FW17 wrote:Honda running their engines in reverse and using a jack shaft for the first time since the 2 stroke days. ......
Honda has sacrificed power to handling by using reverse engine and jack shaft. So new engine looks like down on power but actually not.
reverse running can improve cornering ........
there is (angular) momentum stored in the rotation of engine parts, transmission parts, and wheels
more in the engine than in the wheels, especially in the lower gears
overall this stored momentum is the algebraic sum of eg that stored in engine-sense rotation and that stored in wheel-sense rotation
so reversed engine rotation has effects that act against wheel rotation effects
by the conservation of angular momentum two 'gyroscopic' torques arise in cornering .......
as a reaction to the rotating parts being displaced (ie in yaw and in roll) about any axis other than their own axes of rotation
these gyroscopic torques are proportional to the angular velocities of yaw and roll displacements ......
and to the rotating parts angular velocity (equivalent to their rpm) and their polar moments of inertia
entering a corner the machine is rolling fast but yaw is still quite slow .......
the wheels gyroscopic reaction to the roll is a torque tending to yaw them favourably eg the front wheel steers itself in the appropriate direction
reverse engine rotation will give an unfavourable yaw (though this will not directly affect the front wheel)
steady cornering at constant lean (roll having ceased) is all yaw
forward rotating parts give an 'overturning' gyro reaction torque (ie acting against lean) - this demands more lean for a given corner
but reverse rotating parts give a favourable gyro reaction torque (ie acting with lean) - this demands less lean for a given corner
the reverse rotating engine effect will outweigh the forward rotating wheels and such a machine needs less lean for a given corner !!
(significantly less in tighter corners at today's speeds)
the above can be checked using of a bicycle rear wheel
Tony Wilson-Jones of Royal Enfield wrote on steering (forward-rotation) effects in the 1951-2 Proceedings (Auto Div) of the Inst Mech Eng
this effect is far greater in eg 1000cc Moto GP .......
than eg in eg 50cc GPs of the 1960s, such machines being said to need less lean than the large-engined (forward-rotation) machines
(and there was the quite recent case of the front brake discs/rotors that were gear-driven in opposite rotation to the wheel rotation !)
