I have read this thread with a great deal of interest as an engineer and
pilot. What I find most interesting is that the down force increases as the
square of the velocity, which is also what the centrifugal force on the car
in a "constant radius" turn increases by. So why the advantage of going
faster? Three _possible_ reasons. First, the down force is present before
the turn and makes turn-in more abrupt and effective. Second, the down
force increases the contact patch area of a wide compliant tire, making
ultimate shear stress higher. Third, the down force is not at the C.G. of
the car and results in better balance in cornering.
Note: I have _never_ driven a winged car, so I have absolutely no idea of
which of these possibilities may be dominant (or even noticeable). Just fun
thoughts......
Brent
> -----Original Message-----
> From: owner-autox@autox.team.net [mailto:owner-autox@autox.team.net]On
> Behalf Of ttarleto@ix.netcom.com
> Sent: Tuesday, January 05, 1999 9:11 PM
> To: autox@autox.team.net
> Subject: Downforce
>
>
> Hi ,
> I can't give a number for a ground effect car , as each car is very
> different. FYI , a wing can produce lots of downforce at 50mph.
> Each wing has a different Lift/Drag Cofficient, but here are some
> popular wing designs and the amount of lift [downforce] they produce.
> formula here is lift, lb = .00256xClxSxV2 Cl is lift cf, S= airfoil area
> in sq ft, V = speed in mph; for all you math heads.
> A clark Y wing @ 32sq ft = 174 lb at -10 deg of attack and 256
> lb at15 deg
> THIS IS WITHOUT ANY FLAPS OR GURNEY LIPS.
> a 23012 wing with a slotted flap run at 40 deg of attack has a Cl of 2.7
> or 553 lb of force.
> This is a lot of extra grip on a 1200lb modified car.
> This is all at 50mph.
> Tom Tarleton
>
>
>
|