Hawker Tempest

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Hawker Tempest
Hawker Tempest II, RAF Museum, Hendon
Type	Fighter/Bomber
Manufacturer	Hawker Aircraft Limited
Maiden flight	2 September 1942
Introduced	1944
Status	Retired
Primary user	Royal Air Force
Number built	1,702
Developed from	Hawker Typhoon
Variants	Hawker Sea Fury

The Hawker Tempest was a British fighter aircraft primarily used by the Royal Air Force (RAF) in the Second World War. The Tempest was an improved derivative of the Hawker Typhoon, and one of the most powerful fighter aircraft used in the war.

[edit] Design and Development

^[1][2] During development of the Typhoon the design team, under the leadership of Sydney Camm, were already thinking of ways in which the aircraft could be improved. This process resulted in the Hawker P. 1012 (or Typhoon II).

Although the Typhoon was basically a good design Camm and his design team were disappointed with the wing which proved to be too thick in its cross section; this created problems with the airflow and inhibited the performance of the aircraft, especially at higher altitudes. In March 1940 a few engineers had been assigned to investigate the new low drag laminar flow wing that NACA in the USA had developed and which had been used in the new North American Aviation designed P-51 Mustang. The new laminar flow wing adopted for the Tempest series had a maximum Thickness to chord ratio, of 14.5 % at the root tapering to 10% at the tip. By comparison the Typhoon's wing, using a NACA 23-series wing section, was substantially thicker - 19.5% (root) to 12% (tip). The maximum thickness of the Tempest wing was set further back at 37.5% of the chord versus 30% for the Typhoon's wing.

The wingspan was originally greater than that of the Typhoon at 43 ft (13.1 m), but the wingtips were later "clipped" and the wing became shorter; 41 ft (12.5 m) versus 41 ft, 7 in (12.7 m). The wing planform was changed to an elliptical shape to accommodate the 800 rounds of ammunition for the four Hispano 20 mm cannon, which were moved back further into the wing. The new elliptical wing had greater area than the Typhoon's. ^[3]

The thinner wing also displaced fuel tanks that had been fitted into the leading edge of the Typhoon's wing. This greatly reduced fuel capacity but Hawker engineers added a new 21 inch (53 cm) bay ahead of the cockpit accommodating a 76 gallon fuel tank, giving a maximum of 360 gallons and an operational radius of 500 miles, almost double that of the Spitfire IX. Another important feature of the new wing for the Tempest I was Camm's proposal that radiators for the new Napier Sabre IV engine were to be fitted into the leading edge of the wing inboard of the undercarriage. This eliminated the distinctive "chin" radiator associated with the Typhoon and improved aerodynamics.

A further improvement of the Tempest wing over that of the Typhoon was the exceptional, flush riveted surface finish, essential on a high performance laminar flow airfoil. Fortunately for the pilots the new wing and airfoil, and the four bladed propeller unit, eliminated the high frequency vibrations that had plagued the Typhoon.

The redesigned main undercarriage legs were longer and set further apart (16 feet) to improve stability at the high landing speed of 110 mph (180 km/h) and to allow tip-clearance for a new four-blade propeller of 14 feet diameter. They were also designed to shorten as they retracted.^[4] The main wheels also needed new thin tyres in order to fit within the wing. Finally, the retractable tailwheel was fully enclosed by small doors.

The Tempest I HM599

Camm and the Hawker design team placed a high priority on making their aircraft easily accessible to both air and ground crews; to this end the forward fuselage and cockpit areas of the earlier Hurricane and the Tempest and Typhoon families were covered by large removable panels providing access to as many components as possible, including flight controls and engine accessories. Both upper wingroots incorporated panels of non-slip coating. For the pilot a retractable foot stirrup under the starboard root trailing edge was linked to a pair of handholds which were covered by spring loaded flaps. Through a system of linkages, when the canopy was open the stirrup was lowered and the flaps opened, providing easy access to the cockpit. As the canopy was closed the stirrup was raised into the fuselage and the flaps snapped shut.

The new design was finalised by October 1941 and the Air Ministry issued specification F.10/41 that had been written to fit the aircraft. A contract for two initial prototypes was issued the next month. The aircraft was originally named the "Typhoon Mark II" but was renamed "Tempest" in January 1942 when more prototypes with various experimental configurations were ordered. The problems experienced with delivery of engines led the Air Ministry to ask for six prototypes with different engines so that if a delay hit one engine an alternative would be available. This gave the Mk I (aircraft HM599) with a Sabre IV, two Mk IIs (LA602 and LA607) with the Centaurus IV, MK III (LA610) with a Griffon IIB, Mk IV (LA614) with a Griffon 61 and the Mk V (HM595) with the Sabre II.

The first Tempest prototype, the Mark V, flew on 2 September 1942. This aircraft retained the Typhoon's framed canopy, automobile-style door, the Sabre II engine, and "chin" radiator. It was quickly fitted with a bubble canopy like the later Typhoons and a modified tailfin that almost doubled the control surface area. The horizontal tailplanes and elevators were also increased in span and chord (these were also fitted to late production Typhoons.)

Tempest V prototype HM595.

Test pilots found the Tempest a great improvement over the Typhoon in performance, although it was "pretty tricky to fly". The Air Ministry had already ordered 400 Tempests in August but production of the new Sabre IV engine ran into protracted problems and delays. The second prototype, the "Tempest Mark I" with the Sabre IV did not fly until 24 February 1943.

This prototype also had at first the older Typhoon cockpit and vertical tailplane. Elimination of the "chin" radiator did much to improve performance and the Tempest Mark I was the fastest aircraft Hawker had built to that time, attaining a speed of 466 mph (750 km/h).

Continual problems with the Sabre IV meant that only one Mark I (HM599) was built; consequently Hawker went into production with the Sabre II engined "Tempest V". The first rolled off the production line on 21 June 1943. The first Tempest Vs delivered had the long-barrelled Mark II 20 mm Hispano cannon. Later production aircraft used the short-barrelled Mark V Hispano cannon, eliminating the protruding barrels - though these had not been as prominent as on the Typhoon.

The ultimate offshoot of the Typhoon and Tempest family was the Fury/Sea Fury.

[edit] Tempest Mark V

The Tempest V JN729 [1] Small blisters covering the spar to spar boom securing bolts can be seen on the wing root fairing. The longer barrels of the Hispano II cannon can also be seen.

In his book The Big Show, French ace Pierre Clostermann, who flew Mk Vs with Nos. 274 and 3 squadrons of the RAF in 1944-45, describes flying the fighter: "Thanks to its 2,400 hp engine it had a considerable margin of excess power and its acceleration was phenomenal. It was pretty tricky to fly, but its performance more than made up for it..."^[5] Some of the assets of the Tempest V were its high cruising speed (nearly 400 mph using 1,420 hp), good acceleration, excellent climbing and diving speeds, especially at low to medium altitudes. All of these are vital in air combat which, during the Second World War, rarely got into the tail chasing, close-quarter "dog fights" so beloved of filmmakers.

The Mk V was a much different Tempest to the Mk I with many improvements over preceding variants. The Mk Vs received the initially problem-plagued Napier Sabre II series engines developing in excess of 2,000 hp with their H-24 cylinder configuration. Unlike the Mk I aircraft, the wing root oil coolers were moved to directly behind the main "chin" radiator.

Examination of captured Fw 190s brought about improvements in the windscreen/ side windows; by careful design and positioning of the frame structure blind spots were reduced to an absolute minimum.

During production of the first batch of 100 (JNxxx serialled) Tempest Vs changes were progressively introduced:^[6][1][2]

• The rear fuselage fuselage/empennage joint originally featured the 20 external reinforcing "fishplates" first seen fitted to the Typhoon. Sometime during this production batch the rear fuselage was modified and became detachable.

• The first Tempest Vs used long barrelled Hispano Mk. IIs which projected ahead of the wing leading edges. These were later replaced by short barrelled Mk. Vs which were flush with the leading edges.

• "Five spoke" wheels, of a similar pattern to those of the Typhoon, were later replaced by a reinforced "four spoke" pattern.

• Initially Tempest Vs used a built-up rear spar pick-up/bulkhead assembly (just behind the cockpit) which was adapted from the Typhoon. Small blisters on the upper rear wing root fairing covered the securing bolts. This was later changed to a new forged, lightweight assembly which connected to new spar booms: the upper wing root blisters were replaced by small "teardrop" fairings under the wings.

• The new spar structure also allowed the wings to carry up to 2,000 lb (908 kg) of external stores. Also developed specifically for the Tempest by Hawker was a streamlined 45 gallon "drop tank" and carrier fairing; the redesigned wing incorporated the plumbing for these tanks, one to each wing.

• The ailerons were fitted with spring loaded tabs which lightened the aerodynamic loads, making them easier for the pilot to use and dramatically improving the roll rate above 250 mph.

• Different models of the Sabre II were introduced. The later versions were capable of producing over 2,400 hp (1,789 kW) on emergency boost for short periods of time.^[7]

As in all mass-produced aircraft, there may have been some overlap of these features as new components became available. In mid to late 1944 other features were introduced to both the Typhoon and Tempest:

• A Rebecca transponder unit was fitted, with the associated aerial appearing under the portside centre section.

• A small, elongated oval static port appeared on the rear starboard fuselage, just above the red centre spot. This was apparently used to more accurately measure the aircraft's altitude.

Unusually, in spite of the Tempest V being the RAF's best low to medium altitude fighter, it was not equipped with the new Mk IIC gyroscopic gunsight, an asset which was fitted in RAF Spitfires and Mustangs from mid-1944 and one which considerably improved the chances of shooting down opposing aircraft. Tempest pilots continued to use the Mk.IIL reflector gunsight until just after the Second World War, when the gyro-gunsight was introduced in Tempest IIs.

Externally the Tempest V bore a strong resemblance to the Typhoon: the longer nose, thinner wings and larger tail unit, with a gracefully curved dorsal fin, enhanced the looks of the fighter, and were the most noticeable differences.

SN345 with experimental 47mm class P guns.

Two Tempest Vs, EJ518 and NV768, were fitted with Napier Sabre Vs and experimented with several different Napier made annular radiators, with which they resembled Tempest IIs. NV768 was later fitted with a ducted spinner, similar to that fitted to the Fw 190 V1.^[1][8]

Another experimental Tempest V was SN345, which was fitted with two Vickers 47 mm "P" guns, one under each wing in a long "pod".^[9][1][8]

[edit] Tempest II

The prototype Tempest II LA602 showing original Typhoon tail unit.

While Hawker was working toward the introduction of the Tempest V, Sydney Camm and his crew were also revisiting the Bristol Centaurus 18 cylinder radial engine, incorporating it into two other Tempest prototypes.

The first Centaurus powered Tempest, the "Tempest Mark II" LA602, flew on 28 June 1943 with a Centaurus IV (2,520 hp, 1,879 kW) driving a four-blade propeller. LA602 initially flew with a Typhoon type fin and rudder unit. This was followed presently by the second, LA607, which first flew on 18 September 1943 and was assigned to engine development. Apart from the new engine and cowling the Tempest II prototypes were similar to early series Tempest Vs. The main airframe difference was the addition of carburettor air intakes in the inner leading edges of both wings, with an oil cooler and air intake in the inner, starboard wing.

The radial engine installation owed much to examinations of a captured Focke-Wulf Fw 190, and was unprecedentedly clean and effective. In spite of the promise of a more reliable powerplant than the Sabre there were frustrating problems, including overheating, unreliable and leaking exhausts, insufficient crankshaft lubrication and propeller reduction gear seizures. There were also problems with vibration, but they were fixed by replacing the original "rigid" eight point engine mounts with six point rubber-packed shock mounts. In a further attempt to alleviate engine vibration the four blade propeller was replaced with a five blade unit; eventually a finely balanced four bladed unit was settled on.

Physically, the Tempest II was longer than the Tempest V (34 ft 5 in (10.5 m) versus 33 ft 8 in (10.3m)) and three inches lower. The weight of the heavier Centaurus engine (2,695 lb, 1,222 kg versus 2,360 lb, 1,070 kg) was offset by the lack of a heavy radiator unit, so that the Tempest II was only some 20 lb (9 kg) heavier overall. Performance was improved; maximum speed was 442 mph (711 km/h) at 15,200 ft (4,633 m) and climb rate to the same altitude took four and a half minutes compared with five minutes for the Tempest V. Service ceiling was increased to 37,500 ft (11,430 m).^[1][8]

Late production Tempest F.B Mk. II showing bomb racks under the wings

The Centaurus was generally regarded as superior to the Sabre, particularly in terms of reliability, and the engine and Tempest airframe proved an excellent match. The combination looked so promising that a contract for 500 of the type was placed as far back as September 1942, but Gloster was overloaded with production of the Typhoon and development of the Gloster Meteor, and there was no way the company could handle the additional load.

Tempest Mark II production was allocated to Bristol, and the switch delayed production even more. The first Tempest II was rolled off the line on 4 October 1944. With the end of the Second World War in sight, orders for the Tempest II were trimmed or cancelled; after 50 Tempest IIs had been built at Bristol's Banwell facility, production was stopped and shifted back to Hawker.

A total of 452 Tempest IIs were built, including 136 basic Mark IIs and 316 "Fighter Bomber Mark IIs" (FB II). They were built mostly by Hawker and generally with Centaurus V engines, and of that number 300 were completed after the war. The Tempest II, despite its slightly improved performance and better reliability, never saw combat. Tempest IIs produced during the war were intended for combat against the Japanese, and would have formed part of "Tiger Force" but the Pacific War ended before they could be deployed. The RAF passed 89 Tempest FB IIs to the Indian Air Force in 1947, while another 24 were passed on to the Pakistani Air Force.

[edit] Tempest VI

The production Tempest VI, NX135, pictured at Langley in 1945

Various engineering refinements that had gone into the Tempest II were incorporated into the last Tempest variant, the "Tempest VI", which was fitted with a Sabre V engine with 2,340 horsepower (1,700 kW). The more powerful Sabre V required a bigger radiator which displaced the oil cooler and carburettor air intake from the radiator's centre. Air for the carburettor was drawn through intakes on the leading edge of the inner wings, with the oil cooler being fitted behind the radiator. Most Tempest VIs were tropicalised with an air filter fitted in a fairing on the lower centre-section. Hundreds of Tempest VIs were ordered, though only 142 were built. The last piston-engined fighter in RAF service was a Tempest VI. For a long time it was thought that there were Tempest VIs converted for target towing: none of the service histories of the aircraft show TT conversions and no supporting photographic evidence has been found.

[edit] Drawing Board Designs

In 1944, in response to F.13/44 Sydney Camm started a design, the P.1027, for a slightly enlarged Tempest powered by a Rolls Royce R.46, which was projected to develop around 2,500 to 4,000 hp (1,864 kW. to 2,983 kW). This engine would have driven eight-blade contra-rotating propellers. The radiator was to be moved into a ventral bath under the rear fuselage and wing centre section: the wingspan was 41 ft (12.5 m) and the length was 37 ft 3 in (11.4 m).^[1] The design was soon dropped in favour of the P.1030, which featured wing leading edge radiators and larger overall dimensions of 42 ft (12.8 m) wingspan and 39 ft 9 in (12.1 m) long. Top speed was expected to be in the region of 508 mph (817 km/h), with a rate of climb of 6,400 ft/min (1,951 m/min). Service ceiling was projected to be 42,000 ft (12,802 m).^[1][10]

Both tenders were dropped when Camm decided to follow the more promising jet engine designs he was working on.

[edit] Service History

[edit] Tempest V in combat

The Tempest V was in the hands of operational squadrons by April 1944; 3 Squadron was the first to be fully equipped, closely followed by 486 (NZ) Squadron (the only non-RAF unit to be equipped with the Tempest during the Second World War). A third unit 56 Squadron initially kept its Typhoons and was then temporarily equipped wth Spitfire Vbs until sufficient supplies of Tempests were available^[11]

Early production Tempest V of 486 Sqn. April 1944. JN766 still has factory applied black and white Typhoon style underwing recognition bands (see "Invasion stripes")

By the end of April 1944, these units were based at RAF Newchurch a new "Advanced Landing Ground" (ALG), where they formed No. 150 Wing RAF, under the command of Wing Commander Roland Beamont. Most of the initial operations carried out comprised high altitude fighter sweeps, offensive operations known as "Rangers" (long-range sorties inside enemy territory, specifically to attack ground vehicles) and anti-shipping reconnaissance. In June 1944, however, the first German V-1 flying bombs were launched against London and the Tempest's excellent low-altitude performance made it one of the preferred tools for dealing with the small fast-flying unmanned missiles. Tempest squadrons racked up a considerable percentage of the total RAF kills over the flying bombs (638 of a total of 1,846 destroyed by aircraft).^[12]

Early Tempest V of 3 Sqn. Note Invasion stripes painted on by the ground crew. The longer cannon barrels can be seen on the port-side wing.

The Tempest was also deployed in support of the Allied armies advancing across northern Europe and engaged Luftwaffe aircraft when they could be found. Operation Market Garden, the Airborne attempt to seize a bridgehead over the Rhine had Tempest units, based at forward airfields in England, flying in support. After Market Garden, Tempest squadrons moved to the European mainland. The Tempest force consisted of 122 Wing (3 Sqn., 56 Sqn., 80 Sqn., 274 Sqn. (to March 1945), and 486 Sqn.); from October 1944 122 Wing was based at B.70 Volkel Air Base near Uden, Netherlands. In February 1945, 135 Wing (33 Sqn., 222 Sqn. and (from March 1945) 274 Sqn.) was formed and was based at B.77 Gilze-Rijen airfield, Netherlands.

In December 1944, the first month of operations, 52 German fighters were downed and 89 trains destroyed, for the lost of 20 Tempests. Following the Luftwaffe's Operation Bodenplatte of 1 January 1945, No. 122 Wing bore the brunt of low to medium altitude fighter operations for the Second Tactical Air Force. Spitfire XIVs of 125 and 126 Wings often provided medium to high altitude cover for the Tempests. The Wing came under intense pressure, losing 47 pilots in January.

Tempests also scored a number of kills against the new German jets, including the Messerschmitt Me 262. Hubert Lange, a Me 262 pilot, said: "the Messerschmitt Me 262's most dangerous opponent was the British Hawker Tempest — extremely fast at low altitudes, highly-manoeuvrable and heavily-armed."^[13]Some were destroyed with a tactic known as the "Rat Scramble".^[14][5][15] Tempests on immediate alert took off when an Me 262 was reported to be airborne. They did not intercept the jet, but instead flew towards the Me 262 and Ar 234 base^[16] Rheine-Hopsten.^[17] The aim was to attack jets on their landing approach, when they were at their most vulnerable, travelling slowly, with flaps down and incapable of rapid acceleration. The Germans responded by creating a "flak lane" of over 150 quadruple 20 mm guns at Rheine-Hopsten, to protect the approaches.^[18] After seven Tempests were lost to flak at Rheine-Hopsten in a single week, the "Rat Scramble" was discontinued. For a while, in March 1945 a strict "No, repeat, No ground attacks" policy was imposed; this only applied for a few days.^[1]

The top scoring Tempest pilot was Squadron Leader David C. "Foobs" Fairbanks DFC, an American who joined the Royal Canadian Air Force in 1941. By mid-1944, he was flying with 274 Squadron. When he was shot down and made a POW in February 1945, he had destroyed 12 German aircraft (and one shared) to make him the highest scoring Tempest ace.

[edit] Variants

• Typhoon Mk II : The original designation of the Hawker Tempest.
• Tempest Mk I : Prototype fitted with the Napier Sabre IV piston engine, one aircraft.
• Tempest Mk III : Prototype fitted with the Rolls-Royce Griffon piston engine.
• Tempest Mk IV : Tempest Mk III prototype re-engined with a Rolls-Royce Giffon 61 piston engine.
• Tempest Mk V : Single-seat fighter, fighter-bomber aircraft, powered by the Napier Sabre II piston engine, 801 built at Langley.
  • Tempest Mk V Series 1 : The first 100 production aircraft were fitted with four long-barrel 20-mm Mark II Hispano cannons.
  • Tempest Mk V Series 2 : The other 701 production aircraft were fitted with four short-barrel 20-mm Mark V Hispano cannons.
  • Tempest TT Mk 5 : After the Second World War a number of Tempest Mk Vs were converted into target tugs.
• Tempest F Mk II : Single-seat fighter aircraft for the RAF, powered by a Bristol Centaurus radial piston engine, 402 built by Hawker at Langley and 50 by Bristol Aeroplane Company, Banwell.
  • Tempest FB Mk II : Single-seat fighter-bomber with underwing pylons for bombs and rockets.
• Tempest F Mk VI : Single-seat fighter aircraft for the RAF engined with the Sabre V (2 340 hp), 142 built.

[edit] Operators

Main article: List of Hawker Tempest operators

•  Canada
•  India
•  New Zealand
•  Pakistan
•  United Kingdom

[edit] Specifications (Tempest V)

Data from Jane’s Fighting Aircraft of World War II:^[19][20]

General characteristics

• Crew: One
• Length: 33 ft 8 in (10.26 m)
• Wingspan: 41 ft 0 in (12.49 m)
• Height: 16 ft 1 in (4.90 m (tail down))
• Wing area: 302 ft² (28 m²)
• Empty weight: 9,250 lb (4,195 kg)
• Loaded weight: 11,400 lb (5,176 kg)
• Max takeoff weight: 13,640 lb (6,190 kg)
• Powerplant: 1× Napier Sabre IIA or IIB or IIC liquid-cooled H-24 sleeve-valve engine:, 2,180 hp (1,625 kW) Sabre IIA at + 9 lb/in2 boost at 7,000 ft (2,133 m), 4000 rpm ^[21]
• Propellers: Four-bladed Rotol or de Havilland propeller

Performance

• Maximum speed: 432 mph (695 km/h) Sabre IIA at 18,400 ft (5,608 m)
  , Sabre IIB 435 mph at 19,000 ft (700 km/h at 5,791 m)
• Range: 740 mi (1,190 km)
  1,530 mi (2,462 km) with 90 gallon drop tanks
• Service ceiling 36,500 ft (11,125 m)
• Rate of climb: 4,700 ft/min (23.9 m/s)
• Wing loading: 37.75 lb/ft² (184.86 kg/m²)
• Power/mass: 0.21 hp/lb (0.31 kW/kg)

Armament

• 4× 20 mm Mark II Hispano cannons, 200 rounds per gun
• 2× 500 lb or 1,000 lb (227 kg or 454 kg) bombs
• 8× 3 in (75 mm) RP-3 rockets (post-Second World War)
• Provision for 2 x 45 gallon or 2 x 90 gallon drop tanks.

[edit] See also

Related development

• Hawker Typhoon
• Hawker Fury/Sea Fury
  

Related lists

• List of aircraft of the RAF
• List of aircraft of the RNZAF and RNZN
  

[edit] References

[edit] Notes

[edit] Bibliography

• Tempest at War DVD, IWM Footage.

[edit] Further reading

• Shores, Christopher and Thomas, Chris. Second Tactical Air Force Volume One. Spartan to Normandy, June 1943 to June 1944. Hersham, Surrey, UK: Ian Allan Publishing Ltd., 2004. ISBN 1-903223-40-7.
• Shores, Christopher and Thomas, Chris. Second Tactical Air Force Volume Two. Breakout to Bodenplatte, July 1944 to January 1945. Hersham, Surrey, UK: Ian Allan Publishing Ltd., 2005. ISBN 1-903223-41-5.
• Shores, Christopher and Thomas, Chris. Second Tactical Air Force Volume Three. From the Rhine to Victory, January to May 1945. Hersham, Surrey, UK: Ian Allan Publishing Ltd., 2006. ISBN 1-903223-60-1.

[edit] External links

Wikimedia Commons has media related to:

Hawker Tempest

• Vectorsite article
• The Hawker Tempest Page
• Hawker Tempest V Performance
• U.S report on Tempest V