Single-Aisle Turboelectric Aircraft with Aft Boundary Layer Propulsion (STARC-ABL)


NASA is investigating cutting-edge Electrified Aircraft Propulsion (EAP) technology to drastically lower fuel consumption and pollution levels from single-aisle commercial aircraft carrying about 150 passengers in this new era of electric flight. In order to improve vehicle performance through innovative aerodynamic designs and technology, the Single-Aisle Turboelectric Aircraft with Aft Boundary Layer Propulsion (STARC-ABL) idea was created.


In order to maximize aerodynamic benefits while in flight, STARC-ABL uses an innovative electric aft propulsor powered by two under-wing turbofan engines while maintaining a traditional turbine and airframe design.


This aircraft idea could potentially lower fuel use by 7–12% while operating with the same range, speed, and airport infrastructure as existing regional jets. It would also highlight the fundamental advantages of partly turboelectric propulsion systems for next-generation aircraft.

Maximizing performance and aerodynamic efficiency

A crucial initial step in decreasing drag, which slows down a vehicle and increases fuel usage, is controlling the airflow around it. Innovative boundary layer ingestion (BLI) technology, which is a characteristic of STARC-ABL, aids in controlling the boundary layer—a region of slower-moving air—near the aircraft’s surface.

The NASA Electric Aircraft Testbed (NEAT) facility where STARC-ABL will be tested is depicted in an artist’s impression | NASA

A BLI fan mounted on the vehicle’s tail, which is integrated with the aircraft’s propulsion system, aids in ingesting the layer of slower-moving and frequently more turbulent air. Then, to create thrust, this air is reaccelerated from the boundary layer at the surface of the airplane.

STARC-ABL relies on propulsion-airframe integration, or effectively integrating the propulsion system with the airflow surrounding the airframe, to obtain maximum performance (PAI). The aircraft’s turbofan engines are equipped with generators that produce electricity and power the rear motor.

STARC-design, ABL’s which features two wing-mounted turbofan engines and a rear motor, is visualized | NASA

Smaller wing-mounted engines can be used thanks to the novel addition of a rear motor that provides additional thrust, helping to reduce drag and fuel consumption while also reducing overall aircraft weight. The turbofan engines can produce megawatts of electricity in addition to thrust, which can be utilized to power the aircraft’s electrical systems, including cabin conditioning and onboard instruments.

High-Efficiency Megawatt Motor (HEMM) is the generator used by STARC-ABL, which calls for an advanced 2-3 MW power system. The HEMM, a 1.4 MW electric machine, reduces drag and fuel consumption for STARC-AB and offers three times less heat and weight loss than contemporary aircraft motors and generators.

Image of the High-Efficiency Megawatt Motor created by an artist (HEMM) | NASA

During the concept plane’s development, STARC-ABL will go through a lot of testing at the NASA Glenn Research Center’s Electric Aircraft Testbed (NEAT).

Future airliners will be able to successfully transition away from conventional jet engines and toward a more sustainable future for aviation thanks to the technology revealed by this proposal.

STARC-ABL, which is expected to join the commercial fleet around 2035, will be crucial in showcasing the capabilities of turboelectric systems and parts for more environmentally sustainable air travel.