COMBAT PERFORMANCE WITH 90 GALLON LONG-RANGE TANKS
50. As the Spitfire XIV has a very short range it has been assumed that when a long-range tank is to be carried, it is most likely to be the 90 gallon tank rather than the 30 gallon or 45 gallon. Pending further instructions, no drops or trials have been carried out with the 30 gallon or 45 gallon tanks. The aircraft's performance with either can be estimated from the results given below of trials with the 90 gallon long-range tank.
Drops
51. The aircraft was fitted with assistor springs as for the Spitfire IX. Two drops were made with empty tanks at 50 ft and 25,000 ft, A.S.I. 250 mph, with no trouble. Cine photographs were taken and show the tank dropping quite clear of the aircraft. Further trials would be necessary to check these results thoroughly.
Speeds
52. About 20 m.p.h. is knocked off the maximum speed and correspondingly off the speed at intermediate throttle settings. The aircraft is still faster than the FW.190 (BMW.801D) and the Me.109G above 20,000 ft.
Climb
53. Climb is most affected. With a half-full tank its maximum climb becomes identical with the Spitfire IX without the tank. Even with a full tank it can therefore climb as fast as the FW.190 or Me.109G. Its zoom climb is hardly affected.
Dive
54. So long as the tank is more than 1/3 full, the dive acceleration is similar.
Turning Circle
55. The Spitfire XIV now has a definitely wider turning circle than before, but is still within those of the FW.190 (BMW.801D) and Me.109G.
Rate of Roll
56. Similar.
Conclusions
57. Even with the 90 gallon tank, the Spitfire XIV can equal or outclass the FW.190 (BMW.801D) and the Me.109G in every respect. Its main advantages remain the tight turn and maximum climb.