Champ car undertray

[Ospi]

Hi all,

Im wondering if anybody has photos of the undertray of a champ car. Reason is im working on a formula SAE car for university and we are researching the possibility of implementing ground effects on the car this year. So if theres any photos of the undertray of the car lying around that would be greatly appreciated.

Thanks.

[Notso Swift]

Ground effects at 40 kph?

[Goran Malmberg]

I don’t have any pictures to show, but I have looked at most undertrays on any kind of race car. Aero is an area where it is very hard to "copy" anything
as small variations is of big influence. However, it is a good idea to take a close look at what has been done to other cars as it might enlighten one about layouts.
As Notso ask, "Ground effects at 40 kph?", I have tried a flat underside at different rake and at a ground setting of 3". Measured at the shifter location under the car and at 90 mph it could be raked to pull 3" of water. But as well to produce a lift, raked the other way.
The area under the car is quite large so we will have some "effect", and a simple calculation will tell what will happen at other speeds. But of course we got other numbers out the sides of the car.
I am not a guru of ground effect, but I have seen that understanding "aero" is mandatory to get results, and what we see on other cars must be looked at in its relation to circumstances.
Not really an answer to your Q, just some thinking...
Regards Goran Malmberg

[Ospi]

Yeah, eventhough the cars genarally only corner at 60kph, if done correctly GE can actually still help. Performance isnt the reason we are doing it though, its to give the team an opportunity to learn about it and understand it which will be invaluable experience down the road.

[Goran Malmberg]

Originally Posted by Ospi

Yeah, eventhough the cars genarally only corner at 60kph, if done correctly GE can actually still help. Performance isnt the reason we are doing it though, its to give the team an opportunity to learn about it and understand it which will be invaluable experience down the road.

Anything but higher pressure under the car is good, and if we just get an inch of water Gf, we will go faster around the track. Everything counts.
I am working with designing a Corvette right now, which is supposed to take advantage of Gf . I will show some numbers later on which could be interesting as it is a "one man job without very much money". Which means that it is the kind of result anybody could calculate to get (or hopefully better ). Allthrought I am 63 years old I am doing this for the same reason as you, learn more.
Goran Malmberg

[zac510]

There has been tons of media coverage of the new Panoz Champcar so I'd be surprised if there weren't some images of the underbody in one of the technical magazines.
You may also want to look at the GP2 tunnel/skirt configuration?

[ubrben]

Originally Posted by Ospi

Hi all,

Im wondering if anybody has photos of the undertray of a champ car. Reason is im working on a formula SAE car for university and we are researching the possibility of implementing ground effects on the car this year. So if theres any photos of the undertray of the car lying around that would be greatly appreciated.

Thanks.

You have complete freedom with the undertray, why do you want to look at a highly regulated spec-series undertray?

Copying F1 or Champ Car ideas is the quickest way to losing in FSAE IMHO.

Questions:

Do you have a good wind tunnel?
Do you have access to good CFD software?
Do you know how to use the CFD software NOW?

If the answer to any of those questions is no, don't do an aero package for the car. A bad aero package is worse than no aero package in FSAE.

Ben

[Ospi]

To answer your questions:
Kinda
yes
yes

At the moment we arnt deffinately going to incorperate in into the car, its just a research and investigation stage for now. We dont want to copy CC type undertrays but we want to study them and learn how they work. If anythign this year will be a simple design to help the team learn about GE and progressivly research and develop it for the coming years.

[flavorPacket]

if you're doing this to learn, don't put it on the car at competition. the judges will tear you in two.

[ubrben]

Quite right - we will :-)

Either design it as an integral part of the car from day 1 or not. Don't add it in later.

By all means do the research, but be big enough to realise that you need to wait a year to put it on a car.

Ben

[Suddenlee]

Hi,
If I am your FSAE Judge, you REALLY need to be able to justify your aero decision!
PC

[flavorPacket]

don't take it lightly. the teams with the BEST aero packages (UMR etc), 100s of hours in the tunnel, excellent 3d CFD models, the whole shebang, still get killed in design.