WW2-fighter and critical Mach speed

Originally Posted by KraziKanuK

No pitot tube? It carried a pitot comb 14" wide.

Standard practice was to tape over the gun ports. There was also a pitot added at each wing tip. The P-51, tested at the same time, had its guns and radio removed. It had its normal pitot removed, and as on the Spit, one added at each wing tip. The Spit reached M 0.89 while the P-51, M 0.80.

Dragging a rake is not the same as pushing a tube. Figures I've seen for the P-51B are M 0.84, and the statement that the D model was about 0.02 lower than the B model because of the bubble top and slightly thicker wings.

British tests got lower numbers than US tests, you are probably only looking at the British tests. In the British tests, they very meticulously recorded the fraction of mach for the Spitfire at very small altitude intervals, and the highest it reached was 0.89 but it was quite a bit lower through most of the dive. For the P-51 they did not record so many samples so the two tests are not comprable.

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Lunatic

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Lunatic

[delcyros]

0.89 is for the Spit is overated. Even it´s smaller (in diameter) airscrew caused schockwaves and they did interfere with fuselage and tail (I agree, 33 inches are not enough to ensure no interfere and shockwave effects caused by the airscrew). And it lost its aircrew on that dive. Recovering alone doesn´t proove that it was no terminal dive Mutke´s claim to break Mach 1 in a Me-262 dive (which I don´t believe) underlines that. He was able to recover from his terminal dive at very high subsonic speed (but not Mach 1, the airframe of the Me-262 couldn´t sustain the stress). Anyway I believe the spit has the highest critical Mach number of prop driven planes. What about any pusher-prop layouts? Any datas?

[delcyros]

Sad. I did not succed in finding critical Mach datas for the XP-72 (74?) Black Bat and the japanese J7 Schiden. Can anyone help? Would be very interesting. Here is the critical Mach number for the Arado 234 B: 0.82. I did not find a data for the He-162, but (try google) i found a statement, that it should have the highest, tactically useful, Mach number of planes in ww2. (?)

[wmaxt]

Originally Posted by delcyros

0.89 is for the Spit is overated. Even it´s smaller (in diameter) airscrew caused schockwaves and they did interfere with fuselage and tail (I agree, 33 inches are not enough to ensure no interfere and shockwave effects caused by the airscrew). And it lost its aircrew on that dive. Recovering alone doesn´t proove that it was no terminal dive Mutke´s claim to break Mach 1 in a Me-262 dive (which I don´t believe) underlines that. He was able to recover from his terminal dive at very high subsonic speed (but not Mach 1, the airframe of the Me-262 couldn´t sustain the stress). Anyway I believe the spit has the highest critical Mach number of prop driven planes. What about any pusher-prop layouts? Any datas?

Stabilizers carry their own shock wave, hence the Stabilator on any high transsonic/supersonic aircraft.

"Kelly" Johnson felt as late as the 80s that raising the tail on the P-38 was counter productive. I don't know what he bassed that on. Source Warren Bodie interview with C "Kelly" Johnson.

[delcyros]

Could be very interesting. Where can I read that Interview?
Thanks!