Spitfire VIII Conversion JF.319
Level Speed Tests With Griffon R.G.5.S.M. Engine
18 lb/sq. in. Boost Rating
Summary of Results
At the all up weight for the Spitfire XIV i.e. 8400 lb. and at 18 lb/sq.in. and 2750 r.p.m., the results are:-
(a) Maximum level speed in F.S. gear, 447 m.p.h. at 25600 ft.
(b) Maximum level speed in M.S. gear, 389 m.p.h. at 6000 ft.
Spitfire F. Mk. VIII(Conv) (Prototype Mk.XIV) JF.319
(Griffon RG5SM)
Climb and level speed performance and position error
(i) On the climb at combat rating.
| Max. rate of climb in MS supercharger gear | 5,040 ft/min. at 2,100 ft. |
| Max. rate of climb in FS supercharger gear | 3,550 ft/min. at 22,100 ft. |
(ii) In all-out level flight.
| Max. true air speed in MS supercharger gear | 391 mph at 5,500 ft. |
| Max. true air speed in FS supercharger gear | 446 mph at 25,900 ft. |
June 1944
Spitfire XIV low altitude speed at +21 lbs./sq.in.
20 July 1944
Speeds of F.Mk. XIV (Griffon 65)
August 1944
Spitfire XIV RB.176
(Griffon 65)
Top level speed at +25 lbs/sq.in. Boost
Spitfire XIV
(Griffon 65)
Climb and Level Speed Performance (+18 Boost)
Comments from No. 610 Squadron ORB relating to performance of Spitfire XIV
Climb and Speed at +18 lbs Boost Supermarine, October 1944. There was much discussion during the summer and fall of 1944 between the Air Ministry, Supermarine and Rolls-Royce as to whether, for production reasons, the Spitfire XIV should switch to a .45 reduction gear to match that of the Spitfire 21 or retain the .51 gear. It was decided that the advantages of the .51 were such that it would be retained for the Spitfire XIV.
Spitfire Mk XIV versus Me 109 G/K: A comparison of performance
