How long of a rod is needed?

[Zxcvbnm123]

I am currently using a 40 cm rod and I feel the vehicle is going too slow. Would a 30 or 20 cm rod be enough to cover a distance of 11m?

[PM2017]

It really depends on the ratio between the diameters of your axles and wheels. IIRC, the formula (assuming the lever arm starts directly over the drive axle) is this:

Distance = 2*Lever Arm Length*(diameter of wheel/diameter of axle).

Obviously, this idealizes the situation and does not take into account/find the coefficient of friction, mass, rotational inertia, the time/acceleration etc.

[MTV<=>Operator]

I'm just wondering, around what length lever arms has everyone been using? I know it depends on wheel and axle diameter, but are people still using shorter lever arms (15-18cm) that wind all the string off the axle soon after reversing, or are people using longer lever arms (20-25cm) that unwind fully at the VTP?