geometry A variable geometry aircraft is able to change its physical configuration during flight. Some types of variable geometry craft transition between fixed wing and rotary wing configurations. For more about these hybrids, see powered lift. Variable planform Variable-sweep wing or Swing-wing. The left and right hand wings vary their sweep together, usually backwards. The first successful wing sweep in flight was carried out by the Bell X-5 in the early 1950s. In the Beech Starship, only the canard foreplanes have variable sweep. Oblique wing: a single full-span wing pivots about its midpoint, as used on the NASA AD-1, so that one side sweeps back and the other side sweeps forward. Telescoping wing: the outer section of wing telescopes over or within the inner section of wing, varying span, aspect ratio and wing area, as used on the FS-29 TF glider. Detachable wing. The WS110A study proposed a long wing for subsonic takeoff and cruise, which then detached the outer panels to drop away, leaving a short-span wing for supersonic flight. (See also Slip wing below.) Extending wing or expanding wing: part of the wing retracts into the main aircraft structure to reduce drag and low-altitude buffet for high-speed flight, and is extended only for takeoff, low-speed cruise and landing. The Gérin Varivol biplane, which flew in 1936, extended the leading and trailing edges to increase wing area. Folding wing: part of the wing extends for takeoff and landing, and folds away for high-speed flight. The outer sections of the XB-70 Valkyrie wing folded down during supersonic cruise. (Many aircraft have wings that may be folded for storage on the ground or on board ship; these are not folding wings in the sense used here.) Variable section Variable incidence: the wing plane can tilt upwards or downwards relative to the fuselage. The wing on the Vought F-8 Crusader was rotated, lifting the leading edge on takeoff to improve performance. If powered prop-rotors are fitted to the wing to allow vertical takeoff or STOVL performance, merges into the powered lift category. Variable camber: the leading and/or trailing edge sections of the whole wing pivot to increase the effective camber of the wing and sometimes also its area. This enhances manoeuvrability. An early example was flown on the Westland N.16 of 1917. Variable thickness: the upper wing centre section can be raised to increase wing thickness and camber for landing and take-off,