Towards Long-endurance Flight: Design and Implementation of a Variable-pitch Gasoline-engine Quadrotor

TL;DR

This paper introduces a novel design methodology for a gasoline-engine quadrotor with variable-pitch rotors, achieving significantly longer flight endurance of 2-3 hours through careful component selection, drivetrain design, and control tuning.

Contribution

It presents a comprehensive design approach for a long-endurance quadrotor using variable-pitch rotors and gasoline engines, verified by a successful prototype flight.

Findings

Achieved a flight time of 2-3 hours with the prototype.

Successfully minimized airframe vibration and managed power transmission.

Demonstrated stable flight with the designed gasoline quadrotor.

Abstract

Majority of today's fixed-pitch, electric-power quadrotors have short flight endurance ($<$ 1 hour) which greatly limits their applications. This paper presents a design methodology for the construction of a long-endurance quadrotor using variable-pitch rotors and a gasoline-engine. The methodology consists of three aspects. Firstly, the rotor blades and gasoline engine are selected as a pair, so that sufficient lift can be comfortably provided by the engine. Secondly, drivetrain and airframe are designed. Major challenges include airframe vibration minimization and power transmission from one engine to four rotors while keeping alternate rotors contra-rotating. Lastly, a PD controller is tuned to facilitate preliminary flight tests. The methodology has been verified by the construction and successful flight of our gasoline quadrotor prototype, which is designed to have a flight time of 2 to 3 hours and a maximum take-off weight of 10 kg.