[EricH]

Originally Posted by mman1506

I don't want to be a dream crusher but to get the proper rpm to run a reasonable propeller(Cim tops out at about 3000 rpm under load) you would need a gearbox which would add more weight to the system.

A quadcopter's motor loading is nothing like an FRC robot's motor loading. The closest approximation would be a shooter wheel with no shots going through. The CIMs should be running around 5000 RPM for quadcopter use. (This is lower than the free speed, but not by anywhere near 2000 RPM lower.)

I would say a gearbox might be helpful--I want to say a 1:2 or higher to get closer to a nitro engine--but I think there's something that would be even more helpful. It's called a BaneBots RS-775-18. You're allowed 4 of them in FRC, and they run reasonably high power and definitely high speed if you take the planetary gearbox off. They're similar power to a CIM, but aiming more on the speed side than the torque side, which is better for propeller usage, and they're lighter, which is better for flight usage. An RS-550 might also work.