- Nov 26, 2001
- Total Time
Im sorry if this is bad, but i have no idea what it is???
You and asolo gave two causes of Mach tuck. FWIW, I think asolo's explanation is the most commonly referenced cause. Indeed, the aft CP shift as local V increases above M1 causes a nose-down pitch tendency due to the movement of the pressure wave. And as you mention, the resulting flow-induced separation can cause the elevator to operate in turbulent, aerodynamically dead air, resulting in lost tail-down force. But also remember that the H-stab is an airfoil with locally high velocities. As such, it is possible that it has its own shockwave attached in front of the elevator. If this is the case, the elevator will again be operating in aerodynamically dead air, resulting in loss of tail-down force. Of course, the last case doesn't typically happen with an all-movable tail.Cornelius said:I think it may also have something to do with airflow separation after the shockwave which may cause the h-tail not to be as efficient.
Hey Walkthasky, what have you been up to at Commutair? I've been on reserve the last 3 days and pretty much sitting by the pool all day long dreaming of having a beer.
Basically, it's the altitude where Mmo and Vs are equal. Vs remains the same with altitude, but Mmo expressed as IAS decreases with altitude. (A given IAS results in a higher TAS, which is what compressibility effects are based on, at higher altitudes.) As such, any increase in speed will result in a shock stall, and any decrease in speed will result in a generic aerodynamic stall.want2fly said:What's coffin corner?