Originally posted by juzz:
Sorry, Me 262 does 514mph at sea level.
Wow, those guys at Rebublic must have been 10x better at aerodynamics than the guys at Goodyear - they only got 399mph out of the F2G with the same engine...
According to what I have read, the 262 cannot sustain full throttle for more than three minutes at sea level. After that, the EGT goes off the scale and the turbine wheel begins to demonstrate the ductility of Silly Putty. My pal George Ceuleers chased a 262 for 120 miles across Germany in his P-51D-15.
The 262 would pull ahead by two or three miles, but had to reduce power to prevent over-temping the engines. Ceuleers would close up, and the 262 pilot would push up the throttles again to open the gap. This went on until one of the engines finally failed under the strain. George closed in and shot down the German. This 262 pilot survived the war and later testified to Ceuleer's story being accurate. The chase took place at "rooftop levels". I have grave doubts that the Me 262 could outrun the P-72 down low.
As to the XF2G-1: This was no more than an early model FG-1 (Birdcage type) with a poorly designed engine installation. The cowling design made considerably greater drag than that of the FG-1. Moreover, the XF2G-1 used the early R-4360-4 engine, which although rated for 3,000 hp at sea level, never produced more than 2,650 hp. Looking at the P-72, we find that it was a much cleaner installation, and its drag coefficient was 20-25% lower than the big, ugly Goodyear. Later, when more power was available, and the installation had been cleaned up somewhat, the F2G-1 could pull 425 mph at sea level. A notable difference between the Goodyear and the XP-72 was in available power. The R-4360-13 truly generated 3,000 hp. Other problems plagued the XF2G-1, such as requiring a large amount of rudder displacement to offset the severe propwash that impinged on the vertical stabilizer. This also added drag and reduced maximum speed.
The factory test documents, signed off by the AAF list 480 mph recored at sea level on 4/14/44 with Carl Bellinger. Ken Jernstedt confirmed that speed two weeks later. Republic's 480 mph sea level speeds are not only accurate, but do not reflect the final production version planned to have 4,000 hp.
This configuration was expected to produce speeds in excess of 500 mph at sea level, with 522 mph at 25,000 feet being a reasonable figure for the power available. This configuration would have included a six blade, contra-rotating prop, rather than the four blade unit installed on Prototype #1.
My regards,
Widewing