F-111 Swing Wing: "Variable Wing Sweep Mechanism Demonstration" ~(1965) General Dynamics; JQ Music
Please considering supporting the channel through my patreon link to help continue the consistent uploads. https://www.patreon.com/oldmoviesreborn Thanks. Demonstration of wing sweep in 1965. https://en.wikipedia.org/wiki/Variable-sweep_wing A variable-sweep wing, colloquially known as a "swing wing", is an airplane wing, or set of wings, that may be swept back and then returned to its original position during flight. It allows the aircraft's shape to be modified in flight, and is therefore an example of a variable-geometry aircraft. Typically, a swept wing is more suitable for high speeds, while an unswept wing is suitable for lower speeds, allowing the aircraft to carry more fuel and/or payload, as well as improving field (take-off and landing) performance. A variable-sweep wing allows a pilot to select the correct wing configuration for the plane's intended speed. The variable-sweep wing is most useful for those aircraft that are expected to function at both low and high speed, and for this reason it has been used primarily in military aircraft. A number of successful and experimental designs were introduced from the 1940s into the 1970s; however, the recent advances in flight control technology and structural materials have allowed designers to closely tailor the aerodynamics and structure of aircraft, removing the need for variable sweep angle to achieve the required performance; instead, wings are given computer-controlled flaps on both leading and trailing edges that increase or decrease the camber or chord of the wing automatically to adjust to the flight regime. This is another form of variable geometry, although it is not commonly called such. The 1931 Westland-Hill Pterodactyl IV was a tailless design whose lightly swept wings could vary their sweep through a small angle during flight. This allowed longitudinal trim in the absence of a separate horizontal stabiliser. Later, experimental aircraft were built to study the effects of a simple swept wing. The first of these was the Messerschmitt Me P.1101 whose sweep angle could be changed on the ground. World War II in Europe ended before the P.1101 could be completed. Soon afterwards, the P.1101 was taken to the United States for study at Bell Aircraft, but because of missing documentation and structural damage, Bell decided against completing it. Instead, a close copy was constructed which featured wings that could adjust sweep angle in flight. One problem discovered while testing the Bell X-5 was that as the wing pivoted rearward, the lift vector also moved to the rear, pushing the nose down. A system to compensate for this basic effect had to be added for any such design to be viable. Immediately after the war (1949) Barnes Wallis had started work on variable geometry to maximise the economy of supersonic flight. Initial work was on the military "Wild Goose" project, then he went on to the "Vickers Swallow", intended to achieve a return flight from Europe to Australia in 10 hours. It had a blended wing tailless design and he successfully tested several models including a six-foot scale model at speeds of up to Mach 2 in the 1950s but government backing was withdrawn. Wallis and his team presented their work to the Americans seeking a grant to continue their studies but none was forthcoming. In March 1949, the aeronautical engineer L. E. Baynes AFRAeS designed and patented a supersonic variable-sweep wing fighter. He lodged patent applications in Britain and subsequently in May 1956 was granted a US Patent (2,744,698) for "High Speed Aircraft Wing and Tail Surfaces Having Variable Sweep-back". In February 1951 he applied for another patent (granted as US 2,741,444 in April 1956) for a supersonic variable-sweep wing and tail fighter ["High Speed Aircraft Having Wings With Variable Sweepback"]. The design was built and wind tunnel tests were completed successfully, but due to budget constraints at the time, the design failed to receive government backing. A variable-sweep wing was tried on the Grumman F10F Jaguar in 1952. The XF10F never entered service; it possessed extremely poor flying characteristics and rather vicious spin tendencies. The idea was again revived in the early 1960s as a way to reconcile ever-growing aircraft weights (and thus wing loading) with the need to provide reasonable takeoff and landing performance. The United States adopted this configuration for the TFX (Tactical Fighter Experimental) program, which emerged as the General Dynamics F-111, the first production variable-sweep wing aircraft.
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