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1. According to instructions from Air Ministry (D.A.T.) and from Headquarters, A.D.G.B., letter reference ADGB/S.29156/Air Tactics dated 29th February 1944 refers, tactical trials have been completed with the Tempest V. Aircraft No. JN.737 was delivered by the Hawker Aircraft Company on 8th January 1944 and was operationally loaded. The operational weight is 11,400 lbs. 2. In order to give a clear picture of the Tempest V it has been compared fully with its nearest stable companion, the Typhoon IB. In addition, tactical comparisons have been made with the Mustang III and Spitfire XIV. Combat trials have been carried out against the Me.109G, FW.190 (BMW)801D and suggestions made for combat with the new FW.190 (DB.603). 3. In its present form, the Tempest V is a low and medium altitude short-range fighter, armed with 4 x 20 m.m. cannon in the wings. It is fitted with a Napier Sabre II engine of approximately 2090 h.p. (same as Typhoon IB). As yet no provison has been made for the carrying of long range tanks, bombs, or R/P. In appearence it is very similar to the latest Typhoon IB except that it has a 4-bladed propeller, much thinner wings, and larger tail surfaces. 4. The cockpit is very similar to the Typhoon. For this reaason, and because the Tempest is easier to fly, a Typhoon pilot will take to the Tempest from the moment he is airborne. Fuel Cocks 5. In the Tempest the fuel cocks are different. There are three tanks - nose, main, and interspar, any of which may be selected. The main tank should be the last to be emptied, as the bottom of the tank is funnel shaped to enable the last drop to be consumed. At present there is no nose tank fitted. Undercarriage Position Instrument 6. This is the same as that on the Typhoon, with the exception that the red lights do not go out until the undercarriage doors have locked shut, in addition to the wheel being locked up. 7. The Typhoon belonging to this Unit had the "prison bar" type of cockpit. This made the Tempest seem much easier to land and take-off. In the air, the engine of the Tempest is very smooth, considerably increasing the pilots confidence. The effect of all the flying controls is far more positve, making the Tempest as delightful to fly as its smaller contemporaries, and much more pleasant than the Typhoon. It feels more solid and easier to control than most aircraft at speeds over 400 I.A.S. (a) The rudder is more effective in preventing skid than that of the Typhoon, although it is still heavy. Less change of trim is necessary with change of speed, but considerable change of trim is still necessary with change of engine settings.Formation Flying. 8. Similar. There is no difficulty. The clear view increases confidence. Low Flying 9. The Tempest is much easier to low-fly than the Typhoon and the Spitfire. It is thought that this is partly due to a better view, easier handing, and a sense of solidity. Night Flying 10. The Tempest is very nice to handle and easy to fly at night. The exhausts cannont be seen from the cockpit and therefore cause no embarrassment. The stability of the Tempest makes it much more pleasant to fly than the Typhoon. The cockpit lighting is satisfactory, except the the undercarriage warning light is unblinkered. This can be remedied by replacing for day and night with bulb holders. The landing lamp is not very effective. For night fighting it might be necessary to fit glare-less exhaust shrouds, as the open exhaust stubs cause a glare that can be seen on a dark clear night from 1,000 feet. Compressibility Speeds 11. Because the Tempest V increases speed so rapidly in the dive, it is not difficult to enter compressibility range at high altitudes (approaching speed of sound). This can only be done in a dive. The maximum permissible airspeeds at various heights are :- |
| I.A.S. | Height |
| 370 | 30,000 |
| 410 | 25,000 |
| 450 | 20,000 |
| 490 | 15,000 |
| 540 | 10,000 |
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12. The following is a summary of the R.A.E's instuctions (Report No. Aero.1906) should the speeds at height be exceeded by any type of aircraft. In the dive, the nose may suddenly tend to drop. On no account must the trimming wheel be used to prevent it doing so, but only backward pressure on the stick. When the aircraft has reached a lower altitude where the speed of sound is greater, the aircraft will come out of the compressibility range and behave normally, being pulled out of the dive. Had the trimming wheel been used to prevent the nose dropping when in the compressibility range, there would have been a very sudden nose-up tendency on coming out of the compressibility range. The result of a such a sudden change of trim is liable to cause structural failure. 13. The comparison is fairly close and clear because the aircraft are fairly similar, differing chiefly in wing section only. The wing loadings are similar (37.4 lbs. Tempest, and 39.7 lbs. Typhoon) Radius of Action 14. The Tempest, as it stands, (no nose tank or long range tanks) has approximately the same range as the Typhoon IB without long-range tanks. The fuel and oil capacities of the Tempest are 132 gallons and 14 gallons respectively, compared with 154 gallons and 16 gallons of the Typhoon. The fact that the Tempest cruises at 15-20 mph faster than the Typhoon at the same engine settings approximately cancels out the discrepancy in fuel load. A Tempest fitted with a nose tank (30 gallons) and the 45 gallon long-range tanks (252 gallons total) would have about 1 1/4 times the range of a Typhoon IB with maximum fule load (243 galls. total). Speeds 15. According to the offical speed curves, the maximum speeds of the Tempest at all heights are 15-20 mph faster. This is also true for all intermediate settings. Climbs 16. The Tempest climbs at a slightly steeper angle and at the same airspeed producing 200-300 ft. increase in maximum rate of climb. Because of its greater cleanliness, its zoom climb is much better. Dive 17. For the same reasons as the zoom climb, the Tempest pulls ahead. As the speed is increased it does so more rapidly. The fact is it has the best acceleration in the dive yet seen at this Unit. Turning Circle 18. Very Similar. Any difference appears to be in favour of the Typhoon. This is too slight to alter combat tactics. Rate of Roll 19. The Tempest has the better rate of roll at all speeds Conclusions 20. Taken all round, the Tempest V is a great improvment on the Typhoon IB. Search View and Rear View 21. The all-round view from the pilot's cockpit is excellent, especially the rear view. This has been made possible by the "tear drop" hood which gives the pilot a better all-round unobstucted view than any other aircraft- Hun or friendly. It is also fitted to some Typhoons. Sighting View and Fire-Power 22. The aircraft is fitted with the Mark II sight. The installation should be modified in some cases to produce direct reflection on to the windshield. The sighting view is about the same as the Typhoon, being approximately 4 1/2 degrees. It is also fitted to some Typhoons. 23. The Tempest is a steady gun platform. Air-to-ground the aircraft has the same slight tendency as the Typhoon to fly into the ground, being not so good as the Spitfire in this respect. The guns cannot be depressed any lower than parallel to the datum, so this defect cannot be overcome. Armour 24. Of a similar design and installation as on the Typhoon aircraft, with the exception that the head-piece is a trifle larger in size. Thickness of headpiece - 9 mm Thickness of back pieces 6 m.m. All fuel tanks are self-sealing. Bullit-proof windscreen is of "Dry-cell" type. Front side of outer gun ammunition tanks have a piece of 1/8" armour plate. 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. Range and Endurance 31. Rough comparisons have been made at the maximum continuous cruising conditions of each aircraft (3150 revs. +4 1/2 lb/boost Tempest, 2400 revs. +7 lb. boost Spitfire XIV). 31A. 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.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. long-range tank Spitfire). Maximum Speed 32. From 0 - 10,000 ft. the Tempest is 20 mph faster than the Spitfire XIV. There is little to choose until 22,000 ft. when the Spitfire XIV becomes 30-40 mph faster, the Tempest's operational ceiling being about 30,000 ft. as opposed to the Spitfire XIV's 40,000 ft. Maximum Climb 33. 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 throughout the manoeuvre. If the climb is prolonged until climbing speed is reached, then, of course the Spitfire XIV will begin to catch and pull ahead. Dive 34. The Tempest gains on the Spitfire XIV. Turning Circle 35. The Spitfire XVI easily out-turns the Tempest. Rate of Roll 36. The Spitfire XIV rolls faster at speeds below 300 mph, but definitely more slowly at speeds greater than 350.00 mph. Conclusions 37. The tactical attributes of the two aircraft being completely different, they require a separate handling technique in combat. For this reason, Typhoon squadrons should convert to Tempests, and Spitfire squadrons to Spitfire XIV's, and definitely never vice-versa, or each aircraft's particular advantages would not be appreciated. Regarding performance, if correctly handled, the Tempest is better below about 20,000 feet and the Spitfire XIV above that height. Maximum Speed 38. The Tempest is nearly 50 mph faster at all heights. It is estimated that the Tempest V may be very slightly faster than the new FW.190 (DB.603) up to 20,000 ft. Climb 39. Except below 5,000 feet the FW.190 (BMW.801D) has a slightly better maximum rate of climb. Because of the Tempest V's speed and clean lines however, the Tempest has a markedly better zoom climb, where the speed is kept high. Against the new FW.190 (DB.603) it is estimated that the Tempest will have a markedly superior climb below 5,000 feet, but a similar maximum climb above that height. Dive 40. The Tempest pulls away rapidly in a dive from all heights. Turning Circles 41. There is very little difference in turning circles between the two aircraft. If anything a very slight advantage lies with the Tempest. Rate of Roll 42. The Tempest V cannot compare with the FW 190. Conclusions 43. Similar tactics should be used against the FW.190 as used by the Typhoon squadrons, advantage being taken of high speed. Such handling should prove most effective. The Tempest has an exceptional ground height performance even (estimated against the FW.190 (DB.603). Maximum Speed 44. The Tempest V is 40 - 50 mph faster up to 20,000 feet when the difference in speed rapidly diminishes. Climb 45. The Tempest is behind the Me.109G at all heights, but being almost similar below 5,000 feet. The Tempest is only slightly better in a zoom climb if the two aircraft start at the same speed, but if the Tempest has an initial advantage, it will hold this advantage easily providing the speed is kept over 250 mph. Dive 46. Initial acceleration of the Tempest is not marked, but a prolonged dive brings the Tempest well ahead. Turning Circle 47. The Tempest is slightly better, the Me.109G being embarrassed by its slots opening near the stall. Rate of Roll 48. At normal speeds there is nothing in it, but at speeds over 350 mph the Tempest could get away from the Me.109G by making a quick change of bank and direction. Conclusions 49. In the attack, the Tempest can always follow the Me.109 except in slow, steep climb. In the combat area the Tempest should maintain a high speed, and in defense may do anything except a climb at slow speed. Gun Harmonisation 50. Harmonisation was carried out in accordance with the pattern issued by Headquarters, Fighter Command, No.FC/G.208 dated 15.11.43. Gun Firing 51. Two air shoots have been carried out. First shoot. Low altitude - 100%Re-Arming 52. Gun loading platforms are issued and used during these trials. With two Armourers only, the time taken for re-arming was as follows:- First test - 17 minutes Second test - 12 minutes Operational load Port & Starboard Inner - 150 rounds Port & Starboard Outer 140 rounds Cine-gun Installation and Harmonisation 53. Cine-gun fitted with extension lens and harmonized center. It is impossible with the installation to harmonize a quarter from the top. The camera is fitted on the starboard side of the engine. Considerable vibration has been experienced causing the door on the cine-gun to fly open. This has been remedied by putting a 'U' shaped clip over the top of the camera. No trouble has since been experienced in any condition of flight, incorporating this modification. Radio 54. One V.H.F. set is fitted, the control box being on the left-hand side of the cockpit. Oxygen 55. Normal British type Oxygen is fitted, the master cock in the cockpit being on the left-hand side of the seat, as is the Typoon. Engine Temperatures 56. The glycol radiator flap is controlled by a lever on the left. When closed the engine runs hot, and overheats quickly in the climb, so that it is necessary to climb with the flap open, when the temperature increases very slowly to maximum. 57. As the Typhoon, care must be taken to keep the booster coil button pressed. It is a good thing after doping to pump up the carburettor pressure before pressing starter buttons. 58. Normal Typhoon equipment can be used with the exception of gun loading platforms. 59. The Tempest V is superior to the Typhoon in all respects. It is faster than any other fighter up to medium altitude and has the best zoom-climb and dive charateristics yet seen by this Unit. The ailerons have less tendency to stiffen up especially at speeds oover 350 mph, where it will out-roll any Spitfire. 60. The modification to the sight bracket (para. 22) reduces the likelihood of injury to the pilot in the event of a forced landing, and improves the foward view considerably. |