|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.
|(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.
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
Rate of Roll
Search View and Rear View
Sighting View and Fire Power
BRIEF TACTICAL COMPARISON WITH TEMPEST V
Range and Endurance
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).
Rate of Roll
TACTICAL COMPARISON WITH MUSTANG III
Radius of Action
Rate of Roll
COMBAT TRIAL AGAINST FW.190 (BMW.801D)
Rate of Roll
COMBAT TRIAL AGAINST Me. 109G
Rate of Roll
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.
Rate of Roll
Cine-gun installation and harmonisation
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
SHORT TACTICAL TRIALS OF EXPERIMENTAL SPITFIRE XIV
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