Design and Development of a Dynamically, Scaled Distributed Electric Propulsion Aircraft Testbed

This paper details the motivation and design of a dynamically-scaled, distributed electric ducted fan testbed aircraft that was developed at the University of Illinois at Urbana-Champaign as part of a Phase I NASA STTR, in collaboration with Empirical Systems Aerospace. A 21 % subscale model of a Cirrus SR22T was developed and instrumented to perform system identification flight testing in support of dynamics model validation. A new wing configuration, featuring a series of electric ducted fans integrated into the wing upper trailing edge, was designed in order to provide a platform to investigate and quantify the effects of propulsion-airframe interactions and the effectiveness of propulsive-based control. Analysis and trade studies were performed to select an appropriate fan configuration that provided sufficient differential thrust to allow similar propulsion-based yaw control authority as the rudder control surface of the baseline vehicle. Wind tunnel experiments were performed on select propulsor combinations of motors, electronic speed controllers, and fans to validate performance specifications and capabilities. The new distributed electric propulsion wing was built and integrated into the baseline Cirrus and a simplified ground testing apparatus was constructed to validate the propulsion system before flight. The feasibility of scaling the designed distributed electric propulsion concept to a full-size equivalent general aviation aircraft was then explored.