NASA's subsonic ultra efficient transport plane program moves ahead

Boeing's hybrid wing body aircraft concept has turbofan engines on top of the back end, flanked by two vertical tails to shield peop...

Boeing's hybrid wing body aircraft concept has turbofan engines on top of the back end, flanked by two vertical tails to shield people on the ground from engine noise

NASA is working to develop next breakthroughs in commercial aviation, as part of its New Aviation Horizons, an ambitious 10-year accelerated research plan announced earlier this year to develop more greener passenger jets.

This ambitious undertaking by NASA plans to design, build and fly a variety of experimental ultra-efficient subsonic transport aircraft, or “X-planes” featuring dramatically reduced fuel consumption, emissions and noise.

 As a part of it NASA recently awarded six-month contracts to four companies, Aurora Flight Sciences Corporation, Dzyne Technologies, Lockheed Martin and Boeing, who will each define the technical approach, schedule, and cost for one or more large-scale, subsonic X-plane concepts.

Lockheed Martin's HWB Concept

Each company is to detail their specific X-plane system requirements for a piloted experimental aircraft capable of sustained, two to three hours of powered high subsonic flight, as well as conducting at least two research flight sorties per week over the course of a year-long program.

The requested information is to be built around a plan that would see the selected experimental aircraft eventually flying no later than 2021.

NASA has selected five X-plane concepts envisioned for possible further development.

Aurora's D8 "Double Bubble" concept

Aurora Flight Services for the D8 “Double Bubble,” a twin-aisle, largely composite airliner in which the fuselage is shaped to provide lift – enabling smaller wings – and the jet engines are mounted atop the rear tail area, which takes advantage of the air flow over the aircraft to both improve engine efficiency and reduce noise in the cabin and on the ground below.

Dzyne Technologies for a smaller regional jet-sized aircraft that features a blended wing body (BWB) design in which the lines of a traditional tube and wing airliner are shaped to become one continuous line in which the seam between the wing and fuselage is nearly indistinguishable. As an aerodynamic shape, this configuration increases lift and reduces drag.

Lockheed Martin for its Hybrid Wing Body, which includes features of the BWB on the forward part of the fuselage but has a more conventional looking T-shaped tail, with its jet engines mounted on the side of the hull but above the blended wing. Increased lift, reduced drag and quieter operations are all potential benefits.

Boeing’s blended wing body concept. Credits: Boeing

Boeing for both its BWB concept – versions of which the company has flight tested with its subscale X-48 program in partnership with NASA – and a Truss-Braced Wing concept, which features a very long, aerodynamically efficient wing that is held up on each side by a set of trusses connecting the fuselage to the wing. Otherwise the aircraft appears more conventional than the other X-plane concepts under consideration.

Preliminary design work already has begun on a half-scale X-plane called the Quiet Supersonic Technology, or QueSST, a piloted supersonic aircraft that generates a soft thump, rather than the disruptive boom currently associated with supersonic flight.

X-57 Maxwell featuring distributed propulsion

Work also is underway on the X-57 Maxwell, a general aviation-sized electric research airplane. Maxwell will fly for the first time in early 2018 and demonstrate battery powered, distributed electric propulsion.

Transport-sized electric aircraft could reduce energy use by more than 60 percent and harmful emissions by more than 90 percent. This was the first project to get an X-plane number designation in a decade..