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Or would have been considered necessary. Certainly, the B-36 qualified as an unusual project, especially as its development started in something like 1942.
The problems of flight at high speeds were subject to serious investigation well before WW2: in the 1930s there was an international conference (in Italy) entitled "High Velocities in Aviation" (it was the Fifth Volta conference, in 1935). During this conference, the NACA representative (Eastmann Jacobs) presented Schlieren photographs, data from the NACA High Speed Wind Tunnel, etc Theodore von Karman (Caltech GALCIT, the predecessor of JPL) also got to go. Busemann presented a paper analyzing swept wings (with supersonic edges); Betz noted that swept wings would also be beneficial for transonic flight (around M=1, where there are local areas of supersonic flow, but the freestream velocity is subsonic). Robert T Jones (the aerodynamicist, not the golf course designer) published his paper about the analysis of swept wings during WW2. In other words, the NACA in the US and likely the UK (which had its fluid guys: google James Lighthill) knew the benefits of swept wings. This doesn't mean that industry had been paying attention, though: propeller aircraft were too slow to worry much transonic flow except in dives, and the P-80 -- the P-80A was just about as fast as the Me262 -- seems to have had superior airfoils, so sweep was unnecessary. This permits a lighter wing, as the structural length of a wing depends on 1/cos(sweep). An unswept wing also precludes a lot of negative flight control characteristics at high angles of attack.
Thanks swampyankee.
Something about the F-86:
North American had produced the highly successful propeller-powered P-51 Mustang in World War II, which saw combat against some of the first operational jet fighters. By late 1944, North American proposed its first jet fighter to the U.S. Navy which became the FJ-1 Fury. It was an unexceptional transitional jet fighter which had a straight wing derived from the P-51.[4][5] Initial proposals to meet a United States Army Air Forces (USAAF) requirement for a medium-range, single-seat, high-altitude jet-powered day escort fighter/fighter bomber were drafted in mid-1944.[6] In early 1945, North American Aviation submitted four designs.[6] The USAAF selected one design over the others, and granted North American a contract to build three examples of the XP-86 (eXperimental Pursuit). Deleting specific requirements from the FJ-1 Fury, coupled with other modifications, allowed the XP-86 to be lighter and considerably faster than the Fury, with an estimated top speed of 582 mph (937 km/h), versus the Fury's 547 mph (880 km/h).[6] Despite the gain in speed, early studies revealed the XP-86 would have the same performance as its rivals, the XP-80 and XP-84. It was also feared that, because these designs were more advanced in their development stages, the XP-86 would be canceled.
Crucially, the XP-86 would not be able to meet the required top speed of 600 mph (970 km/h);[7] North American had to quickly come up with a radical change that could leapfrog it over its rivals. The North American F-86 Sabre was the first American aircraft to take advantage of flight research data seized from the German aerodynamicists at the end of the war.[8] This data showed that a thin swept wing could greatly reduce drag and delay compressibility problems which had bedeviled even prop-powered fighters such as the Lockheed P-38 Lightning approaching the speed of sound. By 1944, German engineers and designers had established the benefits of swept wings based on experimental designs dating back to 1940. Study of the data showed that a swept wing would solve their speed problem, while a slat on the wing's leading edge which extended at low speeds would enhance low-speed stability.
Because development of the XP-86 had reached an advanced stage, the idea of changing the sweep of the wing was met with resistance from some senior North American staff. Despite stiff opposition, after good test results were obtained in wind tunnel tests, the swept-wing concept was eventually adopted. Performance requirements were met by incorporating a 35° swept-back wing, using NACA 4-digit modified airfoils, using NACA 0009.5-64 at the root and NACA 0008.5-64 at the tip,[9] with an automatic slat design based on that of the Messerschmitt Me 262 and an electrically adjustable stabilizer, another feature of the Me 262A.[10][11][12] It should be noted that many Sabres had the "6-3 wing" (a fixed-leading edge with 6 inches extended chord at the root and 3 inches extended chord at the tip) retrofitted after combat experience was gained in Korea.[10][13] This modification changed the wing airfoils to the NACA 0009-64 mod at the root and the NACA 0008.1-64 mod at the tip.[9]
Delays caused by the major redesign meant that manufacturing did not begin until after World War II. The XP-86 prototype, which would lead to the F-86 Sabre, was rolled out on 8 August 1947
North American F-86 Sabre - Wikipedia, the free encyclopedia
Again there's a mention about German data being used in benefit of the project. swampyankee, this is a total myth in your view?
