Thanks Neil
We kind of got lost there for a while....confusion about terminoligy and focus
on front to rear bias. This is back to my original inquiry....if a low polar
moment benifits a car that needs to turn quickly does a high polar moment
benifit a car that needs to go straight?
Glenn
"Albaugh, Neil" <albaugh_neil@ti.com> wrote:
Apparently this was too long to get posted the first time I sent it, so I
deleted Glenn's original message-- sorry, Glenn.
Neil
-----Original Message-----
From: Albaugh, Neil
Sent: Monday, June 16, 2003 9:20 AM
To: 'Glenn Ridlen'; 'Keith Turk'; 'land-speed@autox.team.net'
Subject: RE: Weight and Balance stuff again
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
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