Will Flapping Wingtips Enhance Aerodynamic Performance?

Efforts to reduce aircraft fuel burn includes extending wingspans, but navigating airport gates puts a limit on commercial airliner wingspans. Wing design modifications that achieve aerodynamic efficiencies without extending wingspans include drag-reducing winglets. A new twist on this is the flapping wing tip—which some have likened to actively folding (hence “flapping”) wingtips. Airbus calls the flapping wingtip mechanism the “semi-aeroelastic hinge.” It can be locked to remain rigid, or unlocked to freely flap in flight....