The Tempest was born out as an attempt to address the shortcomings of Hawker Typhoon.  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 aero-dynamic 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.  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 lIB 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 V’s were Nos. 3 and 486 at Newchurch, Dungeness, the first of these receiving its equipment early in 1944.  By May, five Tempest V’s had been lost due to engine failure, and this was discovered to be due to an over-speeding of the airscrew, resulting in an uncontrollahle increase in engine revolutions, the failure of the bearings and the collapse of the oil system.  In June modified airscrews 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 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.

Seven Tempest squadrons flew air-to-air combat and claimed 240 kills (some 20 of them Me 262 jets). Most successful Tempest ace, D. C. Fairbanks (US) recorded 11 kills flying Mk.V "Terror of Rheine". Second with nine kills came W. E. Schrader (NZ).  The most famous Tempest Pilot was the Free French Pierre Clostermann, who added four kills to his tally of 11 (some sources state 18 kills, the precise number is unknown).

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 1. 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 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 lIB 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.

Dimensions: Span, 41 ft. 0 in. ; length, 33 ft. 8 in. ; height,  16 ft. 1 in. ; wing area, 302 sq. ft.  

Armament: Four 20-mm. Hispano Mk. V cannon with  150 rounds per gun, and eight 60-lb. rocket  projectiles

or two I,OOO-ib. bombs.

Power Plant: One Napier Sabre lIB 24-cylinder, liquid-  cooled, horizontal-H engine providing 2,420  h.p.

at 3,850 r.p.m. at sea-level, and 2,045 h.p.  at 13,750 ft.

Weight: Empty, 9,250 lb.; loaded, 11,400 lb.; maximum, 13,500 lb.

Performance: Maximum speed, 435 m.p.h. at 17,000 ft., 416  m.p.h. at 4,600 ft., 392 m.p.h. at sea-level;

maximum cruising speed, 391 m.p.h. at 18,800  ft.; initial climb rate, 4,700 ft./min.; time to  10,000 ft., 2.7 min.;

time to 20,000 ft., 6.1  min.; service ceiling, 36,000 ft.; range at  210 m.p.h. at 5,000 ft., (160 Imp. gal.) 820  miles.