A folding wing is a design feature of aircraft to save space in the airfield, and time, and is typical of naval aircraft that operate from the limited deck space of aircraft carriers. The folding allows the aircraft to occupy less space in a confined hangar because the folded wing normally rises over the fuselage decreasing the floor area of the aircraft. Vertical clearance is also limited in aircraft carrier hangar decks. In order to accommodate for this, some aircraft such as the Supermarine Seafire and Fairey Gannet have additional hinges to fold the wingtips downward, while others such as the S-3 Viking have folding tails.
Short Brothers, the world's first aircraft manufacturer, developed and patented folding wing mechanisms for ship-borne aircraft (Short Folder), the first patent being granted in 1913. The wings were hinged so that they folded back horizontally alongside the fuselage, usually being held in place by latches projecting sideways from the rear of the fuselage.
Since the monoplane supplanted the biplane in the late 1930s, virtually all fixed-wing aircraft designed for shipboard duty have been equipped with folding wings. Notable exceptions include the SBD Dauntless, F2A Buffalo, and A4D/A-4 Skyhawk (all USN types) and the Sea Harrier (British). All four are relatively small designs.
Folding surfaces are rare among land-based designs, and are used on aircraft that are tall or too wide to fit inside service hangars. Examples include the Boeing B-50 Superfortress and its folding tail. The Saab 37 Viggen and the Boeing 377 Stratocruiser have foldable rear fins that make them lower for entering hangars. The Boeing 777 twinjet wide-body airliner was offered with folding wingtips for confined airports, but no airline purchased this option. Both Boeing 777X models will feature a shorter and simpler folding wingtip than was planned for the earlier Boeing 777. This will provide an extra 7 metres of wingspan in flight, yet the plane will still fit inside the same airport gates as the 777-300.
A V-22 Osprey with wings rotated to run the length of the fuselage
Folding wings planes on flight deck
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