1. In accordance with instructions from Headquarters, A.D.G.B., tactical trials have been completed on Spitfire XIV. Aircraft No. RB.141 was delivered to this Unit on 28.1.44 for comparative trials with the Tempest V. It was discovered that this aircraft was not representative of production aircraft for Squadrons, and Spitfire XIV No. RB.179 was made available and delivered on 25.2.44. The operational weight with full fuel and ammunition is 8,400 lbs. To give a clear picture to the greatest number, the Spitfire IX (maximum engine settings +18 lbs boost, 3,000 revs) has been chosen for full comparison, and not the Spitfire XII which is a low altitude aircraft built only in small numbers. Tactical comparisons have been made with the Tempest V and Mustang III, and combat trials have been carried out against the FW 190 (BMW 801D) and Me 109G.


2. The Spitfire XIV is a short range medium-high altitude fighter, armed with 2 x 20 mm cannon and 4 x .303 Browning guns in the wings. It is fitted with a Griffon 65 engine of approximately 2,000 h.p. Pick-up points are provided for carrying of 30 gallon, 45 gallon or 90 gallon drop tanks. At present there are no bomb racks. In appearence is is very similar to the Spitfire XII with normal wings, except that it has a five-bladed propeller. The fin and rudder have been further modified.

The Cockpit
3. The pilot's cockpit is generally similar in layout to all Spitfire cockpits, but has been considerably improved in some respects.

(a) A larger throttle quadrant has been fitted, incorporating a greatly improved friction damper for throttle and pitch levers. For normal conditions the throttle and pitch may be used together as one. If this is done, the boost and rpm obtained should be as follows:-


(b) The electric master switch is now on the left-side of the dashboard, and is interconnected by means of a sliding bar with the main engine switches, which cannot be switched on when the master switch is off.

(c) An additional green light has been introduced under the undercarriage indicator, which goes out when the tail-wheel is retracted.

(d) The engine is started by means of a Coffman Cartridge Starter, which has given considerable trouble both on this aircraft and RB 141.

(e) The Compass The normal position of the compass was very bad, only a portion of the instrument being visible without unlocking the Sutton Harness and bending right down in the cockpit. A modification was introduced on aircraft RB 179, lowering the bracket holding the compass to enable the pilot to obtain a better view. The instrument can now be seen and reached by the pilot with the greatest ease without unlocking the Sutton Harness or bending down.

(f) Rudder Trim As the Griffon engine revolves in the opposite direction to the Merlin, likewise the propeller, the tail trim, if not left central, should be wound back for take-off and not forward.


5. In most respects this aircraft is similar to the Spitfire IX, except for some very marked changes in trim with alteration of throttle setting below 0 boost. This applies principally to the rudder, despite the incorporation of the servo-operated trimming tab. This is the one bad characteristic of this aircraft. The elevators also require more frequent trimming than in a Spitfire IX.

6. The aircraft is nose-heavy and considerable care must be exercised in taxying, particularly in a strong wind.

7. During take-off the aircraft tends to swing to the right and to drag the right wing; full power should therefore not be used immediatelllly on opening the throttle, but only when the aircraft is almost airborne, ie +6 lbs boost is quite sufficient. The nose must not be allowed to fall lower than the horizon as the propeller clearance is very slight.

Turning Stall
8. The Spitfire XIV gives less warning of a stall in a tight turn than a Spitfire IX, though the same pre-stall characteristic ("shuddering") occurs. This is a good point as it allows sighting to be maintained nearer the stall. This aircraft tends to come out of a dive in a similar manner to other Spitfires.

9. The landing run is slightly longer and the aircraft sinks rather more rapidly than a Spitfire IX on landing. In all other respects the landing is quite normal and very easy. There is no tendency to swing.

Formation Flying
10. Quite straightforward, similar to the Spitfire IX.

Low Flying
11. The view from the cockpit is as good as from the Spitfire IX, the longer nose making no appreciable difference. Engine handling is a little more inconvenient because of the recurring trimming changes to elevators and rudder. The aircraft does not therefore handle quite so well as the Spitfire IX near the ground.

Night Flying
12. Night flying was carried out with and without blinkers, under condition of half moon, 9/10th cloud. Cockpit lighting is satisfactory except that there is no compass light. The exhaust glow is rather a brilliant blue, being brighter than the Spitfire IX. Without blinkers this causes no inconvenience in the air, providing the pilot does not sit too high in the cockpit. When taking off, the throttle must be opened very slowly to prevent the swing; at the same time the tail must be raised as soon as possible so that the Flarepath can be seen. When landing an approach speed of 120 m.p.h. is recommended, engine-assisted, in order that the flarepath may be seen over the nose. The aircraft is then levelled off before the Flarepath is reached, so that a landing may be made reasonably near the beginning of the Flarepath. When the lighting conditions are less than the equivalent of half moon, blinkers are recommended. Blinkers cause some interference with view during day flying and make taxying at night very difficult. The pilot's view at touch-down is also further restricted. They are not therefore recommended except when taking-off or landing on a dark night. From the ground the exhaust flames can easily be seen when the aircraft is flying at 1,000 feet.


13. The tactical differences are caused chiefly by the fact that the Spitfire XIV has an engine of greater capacity and is the heavier aircraft (weighing 8,400 lbs. against 7,480 lbs. of Spitfire IX).

Range & Endurance
14. The Spitfire XIV, without a long-range tank, carries 110 gallons of fuel and 9 gallons of oil. When handled similarily, the Spitfire XIV uses fuel at about 1 1/4 times the rate of the Spitfire IX. Its endurance is therefore slightly less. Owing to its higher speed for corresponding engine settings, its range is about equal. For the same reasons, extra fuel carried in a long-range tank keeps its range about equal to that of the Spitfire IX, its endurance being slightly less.

15. At all heights the Spitfire XIV is 30-35 mph faster in level flight. The best performance heights are similar, being just below 15,000 and between 25,000 and 32,000 ft.

16. The Spitfire XIV has a slightly better maximum climb than the Spitfire IX, having the best maximum rate of climb yet seen at this Unit. In the zoom climb the Spitfire XIV gains slightly all the way, especially if full throttle is used in the climb.

17. The Spitfire XIV will pull away from the Spitfire IX in a dive.

Turning Circle
18. The turning circles of both aircraft are identical. The Spitfire XIV appears to turn slightly better to port than it does to starbord. The warning of an approaching high speed stall is less pronounced in the case of the Spitfire Mk XIV.

Rate of Roll
19. Rate of roll is very much the same.

Search View and Rear View
20. The search view from the pilot's cockpit is good; the longer nose of the aircraft interferes with the all-round visibility, which remains the same as that of the Spitfire IX. Rear View is similar.

Sighting View and Fire Power
21. The sighting view is slightly better being 4 deg (140 m.p.h.) as against 3 1/3 deg. The two bulges at the side cause little restriction. The firepower is identical with the Spitfire IX.

22. As for the Spitfire IX

23. The all-round performance of the Spitfire XIV is better than the Spitfire IX at all heights. In level flight it is 25-35 m.p.h. faster and has a correspondingly greater rate of climb. Its manoeuvrability is as good as a Spitfire IX. It is easy to fly but should be handled with care when taxying and taking off.


Range and Endurance
24. Rough comparisons have been made at the maximum continuous cruising conditions of both aircraft. (3150 revs. +4 1/2 lb. boost Tempest, 2400 revs. +7 lb. boost Spitfire XIV).

24A. The best heights of each aircraft are very different, producing the following results:-

The Tempest is faster and goes further up to 10,000 ft. From 10,000 - 20,000 ft. both aircraft cruise at about 300 I.A.S. Above 20,000 ft. the Tempest cannot maintain its high crusing speed and no comparisons can be made with the Spitfire XIV which increases its ground speed and range up to 29,000 ft.

These comparisons remain the same with the full fuel loads at present available (2 x 45 gall. long range tank Tempest, 1 x 90 gall. longe range tank Spitfire).

Maximum Speed
25. From 0 - 10,000 feet the Tempest V is 20 mph. faster than the Spitfire XIV. There is then little to choose until 22,000 feet, when the Spitfire XIV becomes 30-40 mph. faster, the Tempest's operational ceiling being about 30,000 feet as opposed to the Spitfire XIV's 40,000 feet.

Maximum Climb
26. The Tempest is not in the same class as the Spitfire XIV. The Tempest V however, has a considerably better zoom climb, holding a higher speed thoughout the manoeuvre. If the climb is prolonged until climbing speed is reached then, of course, the Spitfire XIV will begin to catch up and pull ahead.

27. The Tempest V gains on the Spitfire XIV.

Turning Circle
28. The Spitfire XIV easily out-turns the Tempest.

Rate of Roll
29. The Spitfire XIV rolls faster at speeds below 300 mph., but definitely more slowly at speeds greater than 350 mph.

30. The tactical attributes of the two aircraft being completely different, they require a separate handling techique in combat. For this reason Typhoon squadrons should convert to Tempests, and Spitfire squadrons to Spitfire XIVs, and definitely never vice-versa, or each aircraft's particular advantages would never be appreciated. Regarding performance, if correctly handled, the Tempest is the better below about 20,000 feet and the Spitfire XIV the better above that height.


Radius of Action
31. Without a long range tank, the Spitfire XIV has no endurance. With a 90 gallon long-range tank it has about half the range of the Mustang III fitted with 2 x 62 1/2 gallon long range tanks.

Maximum Speed
32. The maximum speed are practically identical.

Maximum Climb
33. The Spitfire XIV is very much better.

34. As for the Spitfire IX. The Mustang pulls away, but less markedly.

Turning Circle
35. The Spitfire XIV is better.

Rate of Roll
36. The advantage tends to be with the Spitfire XIV.

37. With the exception of endurance no conclusions can be drawn, as these two aircraft should never be enemies. The choice is a matter of taste.


Maximum Speeds
38. From 0 - 5,000 ft and 15,000 - 20,000 ft., the Spitfire XIV is only 20 m.p.h. faster; at all other heights it is up to 60 m.p.h. faster than the Fw 190 (BMW.801D). It is estimated to have about the same maximum speed as the new Fw 190 (DB.603) at all heights.

Maximum Climb
39. The Spitfire XIV has a considerably greater rate of climb than the FW 190 (BMW.801D) or (estimated) the new Fw 190 (DB.603) at all heights.

40. After the initial part of the dive, during which the FW 190 gains slightly, the Mk XIV has a slight advantage.

Turning Circle
41. Spitfire XIV can easily turn inside the FW 190, though in the case of a right-hand turn, this difference is not so quite pronounced.

Rate of Roll
42. The FW 190 is very much better.

43. In defense, the Spitfire XIV should use its remarkable maximum climb and turning circle against any enemy aircraft. In the attack it can afford to "mix it" but should beware of the quick roll and dive. If this manoeuvre is used by the FW.190 and the Spitfire XIV follows, it will probably not be able to close the range until the FW.190 has pulled out of its dive.


Maximum speed
44. The Spitfire XIV is 40 m.p.h. faster at all heights except 16,000 ft. where it is only 10 mph faster.

Maximum Climb
45. Same results. At 16,000 ft. indentical, otherwise the Spitfire XIV out-climbs the Me.109G. The zoom climb is practically identical when the climb is made without opening throttle. Climbing at full throttle, the Spitfire XIV draws away from the Me.109G quite easily.

46. During the initial part of the dive, the Me.109G pulls away slightly, but when a speed of 380 m.p.h. is reached, the Spitfire XIV begins to gain on the Me.109G.

Turning Circle
47. The Spitfire XIV easily out-turns the Me.109G in either direction.

Rate of Roll
48. The Spitfire XIV rolls much more quickly.

49. The Spitfire XIV is superior to the Me.109G in every respect.


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.

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.

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.

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.

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.

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.


Gun Harmonisation
58. As for the Spitfire IX.

Gun Firing
59. Trials were carried out without any troubles or difficulties.

60. As for the Spitfire XI.

Cine-gun installation and harmonisation
61. There is no difference in installation, but in the Spitfire XIV the camera is fitted on the port side.

62. One V.H.F. set is fitted as in the Spitfire IX.

63. Normal Bristish type oxygen system, as in all Spitfires.

Engine Temperatures
64. The glycol shutters are automatically controlled. There was no overheating at any time, except during sustained climbs at maximum boost and r.p.m. when the glycol temperature once exceeded 105 deg C.


65. The aircraft is generally more difficult to start than the Spitfire IX. Care should be taken not to over-dope it and one third of a pump full is usually quite sufficient when the engine is warm.


66. Careful watch should be maintained on the Rolls-Royce Auxilary Gear Box oil contents level. The aircraft under test (RB.179) suffered with a bad oil leakage, all oil being consumed or lost in a 30 minute flight. This was cured by a careful check and tightening of all connections and plugs, when the consumption was decreased to approximately 1/2 pint per hour.

67. Touble has also been experienced with the Coffman Starter Breech sticking. A daily shot with a grease gun on the grease nipple provided helped to eliminate this stickiness. Normal Spitfire equipment was used throughout the trials.


68. The Spitfire XIV is superior to the Spitfire IX in all respects.

69. It has the best all-round performance of any present-day fighter, apart from range.

70. Modification to the compass bracket, to enable the pilot to obtain an unresticted view of the compass, should be incorporated.

AFDU Wittering July 1943 Spitfire XIV JF317



On instructions from Headquarters, Fighter Command, an experimental Spitfire XIV JF317 (Griffon 61) was made available by A&AEE for three days for short tactical trials. The trials took the form of a direct comparison with a Spitfire VIII (Merlin 63) JF664, and flying took place from 27 to 29 July 1943.


The aircraft used is a conversion of the Spitfire VIII. The larger engine involves a much longer engine cowling and the extra weight forward has been balanced by ballast in the tail. The fin has been increased in area to help directional stability and a large rudder is fitted. This aircraft had the normal span wings of the Spitfire VIII with small span ailerons, but the extended wing tips had been replaced by the standard wing tips as on the MK IX. The engine is not representative of production as the FS gear is higher and the MS lower. A five blade propeller is fitted. The engine had a Bendix injection carberator and boost for combat is limited to plus 15 lbs. The Spitfire VIII weighed 7,760 lb, the XIV 8,376.

Performance- Speeds near the ground are identical, at 10,000 and 15,000 feet the Spitfire VIII is faster, at 20/25,000 ft. similar, at 30,000 ft. and over the Spitfire XIV accelerated faster and was the superior aircraft.

Climb- Zero to 30,000 feet the Spitfire VIII is the better aircraft, at 30,000 ft. and over the Spitfire XIV is by far the better.

Manoeuvrablility- The elevator control of the Spitfire XIV was found to be much heavier than that of the Spitfire VIII, unpleasantlly so, and the other controls felt to be slightly heavier than on previous Spitfire Mks. In spite of heavier controls the Spitfire XIV is more manoeuvrable than the Spitfire VIII in turns at all heights. Spins were carried out in the Spitfire XIV at 25,000 feet. The aircraft did not spin voluntarily but had to be put into and held in the spin. Instead of spinning in the normal nose down attitude, the nose of the aircraft oscillated from an almost verticle position downwards to a position with the nose well above the horizon, so that the aircraft was tail down. It spent most of its time in this flat position from which, after four turns, recovery was fast by the normal method or slower if the controls were released. It never appears to become uncontrollable.

Search view- Pilots view is superior on the Spitfire Mk XIV due to the lower engine cowling.

Range and Endurance- Both aircraft carry the same amount of fuel (96 gallons in the main tank and 27 gallons in two wing tanks.) Refueling checks made to compare consumption showed than when the two aircraft stayed together throughtout the trials, the Griffon engine was using approximately 10-15 gallons more fuel per hour than the Merlin.

Conclusions- Of the two aircraft the Spitfire VIII is preferable at all heights up to about 25,000 feet except for its turning capabilites. It is much lighter on the elevators and easier for the average pilot to fly. Its performance and fuel consumption are better. The Spitfire XIV is superior above 25,000 and with its better turning characteristics it is more than a match for the Spitfire VIII. The difficulties of trimming will probably be reduced as pilots gain familiarity.

Stall: Flaps up 87, Flaps down 75
Engines: Griffon 65 2,035 hp @ 7,000 feet, Griffon 85 2,750 hp @ 8,250 feet, Griffon 61 1,785 hp @ Take off (2,750 rpm)
Range: 460 normal, 860 max
Endurance: 1.9 hr
Service Ceiling: 43,000 feet

[WWII Aircraft Performance] [Spitfire Mk XIV Performance] [Weights and Loading Data] [Handling Trials]