ADFU comparison between Mustang III (P-51B/C) and Tempest V (Serise I)
""COMPARISON WITH MUSTANG III
Range and Endurance
25. By comparison the Tempest without nose tank or long-range tanks, has no range. When the extra fuel is available it should have a little more than half that of the Mustang III fitted with two 62.5 gallon long-range tanks, but without the extra 71 gallon body tank.
Maximum Speed
26. The Tempest V is 15-20 mph faster up to 15,000 ft., there is then no choice to 24,000 ft, when the Mustang rapidly pulls ahead, being about 30 mph faster at 30,000 ft.
Climbs
27. These compare directly with the results of the speed tests. At similar performance height the Tempest has a better zoom climb.
Turning Circle
28. The Tempest is not quite as good as the Mustang III.
Rate of Roll
29. The Tempest is not so good. This attribute may be improved upon later aircraft with re-designed ailerons.
Conclusions
30. The Mustang III has superior range of action and general performance above 24,000 ft. Conclusions should not be drawn below this height, but the Tempest has a much better rate of climb and speed below 10,000 feet. ""
Seems to me that the RAF thought the Tempest V was significantly better below 10,000 feet.
I'd probably pick the Tempest V up to about 18,000 feet, particularly those with the later Sabre IIB rated a +11 lbs. It was probably the fastest Allied figher below 15,000 feet, with 2240 hp at its disposal. The P-51 was probably a little more nimble in the turn, but I'd say the Tempest rate of climb and seed of the Tempest V would of been an excllent asset for it.
This comparison was done with a Tempest V Serise I without the spring tab alierons (first 100 or so delivered I think). When the spring tabs were fitted the initial roll was notably improved and rate of roll increased slightly.
