page_title: Supercritical airfoil
section_title: History
hierarchical_section_title: Supercritical airfoil / History
caption_attribution_description: A Vought F-8A Crusader was selected by NASA as the testbed aircraft (designated TF-8A) to install an experimental Supercritical Wing in place of the conventional wing. The unique design of the Supercritical Wing (SCW) reduces the effect of shock waves on the upper surface near Mach 1, which in turn reduces drag. The F-8 Supercritical Wing (SCW) project flew from 1970 to 1973. Dryden engineer John McTigue was the first SCW program manager and Tom McMurtry was the lead project pilot. The first SCW flight took place on 9 March 1971. The last flight of the Supercritical wing was on 23 May 1973, with Ron Gerdes at the controls. Original wingspan of the F-8 was 35 feet, 2 inches while the wingspan with the supercritical wing was 43 feet, 1 inch. F-8 aircraft were powered by Pratt &amp; Whitney J57 turbojet engines. The TF-8A Crusader was made available to the NASA Flight Research Center by the U.S. Navy. F-8 jet aircraft were built, originally, by LTV Aerospace, Dallas, Texas. Rockwell International’s North American Aircraft Division received a $1.8 million contract to fabricate the supercritical wing, which was delivered to NASA in December 1969.
context_page_description: A supercritical airfoil is an airfoil designed primarily to delay the onset of wave drag in the transonic speed range.
  Supercritical airfoils are characterized by their flattened upper surface, highly cambered aft section, and larger leading-edge radius compared with NACA 6-series laminar airfoil shapes. Standard wing shapes are designed to create lower pressure over the top of the wing. Both the thickness distribution and the camber of the wing determine how much the air accelerates around the wing. As the speed of the aircraft approaches the speed of sound, the air accelerating around the wing reaches Mach 1 and shockwaves begin to form. The formation of these shockwaves causes wave drag. Supercritical airfoils are designed to minimize this effect by flattening the upper surface of the wing.
  The origins of the supercritical airfoil can be traced back to the German aerodynamicist K. A. Kawalki, who designed a number of airfoils during the Second World War. Following the end of the conflict, multiple nations continued research into the field, including Germany, the United Kingdom, and the United States.
context_section_description: The supercritical airfoil was first suggested by aerodynamicists in Germany during the Second World War. During 1940, K. A. Kawalki at Deutsche Versuchsanstalt für Luftfahrt Berlin-Adlershof designed a number of airfoils characterised by elliptical leading edges, maximal thickness located downstream up to 50% chord and a flat upper surface. Testing of these airfoils was reported by B. Göthert and K. A. Kawalki in 1944. Kawalki's airfoil shapes were identical to those subsequently produced by the American aerodynamicist Richard Whitcomb. The aviation authors Ernst Heinrich Hirschel, Horst Prem, and Gero Madelung have referred to the supercritical airfoil as being of equal importance, in terms of aerodynamics, as the innovation of the swept wing to high speed aircraft.
  During the 1950s and 1960s, a number of different high speed research aircraft equipped with conventional airfoils repeatedly encountered difficulties in breaking the sound barrier, or even reaching Mach 0.9. Supersonic airflow over the upper surface of the traditional airfoil induced excessive wave drag, as well as a form of stability loss known as Mach tuck. Aerodynamicists determined that, by appropriately shaping the airfoil used, the severity of these problems could be greatly reduced and allow the aircraft to attain much higher speeds; this is the basis of the supercritical wing. Its design allows the wing to maintain high performance levels at speeds closer to Mach 1 than traditional counterparts. 
  Between 1959 and 1968, the British aerospace manufacturer Hawker Siddeley Aviation, based in Hatfield, England, designed its own improved airfoil profiles, which were sometimes referred to as rooftop rear-loaded airfoils. Hawker Siddeley's research subsequently served as the basis for the supercritical wing of the Airbus A300, a multinational wide-body airliner which first flew during 1972. In parallel, postwar Germany and the Netherlands also conducted their own research efforts into optimal transonic airfoil designs, intending for these efforts to support civil aviation programmes. Up until the 1970s, there was considerable focus upon developing an airfoil that performed isentropic recompression, a shock-free return of the airflow to subsonic speeds.
  In the United States, the supercritical airfoil was an area of research during the 1960s; one of the leading American figure in the field was Richard Whitcomb. A specially modified North American T-2C Buckeye functioned as an early aerial testbed for the supercritical wing, performing numerous evaluation flights during this period in support of the research effort. Following initial flight testing, the new airfoils were tested at increasingly higher speeds on another modified military aircraft, the TF-8A Crusader.
  While the supercritical airfoil has been initially work on by NASA as part of the United States' National Supersonic Transport programme, the supersonic airliner that was being developed to harness it, the Boeing 2707, was ultimately cancelled due to a combination of technical challenges and relatively high costs. Despite this, the work was one aspect of the programme that survived the cancellation of its principal intended recipient. The supercritical airfoil shape was incorporated into the design of the supercritical wing.
  In such a manner, the technology has subsequently been successfully applied to several high-subsonic aircraft, noticeably increasing their fuel efficiency. Early examples include the Boeing 757 and Boeing 767 airliners, both of which were developed during the 1980s. According to Hirschel, Prem and Madelung, the supercritical wing has been regarded as being an essential element of modern jetliners, pointing towards its use on Airbus' product range.
  During 1984, Kawalki's research was cited as the basis for a formal objection against the US patent specification that had been issued for the supercritical airfoil. Around this time, Kawalki's work was reportedly playing an active role in the design of new airliners, such as the Airbus A310. Additionally, some aircraft have been redes
caption: NASA TF-8A in 1973
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