Armstrong, M., Ross, C., Blackwelder, M., and Rajashekara, K., "Propulsion System Component Considerations for NASA N3-X Turboelectric Distributed Propulsion System," SAE Int. J. Aerosp. 5(2):344-353, 2012, doi:10.4271/2012-01-2165.
NASA's N3-X aircraft design under the Research and Technology for Aerospace Propulsion Systems (RTAPS) study is being designed to meet the N+3 goals, one of which is the reduction of aircraft fuel burn by 70% or better. To achieve this goal, NASA has analyzed a hybrid body wing aircraft with a turboelectric distributed propulsion system. The propulsion system must be designed to operate at the highest possible efficiency in order to meet the reduced fuel burn goal. To achieve maximum efficiency, NASA has proposed to use a superconducting and cryogenic electrical system to connect the electrical output of the generators to the motors. In addition to being more efficient, superconducting electrical system components have higher power density (kW/kg) and torque density (Nm/kg) than components that operate at normal temperature. High density components are required to minimize the weight of the electric propulsion system while meeting the high power demand. Minimizing the electric propulsion system weight helps to reduce the amount of fuel required for propulsion. In this paper, evaluation of the electrical system components such as cryogenic and superconducting generators, motors, power converters, DC and AC cables, energy storage, circuit breakers, and fault-current limiters is presented. A review of the present status of these components and sub-systems is also presented and the progress of technology for future applications is discussed.