10:1 Cycloid Heli Gearbox

thingiverse

It's always cycloids with me lately, isn't it? This is my second attempt at making a gearbox that fits motors from a crashed RC helicopter. The first one works acceptably - I don't say it flies as much as "whirls its blades around alarmingly". Unlike previous attempts, this one has no preferred rotation of direction. It cannot be backdriven - if you try to let the motor freewheel, it will just seize! Required materials: 1 x 625 ball bearing, probably epoxy to hold the cam in place, 30mm M3 and 14mm M3 bolts (4), M3 nuts (4), main motor and mounting bolts from the "Sanhuan 8827 RC Helicopter" aka Pioneer X8, mounting bolts and a pair of "A" or "B" blades from above helicopter, a mess of 4.5 mm ammunition. Four 4.5mm balls are used to join the wobbling gear to the output plate as shown in picture three. A bunch more are used in a thrust bearing as shown in the cutaway view. Source files can be found at http://burningsmell.org/3d/heli/.