Chassis bottom?

[Moody]

Hey guys,

Is there any reason that I don't see a flat-bottomed chassis out there? I understand that suspension mounting points determine a great deal of chassis geometry, but is there any disadvantage to a flat bottom?

- matt

[vinHonda]

Well......aren't all chassis flat at some point? Aren't most of the chassis flat? Ours gets pretty flat near the drivers butt.

Vinh

University of Toronto Formula SAE Racing Team
www.fsae.utoronto.ca (http://www.fsae.utoronto.ca)

[yofa]

Flat bottoms aren't really performance enhancers. They're usually rules in the racing formula that dictate the bottom of the car should be flat for the sake of moving more aero devices up in plain view, adding sponsor real-estate on larger wings and slowing cars in corners. If the rules for underbodies were unrestricted, F1 and sports cars would be creating mega downforce and wings would be smaller. I believe CART has close to unrestricted undebodies.

If you're asking why not more cars have aerodynamic undertrays, that's because it's damn hard to design a useful one at our speeds. UTA seem to have very effective underbody aerodynamics. Simply making a flat bottom will not blow away the competition.

Bob Mai - yofa@shaw.ca
Steering/Suspension
University of Manitoba/Red River College

[Andy K]

Our last chassis was designed to be completely flat all the way from the front bulkhead to the rear plane of the diff box, with our suspension points fully integrated in the frame tubes. This decision was made purely for ease of manufacturing.

Our new chassis has undergone significant changes, but still retains a completely flat bottom. Then again we're adding some cool stuff, but I am not at liberty to divulge such information.

Andris Kanins
McGill Racing Team
2002/2003 Body Design
2003/2004 Suspension

[Halloween]

Obviously you want to fabricate a shape that adds downforce. However, due to the small size of our cars, we are very limited in space, and almost any shapping of the undercarriage for the most part, will result in a higher cg.

I would look at the rear end of a Ferrari Challenge Stradale, they work an upside down scallop shape on the rear of the underside of the car. If you could do that aft of the engine, you might could get some downforce without raising any components of your car.

[Moody]

Thanks for all the input, fellas. We would not even consider the aero benefits right now - I was asking based on a manufacturing standpoint.

Thanks again!

- matt

Matt Moody
Crimson Racing
University of Alabama FSAE
matt@pepper.net