The work is funded by NASA’s Aeronautics Research Mission Directorate in Washington. The agency’s Fundamental Aeronautics Program is focused on developing technology that will enable aircraft to meet national goals for reduced fuel consumption, emissions and noise. The program’s Subsonic Fixed Wing Project oversees the work at the agency’s Glenn Research Center in Cleveland and Langley Research Center in Virginia.

The team leaders, projects, contract amounts and periods of performance are:

• Boeing Research & Technology, Huntington Beach, Calif., Subsonic Ultra Green Aircraft Research, or SUGAR, $8.8 million, three years

• Massachusetts Institute of Technology (MIT), Cambridge, Mass., Aircraft and Technology Concepts for N+3 Subsonic Transport, $4.6 million, three years

• Cessna Aircraft Company-Cessna Citation, Wichita, Kan., Star-C2 Protective Skins-Materials & Requirements Development, $1.9 million, 27 months

• Northrop Grumman Systems Inc., El Segundo, Calif., High Lift Leading Edge Ground Test, $1.2 million, 14 months

Boeing. The Boeing Research & Technology (BR&T) award continues the work of the SUGAR (Subsonic Ultra Green Aircraft Research) Project, which looked at truss-based wing aircraft designs and hybrid electric engine technology. The Boeing subsonic team, which includes BR&T, Boeing Commercial Airplanes, General Electric and Georgia Tech, looked at five concepts as part of the SUGAR (Subsonic Ultra Green Aircraft Research) project. The concepts include two conventional reference configurations, similar in appearance to a 737 (nicknamed SUGAR Free and Refined SUGAR); two versions of a new design high span, strut-braced wing aircraft (referred to as SUGAR High and SUGAR Volt); and a hybrid wing body configuration (called SUGAR Ray).

In its earlier assessment, the team found that the SUGAR Volt concept (which adds an electric battery gas turbine hybrid propulsion system) can reduce fuel burn by greater than 70% and total energy use by 55% when battery energy is included. Moreover, the fuel burn reduction and the ‘greening’ of the electrical power grid can produce large reductions in emissions of life cycle CO₂ and nitrous oxide. Hybrid electric propulsion also has the potential to shorten takeoff distance and reduce noise.

The SUGAR team’s report concluded that hybrid electric engine technology “is a clear winner, because it can potentially improve performance relative to all of the NASA goals.”

The new contract will allow the team to start collecting higher fidelity data on its concepts. Under the contract, the team will design, construct and test wind tunnel mockups and computer models of the airplane. The team also will study lightweight materials and engine concepts for even more futuristic planes that could fly between 2040 and 2045.

MIT. The MIT team is moving forward with work on its “double bubble” airplane design. Its concept is a dual fuselage, two partial cylinders placed side by side, that would create a wider structure than the traditional tube-and-wing airliner. In the initial development of the design, the team also moved the engines from wing-mounted locations to the rear of the fuselage. Unlike the engines on most transport aircraft that take in the high-speed, undisturbed air flow, the D-series engines take in slower moving air that is present in the wake of the fuselage.

Known as the Boundary Layer Ingestion (BLI), this technique allows the engines to use less fuel for the same amount of thrust, although the design has several practical drawbacks, such as creating more engine stress.

Under the new contract, the team will develop the technologies identified during the first study and build a model for testing. MIT also will explore the challenges of high-efficiency, small-core engine technology—the idea that it is not necessary to increase an engine’s size to increase efficiency in delivering power.

Cessna. The Cessna Aircraft Company team will focus on airplane structure, particularly the aircraft outer covering. Engineers are trying to develop what some call a “magic skin” that can protect planes against lightning, electromagnetic interference, extreme temperatures and object impacts. The skin would heal itself if punctured or torn and help insulate the cabin from noise. The NASA funding will help the company develop, integrate and test the structural concept.

The skin will be made from a material called STAR-C2, which stands for “smoothing, thermal, absorbing, reflective, conductive, cosmetic”.

The Northrop Grumman team will test models of the leading edge of the wing. If engineers can design a smooth edge without the current standard slats, airplanes would be quieter and consume less fuel at cruise altitudes because of the smoother flow of air over the wings.