drgondog
Major
Without diving deep into the weeds, on or about Mcr a lot of bad things begin to alter the mechanics of flight associated with the wing as a result of the chosen airfoil. Most conventional airfoil/wings had a max thickness to chord ratio (fat part of wing) at 25-30%. The velcity gradient from LE to the place on the wing (usually Max T/C) reaches Mcr at the thickest part and creates a shock wave as the airflow transitions from subsonic to supersonic. When that occurs the Center of Pressure of the wing is moved aft, creating a Mach Tuck or Nose Tuck in which the pitching moment overwhelms the ability of the elevator to restore pith control... further complicated by wake turbulence immersing the elevator.You have forced me to check my sources.
In early 1944, the Americans were losing escort fighters when they dove down on Germans at high speed. I presume their controls locked up. I assume bomber interceptor interception took place at a bit over 30,000ft. Brown's terminology is interesting. He talks about tactical (manoeuvring) and critical (loss of control) Mach numbers. The tactical Mach numbers of the P-38H and the P-47C were 0.68 and 0.71, respectively.
The Mustang with unique high speed airfoil/wing design had the max T/C further aft, the velocity gradient was less (delaying formation of shock wave) and movement of Center of Pressure.
Same phenomena as described above.I am a bit puzzled by all this. Roland Beamont tested Hawker Typhoons by diving from 30,000ft, I think at around 45°. Their controls locked up. It appears to me that a Typhoon would have difficulties doing much more than 300mph at 30,000ft. At around 15,000ft, the speed of sound would increase sufficiently to drop the Mach number to the point where the aircraft could be controlled. Beamont died of old age in 2001.
They were usually chasing the Fws so the Fw 190 was delighted to be set free.I don't understand why the Thunderbolts and Lightnings were unable to pull out. If they pull out at 15,000ft, they would be vulnerable to Fw190s. Otherwise, they slowly or quickly (respectively) climb back up the bomber altitude, or they fly home. It would be wise for the Thunderbolt to get his ass up above 25,000ft.
As described, yes.Diving from top speed at 40,000ft, the stripped and instrumented SpitfireXIs started to gently shake at Mach 0.83. Does this translate to tactical Mach number?