The final stages of the Hawker Typhoon assembly line showing the engine feeder track on the left and in the foreground.
The Hawker Typhoon was a British single-seat fighter-bomber, produced by Hawker Aircraft. While the Typhoon was designed to be a medium-high altitude interceptor, and a direct replacement for the Hawker Hurricane, several design problems were encountered, and the Typhoon never completely satisfied this requirement. Other external events in 1940 prolonged the gestation of the Typhoon.
Nicknamed the Tiffy in RAF slang, the Typhoon’s service introduction in mid-1941 was also plagued with problems, and for several months the aircraft faced a doubtful future.However, in 1941 the Luftwaffe brought the formidable Focke-Wulf Fw 190 into service: the Typhoon was the only fighter in the RAF inventory capable of catching the Fw 190 at low altitudes and, as a result, secured a new role as a low-altitude interceptor. Through the support of pilots such as Roland Beamont the Typhoon also established itself in roles such as night-time intruder and long-range fighter. From late 1942 the Typhoon was equipped with bombs; from late 1943 ground attack rockets were added to the Typhoon’s armoury. Using these two weapons, the Typhoon became one of the Second World War’s most successful ground-attack aircraft.
A line of Typhoon main plane assembly fixtures.
Even before the new Hurricane was rolling off the production lines in March 1937, Sydney Camm had moved on to designing its replacement. This was to be a big fighter designed around the large and more powerful 24-cylinder Napier Sabre engine. The work proved useful when Hawker received Specification F.18/37 from the Air Ministry in January 1938 which asked for a fighter based on either the Sabre or the Rolls-Royce Vulture engine. Both engines used 24 cylinders and were designed to be able to deliver over 2,000 hp; the difference between the two was primarily in the arrangement of the cylinders – an H-block in the Sabre and an X-block in the Vulture.
The two designs became known as the ‘R’ and ‘N’- from the initial of the engine manufacturer - and were very similar; the Vulture-powered R type, which became known as the Tornado, had a rounder nose profile and a ventral radiator, whereas the Sabre-powered N - the Typhoon - had a flatter deck and a chin-mounted radiator. The basic design of both was a combination of traditional Hawker and more modern construction techniques; the front fuselage structure, from the engine mountings to the rear of the cockpit, was made up of bolted and welded duralumin or steel tubes, while the rear fuselage was a flush-riveted, semi-monocoque structure. The forward fuselage and cockpit skinning was made up of large, removable duralumin panels, allowing easy external access to the engine and engine accessories and most of the important hydraulic and electrical equipment.
A Hawker Typhoon in flight.
The first flight of the first Typhoon prototype, P5212, made by Hawker’s Chief test Pilot Philip Lucas from Langley, was delayed until 24 February 1940 because of problems with the development of the Sabre engine. Although unarmed for its first flights, P5212 later carried an armament of 12 .303 in Browning machine guns, set in groups of six in each outer wing panel; this was the armament fitted to the first 110 Typhoons, known as the Typhoon IA. P5212 also had a small tail-fin, triple exhaust stubs and no wheel doors fitted to the centre-section. On 9 May 1940 the prototype suffered from a mid-air structural failure, at the joint between the forward fuselage and rear fuselage, just behind the pilot’s seat. Philip Lucas could see daylight through the split but, instead of baling out, he was able to land the stricken Typhoon and was later awarded the George Medal.
Drilling jigs made of steel strips and in three sections are located over the interspar structure to drill the rib flanges for the attachment of the skin plating.
With the undercarriage leg in place and the hydraulic circuit completed, a preliminary actuation test of each leg is made with a hand pump.
As a result of the delays the second prototype, P5216, first flew on 3 May 1941: P5216 carried an armament of four 20 mm Hispano Mk II cannon, each with 140 rounds per gun and was the first prototype of the Typhoon IB series. In the interim between construction of the first and second prototypes the Air Ministry had given Hawker orders to proceed with the construction of 1,000 of the new fighters. It was felt that the Vulture engine was more promising, so the order covered 500 Tornadoes and 250 Typhoons, with the balance to be decided once the two had been compared. As a result of good progress by Gloster the first production Typhoon, R7576, was first flown on 27 May 1941 by Michael Daunt, just three weeks after the second prototype.
An undercarriage actuation test in progress on a set of port and starboard Typhoon wings.
Drilling in progress in the main jig for one of the quarter monocoque sections. Quarter frames, stringers and skin plating are all located in the jig and and drilled through the gate.
The assembly fixture in which the Typhoon rear fuselage quarter sections are aligned and prepared for rivetting.
Typhoon Production: the fuselage assembly track from the finishing end.
In 1941 the Spitfire Vs which equipped the bulk of Fighter Command squadrons were outclassed in combat with the Focke-Wulf Fw.190 and were suffering heavy losses. The Typhoon was rushed into service with 56 and 609 Sqns in the summer of 1941 in an attempt to counter the Fw.190. This decision proved to be a disaster, and several Typhoons were lost to unknown causes.
The Air Ministry began to consider halting production of the Typhoon.The in-flight tail failure was eventually identified, albeit only because one pilot survived and was able to explain what had happened; Mod 286 was a partial remedy, although there were still failures right up to the end of the Typhoon’s service life. The Sabre engine was also a constant source of problems, notably in colder weather, when it was very difficult to start.
The Typhoon did not begin to mature as a reliable aircraft until the end of 1942, when its good qualities became apparent. It was extremely fast, tough and capable. During late 1942 and early 1943, the Typhoon squadrons on the South Coast were finally effective in countering the Luftwaffe’s ‘tip and run’ low-level nuisance raids, shooting down a score or more fighter-bomber Fw.190s.
To counter such attacks Typhoon squadrons kept at least one pair of aircraft flying continuously on standing patrols over the South coast, with another pair kept at ‘readiness’;ready to take off within two minutes, throughout daylight hours. These sections of Typhoons flew at 500 feet or lower, with enough height to spot and then intercept the incoming enemy fighter-bombers. These tactics were successful during early 1943.
A distinctive feature of the Typhoon was the underslung radiator.
The drill jig for the bottom, port and starboard sides of the radiator fairing.
The fixture in which the side and bottom unit of the fairing is drilled for assembly with the front section
The completed fairing for the Typhoon showing the internal structure for oil and engine coolant radiators.
Initial jig assembly of the Instrument Panel in the fuselage decking.
Workers installing the electrical wiring in the decking unit of the Typhoon. This work is broken down into sucessive stanges.
The rear monococque portion of the fuselage with the pilot’s rear armour plate already installed.
As with all front line RAF aircraft, the Typhoon was modified and updated regularly, so that a 1945 production example looked quite different from one built in 1941. In the last months of the war a number of older aircraft were taken out of storage and overhauled, sometimes seeing active service for the first time.
The forward girder fuselage was fitted out with all required equipment before installing to the rest of the aircraft on the assembly track.
The first problem encountered with the Typhoon after its entry into service was the seepage of carbon monoxide fumes into the cockpit. In an attempt to alleviate this, longer exhaust stubs were fitted in November 1941 (‘Mod 239’), and at about the same time the port cockpit doors were sealed. The Pilot’s Notes for the Typhoon recommended that ‘Unless Mod. No. 239 has been embodied it is most important that oxygen be used at all times as a precaution against carbon monoxide poisoning’.
Original caption: The main planes were brought up to the fuselage on trolleys which support them in the assembly position at the correct height for bolting on to the spar fittings of the forward girder fuselage.
The Typhoon was first produced with forward-opening side doors (complete with wind-down windows), with a transparent ‘roof ’ hinged to open to the left. The first 162 Typhoons featured a built-up metal-skinned fairing behind the pilot’s armoured headrest; the mast for the radio aerial protruded through the fairing.From mid- to late 1941 the solid metal aft canopy fairing was replaced with a transparent structure - later nicknamed ‘The Coffin Hood’ - the pilot’s head armour plate was modified to a triangular shape and the side cut-outs were fitted with armoured glass; the first production Typhoon to be fitted with this new structure was R7803. All earlier aircraft were quickly withdrawn and modified.
From early 1942 a rear-view mirror was mounted in perspex blisters moulded into the later ‘car-door’ canopy roofs. This modification was not very successful, because the mirror was subject to vibration. Despite the new canopy structure the pilot’s visibility was still restricted by the heavy frames and the clutter of equipment under the rear canopy; from August 1943, as an interim measure, pending the introduction of the new ‘bubble’ canopy, the aerial mast and its associated bracing was removed and replaced with a whip aerial further back on the rear fuselage.
Starting in January 1943 R8809 was used to test a new, clear, one piece sliding ‘bubble’ canopy and its associated new windscreen structure which had slimmer frames which provided a far superior field of view to the car-door type. From November 1943 all production aircraft,starting with JR333, were to be so fitted.However, the complex modifications required to the fuselage and a long lead time for new components to reach the production line meant that it took some time before the new canopy became standard. In order to have as many Typhoons of 2nd TAF as possible fitted before ‘Operation Overlord’ conversion kits were produced and Gloster, Hawker and Cunliffe-Owen modified older Typhoons still fitted with the car-door canopy.