Boeing Says Radical New Winglets on 737 MAX Will Save Even More Fuel
Dubbed the Advanced Technology Winglet, Boeing says the dual-feather design will cut fuel burn by as much to 1.5% over the 10-12% improvement already expected from the MAX’s other features. The efficiency difference is dependent on the length of the flight.
On a conference call, Boeing 737 MAX chief project engineer Michael Teal explained that extending a traditional winglet upward would yield better fuel efficiency, but the added weight would negate the benefit. By leaving the top portion about the same size as the current 737 blended winglet, however, and adding a bottom feather, the weight penalty is minimized. “The concept is more efficient than any other wingtip device in the single-aisle market because the effective wing span increase is uniquely balanced between the upper and lower parts of the winglet,” he said.
The new winglets are somewhat of a fusion between the design of the blended winglets found on current 737NG’s and the raked wingtips built into Boeing’s 777 and 747-8 jets, Teal said. Unlike the blended winglets, which were designed and produced by the contractor Aviation Partners Boeing, the Advanced Winglet is an in-house Boeing design.
Compared to the wing fences found on the wingtips of Airbus A320 family jets, with which the Advanced Technology Winglet shares a vague resemblance, Boeing’s design will be significantly larger, Teal said. Airbus is moving away from the wing fence design in favor of Sharklets, which closely resemble the blended winglets found on the 737NG.
Low-speed wind tunnel testing on a scale model of the Advanced Technology Winglet has been carried out at QinetiQ in Farnborough, England, while high-speed testing was done at the Boeing Transonic Wind Tunnel in Seattle. The design performed just as expected in the tests, said Teal.
Winglets improve fuel economy by expanding the effective surface area of the wing without adding length to the wingspan. Air that would simply flow off the tip of a bare wing into the ether is recaptured by the winglet and used to add lift.
Wingtip device technology has become a hot sector in recent years as airlines attempt to wring every mile possible out of a gallon of jet fuel amidst wild price increases. A number of designs have made their way to commercial airliners, both on new aircraft and as retrofits to older planes. Boeing says there are no current plans to offer the Advanced Technology Winglet as a retrofit on older 737s, but he did say it would be possible to scale the design to larger aircraft.
Boeing has received orders for a total of 451 Boeing 737 MAX aircraft, which is expected to enter service in 2017.