Making a more efficient, aerodynamic soapbox gravity race car

[orengomotors]

Originally Posted by freebeard

Just a wedge-shaped trailing edge that would give an airfoil cross-section. I said zip-tied because safety officials might want it removable for inspection.

is a good idea.
will a naca 0015 work well for the basic body shape?


what will work better, a flat floor or a curved one?
the "fenders" can look like this:



A narrower, less downforce, and lightless version of that.

[freebeard]

The airfoil and curved floor would produce lift, which would unload the tires for less rolling resistance, but the cornering would suffer. Here's an example of a car that has a curved bottom and flat top, for low-drag downforce; one of Luigi Colani's Bonneville cars.



There's a lot of fabrication work in those fenders, but hey — go for it.

[NickelB NL]

Maybe a stupid idea. But would you like air brakes? Foils witch you use as airbrake and double up as wings for down force to increase cornering speed.

[orengomotors]

Originally Posted by freebeard

The airfoil and curved floor would produce lift, which would unload the tires for less rolling resistance, but the cornering would suffer. Here's an example of a car that has a curved bottom and flat top, for low-drag downforce; one of Luigi Colani's Bonneville cars.



There's a lot of fabrication work in those fenders, but hey — go for it.

some lift isn't bad, it will unload my tires.
last sunday i cornered at a speed of 60 km/h without problem and the car only weights 70 kg, the rules allow a max weight of 170kg car for my age.
So, when the soapbox is finished i will put ballasts in it to reach the 170 kg.
if the car has some lift, it will weight more than 70 kg (actual weight) and have better grip than now, even with lift.

sorry for my English

[orengomotors]

Originally Posted by NickelB NL

Maybe a stupid idea. But would you like air brakes? Foils witch you use as airbrake and double up as wings for down force to increase cornering speed.

i don't see why not. drag? but if you want to brake is no problem. what do you think?

[NickelB NL]

Why i said it as air brakes is that it would be movable. Like in a pedal action flap. When not in use it stays flat in the wind like a neutral piece. Whit a very small frontal section. But when in use you tilt it. Creating drag to brake and increase downforce to corner even harder

[orengomotors]

Originally Posted by NickelB NL

Why i said it as air brakes is that it would be movable. Like in a pedal action flap. When not in use it stays flat in the wind like a neutral piece. Whit a very small frontal section. But when in use you tilt it. Creating drag to brake and increase downforce to corner even harder

Something like the veyron spoiler?

[NickelB NL]

Veyron. Zonda R. P1. Like those yeah. But then simple padle action. While it is so light small flaps will do. If you can add a 40 50 kilograms of downforce it would make alot of difference. While you dont have to put on the normal brake

[SvdM]

The body will obviously be a lot of work, but you might be able to make the suspension components more aerodynamic with simple cardboard wings-shaped covers at first and you can do runs to decide if it's worth the effort to go do more permanent suspension covers.
I also think a slightly curved belly / floor would allow for air to remain attached for longer than a flat floor, but that obviously depends on the design.
Good luck. Looks like uber fun!

[elhigh]

+1 on lengthening the car and laying the driver down. As Freebeard pointed out that will improve the fineness ratio and allow you, with the lower helmet position, to also lower the roll bar and get it out of the wind. Incorporating a fairing into the downwind portion of the rollbar would be good, esp. if you can also have a windshield that will aerodynamically couple to the upwind side of the roll bar. Things could get very sleek at that point.

Your suspension is an aerodynamic mess. If you can fair the fore-and-aft elements together, you have only half as many wakes to contend with.

+1 on adding smoothie discs to the wheels.

Virtually any body at all is going to perform better than your bare tube chassis. If you're breaking 60kmh already, get ready for a big surprise when you add some body panels.

It sounded to me like you were describing how you had added weight to the wheels to make them coast longer. If you're running with weight in the wheels, get it out. Move the weight into the body itself, as low and as centrally located as possible. Lighter wheels accelerate better and give a much smoother ride, and keeping the weight low will allow the car to take turns better.