How do toy pullback motors work, and could I make a pullback motor?

How would I make a pullback motor, and how much weight would it be able to propel? Can pullback motors propel weight in a circular motion?

Thank youHow do toy pullback motors work, and could I make a pullback motor?
I'd suggest if you want to see how it works, get a toy and pull it apart!

Basically, the pullback winds a spring, like a clockwork spring. It stores the energy you impart to it by pulling it back.

When you release it, the spring changes over to propel the toy forward. Either a governor or a flywheel is used to govern the rate at which the spring unwinds, so the toy will not expend all the spring energy quickly by just spinning wheels. When the spring energy is expended, the spring is decoupled from the drive, and the toy stops shortly after the forward inertia ceases. In the case of a flywheel regulated motor, a lot of the spring energy is stored in the spinning flywheel, so after the spring has released all its energy, the flywheel energy carries on until it is then expended.

Yes, such a system drives wheels, so certainly circular motion is possible.

chuys