Design and Performance of the NASA SCEPTOR Distributed Electric Propulsion Flight Demonstrator

TLDR

Distributed Electric Propulsion (DEP) uses multiple propulsors driven by electric motors distributed around the airframe to create beneficial aerodynamic‑propulsion interactions. The NASA SCEPTOR project aims to retrofit a light aircraft with two DEP configurations—leading‑edge small propellers and wingtip cruise propellers—to demonstrate distributed electric propulsion. The design employed a tradespace exploration to generate candidate geometries, which were then reviewed by experts to refine preferences beyond the modeled trade space. The retrofit reduces wing area by 2.5×, lowers cruise drag, and shifts peak lift‑to‑drag to higher speed while preserving low‑speed performance; wingtip propellers further cut propulsive power by 10%, and the overall design achieves an estimated 4.8× energy savings at cruise.

Abstract

Distributed Electric Propulsion (DEP) technology uses multiple propulsors driven by electric motors distributed about the airframe to yield beneficial aerodynamic-propulsion interaction. The NASA SCEPTOR flight demonstration project will retrofit an existing internal combustion engine-powered light aircraft with two types of DEP: small propellers distributed along the leading edge of the wing which accelerate the flow over the wing at low speeds, and larger cruise propellers co-located with each wingtip for primary propulsive power. The updated high-lift system enables a 2.5x reduction in wing area as compared to the original aircraft, reducing drag at cruise and shifting the velocity for maximum lift-to-drag ratio to a higher speed, while maintaining low-speed performance. The wingtip-mounted cruise propellers interact with the wingtip vortex, enabling a further efficiency increase that can reduce propulsive power by 10%. A tradespace exploration approach is developed that enables rapid identification of salient trades, and subsequent creation of SCEPTOR demonstrator geometries. These candidates were scrutinized by subject matter experts to identify design preferences that were not modeled during configuration exploration. This exploration and design approach is used to create an aircraft that consumes an estimated 4.8x less energy at the selected cruise point when compared to the original aircraft.