I and probably everyone else knows that there are mods for this, but I am a stock person. Uses of propellers and rotors include helicopters, old fashioned planes and drones. 3 sizes for each would be nice, like 2m, 1m, and probe size (however small that may be ). Seriously, there would be a ton of cool things to build using these! Sorry I couldn't add more details, but this is probably something you don't really need much detail for.