Just saw that the rules have finally been released, happy reading everyone!
http://www.fsaeonline.com/page.aspx?...c-ec69aae080a3
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Just saw that the rules have finally been released, happy reading everyone!
http://www.fsaeonline.com/page.aspx?...c-ec69aae080a3
There's a *LOT* of issues with the ETC reqliability requirements being defined in therms of throttle % instead of torque % or something of that nature. As it is, there are a lot of cases where drivers request high torque e.g. to come out of a corner while still on the brakes, and we shouldn't be targeting such a strict limit (10% under 'heavy braking) with the analog reliability processor.
There's also a LOT of good and bad changes in here that I wasn't expecting.
Andrew, I just looked at the rules, not an expert in those things but wasn't it always the plan that the rules from the electric cars when it comes to the "torque pedal" would be used for the combustions?
Is there anything different compared to the way electric teams have to "safe" their system that you haven't thought of?
Anyway,
I think the aero rules are not well written. Too complicated, too many words. 2 zones: "allowed here" and "keep out here" would have been much easier and better. Sadly the RC didn't take take the Monash proposal into account...
But besides aero, I haven't found a lot of game changers that would justify a delay of the rules.
80kW for electric cars seem reasonable.
There are a few differences:
-The EV rules (in 2014) differentiate between mechanical and regenerative brakes for the purpose of torque reliability.
-The 2015 IC rules section IC1.16 defines a 'brake plausibility device' which is non-programmable (e.g. built from discrete analog or digital components, not a secondary processor) which evaluates only the braking force (the rules say 'for example, >0.8G without locking the wheels') and the throttle position >10%, and shuts down the throttle power and fuel pump power in the event of an implausibility, in a way that is not resettable without resetting the main kill switch. This is extremely unreasonable, as drivers already request pedal when exiting a corner under heavy braking to either fill the manifold (so torque is ready as soon as they need it) or to spool a turbo. This entire brake plausibility device does not exist in the 2014 EV rules. It would be much more reasonable to ask teams to include processor or control system software failures in their FMEA, and design and reliability-test systems which can detect and handle a processor, control system, or software failure. For example, simply by adding an evaluation of the spark advance angle and/or the presence of spark and fuel control, it is possible to run a high throttle % with low torque % due to retarded spark or partial FSO (e.g. running a 4 cylinder engine on 2 cylinders).
I thought there was a plausability check in the EV rules.
For us it was the "famous" EV 5.6 rule (I still can remember the rule number ;)). We also had to use a non-programmable logic that would open the relays. Still not sure if this is reasonable but should be the same for EV and IC.
But to be fair, we don't have turbos to spool...
It's fair to restrict torque during heavy braking, but not throttle position, as we have multiple ways to control torque and higher efficiency is attained the more open the throttle is (as pumping work goes down). We also have turbo's to spool, which we can do by running a high spark reserve (very retarded spark and increased airflow).Quote:
Originally Posted by JulianH
Not sure if anyone noticed, but FS Austria is listed in the rules as an Official event, congrats to all involved.
I think Austria was official this year as well; might be wrong though...
Rules are..interesting! As a side note to where the rules focus regarding safety should be, please take a look at this:
https://twitter.com/flueglhuegl/stat...76664540565504
Back when I had a job, anyone producing an Engineering specification like these 2015 Rules would be immediately SACKED! So many examples of bad workmanship..... (But how do you sack someone when you don't know who they are, because they keep hiding in the broom cupboard?)
As just one example of this disgraceful work, these current Rules let you have razor-sharp edges ALL OVER your "Aerodynamic Devices" (whatever they are), EXCEPT if those edges happen to be ((forward-facing) AND (horizontal OR vertical)).
So razor-sharp forward-facing edges at some angle other than horizontal or vertical are just fine.
And razor-sharp wing Trailing-Edges are also perfectly legal.
So now that the IRC has made this clear, all aero teams can start designing their TEs to Schick-sharpness (because sharper works better aerodynamically). I suggest a strip of hardened steel (maybe a band-saw blade?) bonded into the TE of the wing. Your gun driver can then get himself into that Zen-zone just before his record breaking lap, by chanting his mantras while honing the TE with a whetstone - "Perfect sharpness, perfect lap... Perfect sharpness, perfect lap...".
Oh, and make sure you bring a copy of the "new improved" Rules to Scrutineering, so that you can prove your car is "legal".
Z
Generally the diagrams dont show the front wing restrictions particularly well, as the diagrams imply that nothing above 250mm is allowed in front of the front wheels, but the text contradicts this implying that once above the tyres in a frontal view a wing is legal.(The diagram T9.3.2 details that between 250-500 in front of the tyres is restricted, but the text T9.2.2 details that above 250 is un-restricted as long as the forward view of the tyres is unobstructed.) Why not just a blanket restriction on front wing height rather than all this complication?
Cal Simraceway(Berkeley), whats the OD of your 8" wheels out of interest? as this would likely make the front wing little restricted. Also DUT are potentially have little restrictions with their small front tyres?
Will read in more depth when I get home from work.
Westly.
Westly, the "general" rules has a restriction above 500mm, making the region above the tyre, but bellow 500mm allowed IMO.
Anyway, for constructive review / editing.....
T3.5.5 the angle of bend braces at less than 45 deg to the tubes bend plane will make the VERY common bent upper side impact tube solution illegal, or at least very wide. Is that the intention? Would it not make more sense to brace a bend perpendicular to the plane of the bend to support rotation of the tube about it's ends?
T6.5.9 Rack attached to frame - Some designs specifically feature unsprung mounted steering gear (ie beam axles). Is the intention here to ban such concepts? Or simply to ensure attachments are suitably strong/rigid?
I.C.1.7.1 Restrictor, supercharger, throttle ONLY - I understand the reasons for this change for the turbo designs, but with bypass/recirculation valves etc banned, this now creates a big issue for any positive displacement supercharger, which are quite happy to operate in partial vacuum. Would a propriety internal relief or bypass valve be considered illegal?
I.C.4.6 IC max voltage. This (60VDC/25VAC) is well below what is seen in the typical motorcycle charging system. Is the intention these systems are no longer permitted and on board charging deleted, or are to modified to comply?
Pete
My reading of T9.4.2 was it only applyes between front the front and rear axles? The diagrams also show no height restriction on the front wing.Quote:
Originally Posted by Pete Marsh
This sounds like it will affect many teams. My reading of this makes our chassis non-compliant unfortunately with a bent supported upper bar.Quote:
Originally Posted by Pete Marsh
I agree with Andrew that rules are overly restrictive in relation to their implementation of ETC. In fact, when he brought that 10% note everywhere to me I knew exactly what it was referencing and think that it is completely unfounded to apply it to FSAE. For those who weren't aware of the blown diffuser era of F1, off throttle maps became a huge thing. The cars basically only closed the throttle on idle and purely controlled torque based off spark and fuel after that. Crazy aero ideas is why it was restricted there, not safety.
http://scarbsf1.com/blog1/2011/05/19...e-engine-maps/
But they sounded awesome:
http://www.youtube.com/watch?v=BmGgvHflXgc
This isn't really relevant to FSAE and restrict us from doing more creative things with the power unit. The rules regarding the ETC plausibility seem more like something that would be required for competition just on ETC safety. If a mechanical throttle sticks open, that's cool just hit the kill switch and no one bats an eye. ETC is put on the car and it becomes restricted to the point that it operates almost exactly like a mechanical throttle with all the electrical wizz-bangs to make sure of it and kill the car if it ever recieves some proper massaging in that one special way....That's no fun. Snowmobile SAE rules are a fair implementation of ETC, I'd reference those.
It looks like the monocoque rules basically want you to build a whole two assemblies if you want to bring one to competition. Much more testing needs to be shown for all composite panels...watch out, they will make you crash test the whole car next and be subjected to the NVH subjective noise test. Maybe install some nicer carpets ;)
IC3.3 Maximum Sound Level
At idle the maximum permitted sound level is 100 dBC, fast weighting. At all other speeds the
maximum permitted sound level is 110 dBC, fast weighting.
Holy crap...let me go pull the muffers off all of my car. Someone must think we should be racing road sedans around these tracks. I think passing 110dBA was equivalent to 120dBC for us at competition and we were well over 114dBA at idle in some instances...
This is not necesarilly bad...there are quite a few teams out there eager to build a monocoque but some times their choices are poor. Think about it, you cannot really fail on designing a spaceframe safetywise, the rules mandate a really large portion of the chassis anyway. Also the smaller WT allowed if tested are more than welcome.Quote:
Originally Posted by MCoach
I think we all agree that wording on the new aero rules is poor; too many words, schematics that contradict the wording and so on. But it is not only that. I did a quick readthrough, and here's an example:
"EV8.2.2 Accumulators must be removed from the car for charging..."
"EV8.3.7 ...In the case that the accumulator is charged outside of the vehicle..."
You kidding me? You just told me that accumulators MUST be charged outside of the car! Seriously, does anyone read the whole thing through before publishing?
Some turbochargers (including the Garrett MGT1238Z which we acquired through the 'FSAE' sponsorship for our CSC clean snowmobile team) include an integral boss for a recirculation valve (Which is plastic).Quote:
Originally Posted by Pete Marsh
A quick google image search found this picture of the turbo: http://www.turbosbytm.com/sites/defa...?itok=FrM5YHLd The recircultion valve mounts to the hole next to the compressor inlet. Within that hole, the 'inner' port goes to the compressor outlet, and is surrounded by a port which connects to the compressor inlet. The recirculation valve moves in this space to recirculate. It's quite integral to the turbo, but the valve is removable as there are several designs (I have a pneumatic and direct-electrical pneumatically piloted one).
While a recirculation valve isn't as important to turbochargers, the question still comes up for integral recirculation valves. As they don't vent to atmosphere, and bypass the restrictor, is there anything wrong with integral recirc valves?
I agree as well, that for a positive displacement supercharger, throttle upstream of the supercharger is a requirement to keep power down without a bypass valve. Even with a bypass valve, most superchargers run a throttle before the supercharger
This needs to be addressed by the rules committee. Would anyone like to submit a question for their evaluation?Quote:
Originally Posted by Pete Marsh
Yes, we measured 116 dBA at idle at Michigan last year, due to the troubles we had balancing a high flow engine that wanted to rev high and a centrifugal clutch that required we keep the revs low at idle (we were sitting on the lean misfire limit, the noise was mostly due to popping).Quote:
Originally Posted by MCoach
We will likely need to at least double our muffler weight to comply with the new noise rules. This is an extremely unfair limit, especially to single-cylinder teams.
Mike, would you like to noise-test my car at warm up/light off idle and see if it passes the 100 dBC test?
I used my team's sound level meter (the same meter we use to test our FSAE car for noise test) on my completely stock 2013 Fiat 500 Abarth and found that, already warm, the car hits 100 dBC fast weighting on the start flare, then drops to between 92 and 96 dBC depending on light-off (it cycles in a torque reserve for catalyst light off even at fully warm idle). This is at roughly 850 rpm.Quote:
Originally Posted by apalrd
If the engine was cold and stayed at the elevated idle for warmup and light off, it would have likely failed the FSAE idle sound test, at 1500rpm. Our FSAE car idles at 2600RPM, I don't know how we can be expected to be better than an OEM street muffler design on a racing car.
MCoach and I then tested his Sentra, with a modified header on a stock exhaust, he too failed the FSAE sound test, peaking the meter at 106+ dBC (for the 100 dBC range setting) at the start flare then decaying to 98 dBC at warm idle (800-900 rpm as well).
Edit:
We later tested both cars according to the noise standard (based on mean piston speed). The Abarth quieted down after it stopped retarding spark for catalyst light-off and passed the FSAE standard test at 5500rpm, but the Sentra failed (at 4500rpm) with a reading of 111 dBC.
After letting both cars sit for 4 hours, we tested again on, on elevated warmup idle. The Abarth failed with a 102 dBC elevated idle (~1500rpm) before settling down to the previously seen ~94 dBC normal idle. The Sentra failed the idle test when warm, at 106 dBC (at ~1100rpm) before settling down as well.
I'm honestly not sure how race cars are expected to be quieter than OEM production cars.
I spent some time watching the dBC readings at Lincoln in 2013 and walked away thinking that something around 115 dBC would be appropriate to force the offending single-cylinder cars with lots of low-frequency content to address their problems while allowing the rest of the cars to carry on without incredible difficulty passing the noise test. Even 4-cylinder cars are going to have trouble passing at 110 dBC without rethinking their silencing for 2015. This is a big jump and some justification for the rule change would be nice.
Regarding the electronic throttle rules, it seems that the new rules strip away most of the advantages of running an electronic throttle.
"IC1.11.2 The electronic throttle must be automatically closed when power is removed from it."
"IC1.12.6 Each TPS must have a separate detachable connector that enables a check of these functions by unplugging it during Technical Inspection."
-Means no reliable, unmodified, off-the-shelf Bosch throttles allowed because they must be driven closed beyond the partially open limp-home position and have a common power supply for the two TPS signals.
APP rules likewise make it difficult to use a reliable, unmodified, off-the-shelf component like the pedal from the Polaris Ranger 900 XP.
These issues are minor, however, compared to the above-mentioned fundamental issue with the proposed electronic throttle control rules. If you cannot decouple throttle position from APP for engine control purposes, what's the point? I thought the point might be to use off-the-shelf components instead of custom components and a throttle cable, but that advantage is gone too.
May I suggest a really relevant noise test style? If we're building a "weekend autocross car" why don't we build to the SCCA noise limits since someone in the rules committee is feeling so inclined to change them.
http://www.scca.com:8090/documents/S...asurements.pdf
A couple things seem to have been cleaned up, and I'm pretty sure I found a rule or two written about because of our team..
However, overall I'm still bothered by how unclear and random many of the rules are. Pretty ridiculous for a competition of this magnitude.
I'm glad I'm not the only one upset about the new noise rules. I hope all of the single cylinder teams are using their time to design mufflers now, rather than getting the rest of the car done. OTS components will no longer pass noise without 2 mufflers in the system, so that will be fun. As MCoach suggested here, and I have suggested to FSAE individuals, the SCCA noise test makes so much more sense that it isn't funny. And yet, here we sit. Apparently FSAE rules committee cares more about "design challenges" than they do about the hearing of the on-track workers. If they cared about a certain situation, then they should test in that situation. Yet again, we see logic seems to have escaped the rules committee.
I still see no definition of "off-axis" impacts for IA's. This is something we got called out for at Lincoln 2013. I had a nice discussion with Mr. John Burford about this in the tech bay. He claimed that any off-axis impact would break our IA off and that we needed to add straps to retain the IA. I pointed out to him that while he may be right, there was no specified magnitude or direction of the off-axis impact that the IA needed to withstand in the rulebook, and therefore we were within the letter of the rules, and we didn't need to add the straps. I told him that if he wanted to call out teams on the off-axis loading condition, that there needed to be a standard test that was performed at the same time as other IA tests to prove that the IA was capable of handling such loading conditions. Apparently that conversation was forgotten when we rolled out of the tech area, or other things like header wrap and the noise levels of teams playing by the rules were deemed more important.
-Matt
We had an identical conversation with a tech inspector at 2014 Michigan. We too were eventually found to be compliant, by the letter of the rules and the testing definition.Quote:
Originally Posted by mdavis
I read over some other relevant competition rules regarding electronic throttle control. Here's the relevant ETC rules from Formula Hybrid (a US competition developed from the Formula SAE rules of the time, which has evolved separately over the last few years).
In fact, the length of the rules governing electronic throttle control are shorter (fewer lines) than the rules governing mechanical throttle controls, which are concerned with the cables jamming, or melting on the exhaust (which is not a concern with ETC throttles). I don't know enough more about Formula Hybrid to know of any team experiences with these rules.Quote:
IC1.6.4 Electrical Accelerator Actuation
When electrical or electronic throttle actuation is used, the throttle actuation system must be of a fail-safe design to assure that any single failure in the mechanical or electrical components of the Accelerator actuation system will result in the engine returning to idle (IC engine) or having zero torque output (electric motor). See also: EV2.2.
Teams are strongly encouraged to use commercially available electrical Accelerator actuation systems.
The methodology used to ensure fail-safe operation must be included as a required appendix to the Design Report. See S4.2.1. A printed copy must be handed to inspectors at the beginning of Electrical Tech Inspection.
Next, I bring the relevant rules from the SAE CSC (Clean Snowmobile Challenge):
The CSC rules also later specify a check of the throttle return spring during dynamic tech inspection (a process where a tech inspector rides the snowmobile on a small closed course to verify the vehicle response is acceptable for CSC, that it meets the minimum required speed, and that it shuts off as expected via the kill switch). In fact, Diesel snowmobiles are not required to run a throttle at all, and must simply retain the 'throttle' input from the driver. Several teams successfully have run ETC systems with great results, including the 2013 and 2014 competition winning teams. Several teams have also caught fire over the years, and there have been no ETC-safety issues ever (as long as I have been competing).Quote:
4.2.6 Throttle Requirements
An adequate return spring on the throttle is required. The throttle must remain on the right side. The throttle will be operated with a direct mechanical operated thumb mechanism located on the handlebar to the rear of the machine (no twist grips). Fly-by-wire throttle systems are allowed.
Next, I bring the Supermileage rules relevant:
Again, they are letting teams determine their own safety and reliability strategy.Quote:
B5.6.7 Throttle Control by Wire
B5.7.1 The engine throttle can be controlled electrically. Provided at least one (1) of the following conditions is met:
(1) The system will immediately return to a closed throttle condition if any part of the system fails.
(2)The kill switch circuit must leave the engine inoperable if any portion of the kill circuit fails. Thisincludes wire breakage and electrical short to chassis.
That's what made it so much more fun. We had no issues with the same IA at MIS 2013. Tech in Lincoln 2013 was really stressful for us, when it really shouldn't have been. We got called on a lot of things that weren't out of the letter of the rule, but were rather judgement calls from the inspectors. The biggest was our seat belts, where because the spec on the belts didn't match the one in the rulebook, the inspector wasn't going to let us through, even after we showed him the spec in the rules that basically says "any belts that carry a given designation meet this standard". I'm sure I lost a few years off my life trying to call HMS, go find the tech inspector (who left the event, right after we got done in the tech bay the first time through), try to find the Chief tech inspector, call HMS back, lather, rinse, repeat. So when the IA was called into question (yet another thing where we met the letter of the rules, but apparently not the inspector's interpretation of things, or actually in this case, another individual at the competition, rather than our actual tech inspector), it was highly annoying and just added more unnecessary stress.Quote:
Originally Posted by apalrd
-Matt
Mcoach
The SCCA noise measurement approach has been tried in Formula SAE with very bad results.
John Burford
Clarity and ambiguity are out the window with the hugely subjective aerodynamic structural requirements rule.
The undefined, completely subjective and ambiguous components are in bold.
Still no definition of what constitutes an aerodynamic device. Does this mean the rule applies to any external wetted surface?Quote:
T9.7.1 All aerodynamic devices must be designed such that the mounting system provides adequate rigidity in the static condition and such that the aerodynamic devices do not oscillate or move excessively when the vehicle is moving. In Technical Inspection this will be checked by pushing on the aerodynamic devices in any direction and at any point.
It also includes a very vague stiffness requirement for "adequate rigidity" when static? "Adequate rigidity" is vague enough without it then having to be subjectively measured...
The undefined aerodynamic devices must not oscillate or move "excessively when the vehicle is moving". No clarity about what excessive movement is nor under what dynamic conditions it pertains to. Presumably measured again by eyeball.
They will check this by "pushing" on the undefined aerodynamic device in any direction at any point. Effectively they can push on any part of the vehicle wetted surface (structural or otherwise) and if they think it moves too much then you have problems.
Then it seems they seek to clarify the rule but do nothing of the sort.
A rule that is vague, completely unclear and is measured by a subjective yardstick is written and stipulated to be "guidance" as to how the rule will be applied? It actually speaks very little about how the rule will be applied and certainly does not provide any guidance.Quote:
T9.7.1 (continued) NOTE: The following should be seen as guidance as to how this rule will be applied but actual conformance will be up to technical inspectors at the respective competitions. The overall aim is to reduce the likelihood of wings detaching from cars whilst they are competing.
Then finally the slightest bit of an engineering requirement in the rule as note 1, yet it still remains ambiguous, subjective, unrepeatable and lacks any way of applying it consistently within a single competition let alone throughout all competitions.
One more use of a very subjective measure and another which in spite of them including a numerical figure (200N), is still only approximately defined. How do they intend on actually applying this approximate 200N load? A scrutineer with a well calibrated elbow?Quote:
T9.7.1 NOTE (continued)
1. If any deflection is significant, then a force of approximately 200N can be applied and the resulting deflection should not be more than 25mm and any permanent deflection less than 5mm.
It goes further to say that resulting deflection cant be more than 25 mm. Between which two points is this 25 mm being measured and how do they plan on actually measuring this movement of 25 mm in free space in any possible direction? Will they bring a CMM arm to each event? Presumably it will again be a subjective assessment.
If wings detaching themselves are such a big problem why not just mandate a tether line (of specified material) tying all wings back to the primary structure.
The tires we used in 2013 were 15" OD, although we upsized to the 10" Hoosier LC0's in 2014.Quote:
Originally Posted by Westly
John,
Could you elaborate on why the implementation did not go as expected? Feedback and understanding as to why the rules have been structured and implemented are as well as any history attached gives significant insight to the teams.
Sound is cumulative. Depending on how close another car is to your car, you may violate the sound threshold. This also causes complication as to which car violated sound. After a few years of this approach, steady-state testing was adopted. Teams were very happy to go away from the SCCA approach. Also under the SCCA approach, many teams would not know they were violating sound until endurance.
John Burford
I think if more leeway was given on sound for an event like accel, have the teams run accel with the microphone set up nearby and if they fail or get close (similar to the SCCA rules) then they are warned or told to fix it. Any runs that are made outside the sound threshold are either dropped or held hostage until a fix is made. I've had this work for a much more amateur and more rule breaking prone class where I held fast lap times for qualifying hostage until either an item was fixed or a penalty was accepted.
We don't have to wait until the endurance to test teams. There are plenty of opportunities to test beforehand. I'm open to much more discussion of the rules topics at hand.
Thank you.
I found, for your viewing pleasure, the relevant US regulations governing electronic throttle control systems. Here is a link to NHTSA FMVSS 124 (NHTSA is National Highway Traffic Safety Administration, FMVSS is Federal Motor Vehicle Safety Standard). FNVSS 124 governs 'accelerator control systems': http://www.gpo.gov/fdsys/pkg/CFR-201...sec571-124.xml
The FMVSS requires two things:
-That there are two energy sources to return the throttle to an idle position. Normally, the first energy source is the throttle motor itself, and the second is the failsafe return spring. For mechanical throttle systems, two return springs are required.
-That the throttle return to idle position (which is allowed to vary based on temperature, emissions calibration, etc.) when the driver LIFTS THEIR FOOT FROM THE THROTTLE PEDAL, or there is a failure of the control system. There is no verbiage to indicate any dependency on the brake in this case, at all.
In fact, NHTSA discussed a 'brake-pedal override' feature to be added to FMVSS 124, following the toyota unintended acceleration scandals of a few years ago. If anyone feels like reading it, here's the link to the proposal: http://www.nhtsa.gov/staticfiles/rul...NPRM_Final.pdf (It's long, I suggest not reading it). Here are a few excerpts:
Quote:
The BTO [Brake Throttle Override] system may check conditions such as vehicle speed, engine revolutions per minute (RPM), brake pedal travel, and pedal sequence (i.e., whether the brake was pressed first and then the gas pedal, or vice versa) to determine if the driver’s intention is to stop the vehicle. Based on these conditions, the BTO system may determine that the combined brake and gas pedal inputs are actually intentional
Quote:
We believe there is no particular safety issue in these situations, and in fact this type of “two-footed” driving capability can be desirable and may be in widespread use.
Quote:
The current language of the test procedure in FMVSS No. 124 is expressed in terms of the return of an observable moving part, i.e., the throttle plate, to a closed or nearly closed position. It does not prescribe other types of vehicle fail-safe responses besides throttle closure. This neglects the variety of ways in which powertrain output in a vehicle with a modern throttle control system can be reduced to an acceptably benign level, e.g., spark adjustment, even though the throttle plate may be at a non-idle position.
Quote:
NHTSA does not believe the intent of the Standard should be construed as merely setting a limitation on throttle position. Instead, it is evident that the fundamental safety purpose of the Standard is to prevent a vehicle's powertrain from creating excessive driving force when there is no input to the accelerator pedal. There would be no safety reason whatsoever to require the throttle to close if that did not limit vehicle propulsion.
Quote:
Even if it is well established that FMVSS 124 does apply to ETC systems, regulating ETC systems by drawing analogies to mechanical systems has undesirable outcomes.
Quote:
Fuel injection and ignition timing are among factors that can be varied without any change in throttle position.
Finally, here's a video of a rally driver (with a highly turbocharged engine) which clearly shows that he uses two pedals (in some cases, it appears three) at the same time. Additional airflow is required to build boost, and honoring a legitimate driver demand is not a safety issue. https://www.youtube.com/watch?v=wdy8CG09rSUQuote:
Modern engines routinely have variable valve lift and/or timing control. In at least one recent engine design, the level of valve control is great enough that the throttle plate no longer throttles the engine during at least part of the engine’s operating range. Instead, air intake is throttled to a large extent by the intake valves themselves while the throttle plate stays in an open position. In such a design, requiring "return of the throttle to the idle position" would be design restrictive without any safety justification.
Ok, it seems that the ETC rules are a bit too extreme... Is Kettering University the only team that has an issue with that (the only team that planned to run it?!) or are the others just silent?
In my experience, Michael and Andrew, complaining about it in this forum does not change anything. You should take it up to the rules committee. When FSG announced some serious Aero restrictions for 2014, the guys from Monash wrote a nice document where they explained why the rules are too strict - not purposeful.
Maybe your team - with the experience of CSC - could try a comparable approach. To be honest, I still think the Germans are much better to talk to compared to the US responsibles, so don't know if this works, but it's worth a shot...
Kevin,
you proposed a delay of the rules for 2016 - do you still think this is necessary? I am sadly not able to fully understand the impact of the changes so don't know if the teams that already started designing their car for Michigan have an issue. If Curtin wants to go to Europe 2015, do they need more changes besides a different aero package?
John, Is there a reason or has it been done before, that we don't use drive by testing (such as on the run up to the brake test or on an accel length road). As I understand this is how noise compliance is tested on motorcycles at most racetracks in australia. Motorcycle racing GCR specify testing to be done towards the end of a straight under full throttle.
I don't know of anywhere where noise is measured with a static vehicle.
Also in regards to the SCCA rule style testing (which sounds similar to the motorcycle noise testing method) why not do the testing on a longer run immediately after brake test?
Nick
The brake check and acceleration run do not test enough of a range of engine events. Many of the sound violations come from off throttle events including backfires that show up while running the endurance event. Putting a meter out on track and handing penalties for sound violations caused frustration for students and organizers. You do not want that simulation to return.
John Burford
Hi Julian,Quote:
Originally Posted by JulianH
Based on my reading of rule T3.5.5 "The support tube must have the same diameter and thickness as the bent tube, terminate at a node of the chassis, and be angled no more than 45 degrees from the plane of the bent tube." our upper side impact bar would not be rules legal. Although we potentially get around this with stressed panels and then structural equivalency.
A few pictures of our 2013 chassis are here, our 2014 side impact is similar. https://www.facebook.com/media/set/?...8650754&type=3
Reading through the new monocoque rules for our first metallic monocoque in 2015, this new section really stumps me:
Is a 0.8mm aluminium skin illegal? And does only the firewall have to be coated with rubber or everything that the driver touches? Obviously they want to electrically isolate the driver in the case of the tractive system energising the chassis but surely a completely conductive box is going to do a better job then a layer of rubber on a part the driver is never going to touch since the seat will separate them from the firewall....Quote:
T4.5.4 EV CARS ONLY
In addition a firewall must separate the driver compartment from all tractive system components.
NOTE: this includes any HV wiring.
The tractive system firewall must be composed of two layers:
a. One layer, facing the tractive system side, must be made of aluminum with a thickness
between 0.5 and 0.7 mm. This part of the tractive system firewall must be grounded according
to FSAE Rule EV4.3.
b. The second layer, facing the driver, must be made of an electrically insulating material. The
material used for the second layer must meet UL94-V0, FAR25 or equivalent. The second
layer must not be made of CFRP.
I think Kettering just has the most familiarity/design maturity due to CSC. I agree with the Kettering appraisal from my current understanding of ETC. As far as I can read, the rules implementation of ETC literally is just replacing a conventional cable with ton of sensors, wires, and a motor without presenting much possibility to reducing pumping losses due to throttling which is really the biggest benefit to ETC. Right now the ETC rules really only let you decouple pedal movement from butterfly movement (you could more-or-less do this with a mechanical cam) and add a whole ton of failure modes into the package which are not present with cable throttle bodies. My team is not ready to implement ETC, but given the current rules I believe we would think twice about doing it from an FMEA sense alone as there really aren't many benefits to outweigh the increase in failure modes or huge amount of design time.Quote:
Originally Posted by JulianH
Julian,
My reasons for proposing the delay were stated as:
- Allowing teams to have plenty of time to adjust to large concept changes
- Allowing time for feedback and development of clearly worded rules with objective scrutineering procedures
- Avoiding situations where teams are not able to travel due to cars becoming illegal, with unreasonable changes required to make them legal in a short time frame
Most of the focus of discussion was on the first point, but I feel much more strongly about the last point. The team I am faculty advisor for was unable to travel to the UK in 2013 because of a minor change to the chassis rules that was not announced prior to the official rules release.
In this set of rules we have all three problems well and truly covered.
These rules have significant conceptual effects
There are quite a few sections which are quite subjective. Hopefully there will be a lot more clarification on the scrutineering procedures in the coming months.
Finally there are lots of small changes that affect the main structure of the car. A lot more monocoque testing, increased restrictions on spaceframes as well as a lot more details about bolted joints. In amongst that there is plenty that could invalidate a car built to the current rules structurally. A grandfathering clause would be really useful for these cases, otherwise teams may have to make fundamental changes to chassis systems. Something that I think would stop affected teams being able to travel. Of course these a preventable by much earlier rules releases.
I think a good argument could be made that expecting smaller wings (or other performance hit) is not too much to ask of traveling teams, but full tear-downs with potentially large structural modifications is going too far.
Without going into details (a lot of points in this rules release) yes I do think a delay would have been the wise choice. What may be helpful now is to look to an earlier release in following years as being a standard. In the discussion we had on the other thread there wasn't any opposition to the idea that rules releases could be made earlier.
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O̶f̶ ̶p̶a̶r̶t̶i̶c̶u̶l̶a̶r̶ ̶i̶n̶t̶e̶r̶e̶s̶t̶ ̶t̶o̶ ̶m̶e̶ ̶i̶s̶ ̶t̶h̶e̶ ̶c̶h̶a̶n̶g̶e̶d̶ ̶w̶o̶r̶d̶i̶n̶g̶ ̶a̶b̶o̶u̶t̶ ̶t̶i̶r̶e̶ ̶t̶r̶e̶a̶t̶m̶e̶n̶t̶.̶ ̶ ̶I̶t̶ ̶a̶p̶p̶e̶a̶r̶s̶ ̶t̶h̶a̶t̶ ̶w̶h̶a̶t̶ ̶w̶a̶s̶ ̶o̶n̶c̶e̶ ̶b̶a̶n̶n̶e̶d̶ ̶o̶u̶t̶r̶i̶g̶h̶t̶,̶ ̶a̶p̶p̶e̶a̶r̶s̶ ̶t̶o̶ ̶b̶e̶ ̶e̶n̶c̶o̶u̶r̶a̶g̶e̶d̶ ̶b̶y̶ ̶w̶a̶y̶ ̶t̶h̶e̶ ̶r̶u̶l̶e̶s̶ ̶a̶r̶e̶ ̶w̶r̶i̶t̶t̶e̶n̶.̶ ̶ ̶T̶h̶i̶s̶ ̶i̶m̶p̶l̶i̶e̶s̶ ̶t̶o̶ ̶m̶e̶ ̶a̶ ̶p̶e̶r̶c̶e̶p̶t̶i̶o̶n̶ ̶t̶h̶a̶t̶ ̶t̶e̶a̶m̶s̶ ̶h̶a̶v̶e̶ ̶b̶e̶e̶n̶ ̶t̶i̶r̶e̶ ̶t̶r̶e̶a̶t̶i̶n̶g̶ ̶a̶n̶d̶ ̶i̶t̶ ̶i̶s̶ ̶t̶o̶o̶ ̶d̶i̶f̶f̶i̶c̶u̶l̶t̶ ̶t̶o̶ ̶a̶s̶s̶e̶s̶s̶ ̶a̶t̶ ̶c̶o̶m̶p̶s̶.̶ ̶ ̶I̶ ̶w̶o̶n̶d̶e̶r̶ ̶w̶h̶a̶t̶ ̶p̶r̶o̶d̶u̶c̶t̶s̶ ̶t̶e̶a̶m̶s̶ ̶h̶a̶v̶e̶ ̶b̶e̶e̶n̶ ̶u̶s̶i̶n̶g̶.̶ ̶ ̶I̶ ̶w̶o̶u̶l̶d̶ ̶i̶m̶a̶g̶i̶n̶e̶ ̶t̶h̶a̶t̶ ̶o̶u̶r̶ ̶t̶e̶a̶m̶ ̶w̶i̶l̶l̶ ̶h̶a̶v̶e̶ ̶t̶o̶ ̶a̶l̶l̶o̶c̶a̶t̶e̶ ̶r̶e̶s̶o̶u̶r̶c̶e̶s̶ ̶t̶o̶ ̶t̶i̶r̶e̶ ̶t̶r̶e̶a̶t̶m̶e̶n̶t̶ ̶n̶o̶w̶.̶
O̶n̶ ̶o̶n̶e̶ ̶h̶a̶n̶d̶ ̶t̶h̶e̶r̶e̶ ̶i̶s̶ ̶a̶ ̶p̶u̶s̶h̶ ̶t̶o̶ ̶h̶a̶v̶e̶ ̶i̶n̶c̶r̶e̶a̶s̶e̶d̶ ̶c̶o̶n̶t̶r̶o̶l̶ ̶o̶v̶e̶r̶ ̶p̶r̶o̶c̶e̶d̶u̶r̶e̶s̶ ̶t̶e̶a̶m̶s̶ ̶p̶e̶r̶f̶o̶r̶m̶ ̶o̶u̶t̶s̶i̶d̶e̶ ̶o̶f̶ ̶t̶h̶e̶ ̶c̶o̶m̶p̶e̶t̶i̶t̶i̶o̶n̶ ̶(̶i̶.̶e̶.̶ ̶c̶o̶m̶p̶s̶ ̶p̶u̶n̶i̶s̶h̶i̶n̶g̶ ̶t̶e̶a̶m̶s̶ ̶f̶o̶r̶ ̶u̶s̶i̶n̶g̶ ̶t̶h̶e̶i̶r̶ ̶c̶a̶r̶s̶ ̶f̶o̶r̶ ̶p̶u̶r̶p̶o̶s̶e̶s̶ ̶n̶o̶t̶ ̶a̶p̶p̶r̶o̶v̶e̶d̶ ̶o̶f̶ ̶b̶y̶ ̶t̶h̶e̶ ̶o̶r̶g̶a̶n̶i̶s̶e̶r̶s̶)̶,̶ ̶a̶n̶d̶ ̶h̶e̶r̶e̶ ̶w̶e̶ ̶h̶a̶v̶e̶ ̶i̶m̶p̶l̶i̶c̶i̶t̶ ̶a̶p̶p̶r̶o̶v̶a̶l̶ ̶o̶f̶ ̶p̶l̶a̶y̶i̶n̶g̶ ̶a̶r̶o̶u̶n̶d̶ ̶w̶i̶t̶h̶ ̶s̶o̶m̶e̶ ̶p̶o̶t̶e̶n̶t̶i̶a̶l̶l̶y̶ ̶v̶e̶r̶y̶ ̶n̶a̶s̶t̶y̶ ̶c̶h̶e̶m̶i̶c̶a̶l̶s̶.̶
Apart from fairly consistently advocating an earlier release of the rules my other favorite hobby horse is to introduce homolgated tyres to the competition. Tyres supplied at the comp for running, by suppliers that can supply a minimum number of approved tyres (i.e. no special one-off tyres). Tyres have always been a considerable expense and waste. Who cares about saving 1-2 litres of fuel when you throw out tyres after 22km? Now we are likely to see another tyres arms race, but with all sorts of treatments as well as the custom tyres starting to appear.
Obviously an earlier release (or at least an early draft release) would enable a decent period of feedback and explanation to occur. Maybe we can start a push to have the 2016 rules released somewhere between feb and may in 2015.
Kev
Thanks for your answer Kevin.
It's always difficult to be "the old car in a new set of rules". I think the "Monash way" to skip every second year and have a car built to the first year of the two year cycle is the better choice. So for Australian teams to be in Europe in even years. I still would love to see all of you guys in Europe every year but I'm sure that the new rules are only one fraction of the issue here. Budget is probably more difficult...
About the tires:
When I was part of the staff at FSA this year, there was one team that obviously soaked their tires in some grip enhancers (when they opened the tire protectors the tires seemed basically "wet"... The scrutineers saw that but the reaction was sooo quickly: "Yes, but we did it before static judging so it's ok". And that was it...
I think it is ok to use tire softeners or what ever because otherwise we had to ban customized tires too (Delft, Eindhoven and Darmstadt are basically able to bring tires "softened" at the competition...).
But what I don't like is that this excessive use of tire softener reduces the life span of the tires and therefore leads to a budget-issue.
In my opinion a new rule should be introduced that only one set of tires is allowed to be used at the dynamic events. Teams can do brake test or testing on an old set but if they enter a dynamic event, they can only run this marked set.
If they think they can run an endurance with softened tires, ok.
But, I think using "suuuper softened" tires for Accel / Skidpad, "medium softened" tires for AutoX and "mildly softened" tires for Endurance is an unfair advantage for the "rich teams". Tires are expensive...
If on track violations are enough for ADR and other non-FSAE motorsport organisations then why should FSAE be different, competitions are often run at motorsport venues, surely fitting to the tracks existing noise restrictions is sufficient.Quote:
Originally Posted by John_Burford
I wasn't really suggesting having a meter permanently on track though, but rather a chance for drive by noise to be tested (similar to the ADR test procedure).
Kev, Big fan of the homologated tyres idea or at least a homologated list with manufacturers guaranteeing the availability of sufficient tyres. Introduce a tyre war...
I'm silently busy with other things. But I agree, they are too extreme and there are some confusing parts in there that I need clarification on with the rules committee.Quote:
Originally Posted by JulianH