reckon they could have signed-up a 10 kg macaque from the Biology lab to do the driving.). Team page says 4 x 25 kW motors, and given that high-G acceleration will put 70-80% of weight on rear-wheels (so fronts NOT capable of much Fx), a Pmax = 60 kW, while GRIP-LIMITED, is also pretty close.

So, comparing Team Toothless's curve B below (ie. the cross-hatched area) with a guessed-at V-T curve for Stuttgart.
1. The area under the two curves MUST be the SAME at 75 metres (assuming nothing funny at FSG?).
2. Stuttgart has a very small extra ET = 3.36s (cf. TT=3.30s) so their "75m area" extends very slighly to the RIGHT of curve B.
3. Stuttgart has a very small extra Vmax = 32m/s (cf. TT=30m/s, and I assume Stuttgart did NOT go faster in mid-run, and then hit the brakes just before the finish line!), so their "75m area" extends slightly ABOVE curve B.
4. The above two differences (2 and 3) means that Stuttgart can have slightly less area at the LEFT side of curve B. So a slightly less steep "launch acceleration", but ONLY SLIGHTLY LESS!

https://lh5.googleusercontent.com/-hwj2i2rl3-I/U9MEUYJs9HI/AAAAAAAAAQw/mklPsKXMcEM/s800/LaunchVTGraph.jpg

So, whichever way you draw Stuttgart's V-T curve, it still has to have a QUITE STEEP launch acceleration so that it can fit its "75m area" within the upper Vmax boundary, and the right-side ET boundary. In round numbers, I guess "quite steep" is ~2 G-ish, if not more. Any less than initial 1.5 G at the left-edge, and the "75m area" is pushed outside the top or right-edges...

And, MOST IMPORTANTLY, Stuttgart's tyres are the SAME tyres, on the SAME surface, as available to ANY OTHER RWD C-CAR TEAM.

Now Stuttgart's front tyres might have been doing maybe 30% of the work during launch (probably less). So take a purely RWD car (E or C), put less rubber on the front, more rubber on the rear, set it up for ~100% weight on the rears at "launch" (say, by giving it ~60%R-static, as noted below), and you have the SAME situation as Stuttgart's, at least as far as tyre-Mu, Fx/Fz, etc., are concerned.

So, bottom line, a RWD C-Car can have the SAME numbers during the most important GRIP-LIMITED phase near the start-line, and NO reason to believe the RWD car (with right sort of driveline) should be any slower.
~o0o~

I've waffled on a bit much, so briefly ...

"I ran some numbers last night and found that a 441 pound car with 60% static rear weight on a 60-inch wheelbase accelerating at 1.5g only needs a CG height of 16-inches to get 100% rear weight transfer..."

The MASS of the car makes NO difference. The "Gs" account for that, and always give the same % weight transfer...

"If the [16" high] CG is causing such massive weight transfer front-to-back, wouldn't that have a dramatic effect on cornering performance as well?"

NO, no, no. Not if you SET-UP the car to suit the different Events.

So for SP, AutoX, and Enduro I would definitely set-up the car with LOWEST POSSIBLE CG, and whatever else is required for good performance there.

But for Acceleration (remember = 75 points!) you could set-up the car with 4" of ground clearance. The Rules say you must have AT LEAST +/-1"of suspension travel, so 1" bump and 5" droop should be OK. (I don't have Rules here just now, but IIRC "shims, spacers..." and other adjustments are allowed.) So getting a 12" CGH up to 16", JUST FOR Acceleration, should not be hard. And not really necessary... (see below).

Or, easier, you can have a special "booster seat" for the driver that has a very thick squab. Given that most seat-backs slope backwards at about 45 degrees, I reckon you could easily move the driver up 4" and back 4". But check Rules on this...

More importantly, with CGH = 12" (0.3 m) and 60%R on a 60" WB (ie. ~0.6 m + 0.9 m = ~1.5 m) means 2 G gives you 100% on the rear. With same CGH, 2.5 G has you "popping a wheelie". However, you become power-limited a bit after 2 metres (see graph), so the Gs drop off and the nose comes down. Also any front-wing aero should start to act by this stage, pushing the nose back down.

So aim for as-low-as-possible CG for "normal running", and with 60%R you only have to bump it up to 0.25 m to 0.3 m for the Acceleration event.
~o0o~

The other big set-up change, hinted at by Harry, is the "rear-anti-squat", perhaps better called "pro-lift" here. Move the rear-suspension's front-pickup points (ie. near MRH) upwards. Quite a lot, say 4+". Now a forward Fx force at the rear-axles pushes the car's CG upward (through the up-to-front sloping n-lines), and by action-reaction, the rear-tyres get forced down onto the road. So more than 100% of car weight is possible on the rear-tyres.

But this increase is only brief, because it only lasts while the car's CG is accelerating upward. So best to start with the CG quite low, so that the pro-lift can last for as long as possible. And you have to find the right balance. Too much pro-lift and you get a nanosecond of great launch, but then the car jumps TOO high, grip is lost, wheels spin..., slow ET. Not enough "wheelie" or "pro-lift" = slow launch, and Team Toothless is laughing at you (although you have beaten most other FSAE teams).

I would suggest that the best way to find this right "balance" is with lots of real testing. Not much space is required, perhaps only 50 metres of straight road, because you are mainly trying to get that first 2 metres right. Well, that and then keeping the power on for the next 10 metres as well (see graph).

If you have all the fancy DAQ stuff, as Kevin says all the THs have (they're as cunning as sewer rats! :)), then you might try plotting the data as a V-T graph, as above. Just keep trying to push the initial part of the curve leftward.

Personally, I reckon a day spent practicing launches would be great fun... :)

Z

Big Bird

08-05-2014, 03:05 AM

Aah, joy oh joy. Some intelligent conversation, and some engagement with Z rather than just ridicule. Nice work on the diagrams too, Z.

Was just signing in to say that you don't need to have a CofG at 16" above the ground for all events - but I see Z has addressed that. No mind.

Part of me is wondering how many teams sweat over the Presentation Event as much as they do over Acceleration???

Cheers all,

Geoff

Kevin Hayward

08-05-2014, 05:03 AM

Geoff,

I'm not sure any of this discussion is implying the accel event is more important than others, just an interesting discussion of the dynamics of launch. Given that just about everything here can be done without sacrificing points anywhere else I say it is valid.

Keep your presentation plugging for the people wearing pocket protectors :)

Right now we are talking about ETs on the 3/64 mile.

Maybe we should take it to another topic, and start another one on the 55m oval :)

Kev

Big Bird

08-05-2014, 06:29 AM

Yo Kev,

The thread is actually about the 2015 rules ;) My comment was just drawing attention to the fact that there are some things that we are very keen on arguing (dynamic events) and some that we sort of forget about.

Anyways, I'm actually really interested in the dynamics of launch, this is turning out to be a damn good thread. Aside from my feeble interjections, of course!

Oh, and if you are putting down Presentation Event presenters - I did it like 6 times for RMIT...

As you were...

DMuusers

08-05-2014, 06:42 AM

At the design review held at FSG the past week, Pat Clarke and Owen Carless confirmed some of the 'rumors' about the new rules for 2015. I'll sum up from what I heard, but in details I might be wrong.

Aero rules:
The rules for the aerodynamic devices such as wings and diffusers will be tightened again. According to the 2 chief judges, a few years ago the aero rules were loosened so that more teams would venture into aerodynamics. This was done because the rules commitee was of the opinion that too little research into aerodynamics was done. They now feel that the time is there to tighten the rules again and make it a bit harder to create a beneficial aero setup. In what shape or form these rules are was not discussed.

4WD electric rules:
There will be a drop in power for 4WD electric cars. How much was not specified and is not known yet.

Design Scoresheet rules:
Pat Clarke and Owen Carless made the 'announcement' that FSG (maybe FSAE? not sure) was looking into evolving the design scoresheet to better reflect current rules and regulations, especially considering the electric vehicles.

I'm only paraphrasing here, so I might have one or two exact details wrong. It would be nice if either Pat Clarke or Owen Carless would comment on this :)

mech5496

08-05-2014, 07:11 AM

THs (on the contrary of common belief) have also benn using internet a lot these days, so lots of info is available if you look into the right places.

...Now a forward Fx force at the rear-axles pushes the car's CG upward (through the up-to-front sloping n-lines), and by action-reaction, the rear-tyres get forced down onto the road. So more than 100% of car weight is possible on the rear-tyres.

But this increase is only brief, because it only lasts while the car's CG is accelerating upward. So best to start with the CG quite low, so that the pro-lift can last for as long as possible. And you have to find the right balance. Too much pro-lift and you get a nanosecond of great launch, but then the car jumps TOO high, grip is lost, wheels spin..., slow ET. Not enough "wheelie" or "pro-lift" = slow launch, and Team Toothless is laughing at you (although you have beaten most other FSAE teams).

Pro-lift forcing an "action/reaction" increase of Fz is a highly dynamic matter because of rotational dynamics (car wants to "pop a wheelie" and has a significant rotational inertia around that axis that works FOR you). Moreover, THs usually opt for 100% anti-dive (or close to that value), because exceeding it by far (having too much pro-lift) might plant the tires very hard in the first few milliseconts but eventually the nose gets back down and tires begin to slip, especially in very powerful drag cars. This is much dependant on track conditions, whether is slippery or not, and available power, so most drag cars are highly adjustable in terms of anti-lift. Moreover, in the matter of nose lift and coming down, front springs and especially dampers play a significant role as well. I would suggest to anyone interested to search the web for a Mr. called Bill Shope...

Kevin Hayward

08-05-2014, 07:12 AM

Oh, and if you are putting down Presentation Event presenters - I did it like 6 times for RMIT...

As you were...

I guess you had to do something if you couldn't fit in the car!

Then again the RMIT guys probably wheeled you into the presentation with you halfway into a rant, then wheeled you out when you were a little bit past halfway through a rant. The judges would have been both astonished and bewildered. Must have been worth a few points.

If we are on the marketing presentation, how would you propose that you maximise the early launch phase of powerpoint to ensure you finish with the most number of words conducted during the event? And does the ridiculously high centre of gravity you possess enable you to exceed over 100% weighty words per sentence?

Kev

Big Bird

08-05-2014, 08:09 AM

What do you mean I couldn't fit in the car? I did skid pad and presentation in 2003. Unfortunately I got the two confused. For my presentation I found myself talking in circles a couple of times, so I turned it around and went in a different direction. I then went off course, meandered around in circles a couple more times, to find that I had actually gone nowhere and I was exactly back where I started. It was all over in just over twenty seconds.

My fastest skid pad time was ten minutes, which was followed by three minutes of questions.

As for launching the presentation, I never found squatting at the back end to be all that helpful. You have to understand, we were running a smaller, lighter presentation than you guys - fewer words, much less weight to them, but less chance of choking when under full power. And I remember our presentation sounded a bit flatter than yours too - but then a single presenter always sounds flatter than four inline...

MCoach

08-05-2014, 06:59 PM

"If the [16" high] CG is causing such massive weight transfer front-to-back, wouldn't that have a dramatic effect on cornering performance as well?"

NO, no, no. Not if you SET-UP the car to suit the different Events.

So for SP, AutoX, and Enduro I would definitely set-up the car with LOWEST POSSIBLE CG, and whatever else is required for good performance there.

But for Acceleration (remember = 75 points!) you could set-up the car with 4" of ground clearance. The Rules say you must have AT LEAST +/-1"of suspension travel, so 1" bump and 5" droop should be OK. (I don't have Rules here just now, but IIRC "shims, spacers..." and other adjustments are allowed.) So getting a 12" CGH up to 16", JUST FOR Acceleration, should not be hard. And not really necessary... (see below).

Or, easier, you can have a special "booster seat" for the driver that has a very thick squab. Given that most seat-backs slope backwards at about 45 degrees, I reckon you could easily move the driver up 4" and back 4". But check Rules on this...

More importantly, with CGH = 12" (0.3 m) and 60%R on a 60" WB (ie. ~0.6 m + 0.9 m = ~1.5 m) means 2 G gives you 100% on the rear. With same CGH, 2.5 G has you "popping a wheelie". However, you become power-limited a bit after 2 metres (see graph), so the Gs drop off and the nose comes down. Also any front-wing aero should start to act by this stage, pushing the nose back down.

So aim for as-low-as-possible CG for "normal running", and with 60%R you only have to bump it up to 0.25 m to 0.3 m for the Acceleration event.
~o0o~

Z

T1.2.3 The vehicle must maintain all required specifications, e.g. ride height, suspension travel, braking
capacity (pad material/composition), sound level and wing location throughout the competition.

Someone's already thought of the super adjustable ride height. Sorry to burst your bubble.
I'm intrigued at the rest of the post though. Thanks.

Big Bird

08-05-2014, 08:10 PM

Fair call MCoach. It is a long time since I've read the rules from front to back. You guys are much closer to the coalface than I these days.

However, my next step if I was confronted with such a rule /constraint would be to seek out definitions, and see if there is room for movement. Ride height must not change - so what is ride height? The distance between the lowest point on the main body and the ground? is it the whole floor plan of the car? Can we design a mechanism that leaves the lowest part of the floor at "ride height" level, and the rest of the car lifts upwards? Maybe an engine/drivetrain tray that can be adjusted up and down for different events.

What does "all required specifications" mean - has anyone asked that question?

The point is that there could be a whole range of interesting and alternative solutions floating around in the margins of our interpretations of the rules. I would point to the recent UWA cars which have a very interesting interpretation of "Suspension". Engineers are very adept at finding reasons to not be different. If the mindset changes from "that's not possible" to "lets see if it is", then things can become very very interesting.

Alumni

08-05-2014, 08:12 PM

T1.2.3 The vehicle must maintain all required specifications, e.g. ride height, suspension travel, braking
capacity (pad material/composition), sound level and wing location throughout the competition.

Someone's already thought of the super adjustable ride height. Sorry to burst your bubble.
I'm intrigued at the rest of the post though. Thanks.

The only real required specification in the rule regarding Ride Height, CoG etc. is passing the tilt table.

I think the more interesting question would be how many teams actually change anything on their car during competition, and why they don't.

I see very few changes being made in between events. The top teams tweak a bit, the middle teams catch up on sleep, and the back-markers are still gluing together bits of carbon. I'd be very curious to see how extending the time for dynamic events would change this, as I know we were always caught between changing set-ups and prepping the car for endurance with our four-ish man team. Also not having dynamics a 30 minute walk from the paddock (at least at MIS and Fontana) would help.

Alumni

08-05-2014, 08:19 PM

P.S. I'm finding it increasingly amusing that the experienced alumni, has-beens, and old guys around here tend to agree more with Z than the still egotistically fragile young budding engineers he's trying to help.

"How dare you insult our theoretically perfect car! Last year GFR won with this same design so it will certainly work for us too!"

Having been there myself, I hope some listen. I wish I had.

murpia

08-06-2014, 05:53 AM

At one point in FSUK, changing car setup between dynamic events was encouraged. That contradicts the 'T1.2.3 The vehicle must maintain all required specifications, e.g. ride height, suspension travel' statement.

Is this a rule inconsistency, or does FSUK cover it in the event rules not the FSAE tech rules?

Regards, Ian

Dunk Mckay

08-06-2014, 06:53 AM

Does that rule not simply mean that it must continue to meet all the rule requirements? In the case of setup surely maintaining the minimum +/- 1" of travel is all that's required, otherwise anything that's adjustable, and passed scrutineering as such can be adjusted. No?

JulianH

08-06-2014, 06:55 AM

Dunk is correct.

The rule does not prevent you from changing the ride height (would be horrible in Germany...) or something else. As long as you don't touch the ground and don't lock your suspension, you can do what ever you want with it.

Alumni

08-06-2014, 07:26 AM

There was not only a single but now multiple people who thought that changing your car set-up during competition was illegal?

My mind has officially been blown for the day.

Dylan Edmiston

08-06-2014, 08:17 AM

The best thing to do would be to have pull/push rods for accel in order to bump up your CG. However, I do not think a part swap would be allowed without going back through tech. So the limitation we have on RH adjustment relates to the length of threads on the rod ends. A funny thing to note about this is that we are adjusting CG, a key thing with tilt testing. So it's possible that a team could make this adjustment and no longer pass tilt.

BeunMan

08-06-2014, 10:20 AM

There was not only a single but now multiple people who thought that changing your car set-up during competition was illegal?

My mind has officially been blown for the day.

Good skidpad times are not quite possible without changing your setup after acceleration. Or try doing the acceleration with your skidpad setup and vice-versa and end high. (Yes I know Delft did it at fsuk this year... exceptions/rule).

Dylan, no a part swap would be 'illegal', that would require a rescrutineering and dsq for the previous dynamic events if I'm correct. otherwise you could rescrutineer haf your car after the accel/skidpad events. As long as the part isn't the same as the one which was scrutineerded.

You can obviously replace a broken part with a part with the same functionality.

But I'm diverting from the original theme of this topic: New rules. Lets wait untill 23rd? of August. Untill then just assume most of what has been said and keep your options open.

BeunMan

08-06-2014, 12:48 PM

Or today:
http://www.sae.org/servlets/cdsNews?OBJECT_TYPE=PressReleases&PAGE=showCDSNews&EVENT=FORMULA&RELEASE_ID=2638

JulianH

08-06-2014, 01:03 PM

I think the rules are a bit too much.

Yes, Aero will still work, but for smaller teams, it will not justify spending time on it. I think the rule makers will get the exact opposite of what they wanted. Instead of "everybody has fairly good working big wings" (Delta between an awesome Monash/GFR/Munich package compared to a "quick and dirty" one is surprisingly small), it will happen that the good big teams will run with efficient, working wings and the smaller teams without them. Bigger delta in my humble opinion...

Looking forward to see the results, I know that the CAD workstations are running already... :)

theTTshark

08-06-2014, 02:02 PM

Trevor

08-06-2014, 02:31 PM

As we have continued to say in our feedback and in the surveys, this increased complexity in the rules benefits the teams with bigger resources and disadvantages smaller teams. I agree with what others have said that this will have the opposite effect of what the rules committee wants, which I would expect is a more even field. History has continuously shown (there are many examples) that tighter limits on the rules benefit bigger teams disproportionately because they have the resources to chase smaller gains in many areas, where smaller teams won't be able to "waste" resources to the same level.

I can confirm the CAD iterations are already running, watch out for 2015!

Dylan Edmiston

08-06-2014, 03:10 PM

Dylan, no a part swap would be 'illegal',
Yes. Just as I said.

If we could do it, it'd be the best thing to do (for desired setup change). I was pointing out the limitation.

Big Bird

08-06-2014, 03:26 PM

So there is no other way to lengthen a pushrod other than the rod ends at either end? Presuming you wanted more extension - you can't design something that could extend further??

Dylan Edmiston

08-06-2014, 03:37 PM

So there is no other way to lengthen a pushrod other than the rod ends at either end? Presuming you wanted more extension - you can't design something that could extend further??

One simple thing to do is add an extra linkage in between to extend threads further out/in. Or an extra point on a bell crank.

Now, a suggestion for this topic, we should create a new thread for this because have derailed from the original topic.

Kevin Hayward

08-06-2014, 06:21 PM

UWA already did it with one of their cars (2006 I think). The pushrods had normal adjustability and a 2 position large adjustment as well. Not difficult to implement.

Kev

Kevin Hayward

08-06-2014, 06:44 PM

Wow on the aero changes. A massive change that will almost certainly see a lot fewer teams designing aerodynamic packages. On first glance it looks like a package designed to the new rules may have worse performance than a package designed to the rules prior to the last big change.

I also wonder how many teams will bother to look at DRS now. The narrow, low rear wing will have a lot less drag.

Unsprung mounting for the front wing almost looks like a necessity now. Springs will likely have to soften to gain some mechanical grip back, which will likely require a higher front wing (if sprung mounted).

Trevor is spot on. These rules will widen the performance gap between the haves and have nots, and fewer teams doing aero work overall.

The other sad thing is that Aero helped to encourage weight reduction. With aero the important number is how much downforce divided by car weight for your grip multiplier. Without that weight isn't as big an influence. What you lose on a tyres sensitivity to vertical load, you gain some back on increased temperature. In the past the lighter cars had almost no grip advantage compared to the heavier ones.

Oh well it was fun while it lasted.

Kev

Dylan Edmiston

08-06-2014, 09:14 PM

I think the aero rules will widen the performance gap for the teams that aren't doing things right (or as well) in the first place. But it is not impossible to have a high performing car with no wings (UF finishing 9th and Auburn 7th with a 1.7pt gap, Univ Mich in 8th). In the case here, we may see a few of the top non aero cars improve relative to the rest of the competition. Rather, the rest of the competition may see a drawback with lessaero. To me it seems like too many teams were adding wings just to be fast and "competitive" and not understanding the fundamentals of aerodynamics.

A lot of people argue that teams with little resources will be hindered because of this. But has it not always been that way? Some teams have had excellent engine development programs, partially due to the resources they have available, and therefore have succeeded because of that. So to level the playing field should we restrict dyno usage to make the less competitive teams more competitive compared to the better teams? I wouldn't say so. This is a design competition. What everyone should get out of this program, more than anything else, is knowledge. Even if someone is designing wings and they are not able to design wings effective enough to be used with the new rules, they will still be walking out with good experience and research for future members to work off of. The new rules also require more creative thinking and hopefully we see some interesting designs.

Kevin Hayward

08-06-2014, 10:17 PM

Dylan,

I don't think that there is ever a case of "just" being able to add wings. Even if your aero justification is poor you still need to figure out how to make them, mount them, allocate appropriate resources etc.

The argument is not that changing aero rules will disadvantage lower resourced teams. The argument is that restrictive rules favour top teams. This would be true in every area. If you turned around and banned interconnected suspension, beams, CVT's (or put heaps of restrictions to make them much more difficult to implement) you are reducing the areas that a lower resourced, but innovative teams can find an advantage.

If there is only one clear concept to build to the whole competition becomes solely about resources and their management. Everyone is building the same thing. When you have a very open rule set even the super highly funded teams will not be able to try all of the concepts. This has been shown over and over again in professional competition.

Also sorry to be an arse but finishing 9th is not high performance. The delta in each of the events to a highly resourced and big aero team (GFR) was:

-3.7 pts Accel
-20 pts Skidpad
-49 pts Autocross
-73 pts Endurance
- 16.5 pts Efficiency

~162 dynamic points deficit.

smaller, but still large deficits to other top aero teams.

Sure the best non-aero cars can beat lower performing aero cars, but you would have to make a very good case for making the statement that the best non-aero cars can compete on a level playing field with the best aero cars. You mention teams not knowing fundamental and implementing wings just for speed, but if your team had made the right decisions you would also be running wings, and be closer in performance to the better teams. I'm not writing this as an attack. But if your points calcs say that you should be running wings, and you don't run wings, then you are making a bad engineering decision. To criticise teams that implement wings on this basis, but do so without full knowledge is a practice in hypocrisy.

Kev

Dylan Edmiston

08-06-2014, 11:09 PM

Also sorry to be an arse but finishing 9th is not high performance. The delta in each of the events to a highly resourced and big aero team (GFR) was:

-3.7 pts Accel
-20 pts Skidpad
-49 pts Autocross
-73 pts Endurance
- 16.5 pts Efficiency

~162 dynamic points deficit.

smaller, but still large deficits to other top aero teams.

Sure the best non-aero cars can beat lower performing aero cars, but you would have to make a very good case for making the statement that the best non-aero cars can compete on a level playing field with the best aero cars. You mention teams not knowing fundamental and implementing wings just for speed, but if your team had made the right decisions you would also be running wings, and be closer in performance to the better teams. I'm not writing this as an attack. But if your points calcs say that you should be running wings, and you don't run wings, then you are making a bad engineering decision. To criticise teams that implement wings on this basis, but do so without full knowledge is a practice in hypocrisy.

Kev

So I guess here is where we define what a high performing car is. If you look at the rest of the top ten teams, where would you make the cut off for a "high performing" car? There is definitely a large gap between my team and GFR (as well as some of the other top teams) and I will never deny that. And saying "beat lower performing aero cars" is somewhat degrading when you look at a top 10 finish (as well as top 10 in Endurance). I also want to be clear that I never said the best non-aero car will be able to compete at the same level as the best aero car. From what I have seen in the competition in the past few years, aero is definitely the way to go for higher performance on the track and my team won't deny that.

Now why are we not running aero? Because of resources! We could come up with a simple airfoil geometry, make the molds, and get wings on without good understanding of the actual profile and aero effects, but where's the fun in that (aside from driving a car with big wings)? Sure we may have seen dynamic performance benefits, but what would you call a worse engineering decision, putting wings on without good understanding of their effects (aero balance, suspension loading, profile design, etc...) in order to, hopefully, increase dynamic performance or having that as a side project for development in future until the team can learn these fundamental effects from the system? And yes, calculating things like the extra loading from aero isn't too difficult, but it also extends into more areas such as rotor design to ensure we won't see failures from the extra forces.

Kevin Hayward

08-07-2014, 12:13 AM

Dylan,

I don't mean to degrade anyone's attempts. I don't think that a team needs to be the best team in the world to achieve good learning outcomes and do a good job. To put a definition on it I would say high performance would mean:

"The car and team are in the running to win the competition. This might be by purely beating everyone, or being good enough that they could take a win if a couple of better teams fail to finish endurance."

I don't like basing a definition on finishing place at all, but the idea of being in the hunt gives some credence to the idea that amongst the higher performing teams there is some trade-off between reliability and performance. It might be better to talk about targets, ie. a concept / team that is capable of scoring within 20-40 points of the best assuming:

4.8 skidpad
4s accel (or whatever history shows as the ideal accel time for IC - obviously contentious here.
some delta to best laptime (maybe this is best done with lapsims and search algorithms, rather than off data)
3L 98 fuel equivalent used (or similar target).
Finish all dynamic heats

We are trying to look at the top 1-2%. Probably works out to be whatever the top 3 does in any given comp. The top 10 includes about 30% of the finishers in a given event. Not even the top quartile. If reliability is evenly distributed amongst the teams (which it is not) that would mean had everyone finished in a 100 cars the 10th place finisher would have finished 33rd. In the case of the comp you mentioned 9 teams that finished below UF had an equal or better autocross score, 13 had a better skidpad score, 18 had a better acceleration score. Prior to the endurance UF was in 18th place dynamically. The top two overall were still the top two, in fact the top 4 overall were in the top 5 dynamically before endurance and pretty much in the same order. Their finishing place was not really determined by anyone else dropping the ball. Too many teams running in the midpack of finishers underestimate how far ahead the high performance teams actually are. This is not a particular attack on UF, or anyone else in a similar position.

In engineering design it is very clear that mistakes in conceptual design are much worse than mistakes in the detail. So yes waiting on implementation to understand the fundamentals, when you are aware of the definite performance benefit that is able to be implemented is the worse engineering decision. Any other statement would go against research and general understanding of the engineering design process.

It is a scientist who waits, the engineer acts.

As for the practical implementation molds aren't required, wings can have fibreglass or aluminium skins. The only reasonable resource limitation is manpower. I am familiar with the UF cars. Beautiful bodywork, and I love the Gulf colour scheme. If you can do that, you can do wings (maybe at the expense of less time on the beautiful bodywork). The understanding (aero balance, suspension loading, profiles) required for initial implementation can be found very easily. McBeath's competition car aero goes through a lot of the good basics with some reasonable numbers, combine that with some Benzing profiles (available on the net), and read the monash papers. You can design and build a pretty good package quite quickly.

The first ECU aero package was designed an built by a couple of first year students in about 6 months and improved laptimes by about 2 seconds over a 60s lap. Later, better built, lighter, more efficient designs followed. This process is improved becuase you have actual data and testing of the more agricultural versions. Needless to say none of the detailled improvements even come close to the initial advantage of having them vs not having them.

I know you probably think this is another response from a guy being a jerk rather than someone trying to point out objective engineering ideas. Sorry for that.

Kev

Dunk Mckay

08-07-2014, 06:42 AM

I have to step in and disagree with the idea that these restrictive aero rules favour the teams with more resources. If there is less potential down-force to be had from aero, then throwing massive resources at it will only gain you 5% now not 20% (not actual values). Teams that weren't running aero before, or were running crap aero (and now won't bother) will able to waste less time designing/debating aero and get on with the rest of their. Ultimately their performance will remain more or less the same and the teams that get huge benefits will now be going slower.

Case and point, because I like my old team: Brunel finished 11th overall at FSUK, I think that's 7th Combustion team, so I'm gonna say they'd have been top 10 if they'd been at Germany this year. The teams biggest drawbacks, as they have always been is budget (mnot tiny, but definitely limited), experience (30-odd brand new team members each year, 5-6 team managers that were new team members the previous year, no useful staff involvement to help carry over knowledge), AND manpower during the build phase (no accomodation provided over summer, so rarely more than 5 or 6 people actually end up working on the car at any one time, often less).
I won't go into all the reasons why, but essentially they end up scraping a car together less that 2 weeks before competition (sometimes much less) and don't really bother preparing statics because they don't have the time. Poor management (due to lack of instruction how to) plays a part.
So top 10 combustion is a pretty good result all things considered. If the team get their act together and start prepping for statics properly and maybe get a car built early enough to improve on the dynamics, then they would glide into the top 5 I should hope. Challenging for the top spot is perhaps a bit of a push, but for a car without aero that's pretty good.

We have been working on aero lately, but didn't get enough testing or data to run at FSUK. They may run it at FSCzech, but ultimately this year's package was about data gathering. Whether or not this data combined with the new aero rules means that they go ahead with a full aero package next year or not, I don't know, we'll see. But if they have the potential to challenge for top 5 wihout aero, then so do 3/4 of the teams out there, and that's with the current rules!

Westly

08-07-2014, 08:00 AM

What frustrates me regarding these rules is there is little transparency as to why the rules were changed and why aerodynamics been targeted. Especially when there are other more serious safety issues present. There are only anecdotal reasons I have seen given for these changes, from the survey and FSAE Forum:

• It is often commented by judges, officials and others that have been involved in the various competitions for many years “wouldn’t it be great to change the rules to offer the students a new challenge”.
• A few of the better funded teams have done well with large wings that attempt to fully exploit the aero regulations, but it has been noted that many teams have followed down this path because other teams have been successful rather than because they understand how the benefits will be achieved.
• It is likely that the aero regulations will need to change in 2015 as there are concerns that the wings are too large, several wings have detached from cars causing concern about the safety of marshals and some of the cars have become unstable such that in several cases they have almost rolled over.”
• This was done because the rules committee was of the opinion that too little research into aerodynamics was done. They now feel that the time is there to tighten the rules again and make it a bit harder to create a beneficial aero setup.

1, The students don’t need greater challenges, the finish rate for fsuk and Michigan enduro was 24% and 32% respectivel.) So increasing the challenges is not relevant to most team. Why is this massive lack or reliability not being addressed?! 2. If teams are copying other designs this should be assessed in the design event and other areas can be just as easily copied as well 3. This seems like a knee-jerk reaction: Plenty of cars at fsuk and fsg caught fire or had carbon suspension which were arguably of greater risk, yet no-one even mentioned these occurrences. (I find it amazing that the area of failure, cause and effect is not recorded at competitions, so statistics on these can be gather to guide rules and safety in the future) 4. And the last one, basically they're offended by the size of the current wings… ?

There was an attempt to gain feedback from the FSAE community with the survey. Which now appears unlikely that the results will ever be published, I am unsure if they were even considered? (Why did I bother spending the time to reply!) What happened to this?

A1.1.1 of the rules state, the rules are to: “give teams the maximum design flexibility and the freedom to express their creativity and imaginations there are very few restrictions on the overall vehicle design…. The competitions themselves give teams the change to demonstrate and prove both their creativity and their engineering skills in comparison to teams from other universities around the world”. Yet the design flexibility is being taken away for little reason. They also restrict the ability of teams around the world to compete, as many Australian Teams would need to re-design half built vehicles to be rules legal for 2015. Further, teams can and will fit wings which fit within the boxes given, and it will reduce some of the questions raised by the compromise between cg height and rear wing height/size, reducing the potential to learn from these situations.

In my opinion the further the rules are restricted and have large changes implemented this leads to greater uncertainty,further increasing the gap between the big and small teams as they have the ability to better react to changes, this decreases safety as smaller teams alter designs to suit changes with limited time to consider all consequences, reduces the ability of teams to compete internationally, reduces teams ability to implement any sort of multi-year planning and reduces the range of concepts and approaches available to teams.

Westly

Edit: Dunk, I agree you don't need Aero to place well. FSUK showed that reliability and preparation are king. (14th place was the 500pt cross over and 350 points separated those teams. eek!). With roughly 30 points separating each team, alot of technical improvement is required to make that gap up, ~35kgs of weight reduction, or significant Aero improvements based on our lap simulations. Aero was a good place for teams to actually gain significant performance benefits from technical design when your in the top couple of placings at competition. But the deciding factor to doing well was preparation and reliability in the end, so sounds as though Brunel was lucky more than anything if they finished 2 weeks before comp, and with little testing finished endurance.

Good teams are good, not because of their aero but because of their management, which is why I didn't believe the Aero rules needed to change. Aero was just another feather in their cap, but isn't worth 100s of points like some people believe.
Driver Training, Reliability, Preparation and statics are now even more important with these rules, with Technical Performance Potential between different concepts becoming even closer.

Sorry for writing an essay.

Thijs

08-07-2014, 08:12 AM

Dunk,

I'm going to echo Kevin by saying this, and like him I don't mean to sound degrading.
However, as close to the top as an 11th overall spot might sound, Brunel were over 260 points behind fifth place.
It seems to me to be a bit of a stretch to suggest that that difference (almost a 50% points increase for Brunel) can be overcome by driving a bit earlier and better statics preparation.
Unfortunately the scores of the teams just outside the 'top' drop off very quickly.

Thijs

Luniz

08-07-2014, 08:20 AM

Westly

08-07-2014, 08:33 AM

Double post / sorry

BeunMan

08-07-2014, 10:06 AM

The 'gap' has been there for a while. We did 4 seconds a lap faster than almost everyone else at FSG in 2010 without any aero (Michigan was ~50 sec slower in total on endurance, so > 2 seconds a lap average).

About finishing rates:

FSE 8/40 endurance (20%)
FSC 32/72 endurance (44%) if i counted correctly.

So the average is about near the 30-35% mark which is low.

JulianH

08-07-2014, 10:42 AM

Tristan, to be fair, the number of aero teams back in 2010 was really limited...

I think Aero is a nice gadget to make cars a bit faster. Not a game changer. Lutz is right there.

But, the question is, why we need such "F1-like" restrictions especially on this kind of new area of FSAE. It only lasted about 3 seasons with a large number of teams running them.

I like the 1,2m maximum height rule to prevent some teams going really insane and the "the mounting must be rigid" rule. But the rest is unnecessary.

Still, the rules are the same for everybody and it will be interesting to see the new cars. Sadly they will be a bit ugly :)

DMuusers

08-07-2014, 10:54 AM

I think, with the turbo rules and the larger restrictor, the laptimes of the best combustion teams will only decrease even though wings/diffusers/etc. are limited in design space. I'm quietly confident that some teams (GFR, Monash, Zurich (although they're not combustion), Stuttgart, etc.) will find new inventive ways to reach the same downforce/drag numbers that they are currently running. However, for the most teams, a beneficial aerodynamic setup will become harder. I guess that was the point of these rules, make teams think again before they design something.

As far as game changers, I guess over the entire formula student history very little have occurred. Hopefully these rules will force someone (from teams big or small) to create a new game changer. It's going to be a challenge, and that's fun.

JasperC

08-07-2014, 11:23 AM

Good teams are good, not because of their aero but because of their management, which is why I didn't believe the Aero rules needed to change. Aero was just another feather in their cap, but isn't worth 100s of points like some people believe.
Driver Training, Reliability, Preparation and statics are now even more important with these rules, with Technical Performance Potential between different concepts becoming even closer. With the aforementioned now in my mind worth more than technical development, now even more-so.

I agree that good teams are good because of their management and not because of an aero package. But I think in FSAE it is healthy for different concepts to be similar in performance. With the current aero rules, the decision to run an aero package is a no-brainer (if you have some resources for it). Reducing the difference between aero cars and non-aero cars leaves the option to be competitive regardless of your choice of concept - just like is has been with 4-cyl versus single, petrol vs E85, steel frame vs carbon monocoque. In all cases one choice is probably slightly better than the other, but the quality of execution of your chosen concept is way way more important.

To me that is why FSAE is a beautiful engineering challenge. To be completely on top, you'll have to make a good conceptual choice (which takes a lot of time so requires resources). But a quick 'pen-and-paper' conceptual choice will take you a very long way if you succeed at understanding your own concept and executing it well. For a competition aimed at learning, this is great because students will arrive at the competition and ask themselves why another car is performing at the same level as their own despite looking completely different.

I will be very happy if you can look at the FSG endurance final and see aero and non-aero cars, monocoques and spaceframes, 4-cyl and single, turbo and atmospheric competing with each other (and that's only looking at combustion cars).

Kevin Hayward

08-07-2014, 06:34 PM

I think reduction in aero performance is a good idea, just probably not at the level done here. Having complicated wording and plenty of loopholes is not. The overall height is fine and a sensible value was chosen, as is the requirement to have mounting of a certain strength. I wonder if scrutineers will be applying 200N to the corners of endplates? Load application points (or zones) should be defined. With different scrutineers at different comps we don't want any inspection methods subject to a given view on the day. Teams need to be able to inspect their own cars before the comp and have a good understanding that it is compliant.

Performance could easily be changed (and adjusted) through a few simple measurements:

- Overall height
- Rear overhang
- Front Overhang
- Overall width (or relative to the wheels)

Three of these could have been changed by changing a number (or slight re-wording) already in the rules, the overall height would be added.

Now we have two different widths, a height limit for part of the front, no limit on height for the other part of the front wing, one for the rear, different limits for vertical surfaces with no definition as to how many degrees off perpendicular to the ground is considered vertical. As well as a rule that requires subjective analysis (i.e. "sturdy enough").

Once again the rule changes have come very late for the 2015 season. Australian teams are already most of the way through the build of cars designed for 2015 overseas are pretty much stuffed if designed around aero. International rules (i.e. all of them) should be released at least 18months before the first comp to use them, or allow a grandfathering clause. It causes a lot less distress to teams when they have plenty of time to digest the fact that they may have to radically change their car concept. Like in F1 when the turbos recently returned there will be plenty of moaning but they have no basis for saying they weren't well warned.

I would love to see results of the survey. As much as it was likely a flawed feedback mechanism, it was a good start to engaging the end clients (students) with the product development (FSAE).

Kev

Big Bird

08-07-2014, 07:44 PM

MCoach

08-07-2014, 10:31 PM

Geoff, I hope this isn't too blue to not be the considered the fruit box...
It's not quite as basic as an air cooled single carb, but it started life as a watercooled, single carb.
We kept everything pretty basic, focused on getting a solid platform and getting it all together.

https://www.facebook.com/KetteringFSAE/photos/pb.209138079117577.-2207520000.1407467469./796102420421137/?type=3&theater

If it's not made of steel, it's aluminum, there is not a drop of composite materials on this car. The bodywork is aluminum, the wheels are off of an ATV as well as the diff and radiator and it was the 2nd cheapest car at the Lincoln competition (only 0.07 points behind first).
There isn't much to the driver controls other than a start and kill button and no driver clutch. We put a steering wheel in front of the driver and we ride it out by feel. The entire car is basically built from purchases out of the Summit (Drag) Racing and McMaster-Carr industrial supply catalogs. Parts that required special fabrication were pretty minimal. Even the rear uprights were fabbed from a single 2' x 2' sheet of steel (for both!). Brake rotors were manufactured in one total operation, pretty down and dirty there, no machining.

https://www.facebook.com/KetteringFSAE/photos/pb.209138079117577.-2207520000.1407467955./768258669872179/?type=3&theater

I learned it was a lot harder to fab 0.030" sheet for an entire part than typical tube parts.
We had some engine related problems at Michigan, regrouped, and returned to Lincoln for another top 10 finish.
I'm ready to see some endurance laps...

08-07-2014, 11:30 PM

Wow..., I mow the lawn and ... 3 pages of new posts... So,

Minor, Slightly Off-Topic Post.
==========================

T1.2.3 The vehicle must maintain all required specifications, e.g. ride height, suspension travel...
...
Someone's already thought of the super adjustable ride height. Sorry to burst your bubble.

This strikes me as another one of those "Oh, its just TOOO HARD to go faster. There must be a Rule against it..."

1. As noted earlier, with 60%R you can have a CGH about 25 - 30 cm for good Acceleration. If you manage to get CGH down to 20 cm (8"), then congratulations, and 66%R will work well.

2. If "ride height" is never allowed to be changed, then why does (almost) EVERYONE have adjustable ride-height?

3. From memory, the "required specification" for ride-height has oscillated over the years between "minimum 1 inch measured ground clearance", and "no visible scraping". The "no scraping" Rule is most likely why some Teams fitted 1"+ adjustable ride-height, so low on smooth tracks, but higher on bumpy tracks to stop scraping.

4. Easiest way to make big ride-height changes is with direct-acting SDs, with multiple mounting holes on the chassis for the SD.

5. But better than above is "dynamic" ride-height change via adjustable "anti-squat/pro-lift". This simply requires multiple holes for the forward wishbone-to-chassis mounts. Perfectly legal, IMO.

So, once again: Best "launch" comes from lowish static-CG, then just the right amount of pro-lift for the first few metres.

Z

Westly

08-07-2014, 11:38 PM

Some nice posts here (good one Wes). I’m typing one-fingered today, so my inputs will be short.
- It is not up to the organizers to address reliability
- The teams choose their own destiny
- Think ambitions vs capability….
- Why do rule changes need reasons??
- Agreed more lead time would be nice, for the sake of international entries
- On the other hand, a robust design concept and delivery strategy should be competitive irrespective of a few specification changes
- I’d personally like to see more discussion here quantifying the execution side of things. Most teams are uncompetitive by a margin far greater than their concept’s potential
- I’d still love to see a well-managed team enter a “brown fruit box”. A concept car driven by underspecification and average materials. Underpowered aircooled single with a carb. Wooden chassis? Golf car F&R suspension. Average specs but built to sound engineering principles and delivered well. For comparative purposes of courses. At the end of the weekend, any team that finishes behind the fruit box runs a lap of the endurance track with their pants around their ankles…

Hi Geoff,

I dont believe that it is the organisers responsibility to address reliability, nor should rules be changed to address this, but they can encourage it through design feedback. The australian comp was quite harshly critised by overseas judges in 2012 with all the cars too heavy and out of touch with the leaders in europe amongst\other issues. And this seems to be a common theme from what I have seen, that officials much more greatly encourage optimisation, vehicle lightness and other additional features, rather than simplicity and reliability. If questions were raised by judges/officials, not nessecarily in scored events, not on how much weight they managed to reduce their components by, but what features/systems they have implimented to improve reliabiltiy this would encourage this trend.

Interesting to note: The top 5 in Design at 2014 FSG didnt finish endurance, 1 of the Top 5 in Design at Michigan finished enduro (GFR, 4th) and ETS has won design twice this year (Michigan and North), but failed to compete either competitions endurance.

I know this only addresses a portion of what you are trying to convey, but I need to get back to work!

08-07-2014, 11:40 PM

MAJOR, ON-TOPIC, RANT!
======================

This is probably a complete waste of time, because all of the very REASONABLE issues below have been extensively covered before, but are clearly being IGNORED by the Rules Committee.

1. Why are FSAE Officials so keen to tell the students that "FSAE is NOT Mini-F1!", while simultaneously being so determined to TURN FSAE INTO MINI-F1!?
Blind-Freddy can see that these aero-changes take their inspiration directly from F1. (This has been noted by quite a few other posters here).
Very HYPOCRITICAL, and very UN-IMAGINATIVE!

2. Why do the changes have far more blue ink than red (ie. more added words, than subtracted)? Again, clearly part of the on-going trend to turn FSAE into a spec-series, JUST LIKE F1.
So, for example, how long before the students' choice to select their preferred weight-distribution is subverted by some dim-witted Official's brainless opinion as to what "looks" good. Just like in F1, where F:R tyres sizes are very tightly controlled, purely because of one dim-wit's "aesthetic" tastes!

3. Why, despite suggestions going back at least to 2005, are there STILL NO DEFINITIONS of what exactly constitute these tightly controlled "Aerodynamic Devices"???
What is poor young Hu Mi, the Aero-Lead from Team Outer Mongolia, to make of these new Rules?
"Ooooo..., what is 'wicker bill'?
I think ... must be like 'duck bill'... Yes, yes..., because all Westerner have very big nose, like duck... So Rule say we must make VERY BIG nose on car, like duck.
Oooo..., or maybe NOT nose... Who knows...????? Oooo, now my head hurt..."
Clearly, the Rules Committee must be dominated by Arts Majors, because Engineers should know how to put together UNAMBIGUOUS documentation packages. Or, at least, they used to... :(

4. Further to above.
Can a "bodywork nose" extend further forward than 700 mm in front of front-tyres?
How will Hu Mi ever know?
Can "bodywork" extend further rearward than 250 mm behind rear-tyres, or aft and outside-of-the-inside of rear-tyres?
Specifically, could the rear-tyres have drag-reducing streamlined wheelpods behind them? If not, then WHY NOT!? (Oh yes, they're not in F1...)

5. "T9.5.1 Minimum Radii ... of forward facing edges ... 5 mm for horizontal edges ... 3 mm for vertical edges ..."
What about forward-facing edges that are NOT purely horizontal or vertical?
Are sloping edges NOT allowed (maybe because they are too 3-D-ish!)?
And its seems that REARWARD-facing edges can be, and are encouraged to be, RAZOR-SHARP!!!!
Does anyone on the RC think these things through?

6. "T9.7.1 Aero Device Stability ... ADEQUATE rigidity ... move EXCESSIVELY..."
Has anyone ever seen an Engineering Specification that is more wishy-washy than above?
How about "... Aero Devices that you just want to give a big hug ..."?
Would a cleverly designed auto-feathering wing be allowed or banned (ie. a wing that automatically reduces its AoA and DF at higher speeds, by TE or flaps flexing downward)?
Is all this ambiguity specifically left in there so that certain unimaginative Officials can arbitrarily ban the more creative Teams, simply because they don't like them?

7. Finally (for now), WHY SO LITTLE "OPENNESS AND TRANSPARENCY" in this whole business?
Oh yes, that would expose all the Official hypocrisy, and fear of C&I...

It is quite obvious that the Officials proposing the above Rules changes have very limited C&I. They clearly have a preconceived (and extremely DULL) notion of what they want all the Teams to build, and that is a Mini-F1 car!

Z

JulianH

08-08-2014, 04:07 AM

Dunk Mckay

08-08-2014, 11:10 AM

I can see the max 25cm height rule as being an attempt to improve reliability through better cooling airflow enforced on the teams, but that's a bit of a weak argument. Especial considering the loopholes in the rules (anyone thinking about combining GFR's front wing with Greenteam's rear flap? I'll say no more for fear of giving it away completely).

Edit: Dunk, I agree you don't need Aero to place well. FSUK showed that reliability and preparation are king. (14th place was the 500pt cross over and 350 points separated those teams. eek!). With roughly 30 points separating each team, alot of technical improvement is required to make that gap up, ~35kgs of weight reduction, or significant Aero improvements based on our lap simulations. Aero was a good place for teams to actually gain significant performance benefits from technical design when your in the top couple of placings at competition. But the deciding factor to doing well was preparation and reliability in the end, so sounds as though Brunel was lucky more than anything if they finished 2 weeks before comp, and with little testing finished endurance.

Good teams are good, not because of their aero but because of their management, which is why I didn't believe the Aero rules needed to change. Aero was just another feather in their cap, but isn't worth 100s of points like some people believe.
Driver Training, Reliability, Preparation and statics are now even more important with these rules, with Technical Performance Potential between different concepts becoming even closer.

I'm going to echo Kevin by saying this, and like him I don't mean to sound degrading.
However, as close to the top as an 11th overall spot might sound, Brunel were over 260 points behind fifth place.
It seems to me to be a bit of a stretch to suggest that that difference (almost a 50% points increase for Brunel) can be overcome by driving a bit earlier and better statics preparation.
Unfortunately the scores of the teams just outside the 'top' drop off very quickly.

Don't worry, I'm under no illusion that my old team are going to magically jump up to the top. There was certainly a lot of luck involved, as in fact they did not have 2 weeks of testing, but 2 days. 2 weeks is what we usually get. 2 years ago we made the move to designing for reliability above all else (to finish first first you have to finish), which is probably why they finished endurance. They also got "meatballed" because of too much steam coming out the breather (driver hadn't turned the water pump on after the engine had heated up), which cost even more points.

And it's not a case of better statics prep, but actually doing statics prep in the first place.

The point I was trying to make, which you both touched on, is that for a good non-aero car concept and a team with limited resources the potential is there to do very well, !!!IF!!! the team and project is manage properly. Every single shortcoming Brunel has can be probably be traced back to poor management, and perhaps a but of inexperience. So to start accusing any rules of favoring teams with better resources is damn lazy.
The only advantage teams with better resources have is that the team managers can't sit around all day complaining about how bad they have it compared to the rich teams, and have to get off their asses and go do some proper engineering.

I dont believe that it is the organisers responsibility to address reliability, nor should rules be changed to address this, but they can encourage it through design feedback.

I both agree and agree.

I don't think the rules should be changed to improve reliability, not the technical ones anyway. But I do think the organizers are the only body with the ability to impress upon teams the importance of reliability. They are certainly not doing it themselves, and we can scream and shout about it on here all the time but it's not helping.

There's a number of forums that could be used to greater to effect to push this idea, 'Learn to Win' for example, in the UK. They should make it their motto: "To finish first, first you have to finish" and scream it at everyone there all day long. It shoud also be integrated into all of the speeches, seminars and ceremonies at the competition events as well.

It does seem like chasing lower mass and big aero has been a contributing factor, but as I said, I agree that the rules shouldn't take the responsibility of reliability out of the teams hands.

I feel like most teams take it as being all or nothing. Push to be close to the top, or don't even bother. This drives them to push their designs to the limit, the time they spend designing to the limit, and to neglect all else (including good management). Would a shake up of the points system that makes any difference.
If there was only 100 points between the top 10 teams instead of 300, would the be a bigger push to find that extra time to maximize a small points difference? Or would the fact that good points are almost guaranteed even if you're not quite quickest be enough to divert more focus onto finishing in the first place.
What if over half the points came purely from finishing within 150% of the fastest car? Surely just finishing faster than a crawl would become more important and people would take less risk?
What about (as I've suggested before) slashing design points (in half?) if you don't finish endurance?

There are probably plenty of ways to improve reliability across the entire field, without changing the technical rules. But the only body of people with the ability to influence the entire field is the event organizers and rules makers.

mdavis

08-08-2014, 09:54 PM

Maybe I am just getting older, but I have to agree with everything Z says...
Small front wings and narrow rear wings just scream F1... Especially there is simply no reason for a "max 25cm height" front wing just looks!

The Minimum radii rule is still a pain. In the UK 2012 we had to put some stupid tape on the trailing edges because the scrutineer didn't care that the edge was clearly rearward facing, he said everything had to be above the minimum radii. If this will be still enforced 2015, we have incredible inefficient airfoils..

I think the point Kevin made is correct (I said it in my last post): Restrict the height and maybe reduce the front and rear allowed position. That's how to restrict aero, not with stupid keep out zones and "xy percent of the tire must be unobstructed". I simply don't get why the height of the front wing is even considered to be restricted.

I think the teams should send in something like an SES for the Aero mounting with clear rules what the mounting has to withstand, nothing which depends on the mercy of the scrutineers.
As long as we are still going to see flying tires from two design finialists in one endurance, I think there are bigger problems than that.

Last thing about the openness:
As Europe is still the center of electric FSAE, we have the same discussion here: They want to limit the power of 4WD to 55kW and give the 2WDs 80kW. Nobody knows why and what's the point for that. And of course nobody of the Rule-Makers wants to talk. The only really open guys are the Germans (this has to be said!). They are willing to sit down and make their case. Interestingly, they see the whole thing different...

Julian,

I also agree with most of what Z says, but one comment about your point on SES like documentation for aero mounting. The one problem I have with saying "if you're going to have wings, your mounts need to withstand xxxx newtons in direction X, yyyy newtons in direction Y" is that if a team shows up with Monash sized wings, the loading conditions are going to be considerably different compared to ETS sized wings. Unfortunately, removing the flat requirement adds back subjectivity, which is what we're trying to avoid as much as possible.

I agree, the height of the front wing rule is simply stupid. If the rulesmakers wanted to make sure the drivers could see something, have a "colored dot test" where driver must sit in the seat, belted in, full gear and must tell a judge what color a certain dot is, if it's placed x meters in front of the car at y angle from the car centerline.

-Matt

08-08-2014, 10:34 PM

I have had another quick look at these 2015 Rules Revisions. These are described on the SAE site as,

"The long awaited decision on the revised aerodynamic rules changes are now published.
... Though the dimensions are correct there is some final word-smithing to be ..."

Just some "word-smithing", huh?
~o0o~

So...

"T9.2 Location - Front Mounted Devices
T9.2.1 In plan view, no part of any aerodynamic device, wing, under tray or splitter can be:
a. Further forward than 700 mm (27.6 inches) forward of the fronts of the front tires
b. Wider than the outside of the front tires measured at the height of the hubs.
T9.2.2 When viewed from the front of the vehicle the part of the front wheels/tyres that are more than 250 mm (9.8 inches) above ground level must be unobstructed by any part of the aerodynamic device or other bodywork, with the exception of any vertical surfaces (end plates) less than 25 mm in thickness.
Note: 9.2.1 and 9.2.2 apply with the wheels in the straight ahead position."

My interpretation of this, based on my understanding of the English language and the figure attached to the proposed Rules, is that it is PERFECTLY LEGAL to have a "venitian blind" of front wings, with chord = 625 mm, span = full-width of car, and reaching from about 550 mm above ground ALL THE WAY UP TO THE EDGE OF SPACE!!! Or higher, if you want...
~o0o~

And...

"Between the centrelines of the front and rear wheel axles, an aerodynamic device (e.g. undertray) may extend outboard in plan view to a line drawn connecting the outer surfaces of the front and rear tyres ...[blah, blah]"

So it also seems that full-width wings above the cockpit area are legal and can be at ANY HEIGHT AT ALL. Note that the UNDEFINED (!) "undertray" is only given as an "example".
~o0o~

What you have here, dear FSAE students, is some Kindergarten kiddies who have barely learnt how to ride their little push-cars, but are now sitting in the cockpit of the Jumbo jet that you are all flying in. And don't they just love pushing and twiddling with all those little knobs and dials, and making all the pretty lights flash on and off.

If you let them continue with this, then there is only one way it will end. Not pretty.

I strongly suggest that all Teams send official letters, on your School letterheaded paper, to this Rules Committee, and ask for just two things.

1. That you be given the names of the various RC Members who propose these Rules changes. This should include the higher level members who sanction these changes.

2. That those RC Members be held responsible (preferably FINANCIALLY responsible!) for any disputes that arise from the above sort of ATROCIOUSLY WORDED Rules. (For example, when a Team arrives at a competition and is ordered to toss its very expensive mega-front-&-mid-aero-package, even though the Rules do NOT specifically ban it.)

At the very least, the responsible RC Members should be publicly ridiculed.

(I note that it is pointless for me to write to the RC directly, but I will do my best with the public ridiculing. :))

Z

Big Bird

08-09-2014, 02:11 AM

Q. How many arms does a FSAE Organizer have?
A. The same number as you do.

OK, so maybe that is a smart-a**e way of making a point, but having been on both sides of the fence I know how many have opinions on how to improve this thing, and how few are willing to invest their own time in actually doing it.

That is not to say that the proposed rules are worded well, or couldn't be improved. But, especially to the student generation out there - if you want to see change, then get involved.

And sorry, I don't think it is "the organizers" responsibility to lead the teams by the hand through the whole reliability lesson. Personally, I have invested heaps of time and energy writing on these boards about prioritizing and reasoning your way through your projects, and have turned myself inside out thinking up metaphors to bring the lessons back to your everyday lives. I've seen any number of FSAE officials on here (e.g. Edward, Doug, Claude, Pat) offering similar advice about understanding priorities and the value of presenting a reliable, tested vehicle. If the lesson hasn't been learned yet, and if the pain of repeated failures within your own teams hasn't hammered the lesson home, then it isn't going to be learned by tweaking points allocations.

Cheers,

Geoff

Swiftus

08-09-2014, 02:32 AM

Just some "word-smithing", huh?

...ATROCIOUSLY WORDED Rules...

Z

Z - I like to think of this as taking our engineering learning experience to the next level. Before, our customer requirements were quite open. The customer simply asked for an autocross car which would be priced appropriately, able to perform well in structured acceleration, skidpad, autocross, and endurance events, able to be marketed well, and would be found on good engineering design principles. The task was easy to identify.

Too easy to identify. Now the customer has decided that they would like us to meet the exact same deliverables as before but the car must also 'look a certain way'. Sure, marketing a look or defending the engineering design principles which developed the newest generation of cars will be skewed by external forces which has little basis on the deliverables at hand, but it does legitimately make Formula Student more like the real world.

I am positive that every engineer who participates in the wonderfully unrestricted world of Formula Student will leave their team and go to a company where their customer is asking them to design and build the toughest earth digger ever to grace this planet, but it 'must look elegant, like a ballerina'. My cinicism is that the customer will always have at least one deliverable which is impossible or silly when juxtaposed to the rest. Why make Formula Student any different?

If we as engineers are going to have to deal with a unreasonable customer or a 'pointy-haird boss' for the rest of our lives, why let us live in the false eutopia of this reasonably unrestricted design competition? From a logical standpoint, it simply does not make any sense.

---

I would like to thank our 'garbageman' for sitting at his computer and shouting on our behalf.

---

I will clarify my intent. I am not upset with introducing new rules. Nor am I upset with the direct impact it has on my team's performance. I am confident that we will come up with a good solution in the new rules set. What is frustrating is the timing of creating a new set of rules which forces teams already constructing their car for the next season to go back to the drawing board. Additionally, a rules set which is worded so criptically, the gap between 'intent' of a rule and wording of the rule is only widened.

Freddie

08-09-2014, 03:25 AM

Z: While not having the rules in front of me, I'm 90% sure that those "loopholes" that you propose are not loopholes. Both these scenarios are covered in the rules, while not being specifically for aerodynamic devices. But that's how it is, sometimes you have to read the whole rule book to get the context; not read every single rule by it self and scream about it not covering every scenario.

I agree with Jay on the new rules, I find them good enough. Not perfect (I think there are some loopholes), but certainly not that bad as some suggests. My only "fear" is that these rules effectivly make the combination of 13" wheels and aero obsolete. This would mean that a team coming from a 13" no aero car (like us) have a defined "best" development path (transition from 13" to 10" or smaller, then go for aero) instead of being able to choose multiple paths without too much penalty. I would also have preferred to have the rear wing height in relation to the main hoop, to see teams make the trade-off between high roll hoop and aero, but that is a personal opinion.

JulianH

08-09-2014, 03:39 AM

My interpretation of this, based on my understanding of the English language and the figure attached to the proposed Rules, is that it is PERFECTLY LEGAL to have a "venitian blind" of front wings, with chord = 625 mm, span = full-width of car, and reaching from about 550 mm above ground ALL THE WAY UP TO THE EDGE OF SPACE!!! Or higher, if you want...

So it also seems that full-width wings above the cockpit area are legal and can be at ANY HEIGHT AT ALL. Note that the UNDEFINED (!) "undertray" is only given as an "example".

I strongly suggest that all Teams send official letters, on your School letterheaded paper, to this Rules Committee, and ask for just two things.

1. That you be given the names of the various RC Members who propose these Rules changes. This should include the higher level members who sanction these changes.

2. That those RC Members be held responsible (preferably FINANCIALLY responsible!) for any disputes that arise from the above sort of ATROCIOUSLY WORDED Rules. (For example, when a Team arrives at a competition and is ordered to toss its very expensive mega-front-&-mid-aero-package, even though the Rules do NOT specifically ban it.)

At the very least, the responsible RC Members should be publicly ridiculed.

(I note that it is pointless for me to write to the RC directly, but I will do my best with the public ridiculing. :))

Z

The three points you made:

1. The "incredible high front wing": The rule makers introduced to nice little rule "it must be positioned not to hit the driver in an accident." (or something like that). A front wing above the tires will, if failed, hit the driver pretty good. So that's out.

2. Wings above the cockpit area: Are banned by the nice little rule "The driver egress must be unobstructed" (or something like that).

Those things are going to bite you ;) "Luckily" they are not 100% defined, so they can kill you with the "intend" of those rules... The rules commitee made the mistake to define "open wheeler" in the last year and got the Michigan Ann Arbor car as response to mock them. So they will not make that mistake again.

3. Every competition participant signs some funny documents about liability and so on. So we all can write some nice letters but the guys won't care about it...

Geoff,

so far, I'm not too old, not too grumpy to just sit here and shout. I'm trying to reach out to those guys. As I said there is discussion in Europe about the power limit of 4WD Electric cars. So we gathered all the "big teams" with 4WD and sat down with the German organisers. It works. In contrast to that, I was trying to contact the FSAE organisation about the 300V limit at Lincoln that is simply there to prevent those mean European teams to come to the US and win the competition over there. Result: Nothing. It's not like a page with contact details where you can write to Mister Miller or Mister Deakin or Miss Smith about something. It's a closed door organisation.
I really would try to help them out.
After the first drops of "2015 Rules" came out, we proposed to do LapSim with differnet concepts to help them balance the rules (if that's what they want to do). But what was the result? Correct: Nothing.

From what we heard, all those rules are made by gut feeling of some old guys. No data behind it, just "what they like".

A competition that has become so professional (at least in Germany and Austria...) should be better than that when it comes to rule changes.

I mean we can leave the discussion about wings behind. As Jay said, the teams will bounce back, it's not too difficult to trim your package until May. But what comes next? Ban of Single-Cylinders in September 2016 for the 2017 season? Ban of 10'' tires in October 2019? Ban of Carbon Fibre?

So yes, I was trying to help, I am always the first guy to give feedback to the organizers when I participated, I write to them throughout the year with suggestions and yes I will help organize something but I will not be the next guy behind closed doors that isn't allowed to talk about decisions. That's not my outlook on this competition.

Big Bird

08-09-2014, 04:26 AM

Bit disappointing to read that Julian. Anyway, I sent you a PM

Alumni

08-09-2014, 08:06 AM

Julian - I have had the exact same experience with the RC here in the good ole USA.

At one point our team was actually working with our advisory (he had been on the RC in the 90's and still held close ties with many of the active members) and the committee themselves to do some physical testing on proposed rule changes over the summer one year with an old car. Hours before the testing was to begin we got a call that it was all off because a certain member - still very active in the FSAE community - was afraid that his idea for a rule change might not work and he could not deal with being humiliated in front of colleagues and our student team.

I remember being called to a meeting at MIS with some other big team's team captains/chief engineers to "discuss" future rule options with the RC. It turned into such a bickering argument that the then head of the rules committee called the meeting over after 30 minutes, apparently disgusted that we didn't all heap praise on him and thank him for what a great job he was doing. (Ed. - I should note I was still a young pompous college student at this time so my memory may not be telling me the whole truth here...)

Shortly after graduating I worked as a tech inspector as my job would allow it. Every time I offered to give input on the rules as a former participant and current inspector, I was quite rudely denied any input, receiving a typical response somewhere along the lines of "We're all old and have been doing this longer than you, so there is no way you could know more than us." (Again my memory may not be 100% accurate here...)

Kevin Hayward

08-10-2014, 08:02 AM

Geoff,

I think the community has shown it is quite happy to provide constructive feedback for rule changes. What would help is good lead time, and a willingness to put ideas forward. I am not sure what the answer rate was for the aero rules survey, but I could fairly safely say that everyone involved here would have put in a response. Some of the surprise lays in the fact that the final rules were quite a bit different to the options laid out for discussion. It makes it seem as if the feedback willingly given is not worth giving in the first place. This may not be true, but without some sort of communication it is difficult to know one way or another.

I think another area that teams could help (especially with the exclusion zones) is by helping with the diagrams. A good 3d representation would go a long way to describing the intended rule.

I think it would help even if the feedback requested was along the lines of:

"Here are the rules that are coming in 2 years, could the community review them to help with final wording, as well as pick out potential loop-holes."

As far as I understand the process there are a number of tasks in forming reviews:

- Rules review
- Proposing conceptual changes
- Writing the words
- Review of proposed rules
- Communication of rule changes

I can see a part for the community in all aspects of this process without needing to provide direction or take over the process. It would slow the process down to involve the teams in this way, but I think it would be for the best.

Kev

08-10-2014, 09:27 PM

Z: While not having the rules in front of me, I'm 90% sure that those "loopholes" that you propose are not loopholes. Both these scenarios are covered in the rules, ... sometimes you have to read the whole rule book to get the context...

Freddie,

I have just re-read the whole of one of the recent versions of the Rules (there are many versions), ... and NONE of those loopholes are covered.
~o0o~

To repeat my point here, FSAE/FS is supposed to be about "educating the next generation of Engineers".

As such, I would imagine that the Organisers would try to act as "good role-models". One way they could do this is by producing "Rules" that are exemplary models of good Engineering documentation. That is, Rules that are complete (all necessary information in there), concise (no redundant waffle), and thus crystal clear.

Instead, they ambiguously offer this.

* Option 1. - The literal interpretation of the Rules has the cars being ALLOWED to carry large front-wings mounted at driver's-neck-height, and with razor-sharp trailing-edges.

If this is indeed the true "intention" of the Rules, then the Rules Committee should publicly confirm it. They should also explain why they have taken this very IRRESPONSIBLE path, given all their bleating about high-wings being so dangerous. (Maybe they consider an extremely quick and neat decapitation is acceptable?)

* Option 2. - The "intent" of the Rules is that high front-wings, and razor-sharp TEs, are NOT ALLOWED.

In this case the RC should explain why they are so INCOMPETENT that they cannot clearly specify this in their draft Rules. It is not hard! Just some words and figures showing where, and where not, parts of the car can go.

(BTW, because of "The Law of the Excluded Middle", there are NO OTHER OPTIONS. So the RC is guilty of at least one of the above, ie. IRRESPONSIBLE or INCOMPETENT.)
~o0o~

So, to repeat the main point yet again, the problem is not so much the Rules per se, but the fact that a bunch of INCOMPETENT BUFFOONS are messing with them.

Furthermore, these buffoons have locked themselves in the cockpit of the Jumbo Jet that you are all flying in, so they can mess to their heart's content. They refuse to talk to any of the passengers (ie. you students), and they won't even give you their names. But don't they just love fiddling with all those knobs and buttons.

Fortunately for many of you students, FSAE Airlines is not your only option. Some of you have the option of flying with FSUK, or FSG, or others, and it seems that some of those flights do actually have competent pilots in the cockpit.

But if you happen to be onboard Flight FSAE, you might want to start banging on the cockpit door. Or else strap on a parachute, make your way to the emergency exits, and prepare to jump! :)

Z

SomeOldGuy

08-10-2014, 10:22 PM

Pete Marsh

08-10-2014, 10:44 PM

Just so no one starts down the road of high front and over driver wings before the final rules come out... Here is what will keep you from just attaching super high wings everywhere but the back of the car.

T9.7.2 The wing or wings must be mounted in such positions, and sturdily enough, that any accident is unlikely to deform the wings or their mountings in such a way to block the driver’s egress.

But it seems as though if they are mounted rigidly enough there is no limit to the wing height forward of the roll hoop.

Actually, there is plenty of real estate on most cars to be able to MOUNT your rear wing in the "Location - General" area between the wheel base, and such have no restrictions beyond the rear overhang limit and keep out area above the tyres.

My guess is they just want to restrict the rear wing size (or at least make it difficult) for unsprung, or semi unsprung devices, and as long as you are happy to carry the mounting structure etc to go forward of the rear axle you can go big.

Fit Delft's tyres, and a little tweak here and there, and GFR's existing massive front wing is all good. Or just mount it in the general area, and do what you want.

Re wings vs driver - cage it like a sprint car, all good!

Pete

Freddie

08-11-2014, 02:12 AM

Z: I would argue that T4.7.1 (2014 rules) and T9.7.2 (proposed rules) in combination with T4.8 (2014 rules) would close those loopholes quite quickly. At least for now, I can't picture a sound design that passes all these rules in combination.

Though, if what JulianH and Alumni says is true (I can't comment since I haven't been in any rule discussion), that is what I find more troubling. While Formula have made me and others "douchebag engineers", I have yet not met anyone that has not become a lot more humble from the experience, and I like to think that it is a common occurance for everyone involved. It sure helps having your designs blow up (literally or figuratively) a couple of times ...

Dunk Mckay

08-11-2014, 07:03 AM

Actually, there is plenty of real estate on most cars to be able to MOUNT your rear wing in the "Location - General" area between the wheel base, and such have no restrictions beyond the rear overhang limit and keep out area above the tyres.

My guess is they just want to restrict the rear wing size (or at least make it difficult) for unsprung, or semi unsprung devices, and as long as you are happy to carry the mounting structure etc to go forward of the rear axle you can go big.
The section heading might be "Rear Mounted Devices", but the rule says: "In plan view, no part of any aerodynamic device, wing, undertray or splitter can be:[...]" So that applies to all aerodynamic devices regardless of where they are mounted to, the section heading is just indicative of where they might be. Also, please differentiate between "mounted IN a location" and "mounted TO a location" the two are not the same.

Fit Delft's tyres, and a little tweak here and there, and GFR's existing massive front wing is all good. Or just mount it in the general area, and do what you want.

Re wings vs driver - cage it like a sprint car, all good!

Yes to this. If the rule's not changed I can see either a lot of cars being DQ'd in scrutineering based on "scrutineer decides it's not safe", or a major advantage given to teams that are able to afford custom low profile tyres to maximise the potential for the front wing. Another rule that increases the great cost divide.

Pete Marsh

08-11-2014, 07:57 AM

BeunMan

08-11-2014, 11:01 AM

...
Yes to this. If the rule's not changed I can see either a lot of cars being DQ'd in scrutineering based on "scrutineer decides it's not safe", or a major advantage given to teams that are able to afford custom low profile tyres to maximise the potential for the front wing. Another rule that increases the great cost divide.

If I remember correctly there are 6 Inch tyres available for not too much (slicks). Or try even smaller cart tyres, even lower.

DMuusers

08-11-2014, 03:59 PM

Fit Delft's tyres, and a little tweak here and there, and GFR's existing massive front wing is all good. Or just mount it in the general area, and do what you want.

I'm actually not completely sure our tires are the best choice (if you had the choice ;) ) aerodynamics wise, since they're quite wide. Our front wing's width is definitely impacted by these rules, maybe even more so than teams running other tires with smaller widths. Yes, they're lower, but that's not all to the story.

Alumni

08-11-2014, 05:59 PM

If I remember correctly there are 6 Inch tyres available for not too much (slicks). Or try even smaller cart tyres, even lower.

I'll be honest I haven't read the 2015 rules, but is there not still an 8" wheel minimum requirement?

BeunMan

08-12-2014, 05:16 AM

I'll be honest I haven't read the 2015 rules, but is there not still an 8" wheel minimum requirement?
Forgot about that one... 8" are probably available somewhere as well. (Rule T6.3.1)

Dunk Mckay

08-12-2014, 06:25 AM

I disagree, those words appear in section T9.3.1, quite clearly a sub section of 9.3

I don't see how anyone could interpret such a sub heading as being generally applicable to all aerodynamic devises.

And the heading

"T9.3 Location - rear mounted devises: " (assuming there is supposed to be a dash in there)

Not grammatically correct, but however includes the word "mounted", where as you are interpreting it as if it did not. Clearly the word is there for a reason, whatever it is, and the location of the device's mounting on the vehicle is the pertinent factor that categorises the devise, rather than the position of the devise it's self. I can't see how any other interpretation would be possible?

Pete

But they are mounted at the rear. Just not to the rear necessarily.

Even if the way you interpret it is correct. Then you have to get into the semantics of "do the mountings from part of the aerodynamic device?" Most would say no. In which case they are part of the car and the wing/undertray is mounted to them. At which point any aero device will always be considered as mounting to the car where that aerodynamic device is located.

In all cases, when it comes down to an argument about semantics no-one is going to get away with going against the intent of the rules. This does not preclude designs that might go against what the RC envisioned, but you have to be 100% sure that it works for any interpretation of the rules, not just your own version.

Yes, yes, yes, I know I know. We've been over this, the rules aren't clear, "aerodynamic device" isn't even defined, the RC doesn't listen to anyone. So why keep complaining? The rules are what they are, if there's any need for clarification then teams can send in a rules query. There's plenty more senior members could be doing than worrying about semantics (like actually managing their team properly).

The rest of us should probably get on and sign up to try to help out and effect change from within the organisations, or stop being such a grumpy load of old farts.

SomeOldGuy

08-12-2014, 01:03 PM

Reliance on rules inquiries to build our cars is a dangerous thing. My team had a back and forth with some of the people answering the inquiries this last season. The conclusion was if the inspector at comp had a different interpretation of the rule we would have to be compliant with that interpretation and not the one given through the inquiry. We have asked the same question 2 years in a row regarding frame design and received 2 completely different interpretations.
The rules should be clear and concise not up to interpretation.

08-12-2014, 10:28 PM

As expected, I have just received the following PM from Pat Clarke.

==============================================
"Dear Z,

You have received an infraction at FSAE.com Forums.

Reason: Insulted Other Member(s)
-------
The Rules Committee are not incompetent buffoons, irresponsible or negligent. Changes to the rules are given great consideration and under advice.
To refer to them as such reflects poorly on yourself!

Read the rules in total!
-------

This infraction is worth 1 point(s) and may result in restricted access until it expires. Serious infractions will never expire."
================================================

(My emboldening.)
~~~o0o~~~

Pat,

Since you seem to have plenty of time to send me all those "infractions" (into double figures by now?) perhaps you can take a moment to come out of the shadows and answer the following questions publicly.
~o0o~

1a. Given that the last few pages of this thread indicate considerable confusion amongst the students as to where "wings" are allowed, and not allowed, can you please explain how these new Rules can be considered a COMPETENT example of Engineering documentation?

1b. As I have noted earlier, a literal interpretation of these new Rules suggests that "front wings" are allowed at any height above the nose of the car, as long as they are ABOVE the front tyres. Can you please clarify if this is, in fact, the "intention" of these new Rules?

1c. If the "intention" is that "high-mounted front-wings" are NOT allowed, then please tell us what other Rule makes this UNAMBIGOUSLY clear (note that "unlikely ... to block the driver's egress" is about as vague as it gets)?

1d. Putting this the other way around, how UNCLEAR would an Engineering specification have to be for you to consider it incompetent?
~o0o~

2a. I recently visited a team doing some aero-development work. Their prototype wings had Trailing-Edges that were as sharp as it is possible to get with CF-vacuum-bagging methods (ie. razor-sharp!). On questioning this, the Aero-Lead said that he had checked the Rules and the "minimum radii" only applied to some leading-edges, so these wings were fine. So, can you please explain why razor-sharp TEs are allowed, and how this is the "responsible" work of a "competent" Rules Committee?

2b. In the event that the "intent" of the Rules is that razor-sharp TEs are NOT allowed, can you please explain why this was NOT clarified in these latest Rules changes, especially given the ample opportunity to do so within all those added words? And how could this NEGLIGENCE come from a competent RC?
~o0o~

3a. Finally, can you please explain how your attempted SUPPRESSION OF OPEN CRITICISM of these issues will somehow benefit the education of the students? Or do you think that the only type of open discussion that is acceptable is sycophantic praise of an, ahem..., "highly competent and hardworking RC who can never do wrong"?

IS NOT THE FIRST STEP TO TYRANNY THE SUPPRESSION OF ALL CRITICISM?

Z

(PS. While we are here...

4. Will you ever explain to the students, in a meaningful, technical, way, why "migrating Roll-Centres" are such a bad thing? Or, at the very least, how they send "confusing signals" to the driver? If you cannot do this, then why do you keep advising the students that way?

To put it most simply, ARE YOU REALLY INTERESTED IN THE EDUCATION OF THE STUDENTS???)

mech5496

08-13-2014, 02:27 AM

I really think we are drifting out of topic here... To RC or anyone listening, why not define "green" areas/boxes that the teams are allowed to place wings etc. instead of "red" keep-out zones? IMO that would be much more clear to everyone and would keep "creative interpretations" of the rules away. BTW did I mention that I absolutely love creative interpretations? :D

Tim.Wright

08-13-2014, 03:00 AM

4. Will you ever explain to the students, in a meaningful, technical, way, why "migrating Roll-Centres" are such a bad thing? Or, at the very least, how they send "confusing signals" to the driver? If you cannot do this, then why to you keep advising the students that way?

I've been out of touch with the FSAE/academic scene for a few years, but is this migrating roll/pitch centres thing still a thing in the academic world? I'd be pretty disappointed if that was the case.

The industry is slowly moving away from believing this crap but there are still so many books and papers published using these old methods that students don't have much opportunity to learn it the correct way.

Swiftus

08-13-2014, 04:09 AM

why not define "green" areas/boxes that the teams are allowed to place wings...

Better yet, ask some of the big aero teams to help define the rules to meet a target downforce limit. If we have been doing hundreds of simulations and real-world testing to validate our sims every year, we should be the perfect resource to help with defining a set of rules which will limit the downforce of these cars to the necessary 'safe' limit.

BTW did I mention that I absolutely love creative interpretations? :D
Shhhhhhhh. Don't let anyone know any more creative interpretations. :) I am pretty sure the umpteen solutions we have running in sims right now are uglier than was ever intended by our governing body. But hey, it should be most beautiful if it is the best engineering solution, no?

DMuusers

08-14-2014, 11:17 AM

Tobias Michaels has tweeted that FSG will not have a different maximum power between 2WD and 4WD. Though he hasn't specified if it still will be 85kW.

https://twitter.com/TobiasMic

FS Austria has also replied that they will probably do the same as FSG.

https://twitter.com/fsaustria/status/499905140632346624

I think a lot of teams won't attend FSUK 2015 if they do limit the 4WD power more than the 2WD, unless it's the same power limit as FSG sets for both.

Kevin Hayward

08-14-2014, 09:15 PM

From the Tobias' post it looks like there may be two sets of EV power limits. One for FSG and one for others. Why aren't these rules well and truly locked down by now?

We are looking at very late revisions to rules that teams are trying to design to right now. There are less than 10 months before the first comp these rules will be used in. I can't be the only one that thinks this is getting absolutely crazy. Australian cars built this year are already ineligible for 2015 if they are running aero (at least without large changes).

Something needs to change with the timing of these rules.

Kev

MCoach

08-14-2014, 09:42 PM

Kevin, rules are not yet finalized and we're almost done with our chassis design up here....

mech5496

08-16-2014, 02:50 PM

It seems like the FSAE EV rules commitee decided against different power limits on RWD/AWD; despite the fact that I agree with that decision I find it a bit contradictory, and I will explain myself. The whole aero rule debate and the subsequent rules change has occured as the RC wanted a "field equalizer"; rules that require the teams to carefully evaluate the use of aero from first principles, and taht would allow teams without it to be competitive (or at least that was the official reasoning). Till now, running aero (given that the team could allocate some resources) was a n-brainer. Same goes with 4wd in the EV class. If a team has the resources, 4wd is a no-brainer; it allows greater traction under combined acceleration, increased recuperation and (as the rules are now) virtually no cost penalty compared with teams that run a single motor. The lower power limit was supposed to act as an equalizer for all the above; eliminate the advantage in the acceleration event while 4wd's would still have some advantage over all other aspects, making teams to really prioritize and evaluate the drivetrain. Not implementing the proposed rule means a step back; not necessarily at the wrong direction, but back, and it is highly contradictory with the aero rule changes IMO. BTW is there any word on the EV voltage limit for the US competitions?

Adam Farabaugh

08-16-2014, 06:55 PM

If there is going to be a voltage limit change for FSAE Electric the teams need to know. We are getting close to cutting a PO for our battery cells...

It's hard for me to imagine that they would introduce such a change so late (although from a vehicle design standpoint I would be happy) because it would really f*** with teams that are well underway with design. But after reading this whole thread I am not so sure...

Kevin Hayward

08-17-2014, 10:39 AM

The rules are due for a release at the end of this month. I am wondering if there is any chance the changes can be delayed until the next set of rules. From the end of the month we are looking at only a bit over 8 months to the first US comp to run the rules. There is no chance for the Oz teams to redesign to suit for next year, unless they skip the Oz comp.

Holding these rules back until 2016 would make it a nice lead time for the rules, and get us away from late rule sets. With a little effort we could stay on the track of early warnings for rule changes (with final wording) This will provide enough time for the rules committee to get feedback on the precise wording of the rules, and field questions early.

...

I wonder whether these forums could be used as a bit of a working group. We could start a few topics on the particular rule changes and run through the implications. Between the people posting here there is a lot of accumulated knowledge and capability.

Kev

08-17-2014, 11:27 PM

ON A MORE POSITIVE NOTE.
==========================

Here are some positive suggestions for how the FSAE Rule Book could be improved.

First note that good Engineering documentation is COMPLETE and CONCISE.
* "Complete" means that ALL the major INTENTIONS that are desired of the project are clearly spelled out.
* "Concise" means that all the little details that MUST BE MET are included, but ONLY ONCE each.

Importantly, not every possible tiny little detail can be covered in a finite documentation package. But, by the same token, not every little detail needs to be covered. Knowing where to draw the line is a measure of Engineering competence.
~o0o~

DESIGN FREEDOM - Right at the top, the Rules have;
"A1.1.1 To give teams the maximum design flexibility and the freedom to express their creativity and imaginations there are very few restrictions on the overall vehicle design."

This is a clear statement of a "major intent" of the Rules.

Sadly, this Rule used to be at A1.1, but has since been demoted to a sub-clause. Over the years there have been too many restrictions put onto detailed parts of the car design, thus subverting this "big-picture" Rule.

This Rule should be reinstated to its position as one of the major guidelines for the rest of the Rules.

Many of the recently added minor Rules, most of which, frankly, border on being meaningless (see just some examples below), should be deleted.
~o0o~

AERODYNAMIC DEVICES - There is NO NEED for ANY of these detailed Rules. Especially not when it is realised, as should be obvious, that all of the car's bodywork, the wheels and tyres, and even the driver's head, have aero-forces acting on them, so are difficult to distinguish from "aerodynamic devices".

It would be much better to simply put some constraints on where, and where not, parts of the car can be. As Harry said earlier, the Rules could simply specify a "green zone" that the car must be within. (Note that a "red zone", that must NOT contain parts of the car, would also work, but would require more ink. The "red zone" would simply be the complement of the "green zone".)

In keeping with A1.1 above, the specification of the "green zone" should NOT be too restrictive. For example, the current Rules give no restriction to maximum wheelbase, yet no Team has yet built a 10 metre long car in an attempt to maximise downforce from a huge aero-undertray. The track layout puts the most effective constraints on such things, in this case by making very long wheelbase cars difficult to drive around the tighter corners.

As another example, it is the slaloms that keep wheel-track (width) dimensions low, giving no need to mandate a maximum width dimension. If there were no "green zone" Rules covering maximum width, then it is conceivable that a Team could build a narrow-track car, but then fit very wide wings, that, because they are also mounted high enough, do not knock over cones.

So, simply specify the "green zone" as being between two longitudinal-vertical planes that contact the outsides of the wheels/tyres, and that should be enough for an overall width constraint. The current "front and rear overhang" Rules, together with the performance advantage of short wheelbases, are also enough to constrain overall length.

Overall height of the car can similarly be constrained (eg. "maximum one metre high, EXCEPT for the MRH..."). However, this height dimension should be taken from a "floor-reference-plane" that amounts to the horizontal surface that the car (specifically, its chassis) would sit on if its wheels were removed. This removes any ambiguity regarding ride-height adjustments from the suspension.

I agree with Kevin's comments from some time ago, that the competition would be visually more interesting, and a better test of the "big-picture" thinking of the various Teams, if the cars were allowed to look like anything from go-karts to Le Mans roadsters, with F1 somewhere in the middle. At recent comps see the Chinese Xiamen team as a bit-too-complicated-go-kart, and Michigan-Mega-Aero as an almost-LM car. Now imagine a grid with both those boundaries pushed outwards, and also with everything possible inbetween...

This potentially greater range of car designs, and hence greater conceptual challenges to the students, comes from lesser restrictions in the Rules (ie. A1.1). The alternative direction is a "spec-series", like F1.
~o0o~

DRIVER VISIBILITY - It might be argued that freeing-up the Rules this way might result in Teams turning up with inadequate forward visibility. Well, they already do!

Attempts to lower the driver's CG via more reclined seats, combined with FRH Rules, and the FASHION of mounting front spring-dampers on top of the nose, means that many cars already have very poor forward visibility. But the current Rule covering this (ie. T4.7) really does nothing to prevent this.

The current requirement to have a "minimum field of vision" of 200 degrees in Azimuth is MEANINGLESS because it gives no similar specification in Elevation. So it is impossible to test this Rule (ie. "200 degrees Azimuth" at what height???), or even make sense of it. As should be obvious, the steering-wheel, FRH/foot-box/nose area, and the front-wheels, are always within, and thus obstructing, the driver's forward "200 degree field of vision" anyway!

This section of the Rules currently has the sentence,
"The driver must have adequate visibility to the front and sides of the car."
It would be enough to simply move that one sentence to an earlier section of the Rules that covers the "intent" of "safety" (see below), and then DELETE ALL THE REST of this section on "driver visibility".

Rather than unnecessarily complicating an already too long Rulebook, the Officials would better serve the students by pointing out that if the drivers cannot clearly see the track in front of them, then they are much more likely to knock over lots of cones, and thus lose lots of points. It is highly unlikely that a very poor visibility car will be a danger to anyone (think about it), and in the worst case such a car can be pulled off track for reckless driving.

Again, fewer Rules is better.
~o0o~

DRIVER EGRESS - This is another section of the Rules that has been mentioned in connection with the Aero-Rules. It has an entirely separate "intent" to aero, and the two different sections should NOT be conflated.

Specifically, there is currently nothing in the "driver egress" Rules that prevents, or even mentions, aluminium side-pods that might plastically deform in an accident, and thus intrude into the cockpit area, and trap the driver in an ensuing fireball. Bizarrely, the Rules taken as a whole seem to suggest that ONLY wing mounts could possibly trap the driver.

There is a long section at the top of the Rules about "intent...", which includes;
"A3.6 Violations on Intent
The violation of intent of a rule will be considered a violation of the rule itself.
A3.6.1 Questions about the intent or meaning of a rule may be addressed to ..."

There is far too much legalese there for my tastes, but the concept of "intent" is reasonable when covering possibilities that are difficult to accurately predict or specify. One such case is what happens in an "accident", since "accidents" come in many and varied forms.

A reasonable interpretation of the "intent" of the "driver egress" Rule is that the car should be constructed in such a way that the chances of the driver being trapped in the cockpit after an accident are LOW. It should be obvious that these chances can never be zero (eg. they might crash into some chain-link fencing, or lots of other possibilities...). Likewise, it is track layout that has the greatest influence in determining how bad any accidents might be, much more so than, say, wing-mounting systems.

IMO, the "driver egress" section should be put towards the top of the Rules under the general heading of "overall car design" or "safety". The Rule should simply express the intent that the car be designed with driver safety in mind, and specifically that the driver can quickly exit the car after most foreseeable accidents.
~o0o~

There are a lot of other sections of the Rules that would greatly benefit from severe pruning, or deletion. But to sum-up here.

* The Rules should COMPLETELY, and CLEARLY, state the overall "intentions" of the competition.
* The specific details that must be met to comply with above should be as CONCISE as possible.

This is a bit like a GOOD Team's approach to the whole FSAE project, and also a bit like the car that such a Team would build.

Of course, "good Teams" are only good ... when they have competent leadership...

Z