Bf 109 at the onset of the conflict. Examples: PZL P.1 PZL P.7 PZL P.11 PZL P.24 Polikarpov I-153 Loire 46 Inverted gull wing During the 1930s, a derivative of the standard design, known as the inverted gull wing, was developed. It was chiefly used on single engine military aircraft with increasingly powerful engines. Before contra-rotating propellers came into use, such powers required larger diameter propellers but clearance between the propeller tip and ground had to 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. By adopting the inverted gull wing, the landing gear could be shorter and allowed to retract straight back (while twisting through 90º to place the mainwheels atop the lower gear strut ends), the latter factor improving internal wing space. The anhedral of the wing's center-section also permitted the wing and fuselage to meet at the optimum angle for minimizing drag, without using wing root fairings or other measures. Another reason for having an inverted gull wing is to permit clearance for a large external bomb load, as on the Junkers Ju 87 Stuka. The inverted gull wing has been described by aviation author Manfred Griehl as being the most distinctive feature of the Ju 87. These wings, which comprised conventional Junkers double-wing construction, reportedly gave the Ju 87 a considerable advantage over its contemporaries during take-off; relatively large lift forces were created through the aerofoil even when flown at a shallow angle, reducing take-off and landing runs. They also provided a high level of ground visibility to the pilot, as well as enabling the use of a shorter undercarriage. Examples: Aichi B7A Blohm & Voss Ha 137 Junkers Ju 87 Stuka Vought F4U Corsair Mitsubishi A5M first prototype Yermolayev Yer-2 References Citations Bibliography Barnes, Christopher H. and Derek N. James. Shorts Aircraft since 1900. London: Putnam, 1989. . Bridgeman, Leonard. “The Martin Model 162 Mariner.” Jane's Fighting Aircraft of World War II. London: Studio, 1946. . Green, William. "Vought F4U-1, F4U-4 (FG-1 Corsair)". War Planes of the Second World War, Volume Four: Fighters. Garden City, New York: Doubleday & Company, 1973, pp. 188–194. . External links Scale Soaring UK Documentation Section Vought F4U Corsair