Quote:
Originally Posted by RogerM
I would have thought that the armature shaft position relative to the wheel axle would play a part too .... maybe wrong ... will think about it some more.
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No, the position of the motor relative to the rear axle doesn't matter when considering the weight transfer effects of the motor's rotational inertia. I was surprised when I worked it out, too.
<physics>
Here's my understanding/reasoning: The torque the motor exerts on the driveline has to be counteracted by an equal and opposite torque from the chassis, otherwise the motor would just spin in the car and never turn the driveline. Where does the chassis' torque come from? The ground - it loads up some wheels more than others, which is what we call weight transfer. So, how does the motor's position play into this interaction? Well, torques act over distances (Torque = Force x radius). Obviously, the effective distance between the motor and the chassis (I'll just call it the chassis instead of getting into center of mass and etc) is the same as the from the chassis to the motor. Since the two torques mentioned earlier have to be equal (thanks Newton!), the length terms drop out of the equation. So anywhere the motor is on the chassis - behind the rear axle, mid, up front, anywhere - the weight transfer effect is going to be the same. Changing the motor's direction simply changes the direction of the weight transfer, not its magnitude.
</physics>
Hope that all makes sense.