Friction motor

The motor consists of a large flywheel which is connected to the drive wheels of the toy via a gear train with very low gear ratio, so that the flywheel revolves much faster than the wheels.

If higher energies are desired, pushing the vehicle forward repeatedly spins this flywheel up to greater speed.

In some cases, the cars work both in forward and reverse; in other cases, a one-way clutch can disengage a component in the gear assembly to prevent input of rotational effort in the reverse sense.

[citation needed] Some used a zip cord pulled from the vehicle body to accelerate the flywheel directly.

[citation needed] Another system was the Turbo Tower of Power (TTP) in which air expelled from a hand-operated pump pushed turbine blades on the flywheel's rim.

Inside a friction motor on a toy car. Note that the drive wheels are connected via a low gear ratio to a flywheel (bottom).