Originally Posted by
Brian Abraham
Noted Owain
Looks like its been with us for a long time Centaurus.
From
History of Shock Waves, Explosions and Impact: A Chronological and Biographical Reference by Peter O. K. Krehl
The term
shock stall originated in 1936 during high speed aerodynamic wing studies carried out in England at the National Physical Laboratory (NPL). In order to describe the compressibility stalling speed, Earnest F. Relf, a staff scientist at the Aerodynamic Department of NRL, chose the term
shock stall as a shorter and more explicit expression than “compressibility stall” or “compressibility burbling speed”. The British aerodynamicist William Frank Hilton, creator of the term
sound barrier, wrote in his textbook
High Speed Aerodynamics: “The formation of a ‘shock wave’ on a wing will normally cause a separation of flow, and may be called a ‘stall’.
From
Flight Dynamics Principles: A Linear Systems Approach to Aircraft Stability and Control by Michael V. Cook
The
shock stall is sometimes used to describe the abrupt aerodynamic changes experienced when an aeroplane accelerating through the transonic regime first reaches the critical Mach number. At the critical Mach number, shock waves begin to form at various places on the airframe and are accompanied by abrupt reduction in local lift, abrupt increase in local drag, and some associated change in pitching moment. Since the effect of these aerodynamic changes is not unlike that of the classical low speed stall, it is referred to as the shock stall. However, unlike the classical low speed stall, the aeroplane continues to fly through the condition.
Hi,
Interesting information. But I wonder if this is a separate issue with the so-called Shock Stall not being a stall at all but just a buffeting that when experienced by the folks at the time it was discovered, reminded them of the actual stall buffet and therefore named(or misnamed) this phenomenon as a shock stall. The result of which could lead to misunderstanding that one is close to stalling when in fact they are not.