In response to Specification F.18137, design of the Hawker Typhoon was initiated by Sydney Camm in 1937. The Specification required a Rolls-Royce Vulture or Napier Sabre engine, so two prototypes were built initially, that with the Vulture known as the Hawker Tornado. The Sabre-engined version, designated Hawker Typhoon, also encountered powerplant problems. However, these were overcome because the Napier Company could devote more time and effort to development of the Sabre, whereas Rolls-Royce was too concerned with the Merlin to devote adequate resources to improving the troublesome Vulture.
It is an accepted maxim for successful aircraft development that future requirements should always be the principal concern of the chief designer and his project design team. The company which allows itself to become wholly preoccupied with the development of an established design may produce, as a result, an outstanding aeroplane, but the policy is a shortsighted one if no new prototype is following to consolidate this success. Thus, the fact that Sydney Camm, Hawker Aircraft’s chief designer, was at work on a new fighter as a potential replacement for the Hurricane as early as 1937, when the first production aircraft of that type had still to fly, reflected no lack of confidence in the Hurricane’s potentialities but the natural desire to ensure that its service successor would be a product of the same stable.
This massive new fighter, the heaviest and most powerful single-seat single-engined warplane envisaged at the time of its design, was to suffer a long gestatory period. It was to be pressed into operational service before it was fully developed and, in consequence, acquire a worse reputation among its pilots than that of any fighter preceding it. It was fated to be rarely employed in the interceptor role for which it was originally conceived. Yet, despite its vicissitudes, it was to blossom into one of the most formidable weapons evolved during the Second World War; a close-support fighter that was to turn the scales in many land battles and upset many conceptions of land warfare.
In January 1938, barely two months after the debut of the first production Hurricane Hawker Aircraft received details of specification F.18/37, calling for a large single-seat fighter offering a performance at least 20 per cent higher than that of the Hurricane and achieving this with the aid of one of two 24-cylinder engines in the 2,000 hp class then under development (the Napier Sabre “H” type and the Rolls-Royce Vulture “X” type). Sydney Camm had commenced investigating the possibilities of just such a fighter in March 1937, and had already roughed out a design built around the Napier Sabre engine and housing twelve 7.7 mm (0.303 in) Browning guns with 400 rounds per gun in its 40 foot wings. At the proposal of the Air Ministry, Camm also prepared studies for an alternative version of his fighter powered by the Rolls-Royce Vulture engine, and increased the ammunition capacity of both machines to 500 rounds per gun.
Further discussions over military loads and equipment followed, and revised tenders were submitted to Throughout 1938 the Air Ministry at the beginning of 1938 for both the Type “N” and the Type “R”, as the alternative Sabre and Vulture powered fighters had become known. These tenders were formally accepted on April 22, 1938, and four months later, on August 30, two prototypes of each fighter were ordered. Structurally both types were similar: the wings were all-metal, the front fuselage was of steel tubing, and the aft section consisted of a stressed-skin, flush-riveted monocoque; the first Hawker designs to employ this form of construction. Uniformity between the two fighters was, in fact, achieved to a remarkable degree, but the designs did differ in one important respect initially, the Vulture-powered fighter made use of a ventral radiator while the Sabre-driven machine had one of “chin” type.
Construction of the two massive fighters proceeded in parallel, and work progressed simultaneously on the preparation of production drawings. As a result of the slightly more advanced development status of the Vulture engine which had been designed along more conventional lines than the Sabre, the Type “R” was the first of the two fighters into the air, flying in October 1939. Named appropriately enough Tornado, the initial flight trials of the prototype were promising, and a production order for 1,000 Tornados was placed at the beginning of November, it being proposed that the new fighter should be built both by Hawker and by A. V. Roe at Woodford. However, the flight test program soon began to run into trouble. Compressibility effects, about which little was known at that time, began to manifest themselves, and it was decided that the ventral radiator bath was unsuitable for the speeds approaching 400 mph that were being achieved for the first time. The radiator was, therefore, moved forward to the nose, a position already selected for that of the Type “N”, by now dubbed Typhoon; but the first prototype Tornado (P5219) only flew long enough to indicate the beneficial results of the change before it was totally destroyed.
Meanwhile, on December 30, 1939, the first Napier Sabre engine had been delivered to Hawker Aircraft, and the first prototype Typhoon (P5212) emerged from the experimental shop to fly on February 24, 1940. It too became the subject of a quantity production order which, it was planned, should become the responsibility of Gloster Aircraft, whose assembly lines were emptying of Gladiator biplanes and whose design office was already immersed in the development of the Gloster Meteor, the first British turbojet-driven aircraft. Although, like those of the Tornado, the first flights of the Typhoon prototype indicated a promising fighter, the machine proving relatively easy to fly at high speeds, its low speed qualities left much to be desired, and it had a marked tendency to swing to starboard during take-off. The “X” form of the Tornado’s Vulture engine had not permitted installation above the front spar as was the Typhoon’s Sabre and, in consequence, the overall length of the former was 32 ft. 6 in. as compared with the 31 ft. 10 in. of the latter. Owing to the size and weight of the Sabre and the need to preserve center of gravity balance, the Typhoon’s engine was fitted so close to the leading edge of the wing that severe vibration was experienced as the slipstream buffeted the thick wing roots. On an early test flight the stressed-skin covering began to tear away from its rivets, and the Typhoon’s pilot, Philip G. Lucas, only just succeeded in bringing the prototype in to a landing.
Apart from structural teething troubles, the Sabre engine, although a compact and exquisite power plant, called for a considerable amount of development, and it was perhaps fortunate for the future of the Typhoon that, in May 1940, the grave war situation led to the cancellation of all priority for Typhoon and Tornado development in order to allow every effort to be put into the production of sorely needed Hurricanes. Design development was allowed to continue, however, and during 1940 three alternative engine installations were proposed for the Tornado (Fairey Monarch, the Wright Duplex Cyclone, and the Bristol Centaurus) and experimental drawings for the Centaurus installation were completed. Development on the Typhoon included the design of a modified wing containing two 20 mm Hispano cannon in place of the six 7.7 mm (0.303 in) Brownings, the construction of an experimental set of wings containing a total of six cannon, and the initiation of a design study of a Typhoon variant with thinner wings of reduced area and lower profile drag. This latter study was later to arouse interest at the Air Ministry and eventually result in the Tempest. However, by October 1940 enthusiasm had been revived and production of the Tornado and Typhoon reinstated, production deliveries of both being scheduled for the following year.
The Tornado weighed 8,200 lbs empty and 10,580 lbs loaded. Its maximum speed was 425 mph at 23,000 feet. A. V. Roe had prepared a production line at Woodford, and the first production Tornado (R7936) was delivered early in 1941. But this was fated to be the only production Tornado, for difficulties with the Vulture resulted in the decision to remove this power plant from the aero-engine development program, this decision also canceling production of the Tornado. However, in February 1941, Hawker’s received a contract to convert a Tornado to take a Bristol Centaurus radial engine. Among the modifications required were a new center fuselage and engine mounting. The new prototype (HG641) was assembled from Tornado production components and flown for the first time on October 23, 1941. The first Centaurus installation had an exhaust collector ring forward of the engine from which a single external exhaust stack pipe led back under the root of the port wing. This arrangement soon proved unsatisfactory, so the oil-cooler duct was enlarged and led forward to the nose, while twin exhaust pipes led back from the front collector ring through this fairing to eject under the belly of the fuselage. A level speed of 421 mph was attained with the Centaurus-Tornado, and this was slightly higher than that attainable by the Sabre-powered Typhoon, but the Typhoon airframe could not be adapted to take the radial engine. The second prototype Tornado (P5224) had, in the meantime, been completed, and the sole production Tornado (R7936) later played a useful role as a test-bed for deHavilland and Rotol contraprops.
The first production Typhoon IA (R7082) with the 2,200 hp. Sabre IIA engine was completed by Gloster and flown on May 26, 1941. Production of this version, with its twelve Browning guns, was in limited quantity, and those built were used principally for the development of operational techniques. But the cannon-armed Typhoon IB was following closely on the heels of the Mark IA, and the Air Ministry was pressing for its rapid service introduction to counter the new Focke-Wulf Fw 190. Nos. 56 and 609 Squadrons based at Duxford began to receive their Typhoons in September 1941, before the fighter was fully developed, and these squadrons were forced to take on part of the onus of unearthing the new machine’s numerous faults.
The decision to use the Typhoon before it was adequately developed for operational use was ultimately justified by the results, but the price of its premature introduction was high. In the first nine months of its service life far more Typhoons were lost through structural or engine troubles than were lost in combat, and between July and September 1942 it was estimated that at least one Typhoon failed to return from each sortie owing to one or other of its defects. Trouble was experienced in power dives–a structural failure in the tail assembly sometimes resulted in this component parting company with the rest of the airframe. In fact, during the Dieppe operations in August 1942, when the first official mention of the Typhoon was made, fighters of this type bounced a formation of Fw 190s south of Le Treport, diving out of the sun and damaging three of the German fighters, but two of the Typhoons did not pull out of their dive owing to structural failures in their tail assemblies.
Despite this inauspicious start to its service career and the unenviable reputation that the Typhoon had gained, operations continued and the accident rate declined as the engine teething troubles were eradicated, although the tail failures took longer to solve, despite immediate strengthening and stiffening as soon as the trouble manifested itself. In November 1942 No. 609 Squadron, led by Wing Commander Roland Beamont, was moved to Manston in an attempt to combat the near daily hip-and-run raids which were being made by Fw 190s and could rarely be intercepted by Spitfires. The Typhoon enjoyed almost immediate success. The first two Messerschmitt Me 210 fighter bombers to be destroyed over the British Isles fell to the guns of Typhoons, and during the last comparatively ambitious daylight raid by the Luftwaffe on London, on January 20, 1943, five Fw 190s were destroyed by Typhoons.
On November 17, 1942, Wing-Commander Beaumont had flown a Typhoon on its first night intrusion over Occupied France and, subsequently, the fighter was employed increasingly for offensive duties, strafing enemy airfields, ships and railway transport. The success of the Typhoon in the ground-attack role led to trials with two 250 lbs or two 500 lbs bombs which were carried on underwing racks. This load was later increased to two 1,000 lbs bombs, but the Typhoon was not to find its true element until it was adapted to carry airborne rocket projectiles–four under each wing. By D-Day, in June 1944, the R.A.F. had twenty-six operational squadrons of Typhoon IBs. Without its underwing load the Typhoon IB weighed 11,300 lbs; and with two 500 lbs bombs and the necessary racks, 12,400 lbs. Maximum speed was 398 mph at 8,500 feet and 417 mph at 20,500 feet, and an altitude of 20,000 feet could be attained in 7.6 minutes. Between the prototype and production stages several design changes had been made. These included the re-design of the fin and rudder, the redisposition of the wheel fairings and the introduction of a clear-view fairing behind the cockpit. On the first few Typhoon IAs the solid rear fairing was retained; later a transparent fairing was fitted, but this was abandoned in favor of the first sliding “bubble “ hood to be used by an operational fighter.
The Typhoon IB, by now affectionately known as the “Tiffy”, distinguished itself particularly in the Battle of Normandy, where it decimated a large concentration of armour ahead of Avranches, disposing of no fewer than 137 tanks, and opening the way for the liberation of France and Belgium. For use in the tactical reconnaissance role, the Typhoon F.R.IB was developed early in 1945. In this version the two inboard cannon were removed and three F.24 cameras were carried in their place. One Typhoon was also converted as a prototype night fighter, with A.I. equipment, special night-flying cockpit and other modifications. Production of the Typhoon, which was entirely the responsibility of Gloster Aircraft, totalled 3,330 machines.
The earlier Typhoon was plagued with both airframe and engine problems, it was towards the end of 1942 that these problems were rectified. The Typhoon still had a poor rate of climb, but it was found at lower altitudes to be very fast (426 mph) at 18,000 ft. By the end of 1942 it was discovered that the potential was in the aircraft’s ability to function as a very effective fighter bomber and proved effective against trains, tanks, shipping, German Communications especially when equipped with rocket projectiles. The claims by 124 wing 2nd Tactical Air Force are indicative of the potential of the Typhoon’s role as a fighter bomber between June 1944 and January 1945, while operating from bases inside Germany and Holland destroyed 115 tanks, 3 armoured cars, 494 motor vehicles and damaged 292 more vehicles.