JOE_BROWN@HP-USA-om24.om.hp.com wrote:
> How about thinking about a figure skater that spins with her arms
>straight
> out and then speeds up faster and faster as she pulls her arms in closer
>to
> her body. Of course, this is discounting any effect caused by a knee
>that
> has been bashed in with a bat.
>
> Have Fun,
> Joe Brown
One of the first experiments in physics. I sat in a canvas sling seat suspended
from a rope. Was spun around with my arms and legs out, then told to bring
them in
to my body. Took a lot of strength, but boy did the rotation speed up. This
is a
good demonstration of the "change" in polar moment of inertia, and can
demonstrate,
indirectly, the effects of a fixed design differences. But, cars dont throw-up.
{9->
Don Cordier wrote:
Hi Steve,
> Good explanation.
>
> In airplanes, we like to say that the closer the mass to the center of
> rotation (i.e., a spin), the higher the rotation speed and the more
> difficult it is to stop the rotation. This also contributes to the
> "breakaway" action of cars (just one of the factors though...).
>
> I don't know if this contributes to the discussion or causes more
> confusion?
>
> What do you think?
>
> Best regards,
>
> Don Cordier (1968 Lotus Elan S4SE Coupe S/N 36/7947)
> Aviation Consultant
> Glendale, California, USA
> doncordier@earthlink.net
Yes, Don, it does contribute. It shows the other side of the coin. It may be
harder to turn, or reverse the turn, with a higher polar moment of inertia, but
you
also pointed out that once it "let's go" you are in deeper doo-doo to stop the
spin.
All of this is independent of "under-steer"/"over-steer" which simply compound
the
issue.
BTW: A slightly heavier front end (51%, I believe) adds to straight line
stability,
but hurts if your in a spin.
Lesson: There is no free lunch.
> --
Steve Laifman < One first kiss, >
B9472289 < one first love, and >
< one first win, is all >
< you get in this life. >
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