Re: Curves and manual transmissions

[John Denker <jsd@AV8N.COM>]

Quoting Frank Gaul <gaulf@ASTRO.WESTMORELAND.CC.PA.US>:

> Would the increased rpm of engine parts cause increased stability just as it
> is easier to balance on a moving bicycle rather than one that is stationary
> or would the effect be miniscule ?

No.  The RPM of moving parts play no significant role, neither
in the car nor in the bicycle.  A lot of people guess that it
does, but David Jones debunked that idea
  http://www.google.com/search?q=unridable-bicycle

The balance of a moving bicycle depends on (among other things)
the centrifugal force due to moving the center-of-mass along a
curved course.   The force, and also (perhaps more to the point)
the derivative (d force / d curvature) depends on the speed of
the bike and obviously goes to zero when speed=0.

By itself that contributes to controllability.  In conjunction
with various details of the fork it gives you a bit of stability.

====================

Similar remarks apply to gyroscopic effects in an airplane.
Most of the squirrelly behavior of a C-152 (or the like) during
slow flight is due to the helical propwash, which originates in
rotational drag on the propeller blades and affects the vertical
tail/rudder.  It is a fluid-dynamic effect, not a gyroscopic
effect.  There are gyroscopic effects also, but they are so small
that it is difficult to get a student pilot to see them, even if
you go to a lot of trouble to isolate and emphasize them.

The story would be different if you were flying a Sopwith Camel,
wherein the crankshaft was fixed and the rest of the engine
(crankcase and all) rotated.

==============================

There have been quite a few wise words in this thread.  Let me
just emphasize that you need to get to know *your* car.  Some
cars are FWD, others are RWD, and a few are 4WD.  Some have
anti-skid and some don't.  Not all anti-skid systems are created
equal.  Anti-skid systems that work well when you're pointed
straight might not as well when you're in a tight turn.

I agree with M.E. that it's important to get the feel of the
road, especially in challenging conditions.  Slight suggestions:
  1) It is psychologically beneficial to brief the passengers *before*
doing the maneuver.  As the saying goes, people get depressed not
because they're having a bad life, but because they feel out of
control.  Passengers feel out-of-control enough under *normal*
conditions.
  2) If she is of driving age or anywhere near, take her to a big
deserted parking-lot and let her get her own "feel of the road".
There's a church near me that's ideal.  The parking lot is empty
about 150 hours per week, it is not plowed very promptly after a
snowfall, and there are no lamp-posts, curb-stones, nor other
obstructions in the interior -- just acres and acres of flatness.