There is a flat-style DC motor and a round style DC motor end caps, along with an adapter for the motor's shaft to be turned by the 3rd sun gear. I also made a drill attachment to be able to use an electric drill to rotate the planetary gears and wear them in quickly so they're easier to rotate by hand afterwards. I used a couple dabs of grease in the gears and I was able to stack 3 of the gears and it rotates very smoothly (see video). https://youtube.com/shorts/-JX_UhpMC3s?feature=share

I use 2 common DC motors that people would likely get with most electronic kits. I designed these to be able to use the propeller launcher design to teach mechatronics concepts of gear ratios and electrical power generation to students. I was able to light about 6-7 LED's in parallel with it. These motors do not generate enough voltage to overcome the voltage drop of more than 2-3 LED's in series.

I included NikoKun's original files for the handle, 1st gear and 2nd gear but I squished them down in the z-direction to make it it look more proportional to the small motor.

The Ultimate Propeller Launcher: https://www.thingiverse.com/thing:6412255