TRANSLATION PROFILE WITH CHANGE OF EXTRACTION AREA

摘要

PCT No. PCT/GB92/01396 Sec. 371 Date May 25, 1994 Sec. 102(e) Date May 25, 1994 PCT Filed Jul. 28, 1992 PCT Pub. No. WO93/02915 PCT Pub. Date Feb. 18, 1993.A wing, or similar article of airfoil section, has a variable geometry surface for the active control of shock strength and transonic wave drag. In one embodiment, the wing has a region of distensible skin (4) aft of the line of maximum section, which extends along the span of the wing in those areas that experience drag. Pressure means (10, 20, 30) within the wing outwardly deflect the distensible region and produce a local bulge in the expansion surface. This bulge induces pre-shock compression and reduces the effect of the shock. The bulge is retracted by the natural elasticity of the skin material (which can be a conventional aluminum alloy) upon removal of the applied pressure. In another embodiment, the wing has a ramp portion (14) which is outwardly deflectable for the same purpose. The invention is applicable to supercritical and natural laminar flow wings.