Just a thing I am curious about and said I'd ask all you budding aero fellas:

(I'll just preface this by saying I don't understand much about aero and have trouble with most words over 7 letters long...)

Take any 4 wheeled vehicle, a minimum of say 2" ride height, no fancy stuff like movable skirts or the "cooling fan" on the Brabham fan car, whats the most downforce inducing shape? Covered wheels? Flat floor? Big mad wings?

Very much depends what drag co-efficient you want.

Getting downforce is easy.

Getting downforce without inducing shed loads of drag is difficult......

A few links from Bell Perfomance re Downforce / Car aerodynamics.

Link 1
Link 2
Link 3

Yes, Yes, Yes!

I think that the most aerodynamic types of cars (within reason - to accompany a low drag co-efficient) are usually the LeMans type cars...

quote:

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Originally posted by Nosey
whats the most downforce inducing shape? Covered wheels? Flat floor? Big mad wings?

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This puts me in mind of something called an inverted wing. Iirc it's something to do with the shape of the floor and it sucks the car to the ground. I've only ever heard of 2 instances though, first that it's banned in F1 and one car on top gear that was crap at cornering unless you were doing about 50mph..

If anyone has more information on it?

I think youre kinda confused. An inverted wing is just that, its an upside down aerofoil that lifts downwards to provide downforce.

You can incorporate one into the underside of a car as per the old lotus formula cars which had curved weddge shapes in side pods.

Other floor effects rely on a venturi.

Its all in the links above

There other factors to consider in racing cars like too much downforce and not controllable downforce

The early 'wing cars' like the Arrows A2

http://www.interq.or.jp/sun/mm-kas/hakubutu/arrows-a2.jpg

Had a problem where they generated too much downforce at high speed, when not required whcih made the cars bottom out too much, so the designer craftily developed a radiator vent that woudl open to reduce some low pressure. Technically this was a movable aerodynamic device but they didnt get caught.

In the meatime the car was apparently hopeless as when the car acclerated or braked the mose angle would change which as the car was one big inverted wing changed the angle of attack of the wing to the air.

This changed both the amount of downforce and the centre of presure, the point on the car on wchih the centre of the downforce acted.

This caused the drivers problems in braking zones etc and even on the straights

"The cars generally suffered from porposing down the track and especially under braking. This destroyed the vital profile of the airflow through the venturis in the sidepods"

Before it was banned, there were a few cars that were applying downforce directly to the wheels via the knuckles. Much better than applying it to the body for the reasons previously stated.
Have a look into Chapparal. He produced some neat stuff.

As for the inverted wing, just don't screw it up:
http://www.youtube.com/watch?v=srYDvV680gk