The Delft team has recently had it's press presentation, where a short movie was shot:

DUT05 test drive

The text is in Dutch, but a short summary is:

The Delft team has again build a car following the Delft Concept: It weighs 125 kgs, while the engine produces 55 bhp, (15 more than last year). Furthermore, there are some new CF rims, a CF monococque, and a aluminium/steel rear spaceframe. The car does look promising to do very well on the FS event next week!

125 kg! Thats 275 lbs! Amazing

Look forward to seeing it next week.

Certainly looks the part this year! Will be interested to see how various little items hold up over the weekend, drivetrain especially.

What type of cv joint is that on the drivetrain?

Its one of those flex plate joints. I think gkn or rtg makes them. They have a very small misalignment angle.

nice!
thats (kind of) the engine we used, are one cylinders becoming more popular?

are the suspension arms composite?

As the team is probably already on their way to the UK, I'll answer that.
This is the third year Delft has run a single, but they weren't convincing many other teams to switch to singles yet. I think RMITs results in Detroit will have more influence on a possible paradigm shift.

The suspension arms are indeed composite. Rob Woods probably hates it with so much "masterbation" carbon fibre :-)

More pictures at www.dutracing.nl

Igor

This message has been edited. Last edited by: Igor,

Composite parts on our car:

(I might still miss a few)
- Monococque
- Rims
- Nose
- A-Arms
- Pedals
- Drive shafts
- Air inlet system
- Fuel tank
- Oil tank
- shifter
- CV Joints
- Steering colom
- Diff closing ring

FYI we are in the "Best use of Composites Award" competition. ;-)

And those are the main things I can get from my head at this moment. Just visit our pit at Brunthy to see for yourself!

thanks for the answers.
and thanks for the excellent+comprehensive gallery!

At 275lbs you guys can do whatever the hell you want. Its not masterbation if it actually does what it did for you guys. But here is the big question. How fast are you with your declared 5:1 weight to power ratio. If you can produce a 4 sec accel time then you are even furthur from masterbation and straight into big pimpin'. If you cant then something is wrong with you guys. So what is the time?

Tsk, tsk, mutter, mutter (those showboating young boys have gone and made it too complicated again!!!...).

Seriously though (and no offense intended here ), but can somebody please justify the front spring/dampers mounted as high as is physically possible???

Please don't say that the car had to use pushrod-&-rockers to get the motion ratio up for good damper control. The motion ratio as shown isn't far from 1:1, and with such a light car you only need very soft dampers anyway. Likewise don't say that the rockers are there so that you can have a rising rate (undesirable), or for aerodynamic reasons (which they aren't)...

Using coilovers direct to the wheels (F&R) would give a lighter car (maybe 120kg), lower CG height, stiffer installation, lower stiction in the suspension, lower cost, faster build time, more time for testing, fewer things to go wrong...

So please tell me why this isn't just a "fashion based" decision?

Z

quote:

Originally posted by Z:
Using coilovers direct to the wheels (F&R) would give a lighter car (maybe 120kg), lower CG height, stiffer installation, lower stiction in the suspension, lower cost, faster build time, more time for testing, fewer things to go wrong...

I agree with all these points, except for the weight. I think if anything, coilovers direct to the wheels would translate to a slightly heavier car. The coilover would have to be longer (for most geometries we see in FSAE at least), and if you were to use a conventional ARB (as opposed to some crazy UWA style system), it would need to be considerably longer.

Matt Gignac
McGill Racing Team

Haven't we had this argument before?

And Rob, I believe they did 4.0's last year in England, 1st or 2nd in accel, with 15 less HP.

And power/weight figures are useless if you don't include the driver.

Tsk, tsk, mutter, mutter (old farts and their perpetual nagging....)

Z:
You'll have to ask the team when they get back. Weight is not an argument as the rocker and push rod combination probably doesn't weight more than 200g. You'll get similar weight savings by washing the drivers underwear.
The part that really scares me is the skimpy size of their rose-joints.

Rob:
I hadn't noticed your t-shirt add before. Excellent, where can we order one?

Last year they were 2nd in accel with 4.12s but I think the claimed power was a bit on the low side then. We'll see how it goes this weekend.

Igor

quote:

Originally posted by Igor:

You'll get similar weight savings by washing the drivers underwear.

LOL!

Any rules against being bollock naked underneath your race suit fo weight saving purposes?

Pair of shoes and a set of clothes have to be worth at least 2kgs...

Z,

I don't agree with you on the weight part... If you think that losing four rockers with attachments gains approx. 5 kg's you should come to Delft and weigh those parts for yourself. I also agree with Matt that your solution would probably end up heavier, especially when you want to add roll-bars.

There is a regulatory front hoop right there which is very well suited for attaching stuff, so why not (simply) use it? Mounting parts not on the front hoop is always heavier due to the carbon chassis. It is:
low weight (higher cg) + simplicity versus lower cg (probably higher weight) + added complexity

As for the carbon fibre, building a light car is not just about lot's of carbon fibre, we have the facilities to produce many carbon parts, so we use them, but the car isn't light (only) because of the carbon. The word "carbon" does seem to make things special for a lot of people...

Peter
Delft

Denny,

Yeah, like I said before, if you don't stir the pot then the froth and bubble rises to the top and forms a layer of scum - not nice . I'm seeing a lot of "froth and bubble" here (ie. fashion based decisions), so here we go again...

Peter,

I take it you are part of the Delft team. I honestly don't mean any offense here, but I think that most teams that use "rockers" do so because it is "fashionable". Unfortunately, they then delude themselves into thinking that they have used rockers for "rational" reasons. Again, no offense intended . Everybody is subject to self-delusion - aka "peer group pressure". It is only when you realise it that you can control/manage/cure it.

You (and Matt) say that my solution (a direct-to-wheel coilover with no rocker) "would probably end up heavier". How so? I would take your existing coilover, attach the bottom 1/4 of your pushrod as an extension of the damper shaft, and throw away the upper 3/4 of the pushrod, the rocker, and the rocker mounting bracket. Surely this is losing weight? Furthermore, I would attach the coilover to the chassis just above the upper-wishbone rear chassis mount, which is already a "strong point" and probably part of your dashboard bulkhead (or front-roll-hoop?). Moving this coilover chassis mount closer to the centre of the car makes for a shorter stressed chassis, so less weight again (do similar at rear). Also this angle of coilover is more aligned with the worst case forces on the front wheels (ie. from wheelprint to CG), so it reduces the loads on the lower wishbone, so again less weight.

Regarding anti-roll-bars (ARB's). Does your car have them (I didn't see any in the pics)? I personally don't like ARB's. If I had to (say, using someone else's car) then I would only use one ARB (either F or R, not both). The coilovers carry the greatest part of the car's loads, so an ARB only has to carry light loads (for minor adjustments of cornering balance), so the ARB itself only has to be very light. Many of the rocker attached T-bar style ARB's seem excessively heavy, and with too high CG, in my opinion. A conventional U-bar, maybe in carbon-composite, can be made very light, low, and with good structural load paths.

ARB's are only one of many different ways of interconnecting wheels with spring elements. However, because ARB's stiffen the suspension's roll mode AND ITS TWIST (AKA WARP) MODE, they are one of the worst ways of interconnecting the wheels. A better way is to use longitudinal Z-bars to give "anti-bounce-anti-roll". (An ARB is a lateral U-bar or anti-differential-movement spring that connects an end pair of wheels. A longitudinal Z-bar is an anti-similar-movement spring that connects a side pair of wheels. The term "Z-bar" is commonly used - no relation ) Interconnected springing is a big subject, but I bring it up here to point out how "fashion led" current suspension design is. There are good rational justifications for push/pullrods and rockers if you want to interconnect the front and rear wheels. But very few people are even looking at that. I can see no rational justification for rockers on a simple "spring at each corner" suspension.

Z

PS. Igor, "underwear"??? Too complicated!!!

Z,

No offend taken off course and yes I am from the Delft team, the 2004 team however, haven't done much this year.

One of our requirements of the 04 and 05 suspension was the possible placement of ARB's. On the 04 we ended up not using it, since we didn’t need it to balance the car. On the 05 car an ARB can be placed, if you look at the pictures you'll see a hole in the chassis and holes in the rocker needed for the ARB. At the moment the team is testing in England, I don't know if they are using the ARB or not.

If the 05 runs without ARB's; your direct system could have been used and would indeed be lighter, however losing the possibility of an optional (simple) ARB is a difficult choice, as an ARB is a very efficient tool in adjusting balance.

I agree on the fact that most loads go through the shocks and an ARB can be very light, however losing weight with a direct shock system is not as simple as you describe it. For example losing weight on our wishbones will be difficult, at the moment their dimensions are determent by a non-racing load case; handling/unexpected loads. There are practical limits to how far (thin) you can go. The chassis won't be much lighter/stiffer when the load path is shortened in vertical direction (longitudinal is more important), in both cases the loads are transferred into the chassis through the front hoop (='sort of’ dashboard bulkhead).

I have read about Z-bars and it does sound interesting, however I think at Delft we have still plenty of testing to do with the current system and other parts on the car, there is always a lot to do!

quote:

Originally posted by Z:
so here we go again...

Don't worry; I'll be going on a holiday soon

Peter
Delft

READ THE RULES!

3.5.1.4 Drive Train Shields and Guards

quote:

Originally posted by El Joe:
READ THE RULES!

3.5.1.4 Drive Train Shields and Guards

Don't worry, the scatter shield will be on it before competition starts... (Reading rules is something we are quite good at actually )

Peter
Delft