Blueprints, generated from your cube
Set a cube size and these redraw. The flywheel is not a guess — it is sized backwards from the physics: work out the angular momentum the wheel must store to catch your target lean, cap the speed at something a hobby motor actually reaches, and the bolt count falls out. Every drawing downloads as SVG.
Cut list [ live ]
How the flywheel gets sized [ backwards ]
Most builds pick a flywheel that looks about right and then discover the motor cannot use it. This works the other way round:
- From cube size and mass, compute the pendulum inertia about the balancing edge and the gravity torque at your target lean.
- From those, the angular momentum the wheel must be able to store to arrest a fall from that lean: H = √(2·Jp·M·g·l·(1−cos θ)).
- Cap wheel speed at 2000 rpm — above that, hobby gimbal motors run out of voltage headroom. Required inertia is then J = H / ω.
- Compute one bolt's mass from its geometry, work out how many at the bolt-circle radius reach that inertia, and round.
So the bolt count on the drawing is a physics result, not a style choice. Change the target lean and watch it move.
What these drawings are and are not. They are dimensioned concept drawings to build and check against — correct in proportion, in the derived engineering numbers, and in the relationships between parts. They are not a manufacturing package: no tolerances, no fits, no fastener callouts beyond thread size, and the motor bolt circle is an input because it differs per motor. Measure your actual motor before committing. The mass estimate assumes a printed shell at roughly 35% solid plus typical motor, electronics and battery weights — override it the moment you can put the real thing on scales.