Tilt Rotor Tricopter VTOL

What is a tilt-rotor VTOL?

A Tilt-Rotor VTOL (Vertical Take-Off and Landing) is a hybrid aircraft designed to bridge the gap between fixed-wing cruise efficiency and speed, and multirotor take-off and landing flexibility. While traditional fixed-wing aircraft offer excellent range but require runways, and multirotors offer precise hovering but suffer from short flight times, the tilt-rotor tricopter combines the strengths of both systems into a single, efficient platform.

The hard part is the transition — handing off lift from the rotors to the wing while keeping the aircraft stable.

Design & Build

• Airframe: Heewing T2 VTOL kit, with custom mounts for pitot tube, GPS, and optical flow + range finder
• Wingspan: 1200 mm
• Flight weight: 2.5–3 kg
• Flight controller: 30×30 H743 running custom PX4 firmware
• Battery: LiPo 6S, 5000–10000 mAh
• C2 link: ExpressLRS (ELRS) with MAVLink telemetry

Testing

Hover flight control

Hover control was developed and validated in Gazebo simulation, based on an improved version of PX4’s VTOL controller. Forward/backward translation is produced by collective rotor tilt; yaw rotation comes from differential tilt. The fuselage stays level (0° pitch attitude) throughout, which reduces the effect of horizontal wind — especially tailwind — on hover stability.

On a tricopter, the tail motor’s reaction torque has to be balanced somewhere. Two options: trim it with differential tilt of the front two motors, or angle the tail motor itself a few degrees off vertical. I went with the latter, and dialed in the mounting angle by watching the yaw integrator in the flight logs — when the integrator stays near zero during stationary hover, yaw is properly trimmed.

Position hold

GPS + optical-flow position hold during hover — the aircraft holds its spot against drift and wind.

Full flight

Hover → forward transition → fixed-wing cruise with Total Energy Control System (TECS) → backward transition → landing.