Re: [ST] Counter Rotating Brakes

["Emile Nossin" <Emile@xxxxxxxxxx>]

>From: Masiak, Richard
>So then the question is, if you counter precession with a mass rotating
>in the opposite direction and approach zero does that mean the motorcycle
>is now going to steer like a car at speed?

Thank you Matt H for the cue :-).

The answer is no, because precession had nothing to do with the countersteering
(or the way a bike steers) in the first place.

Countersteering, the main principle of controlling a bike, is simply making
your bike fall over to one side by riding the front wheel to the other side.
While the bike falls over to that opposite side (counter-steering) the front
wheel already falls over towards the direction of the turn. While in the
turn it will stay directed towards the direction of the turn. Countersteering
works at every speed. It's just that you need more lean for the same turn
radius with more speed, or more lean for a shorter turn radius with the
same speed.

Precession is the force that tries to resist any change in attitude, in
this case lean angle. It has nothing to do with the stability of a riding
bike (the steering geometry (trail/rake) does that) nor with controlling /
changing the bike's lean angle. At low speed the wheels turn slow, so the
precession (resisting) force is not large, meaning countersteering will
be lighter / easier. At high speed countersteering doesn't change, but
just because heavier (and bodysteering totally useless, that's only meant
for changing the bike's CG to have more groundplay).

With the reverse rotor the precession force will be canceled out (like
active noise reduction) or at least strongly reduced, like at low speed.
Remember you can drag pegs even at really low speed:
http://piloot.smugmug.com/photos/21016258-L-1.jpg
This lean angle is still accomplished with countersteering, there
won't be much handlebar force needed for it. To have this lean angle
at higher speed you normally need quite a lot more force to get it
there, with these rotors the force input should remain light like
at low speed. They are a bit like powersteering (or a tool that
actually removes the natural handicap of heavysteering).

Like an airplane, you still need the bank angle to get thru a turn
(even at low speed, the bank is just nearing zero when speed is nearing
zero as well), otherwise you'd fall over. It would otherwise be like
riding a bike with sidecar thru a turn and suddenly loosing the sidecar....

I hope I described it visually enough to make it logical :-).
Rereading your question I'm actually not sure I understood it
completely... you mean if a bike with counterrotating brakes
rides slow, will it ride like a car driving fast as in force
needed, or just like a car in general (no lean)?

Emile
www.piloot.com

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