Rounded Belly Pan

[Grant-53]

Ride height, angle of attack, and the side curvature all have some effect on flow, lift, and drag. A good discussion is found in "The Leading Edge" by Goro Tamai.

[jeff88]

My idea with this is to basically flip the aerodynamic template upside down. It would never angle up or down more than 10-15°. My main question is if that would be more or less efficient than a flat belly.

The Colani looks to me like a high drag vehicle as well, but if it is less than .2 Cd... Maybe that supports the answer to my question that a rounded belly is better than a flat belly (of course there are other aerodynamic principles involved in the Colani car, but the belly surely has something to do with it).

Also, I'm not suprised that I am not the first to think of/implement this idea. I always have *great* (relatively) ideas, they're just late to the game!

[aerohead]

Originally Posted by jeff88

Was thinking about belly pans and was wondering if it would make a more efficient belly pan to curve it slightly to simulate the tear drop.

What do you think?

Historically,the pans are held as close to the body as possible to minimize frontal area,then at the rear,a diffuser of very shallow angle is positioned can be,to provide some static regain into the wake.
Hucho prefers the longer,shallower diffuser for best drag reduction.
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Dr.Michael Seal's research institute at Western Washington University used inverted wing profile bellys on their series of Viking research vehicles.
I've never seen a Cd below 0.33 published for any of their cars,which suggests that the exotic pans made no dramatic drag reduction.Stability in an ultralight vehicle WOULD be a plus for a down-force-producing pan.