When we look out of the window as our aircraft comes in to land, we are used to seeing flaps and slats deploy, and slots open, as the wing reconfigures to increase lift and reduce landing speed. But, in the cruise, not much happens to the wing except small movements by individual control surfaces as the aircraft maneuvers or responds to turbulence.
Now Boeing and NASA are working on the Variable Camber Continuous Trailing Edge Flap (VCCTEF) system (graphic above), which would smoothly change the wing’s shape continuously throughout the flight. By continuously varying camber, the VCCTEF would provide efficient high lift for takeoff and landing and reduced cruise drag through active control of the twist of a flexible wing.
In a early 1980s joint NASA/US Air Force program called Advanced Fighter Technology Integration (AFTI), the supercritical wing on a F-111A aircraft was replaced with a wing built by Boeing Aircraft Company System called a "Mission Adaptive Wing" (MAW). This wing had an internal mechanism to flex the outer wing skin and produce a high camber section for subsonic speeds, a supercritical section for transonic speeds, and symmetrical section for supersonic speeds. The surface irregularities from leading edge slates was eliminated and trailing edge flap effects reduced. The use of flexible wing skins to produce a smooth upper surface brought this wing a little closer in concept to that of a bird. A digital flight control system provided automatic changes to the wing geometry. The system had four automatic control modes: (1) Manoeuvre Camber Control - adjusting camber shape for peak aerodynamic efficiency; (2) Cruise Camber Control - for maximum speed at any altitude and power setting; (3) Manoeuvre Load Control - providing the highest possible aircraft load factor (4) Manoeuvre Enhancement Alleviation - in part attempting to reduce the effects of gusts on airplane ride. The AFTI/F-111 MAW system had 59 flights from 1985 through 1988. The flight test data showed a drag reduction of around 7 percent at the wing design cruise point to over 20 percent at an off-design condition. The four automatic modes were tested in flight with satisfactory results.
Originally posted by Zaphod58
reply to post by inivux
Actually, in the long term, fewer moving parts. You're losing the flaps on the entire outboard section of wing. You're replacing them with actuators, and flexible skin. So you lose the flap motors, flap tracks, jack screws, all that goes away. So it's quite a weight savings among other things.