Work had been going on in the Hawker design office since 1940 on the development of a new thin wing section. It had already been established that the N.A.C.A.22-series wing section employed by the Typhoon was entirely satisfactory at speeds in the vicinity of 400 m.p.h. but encountered compressibility effects at higher speeds. In dives approaching 500 m.p.h. a very sudden and sharp increase in drag was experienced, accompanied by a change in the aerodynamic characteristics of the fighter, which affected the pitching moment and rendered the machine nose heavy. No actual design work on the new wing was begun until September 1941, and the wing section eventually adopted for development had its point of maximum thickness at 37.5% of the chord. The thickness/cord ratio was 14.5% at the root and 10% at the tip, giving a wing five inches thinner at the root than that of the Typhoon.

This thin wing could not contain a comparable quantity of fuel to that housed by the Typhoon's wing, so a large fuselage tank had to be adopted. This necessitated the introduction of an additional fuselage bay, increasing the overall length by twenty-one inches forward of the c.g. This added length found its inevitable compensation after initial prototype trials in a larger fin and tailplane. The wing area was also increased, and an elliptical planform was adopted, presenting a chord sufficient to permit the four 20-mm. Hispano cannon to be almost completely buried in the wing. All these modifications added up to a radically changed Typhoon, but it was as the Typhoon II that two prototypes were ordered in November 1941. However, in the middle of the following year the name Tempest was adopted. Alternative installations of the Sabre engine were designed for these prototypes; the first (HM595) had a Sabre II and a front radiator similar to that of the standard Typhoon, while the second (HM599) had a Sabre IV engine and wing leading-edge radiators.

A Tempest II powered by the 1879 kW (2,520 hp) Bristol Centaurus of No. 24 Squadron, Royal Air Force, based at Chilbolton 1946

Piloted by Philip Lucas, the first prototype Tempest was flown on September 2, 1942, but prior to this, in February 1942, a production order had been placed and the first production machine flew in June 1943 with Bill Humble at the controls. During flight trials the first Tempest prototype had exceeded 477 m.p.h. in level flight, and the first production model was essentially similar to the first prototype with the chin-type radiator. This was designated Tempest V, and the initial production batch, the Series I, had Mk. II cannon which projected slightly ahead of the wing leading edge, but the Series II had the short-barrelled Mk. V cannon which did not project, and also featured a detachable rear fuselage, small-diameter wheels and a rudder spring tab. Powered by a 2,420 h.p. Sabre IIB engine, the Tempest V attained a maximum speed of 435 m.p.h. at 17,000 feet. The 820-mile range of the Tempest V in clean condition was an appreciable improvement over that of the Typhoon, and was due not only to the small additional quantity of fuel carried but to the aerodynamic refinement of the later machine which permitted a higher cruising speed for the same power.

The first squadrons to be equipped with Tempest Vs were Nos. 3 and 486 at Newchurch, Dungeness, the first of these receiving its equipment early in 1944. By May five Tempest Vs had been lost due to engine failure, and this was discovered to be due to an over speeding of the propellers, resulting in an uncontrollable increase in engine revolutions, the failure of the bearings and the collapse of the oil system. In June modified propellers were fitted which solved the problem, and two days after the invasion of the Continent, on June 8, 1944, the Tempests met enemy aircraft in combat for the first time, destroying three Bf 109G fighters without loss to themselves. On June 13 the first V1 flying bombs were launched against England, and the Tempest, being the fastest low-medium altitude fighter in service with the R.A.F., became the mainstay of Britain's fighter defence against the pilotless missiles, destroying 638 of these weapons by the beginning of September. The Tempest V was also employed on the Continent for train-busting and ground-attack duties.

Meanwhile the second prototype (HM599), designated Tempest I, had proved sufficiently promising for production plans to be initiated. In the light of experience gained with the Centaurus-powered Tornado and the suitability of the Tempest fuselage for the radial engine, a Centaurus version of the Tempest was also initiated as the Mark II, and production drawings were prepared in parallel with those of the Mark I. In the event, the Tempest I was later abandoned while the Mark II was allowed to proceed to the production stage following the successful flight trials with the prototype, LA602, which commenced on June 28, 1943. The first production Tempest II flew fifteen months later, but the first unit, No. 54 Squadron, was not equipped with this fighter until November 1945, and was thus too late to participate in the war. The Tempest II was powered by the 2,500 h.p. Bristol Centaurus V or VI eighteen-cylinder, air-cooled, two-row radial, and attained a maximum speed of 440 m.p.h. at 15,900 feet and 406 m.p.h. at sea-level. Its range on internal fuel was 775 miles and initial climb rate was 4,520 ft./min.

Schemes for the utilization of the Griffon IIB and the Griffon 61 engines accounted respectively for the Tempest III and Tempest IV designations, neither passing the project stage. Nor did an alternative armament proposal based on the use of 0.5-in. machine-guns. The final Tempest variant was the Mark VI, which, appearing in 1945, was powered by the 2,700 h. p. Sabre VA engine and, except in having small intake ducts in the wing roots, was outwardly indistinguishable from the Tempest V. By and large, both the Typhoon and Tempest escaped the fate of so many aeroplanes of being used as test-beds for a variety of experiments. The Typhoon was designed in a naval fighter variant to meet the requirements of specification N.11/40, and one prototype was converted to this standard under the Hawker project designation P.1009. Another Typhoon modification, the P.1010, was to have had leading-edge radiators and a turbo blower, but work on this was not proceeded with.

As part of their engine development program, Napier's designed an annular cowling for the Sabre to replace the familiar chin-type radiator bath. The first such installation was on a Typhoon IB (R8694), but most of the development was undertaken with a Tempest V (NV768) which flew with several different types of annular radiator and hollow spinner. Another experimental Tempest V (SN354) had a 40-mm. gun under each wing in a long fairing. As the Typhoon's immaturity faded it achieved widespread acclaim as a "rocketeer", being transformed from a fighter of dubious reliability into one of the Allies' most potent weapons. Likewise, its progressive development, the Tempest, gained for itself a place in the history of the air war for its part in reducing the depredations of the V1 flying bombs against England.

A Tempest Mk V with D-Day Invasion stripes

Variants

The design study, known originally as the Typhoon Mk 11, was submitted to the Air Ministry, and on 18 November 1941 two prototypes were ordered to Specification F.10141. There were major changes, however, compared with the earlier aircraft, resulting in the name change to Hawker Tempest in early 1942. After cancellation of the Hawker Tornado programme, the alternative engine installations planned for that aircraft were, instead, applied to the Tempest. Thus the two original prototypes became the Tempest Mk 1 with Sabre IV and Tempest Mk V with Sabre II, and four more were ordered. Two Tempest Mk II aircraft were to have the 1879 kW (2,520 hp) Bristol Centaurus, and two Tempest Mk III aircraft with the Rolls-Royce Griffon IIB, becoming Tempest Mk IV when re-engined with the Griffon 61. Only one Griffon-engined aircraft was completed, in fact, as one of the prototype Hawker Furies. Before any of the prototypes had flown the Air Ministry placed contracts for 400 Tempest Mk Is, although these orders were transferred later to other versions. The prototype Tempest Mk 1, its lines not spoiled by the beard radiator of the Typhoon, was flown on 24 February 1943, and later achieved a maximum speed of 750 km/h (466 mph) at 7470 m (24,500 ft). However, the engine programme suffered from technical problems and delays, and the Tempest Mk 1 was dropped.

The first of the Tempest prototypes to fly had been the Tempest Mk V, during September 1942. Retaining the Typhoon's chin radiator it had originally a standard Typhoon tail unit, but this was modified subsequently. The first of 805 Tempest Mk Vs was flown from Langley on 21 June 1943, one of the initial production batch of 100 Tempest Mk V Series 1 aircraft which had four 20-mm British Hispano Mk 11 cannon, their barrels protruding from the leading edges of the wings; the remaining Tempest Mk Vs had short-barrelled Mk V cannon, completely contained in the wings. In 1945, one Tempest Mk V was fitted with a 40 mm 'P' gun under each wing, similar to the 40 mm cannon installation of the Hawker Hurricane Mk IID. After the war had ended some were converted for use as Tempest TT.MK 5 target tugs.

An order for 500 Centaurus-powered Tempest Mk IIs was placed in October 1942, before the first flight of the prototype. This took place on 28 June 1943, the aircraft being powered by a Mk IV engine, superseded by the 1879 kW (2,520 hp) Mk V in production aircraft. These were to have been built by the Bristol Aeroplane Company, the first Bristol-built aircraft being flown on 4 October 1944, but only 36 were completed before production was transferred back to Hawker. The parent company manufactured a further 100 Tempest F.Mk 11 fighters and 314 Tempest FB.MK 11 fighter-bombers with underwing racks for bombs or rockets. In 1947 India ordered 89 tropicalised Tempest Mk lIs from RAF stocks, and in the following year Pakistan ordered 24 similar aircraft. Third and last production version of the Tempest was the Tempest F.Mk VI with the 1745 kW (2,340 hp) Napier Sabre V engine, first flown on 9 May 1944. Intended for service in the Middle East, 142 tropicalised Tempest Mk VIs were built. As in the case of the Mk V, some were converted later as Tempest TT.MK 6 target tugs.

RAF service began in April 1944, when Tempest Mk Vs were delivered to New- church, Kent, where the first Tempest Wing was formed within No. 85 Group. The wing was active during the build-up to the Normandy invasion, but on 13 June the first V-1 flying-bornb fell at Swanscombe in Kent, and the Tempests were among aircraft tasked to combat the menace. Their success can be measured by the fact that of 1,847 bombs destroyed by fighters between June 1944 and March 1945, 481 1/2 were accredited to the Tempest Wing.

Until the end of war in Europe, Tempest MkVs flew 'cab rank' patrols in support of ground forces, moving up to airfields in France and Belgium as the Germans fell back. In addition, they engaged in combat the Luftwaffe's Messerschmitt Me 262 jet fighters, 20 of which were destroyed before VE-Day.

Although plans were made for 50 Tempest Mk IIs to be sent to the FarEast in May 1945, to operate with Tiger Force against the Japanese, the war in the Pacific ended before these aircraft were ready for service. They equipped No. 54 Squadron at Chilbolton in November 1945, this being the only post-war home-based Tempest Mk 11 unit, the others serving in Germany, Hong Kong, India and Malaysia. The Tempest Mk VI was also too late to see wartime service, although this mark was flown later by squadrons in Germany and the Middle East.  

Specifications (Hawker Tempest Mk V)

Type: Single Seat Fighter & Fighter Bomber

Design: Sydney Camm

Manufacturer: Hawker Aircraft Limited with some Mk IIs being built by the Bristol Aeroplane Company.

Powerplant: (Mk V) One 2,180 hp (1626 kW) Napier Sabre IIA 24-cylinder 'H' piston engine. (Mk VI) One 2,340 hp (1745 kW) Napier Sabre V. (Mk II) One 2,520 hp (1879 kW) Bristol Centaurus radial engine.

Performance: Maximum speed 435 mph (700 km/h) at 17,000 ft (5181 m); service ceiling 36,500 ft (11125 m).

Range: Operational: 740 miles (1191 km) on internal fuel. Cruise: 820 miles (1319 km) at 210 mph (337 km/h) 5,000 ft (1524 m). 1,530 miles (2462 km) with external drop tanks.

Weight: Empty 9,000 lbs (4082 kg with a loaded take-off weight of 13,540 lbs (6142 kg).

Dimensions: Span 41 ft 0 in (12.50 m); length 33 ft 8 in (10.26 m); height 16 ft 1 in (4.90 m); wing area 302.0 sq ft (28.06 sq m).

Armament: Four 20 mm Hispano Mk. V cannon with 150 rounds per gun plus two 500 lbs (227 kg) or two 1,000 lbs (454 kg) bombs, or eight 60 lbs (27 kg) rocket projectiles.

Variants: Tempest, Tempest Mk I, Tempest Mk V, Tempest Mk II, Tempest Mk III, Tempest Mk IV, Tempest Mk B Series I, Tempest TT.Mk 5, Tempest F.Mk II (fighter), Tempest FB.Mk II (fighter-bomber), Tempest F.Mk VI, Tempest TT.Mk 6 (target tug).

Avionics: None.

History: First flight (prototype Mk V) 2 September 1942; (Mk 1) 24 February 1943; (production V) 21 June 1943; (Mk 11) 28 June 1943; (prototype VI) 9 May 1944; (production 11) 4 October 1944.