Howard,

Have you thought about using a load cell / strain gauge in conjunction with a flywheel to directly measure torque? This way you dont need a high accuracy to calculate the flywheels second moment of inertia and also no need to accurately time its acceleration.

All you'd need is a load cell (lever mounted off motor housing) and a hall effect sensor on the flywheel to obtain rpm. With a simple 2 channel logger, you can easily obtain torque, rpm = power.

Maybe use an extra 2 channels to log amperage and voltage to obtain electric power, so you can use that to calculate mechanical efficiency at any given rpm.



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