[Yo-Yo]

Does anyone here have any experience with tiny gas or electric motors?

I am looking for something very small and light, that could run at its most efficient constant speed to run a battery charger.

Here is a Harbor Freight generator that uses a gasoline string trimmer sized engine.

[Mr. K]

thank you!

I even thought about using a big RC airplane engine

I am building an electric helicopter (drone) and want to recharge the batteries in-flight

Any engineers here want to get in on the ground floor of a new company?