When I first saw the videos and the speed of those aircraft I thought he had simply pulled it into an accelerated stall and subsequent spin entry. These are some of the factors that come into play;
1a) Speed. The P-51D and it's components were designed for a maximum speed of 437 mph/380 kts. This was in a factory new aircraft with a wing loading of X, and in the thinner, smoother air of 25,000'. Straight and level flight. (Mmo limitations unknown to me.)
1B) The Ghost was flying in the 500 mph/ 435 knt. speed (Mmo unknown). The density altitude was probably in the 6 to 9K range, more turbulent and thicker and more resistance than the factory test flights.
2) Trim is essential to flying a stock P-51D smoothly. Modifications in speed, hp., propellor slipstream,C.G., etc.would have changed it's trim settings. THe racer may have required more trim, and force being exerted on the trim tab, than was engineered by N.A.A. to withstand.
3) The video seems to indicate the racers were flying downwind when passing the stands with a tailwind of 10 to twenty knots. Turning to the downwind would have required a steeper bank, and higher g-load than other turns. This increases as ground speed increases. Maybe he was doing more than 6 G's in the turn.
4) The P-51D and TF-51D I have flown, and got typed in, required more down trim as speed increases to hold level altitude, as do most aircraft.
5) To lose a trim tab would cause a very sharp or even violent pitch up as the aircraft now would try to reduce its airspeed to a speed that it is trimmed for, without the trim tab.
6) This would have been an instantaneous increase of G's above the 6+ needed to make the turn, and would incapacitate or G-Loc'd most any pilot.
7) In lieu of pilot inputs the aircraft pitched up sharply, un "G"ing itself. torsional pressures from the engine still at race power rolled it on it's back and the same pressures now pushing the nose downward at full power. It may not have ever totally un "G" d itself upon impact.
the tailwheel unit extending is direct evidence of the extreme G loads, and the uplocks system failed under those loads.
9) I am typed in the Learjet 35A = 476 knots /Mach .81 and have gotten my S.I.C. checkout on the Citation III, Mach .83 and Falcon 10 496 knots/Mach .91 In all cases when I have been flying these aircraft at their max design speeds we have been in thin air at FL 380 to FL450. Yes the GPS is showing 476 knots or maybe even 500 or 600 knots groundspeed but if you look at the indicated airspeed on the dial corresponding to the Mach is will always be below say 280 knots. The limiting factor on fast subsonic aircraft is always something less obvious than the wing or fuselage. On the III and Lear 35, it's the tail. On the Falcons it's the wing root fairings that will come off in flight if you exceed VNE/Mmo.
Are the reno racers now pulling speeds and G-loads in turbulent thick air never envisioned by the original design engineers?
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