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Re: Weight and Balance stuff again

To: John Goodman <ggl205@yahoo.com>, land-speed@autox.team.net
Subject: Re: Weight and Balance stuff again
From: Glenn Ridlen <gridlen@yahoo.com>
Date: Sat, 14 Jun 2003 15:48:21 -0700 (PDT)
John
I agree that most of the basic principles apply to all cars but I submit that 
the requirements for LSR and road raceing are very different. To demonstrate my 
point... we have an ordinary chevy pick up that acts like it is "on rails" at 
nearly 200MPH on the other hand I doubt that it would be very impressive as a 
road racer.
                                                                                
 Glenn

John Goodman <ggl205@yahoo.com> 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


--- Glenn Ridlen wrote:
> John
> I agree rear engine cars tend to be tail heavy and
> can be problematic..mid engine improves that
> greatly. That is probably the ultimate for low
> moment since the heavy components are in the middle
> of the car. That works really well for road raceing
> and other events where turning quickly and under
> control are important. We are trying to go in a
> straight line.... it seems to me that a high moment
> would be an advantage. 
> 
> Glenn




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