Electro-Mechanical Variable Pitch System

Internal combustion engines are critical for long endurance missions for Group 2 and small Group 3 Unmanned Aerial Systems (UAS) due to the energy density of liquid fuels.  However, fixed pitch propellers do not allow for the extraction of maximum power and efficiency from an internal combustion engine due to the difference in operating speed and loads at which these attributes occur. To solve this problem, variable pitch propellers have been utilized in general and commercial aviation where larger size, weight and packaging (SWaP) constraints have allowed for the use of hydraulicly actuated systems.  For Group 2 and small Group 3 UAS platforms, SWaP constraints are much tighter, thereby eliminating hydraulically actuated system as viable for those platforms.  A patented, electrically actuated ball screw and scotch yoke mechanism, can be utilized for variable propeller pitch, using only small amounts of available electrical power A simple, lightweight and fuel-efficient engine equipped with a variable pitch propeller would enable inexpensive, attritable UAS platforms for long range Intelligence, Surveillance and Reconnaissance (ISR) as well as Suppression of Enemy Air Defense (SEAD) missions.  Inexpensive, attritable platforms would overwhelm and deplete an adversary’s defense weapons systems.  Under the Phase I program, Baker Engineering LLC seeks to prove through design and testing that an electro-mechanical variable pitch propeller system can vary propeller pitch angle while operating through its full speed and load range.