This is a Weight Powered Plane I developed during STEM Class. Basically I saw this video made by Tom Stanton one day where he made a Flywheel Powered Plane with the Flywheel's rotational inertia/energy rotating a propeller.

So I thought, what if I replaced the flywheel with a weight? I can have a rope which is wound around a shaft. This rope has a tiny weight on one end which makes the rope go down and thus turn the shaft.

The shaft spins and the rotational energy either A) goes directly to the propeller (which isn't efficient) or B) goes through a gearbox to make the propeller last longer or give more thrust.

Whoo, that was a lot to say.