Electrified Aircraft Configurations1
Electrification of commercial airliners can help significantly reduce harmful emissions in the atmosphere and improve aircraft performance through innovative technologies and vehicle designs. NASA and its industry partners are exploring six different electrical propulsion architectures for electrified aircraft concepts, including an all-electric system configuration, three hybrid electric system configurations, and two turboelectric system configurations
Types of Electrified Aircraft Concepts
All-electric aircraft systems use batteries as the only source of propulsion power.
Hybrid electric aircraft systems use gas turbine engines for propulsion and to charge batteries that also provide energy for propulsion during flight. Types of hybrid electric aircraft:
A system that uses a battery-powered motor and gas turbine engine both mounted on a shaft that drives fan, so one or both can provide propulsion at any given time.
A system where only the electric motors are connected to the fans, and the gas turbine engine is used to drive an electrical generator which drives the motors and/or charges the batteries.
Series/parallel partial hybrid
A system with one or more fans that can be driven directly by a gas turbine engine, and additional fans that are driven exclusively by electrical motors which can be powered by a battery or a turbine-driven generator.
Turboelectric aircraft systems do not use batteries for propulsion energy during flight, but rather rely on gas turbines to drive electric generators which power inverters and individual direct current (DC) motors that drive individual distributed electric fans. Types of turboelectric aircraft:
A system that uses electric propulsion to provide part of the propulsive power, with the rest provided by a turbofan driven by a gas turbine.
A system that relies fully on gas turbines to drive electric generators which then power inverters and motors to drive disturbed fans.
1The National Academies of Sciences, Engineering, and Medicine, Commercial Aircraft Propulsion and Energy Systems Research: Reducing Global Carbon Emissions, The National Academies Press, Washington, DC, 2016, Chap. 4