kers k e r s

An electric motor puts out max torque from a low rotational speed.

The internal combustion engine outputs the maximum horsepower from the maximum speed a little in the under.

There is prius of toyota to synchronize good part of the both with the planetary gearing or Epicyclic gearing because of an arbitrary rotation.

It looks like an automatic transmission.

In the model of movie though toroidal CVT.

It runs by the motor at low speed, and high speed is a mechanism of running with the engine.

Here seems to be synchronized with at high speed with the planetary gearing.

To synchronize it by an arbitrary rotational speed, high technology might be needed.

The effect of aerodynamics might be expected for the gyroscopic precession to become clear perhaps and to be become visible.