We might all be familiar with the efficiency benefits that winglets can provide, but our ideas of what they’re supposed to look like are quickly changing. Boeing on Wednesday revealed the design for its 737 MAX “dual-feather” winglet, saying the unique shape will provide an extra 1.5 percent gain in fuel efficiency compared with the new “sharklet” upward-swooping winglets under development for Airbus’s new A320neo airliner.
The efficiency improvements from Being’s new split-tip winglet are in addition to the 10 to 12 percent fuel-burn improvement for the 737 MAX from new engines and minor aerodynamic improvements. Artist’s renderings released by Boeing show the new wingtip swept slightly back and with a tip that splits in two. The longer tip points up and the other, shorter tip down. The concept is reminiscent of a split-tip winglet design that Seattle-based Aviation Partners is known to be flight testing called the Blended Split-Tip Scimitar Winglet – but Aviation Partners reportedly was not involved in the 737 MAX winglet’s design.
Winglets add extra wing surface without extending the overall wingspan, increasing lift and reducing drag by converting otherwise-wasted energy in the wingtip vortices into apparent thrust. Boeing says the split ends of its new wingtip design maximize the aerodynamic gain without adding a lot of weight as longer, single winglets do. Boeing aerodynamicists created the design using computer simulations, and then confirmed the expected benefits by testing the winglets in the wind tunnel.
The 737 MAX is scheduled to enter service in 2017.