NASA wants to get a second opinion from Aurora Flight Sciences on the system-level performance of a turboelectric-powered commercial aircraft concept for starting the next iteration of a multi-year design process.
The Manassas, Virginia-based company that announced a pending acquisition by Boeing on 5 October will perform a comprehensive evaluation of NASA’s single-aisle turboelectric aircraft with aft boundary layer propulsion (STARC-ABL) concept.
STARC-ABL is NASA’s leading candidate for a commercial aircraft roughly the size of a Boeing 737-700 that is capable of meeting the agency’s so-called “N+3” goals for emissions in 2035.
The agency previously looked at concepts for an electric aircraft with a truss-braced wing and hybrid wing body with gas generators driving a bank of thrusters arrayed along the trailing edge of the wing.
By contrast, STARC-ABL conforms to the classic “tube-and-wing” external profile of commercial aircraft since the late 1930s, with one exception. An electric-powered fan is mounted on the tailcone, generating power and thrust by ingesting the boundary layer airflow over the fuselage.
In addition to the aft-mounted propulsor, the STARC-ABL’s wings carry geared turbofan engines on both sides of the aircraft. In all, the three electric motors handle 5.4MW of electric power, which is distributed through the aircraft using non-super-conducting, 1,000V-cables.
After beginning work on the project in 2012, NASA has recently wrapped up the second design iteration, known as STARC-ABL Revision B. The agency’s schedule calls for going through two more design iterations over the next three years.
First, however, Aurora Flight Sciences will evaluate whether NASA’s concept on paper is on track to meet the agency’s stringent objectives on emissions.
Along with autonomous flight controls and composite structures, electric- and turboelectric-powered aircraft have become one of Aurora Flight Sciences’ specialties. The company also is working on a Defense Advanced Research Projects Agency (DARPA) programme to develop a hybrid-electric, unmanned aircraft with a distributed propulsion system called the XV-24A Lightning Strike.