gripen,
Quoting from the NACA Report on Maximum Lift Coefficients;
"In the subcritical Mach number region, the maximum lift coefficient obtained in flight by the airplanes tested (F6F-3, P-38, P-51, P-63, P-39) declined steadily with increasing Mach number. As the Mach number was increased in the supercritical Mach number region, the maximum lift coefficient of NACA conventional airfoils continued to diminish as at subcritical Mach numbers, while that of NACA low-drag airfoils reached a minumum at a Mach number between 0.40 and 0.55 and then began increasing until secondary peak values were reached at a Mach number between 0.50 and 0.66."
If I read this right, the effect of the Reynolds number on the lift coefficient of conventional airfoils was more or less linear, increasing geometrically the faster the airplane flew...that is lift decreased progressively in the same manner at supercritical Mach numbers as it did at the subcritical Mach numbers.
The lower-drag airfoils (laminar flow for example) reached minimum lift coefficients between 0.40 and 0.55 and then began to increase as the aircraft approached supercritical Mach numbers. In other words, if this performance was graphed, it would show a low point for lift between 0.40 and 0.55 and would then begin to show a rise, or increase in lift at speeds above Mach 0.55.
Mach .60 at 30,000 feet is roughly 450mph. The only American prop-driven fighter capable of that kind of performance in level flight at that altitude was the P-47. For an aircraft with a laminar flow or similar low-drag airfoil to realize any lift coefficient benefit over a conventional airfoil such as that of the P-47, it would have to be put into a dive.
The fly-in-the-buttermilk in this equation is thrust, determined by propeller efficiency and high-altitude horsepower available for combat. Late model P-47s could maintain sea-level powers of 2700hp all the way to 35,000 feet. The P-51D saw its available power drop from 1700hp at sea level to 950hp at 29,500 feet. The P-38s maintained sea-level powers to altitudes slightly above 26,000 feet after which they began to drop. With full internal fuel and ammo, the P-38 was also heavier than the P-47, which means that the P-47 enjoyed a lower power-loading at higher altitudes than the Lightning.
All this indicates that at normal combat speeds, the Jug had better maneuverability at high-altitudes than either the Pony of the Lightning. This is borne out by the testimony of numerous pilots who have flown all three types: that is, the Jug was the most maneuverable fighter they ever flew at high-altitudes
