Date of Award


Document Type


Degree Name

Master of Science


Department of Aeronautics and Astronautics

First Advisor

Frederick G. Harmon, PhD.


Currently fielded electric-powered small remotely-piloted aircraft (RPA) lack endurance desired by warfighters, and internal combustion engine (ICE) RPAs generate undesirable acoustic and thermal signatures. Hybrid-electric (HE) propulsion systems would combine both electric power for endurance and ICE power for cruise and climb modes. Use of HE systems would eliminate undesirable signatures in addition to providing considerable fuel savings over time. Five components were used in this HE system: the ICE, electric motor (EM), electromagnetic clutch, battery pack, and a propeller. Control of such a system in a small RPA has never been attempted before. A rulebased controller was developed to manage this HE system in C code. This system and its various sensors were analyzed on a custom-built dynamometer test stand that was developed in conjunction with other students. LabView screens were developed to aid this testing and interface with the sensor suite. The controller's performance over 9 distinct operating modes, including 4 operational flying states, were validated to provide the most optimal operation of a HE-RPA system of about 13.6 kg (30.0 lbf).

AFIT Designator


DTIC Accession Number