In what could set the stage for a fundamental shift in commercial aviation, the Massachusetts Institute of Technology (MIT) and Cambridge University scientists have designed a green aircraft that is estimated to use 70 percent less fuel than current planes while also reducing noise and emission of nitrogen oxides (NOx).
The design was one of two that the team presented to NASA last month as part of a $2.1 million research contract to develop environmental and performance concepts. Known as 'N+3' to denote three generations beyond today's commercial transport fleet, the research program is aimed at enabling greener aviation around 2035.
Concepts for subsonic (slower than the speed of sound) and supersonic (faster than the speed of sound) commercial planes were studied by several teams under NASA contracts; the MIT being the involved in subsonic aviation concepts. Their objective was to develop concepts for, and evaluate the potential of, quieter subsonic commercial planes that would burn 70% less fuel and emit 75% less NOx than today's commercial planes. NASA also wanted an aircraft that could take off from shorter runways.
Designing an aircraft that would meet NASA's aggressive criteria while accounting for changes to air travel expected in 2035, when air traffic is expected to double, was known to require radical change. The MIT team designed two options for NASA, the 180 passenger D 'double bubble' series to replace the Boeing 737 domestic planes, and the 350 passenger H 'hybrid wing body' series to replace the 777 class international planes.
The engines of the D series are moved from the wings to the rear of the aircraft, therefore they take in slower moving air. Compared to receiving fast moving air, the engines are able to use far less fuel to produce the same amount of thrust. The skinny wings and smaller tail reduce drag. These are the fundamental reasons for such increased fuel economy, although the plane will travel around 10% slower. Carl Burleson, the director of the Federal Aviation Agency's Office of Environment and Energy, said that the design provides "really good environmental performance".
The MIT team expects to hear from NASA within the next several months about whether it has been selected for the second phase of the program, which will provide additional funds to one or two of the subsonic teams in 2011 to research and develop the technologies identified during the first phase.
