Benefits and Concerns of Hybrid Electric Distributed Propulsion with Conventional Electric Machines

Turboelectric Distributed Propulsion (TeDP) describes a power train consisting of a turboshaft engine which is used solely to provide electrical power through a generator to electric motors driving propulsive fans which are distributed above, below, or inside a wing. Recent advancements in electronics, computers, and power distribution have made distributed propulsion feasible and the purpose of the studies described here has been to integrate this new type of propulsion with real airframes designed to specific civilian and military missions. Empirical Systems Aerospace, Inc. (ESAero) performed SBIR studies for NASA Glenn Research Center in FY09 and FY10 to determine the potential application of cryogenically cooled superconduction to distributed electrical components in regional airliner configurations in the N+3 (2035) timeframe. The results of these studies showed that cryogenically-cooled distributed turboelectric propulsion looks feasible when applied to regional airliners such as the ECO-150-16 configuration created and analyzed during these studies. FY11 work performed by the ESAero staff for NASA Ames Research Center focused on removing cryogenic cooling from the ECO-150-16 configuration in order to advance the application of TeDP to the N+2 (2025) timeframe. In addition, the ESAero staff created a dual use transport configuration as part of this study. This paper describes ESAero’s study results and highlight advantages and areas of concern. The focus of the work was to study how hybrid propulsion could improve efficiency of airport terminal area operations; in other words, what improvements could be provided by TeDP during the first and last 5% of a mission.