Instead of a single-fuselage cylinder, the D series melds two partial cylinders into a distinctive “double-bubble” shape. This adds to the lift and allows for longer, skinnier wings and a smaller tail, reducing drag. The engines sit at the top rear of the fuselage, where they draw in slower-moving air that passes over the plane, using less fuel for the same amount of thrust—a technique known as boundary layer ingestion. To mitigate the engine stress this creates, the plane would travel about 10 percent slower than a 737; the researchers anticipate making up this time through quicker loading and unloading via the plane’s second aisle.(Illustration by Jeremy Cook)
Innovators: Mark Drela, Edward Greitzer, MIT; Jeremy Hollman, Aurora Flight Sciences; Wesley Lord, Pratt & Whitney
Boeing’s 737 is the best-selling jet airliner in history: Today, it carries 29 percent of all U.S. domestic air traffic and is responsible for 25 percent of the industry’s fuel use. A reinvention of this commercial workhorse, called the D series, could burn 70 percent less fuel, emit 75 percent less nitrogen oxide and dampen noise from takeoffs and landings. In short, it could transform air travel into a more environmentally benign practice.