Gull wing

The gull wing is an with a prominent bend in the wing somewhere along the span, generally near the wing root. Its name is derived from the seabirds which it resembles. It has been incorporated in aircraft for many reasons.

Sailplanes

The gull wing was first seen on glider when the Weltensegler flew in 1921. Its wings were externally braced and featured swept-back wingtips. After the aircraft broke up, killing its pilot, the design feature stayed out of popular use. The gull wing made a resurgence in 1930 with Alexander Lippisch's record-breaking "Fafnir". Lippisch used the configuration for its increased wingtip clearance and the ill-founded belief it improved stability in turns. The true success of the Fafnir's gull wing laid primarily in its aesthetic value; the gull wing would be a staple of the high-performance sailplanes of the time, until the 1950s.

Notable gull wing sailplanes:
* DFS Habicht
* DFS Reiher
* Schempp-Hirth Minimoa
* DFS Kranich
* Rhoensperper
* Lippisch Fafnir
* Weltensegler

Seaplanes

The gull wing design found its way into seaplanes by the early 1930s. As engine power increased, so did the need for large propellers that could effectively convert power to thrust. The gull wing allowed designers to ensure adequate propeller tip clearance over the water by placing the engines on the highest point of the wing. The alternative was placing the engine on a pylon. Possibly the first flying-boat to utilize the gull wing configuration was the Short Knuckleduster, which flew in 1933. The Dornier Do 26, a high-speed airliner and transport platform, of which 6 aircraft were built, flew in 1938. The configuration was also used on the US Navy's PBM Mariner and P5M Marlin maritime patrol aircraft. The emergence of long range, land-based jets in the 1950s and the subsequent demise of the seaplane prevented widespread use of the gull wing, although it was still used in some post-war designs, like Beriev Be-12 "Chaika" (the name means 'the gull' in Russian). On the other hand, large seaplanes, with high fuselages, and jet-powered ones, did not need a gull wing design.

Notable gull wing seaplanes
* Dornier Do 26
* Martin PBM Mariner
* Martin P5M Marlin
* Beriev Be-6
* Beriev Be-12

Landplanes

The gull wing design found its way into landplanes in the late 1920s, with Polish inventor Zygmunt Puławski designing the PZL P.1 in 1928. The arrangement he devised is occasionally, known as the "Pulawski Wing" or the "Polish wing". The gull wing was used to improve visibility in a high wing arrangement, because such wing could be thinnest by the fuselage, and in theory, should limit pilot's view no more than A-pillars of a windscreen in a car body. It was used in fighter aircraft like PZL P.11 and Polikarpov I-15 and also in some other planes like Westland Lysander. The "inverted" gull wing was developed at the same time and for the same reason as seaplanes. More powerful engines generally require larger propellers, but clearance between the propeller tip and ground must be maintained. Long landing gear legs are heavy, bulky, and weaker than their shorter counterparts. The Vought F4U Corsair, designed from the onset as a carrier-based fighter, not only had the largest propeller of any U.S. fighter, but was also expected to face rough landings aboard a pitching carrier deck. The inverted gull wing allowed the landing gear to be short, tough, and to retract straight back, improving internal wing space.

Notable gull wing landplanes
* Vought F4U Corsair
* Junkers Ju-87 Stuka
* Westland Lysander
* PZL P.11
* Polikarpov I-153

References

* [http://www.scalesoaring.co.uk/Documentation/Documentation.html Scale Soaring UK Documentation Section]