Quote:
Originally Posted by warped
I think that the direction the motor spins is not nearly as important as most people like to think.
The inertia of the tyres is far more significant than the inertia of the motor.
If this was not true then off road cars with the motor mounted longtitudinally. - (e.g. most shaft drive 4wds, b44 predator etc.) would all be total crap, and tip over to one side every jump.
My zx5 / losi hybrid 2wd should in theory be worse than any 4wd in that respect because only 1 set of driven wheels = less inertia from the tyres.
But I can't see any noticeable effects from torque reaction at all, and it jumps better than any car I've had previously.
The direction the motor rotates is a very small change in terms of car performance and really not worth spending a lot of time worrying about.
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Elvo's the man on this, but here's a couple of things you've not taken into account:
Any car with a longitudinal mounted motor will have a torque reaction. Because Off-Road has so little grip compared to track, you don't notice it. However, the longitudinal mounted motor has disappeared from the Track scene precisely because the torque reaction on acceleration makes the car react badly out of corners. Just because you can't see it in your class, doesn't mean it isn't there!!
Your calculation of the torque reaction only works when the wheels are off the ground - hardly the best situation for them to be in! The torque reaction when they are on the ground is far more important, and for that the direction of the motor is critical. In theory, the mid-motored 2WD cars shouldn't work as well as the rear-mounted - but take into account motor direction and...
Vehicle dynamics is a complex subject where any one asset is traded off with another. It is never as simple as one thing having one effect. If it was, all chassis' would be the same and all cars would handle the same. They don't!! HTH
