Analysis of a Distributed Hybrid Propulsion System with Conventional Electric Machines

Hybrid Aircraft Propulsion System Synthesis (HAPSS) is a computer program that designs, sizes, and analyzes generic hybrid electric propulsion systems for aircraft. The development of this program began with the creation of a fan design tool during a NASA SBIR contract titled “The Design and Integration of a Distributed Fan Propulsion System within a Split-Wing”. Since the completion of this contract in July 2010, the program has expanded to combine the many aspects of a hybrid electric propulsion system. This paper addresses the sizing and performance analysis of a turboelectric distributed propulsion system for a dual-use commercial/military transport using the HAPSS code. This vehicle, developed during a study titled “N+2 Distributed Electric Propulsion Studies”, sponsored by NASA Ames Research Center Environmentally Responsible Aviation (ERA), utilizes conventional “warm” electric machinery rather than superconducting components. The goal of this study was to determine the feasibility of using conventional electric machines in a hybrid aircraft. While it is possible to use conventional electric technology, the associated weight and inefficiencies appear to outweigh many of the potential benefits.