Researchers at MIT say they have come up with designs for a new generation of commercial aircraft that could use as much as 70 percent less fuel than today's airliners.
As part of a $2.1 million NASA grant, the MIT-led team said that its designs for a so-called "N+3" airplane--meaning three generations beyond today's airplanes--could leverage new technologies like advanced airframe configurations and propulsion systems and could deliver the 70 percent fuel savings by around 2035.
In a release, Ed Greitzer, an aeronautics and astronautics professor at MIT, said that meeting NASA's criteria for new, highly-efficient aircraft designs would require a "radical change" from the current aviation paradigm. That's mainly because airplanes largely have the same design today as they've had for the last 50 years--an "easily recognizable 'tube and wing' structure of an aircraft's wings and fuselage."
But Greitzer's team crafted two designs that could upend the traditional airplane paradigm. One is a 180-passenger D "double bubble" series, which could eventually replace the Boeing 737 that is used for so much domestic travel; and the 350-passenger H "hybrid wing body" series, which could take the place of the popular Boeing 777 used for many international flights.
The [MIT] engineers conceived of the D series by reconfiguring the tube-and-wing structure. Instead of using a single fuselage cylinder, they used two partial cylinders placed side by side to create a wider structure whose cross-section resembles two soap bubbles joined together. They also moved the engines from the usual 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.
Planes built with the MIT designs will likely be as much as 10 percent slower, but that time loss could be offset by quicker loading and unloading due to the planes' wider bodies.
It is important that these designs be ready by 2035, the release suggested, because air travel is expected to double by then. But MIT said that a different version of the designs could be crafted much sooner that reduced fuel usage by 50 percent.