Exploring the Feasibility of a Passively Actuated Binary-Pitch Propeller For Group 2 UAVs

Abstract

In the early years of aviation, the type of propulsion system implemented limited aircraft performance. Up until the introduction of the jet engine in 1939, and still today, aircraft used a fixed-pitch propeller based propulsion system. Fixed-pitch propellers have low manufacturing costs and have a weight advantage over other propulsion types. However, when choosing the proper propeller for an aircraft, the designer must compromise between areas of performance, i.e. a propeller designed to optimize take-off performance may have poor performance in cruise, and vice versa. In recent years, unmanned aerial vehicles, or UAVs, have become increasingly popular, both in the amateur hobbyist world as well as in commercial and military applications. As with large-scale aircraft, UAVs suffer in performance largely due to the use of fixed pitch propellers. Large aircraft make use of constant speed propellers driven by oil-based hydraulic systems from the vehicles engine, which are not available for small UAVs. A system is designed, constructed and tested for Group 2 UAVs using the two primary performance points, take-off and cruise, as the basis for analysis. The system is governed by propeller RPM and allows for operator control based on throttle input.