John,
The simple answer, from my point of view, is if you add weight to the
rear for traction, (Conventional wisdom of old), it works great unless
you spin the tires. If it still spins the tires the rear will want to
lead. It has been proven by several that a balanced car handles. The
rule I will live by, which came at great expense and experience, is: The
center of mass behind the center of gravity.
After adjusting the car to the above, I made a check out run with the
tires spinning for over a mile on a loose course, after hitting the
nitrous, and it moved about on the course, but at no time did it seem
uncomfortable. The front wanted to lead.
Tom, Redding CA - #216 D/GCC
John Goodman wrote:
> I respectfully disagree. Road racing cars are surely
> designed to increase tire patch grip via sound
> suspension design, chassis rigidity, springs, dampers,
> aero, etc. but straightline stability is one of those
> extremely important components to any competitive road
> racing vehichle. The kinamatics of what makes a
> formula car track straight (without aero advantage),
> is the same as a streamliner, roadster or any other
> three or four wheel LSR car. You simply can not get
> wrong the center of gravity, centroid axis, center of
> mass, roll centers (front and rear) or other weight
> related factors and expect the car to track straight
> without handeling problems. Forget for a minute that
> much of what I have been talking about relates to road
> racers. Does it make sence that mass must center as
> close to a mid-point in a vehichle for that vehichle
> to track neutral (use your bowling ball example. Equal
> weight front and rear of center of mass)? Would it
> then be natural for the vehicle to take on handling
> behaviors when we add weight front, rear or to both?
> As we add weight to the rear and the distance of that
> weight from the center of mass is increased, that end
> begins to "steer" the car. You illustrated this in
> your hammer example. Same goes for the front of the
> vehichle. Increase the weight and moment arm and the
> car wants to "push" or steer in the direction you get
> the mass moving (not always where you want it to go).
>
> John
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