Well....let's see.....I guess that I moved to the analogy of the weather
vane.....I understand that to some degree and am trying to get from there
to a car (or bike).
On the subject of the "movie", we are also talking about stability "in
flight" of the car. I do however disagree that yaw stability is from the
rudder......that's a control surface....the stabilizer (which is the
subject of the movie to which I referred) is fixed and provides area aft of
the CG to cause the vehicle to turn into the prevailing wind (if it is
large enough in area) and you acknowledged the stabilizer. This is exactly
what I would like my car to do if it gets out of shape on a pass. Also much
like a weather vane? So if the vehicle has more side area aft of the CG
than forward of it, then it follows (to me) that when sideways to the wind
(and course?) the vehicle will tend to turn ito the wind (help correct a
slide, if you like) and proceed on down the course.
This is why I would use the side shape.... because it is like the weather
vane, when the car or bike gets sideways....I don't want to be on a bike
...sideways.....car I can deal with. The area aft of the CG will tend to
blow the car back around into the wind...IF the area is large enough
relative to the area in front of the CG. The CG is comparable to the pivot
point on the weather vane. This is why I think the cutout will tell us
where the CP is ....when the vehicle is sideways. This should affect
roadsters or Sunbeams or any vehicle that would get sideways on a run. I
wonder where the CG is in a roadster relative to the Cp (if Cp is really
what we are talking about). In any case it (side shape) is the profile
that sees the oncoming wind.......when the vehicle is sideways. Not when
the vehicle is travelling into the wind or "on course".
One "movie" on the website I mentioned shows the CP ahead of the
shape....like someone mentioned a day or two ago regarding roadsters....is
that why roadsters like to spin? I don't think the car would "want" to go
forward if that were the case.
I agree with the windshield having a large effect but I think that it is on
drag and would have little effect on keeping the car straight if it got
sideways....now how the windshield would affect the tendency of the car or
bike to become unstable and spin, I have no idea. Probably depends somewhat
on the shape of the windshield I would guess.
Whew!
I AM having fun yet (-: (-: and I really appreciate the discussion. Thanks
Mayf.
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