Published online by Cambridge University Press: 04 July 2016
It has long been known that compressibility affects the maximum lift coefficient at Mach numbers as low as 0·15. A schematic flight envelope (Fig. 1) shows that there are two main phenomena to be considered; the effects of compressibility on the low speed stall, and on the high subsonic speed stall.
In the low speed stall regime there is, in general, a decrease of the maximum lift coefficient with increasing Mach number which is appreciable even at typical aircraft landing speeds. A knowledge of the lift boundary throughout the envelope is necessary if allowances are to be made for gusts and if a safe rough-air performance is to be determined.