Various airfoil design exercises carried out at ARA over the years are described, concentrating on the part played by the inverse methods. The design of an airfoil suitable for the wing of a combat aircraft research model was successful in meeting a number of performance requirements but the inverse supercritical method used gave an unsatisfactory intermediate profile and off-design calculations were necessary to resolve the problem. In a research exercise involving the design of an airfoil suitable for the wing of a transport aircraft to take advantage of full-scale Reynolds number, the inverse supercritical method used produced changes to the geometry in an opposite sense to those finally required. It is suggested that the difficulties with the inverse supercritical methods arose because appropriate design target pressures were not known and because viscous effects were not included in the methods. Subsequent designs of laminar flow airfoils and high-speed propeller blade airfoils are described. For these cases, a technique was used involving a subcritical method, with progressive adjustment of target pressures until a geometry arose with suitable flow development according to a viscous supercritical method, with little use of supercritical inverse methods.
Aerofoil Design Techniques
1990
18 pages
Report
No indication
English