Swap any motor, propeller, battery or ESC for a real part

A selected part now opens with a clear card: its kind and name, then Swap, Inspect, Lock and Hide as plain buttons. Swap lists the real parts that fit, nearest size first: 136 propulsion motors, 15 propellers, 20 batteries, 14 ESCs, 19 servos and 31 bearings, every figure from the maker's datasheet. Each is drawn to its own proportions, and the rows on screen show whether the design stays viable with it fitted.

Click one to see the physics check with it fitted: Viable or Not viable with the reasons, and what it changes, now and with it, for mass, flight time, thrust to weight, hover power and the product's own figures, plus the datasheet caveats (thrust measured on another prop or voltage). Use fits it to this part or to every part of its kind in one undo step; the motor keeps its base on the mount and the propeller rides on its new top. Import parts (JSON) adds your own, validated.