Glenn;
You're right about setups used in road racing. A low polar moment allows a
car to turn quickly-- a definite advantage on a tight road course but it
also means that you need the reflexes of a cat to catch it when it starts to
spin. One of the advantages of a mid-engine configuration is its low polar
moment but another is that it allows more weight to be put onto the rear
wheels. Most high powered mid-engine race cars run a weight distribution of
60% (or a little more) on their rear wheels for optimum traction both in
accelleration and braking. Since weight transfers to the front under
braking, the incredibly hard braking these cars are capable of transfers
enough weight to the front that it's about 50-50 f/r distribution.
The trick to making a car with 60% of its weight on the rear wheels stable
is: suspension geometry at low speeds and aerodynamics at high speeds. We
all discussed "center of pressure" and "downforce" at some length in other
threads.
Regards, Neil Tucson, AZ
/// unsubscribe/change address requests to majordomo@autox.team.net or try
/// http://www.team.net/mailman/listinfo
/// Archives at http://www.team.net/archive
|