Software engineer Joshua Bird built and flew a 3D-printed drone with a single motor, testing it in his bedroom. The design avoids the usual secondary rotor and swashplate by using a hinged rotor and rapid motor speed changes. Speeding up the motor increases reaction torque, while slowing it down applies opposite reaction torque, letting the firmware balance the torque on the drone body.
Each rotor blade sits on a 45-degree hinge, so acceleration pitches one blade up and the other down, changing lift to control roll and pitch. Custom flight and motor controller firmware responds in under 0.2 ms, and 3D-printed stabilizing fins help with yaw. This replaces the heavier, more complex mechanisms found on most rotary-wing aircraft.
The build process involved significant troubleshooting. Bird made a homemade high-speed camera from a Sony camera, flash unit, and microcontroller triggered by the drone's motor controller to diagnose soft propellers, which he then replaced with sturdier 3D-printed filament. Several test flights crashed and damaged walls before the drone flew successfully. It currently relies on fixed-base IR beacon navigation, limiting it to the bedroom; Bird says he wants to add a linear camera so it can fly in other environments in the future.