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Old 05-31-2008, 04:05 PM   #11 (permalink)
SuperTrooper
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Quote:
Originally Posted by Otto View Post
Bingo. Using the traction bar frame to support a boat tail would more than pay for any penalty imposed by the slightly extra weight of the boat tail material. Since the front wheels don't have to turn much in a drag race application, may as well cover them.

The nose cone/bumper cover of that red car are pretty good, but could stand some improvement.

Got undertray? Wheel fairings?

PS: Do the rules require the drag bar to have a wheel on each side, or could you make a presumably lighter drag bar by tapering to just one centerline wheel, perhaps a bit further back? That would make a nice frame for a teardrop boat tail, while still doing its drag bar function.
FWD drag racer have slightly unique needs vs. RWD cars. They need to keep as much weight on the front wheels as they can at all times. The air dams you see on the front of these cars generates enough downforce to put the lower edge almost on the pavement at top speed. There's not enough air going under the car to make an undertray worthwhile. Dragsters and funny cars are usually open on the bottom and it doesn't seem to matter.

A boattail 4-5 feet long would put weight in a place no FWD racer would want it: behind the center of gravity (CG) of the car. Even CF weighs enough that, combined with the leverage, would move the CG toward the rear of the car. The Red racer has probably done as much as you should for a FWD car. Adding a flat panel to smooth the transition of air at the rear of the car probably reduced lift and drag without impacting downforce and CG.

Wheelie bars on FWD are usually spread as far apart as is practical to keep the car as level as possible during launch. If the car were to tilt to one side it would unload one of the front wheels = wheelspin = you lose. I've seen single wheelie bars on dragsters, but full bodied cars usually have 2. Wheelie bars also exist in a disturbed air region behind the car, so aerodynamics is a moot point. They are designed to be as strong and as light as possible.

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