The design window “is closing” on the final configuration of the re-engined Boeing 737 Max narrowbody airliner.
In the past several weeks, Boeing has announced a series of design updates to the 737 Max, including most recently a new “dual feather” winglet concept aimed at further improving the fuel efficiency of the new airliner. The manufacturer has said it expects to finalize the aircraft’s design by the middle of next year. In a May 2 briefing, Michael Teal, 737 Max chief project engineer, said Boeing has finished aerodynamic trade studies of the aircraft, and the new winglet accounts for the final major design update. “As we are closing in on finalizing the configuration of the airplane to ensure that we meet our commitment on schedule, the window is closing fast, so this is pretty much it,” Teal said of the winglet. “As we firm up to final configuration, we’ll continue to optimize these concepts to maximize the performance benefits.”
On April 11, Boeing announced a series of updates to the design of the 737 Max aft body, engine installation and flight-control system. During the May 2 briefing, the manufacturer said the “advanced-technology winglet” design will provide as much as another 1.5 percent fuel-burn advantage on top of the 10- to 12-percent improvement it has promised the Max will deliver over the 737NG.
Teal said the Boeing design combines the raked wingtip feature of the 787 Dreamliner and 747-8 widebodies with an upper and a lower piece. “We recognized there was an opportunity for the new winglet to give our customers a substantial additional benefit,” he said. Engineers predicted the fuel-burn savings using computational fluid dynamics, while scale models underwent testing at low speeds in the QinetiQ wind tunnel in Farnborough, UK, and at high speeds in the Boeing transonic wind tunnel in Seattle.
“While testing was under way, our airframe and structures and manufacturing teams met with the aerodynamics team to make sure we had plans in place to integrate the winglet onto the wing and overall airframe design of the Max in a producible way,” Teal said. “Most important, the team validated that we could do this within our existing schedule for the Max.”
The new winglet provides a total fuel-burn improvement of up to 5.5 percent over a 737 with no winglet at all, Teal said. If realized in service, the percentage gain would exceed the 3.5-percent fuel-burn improvement Airbus claims for the A320 equipped with new “Sharklet” winglets. On April 26, Airbus announced the completion of the first new-build A320 with Sharklets in Toulouse.
The dual-feather winglet design is Boeing’s intellectual property, executives said. The manufacturer currently does not plan to retrofit it on 737NGs equipped with blended winglets from Seattle-based Aviation Partners, said Beverly Wyse, 737 program vice president and general manager. ’