De Havilland DH115 T.55 Vampire

The origins of the Vampire date back to 1941 when the de Havilland Company began investigating the possibility of building a turbojet engine along with a fighter aircraft to go with it. Consequently, de Havilland's Frank Halford developed the 2,700 lb thrust Goblin 1 engine that ran successfully for the first time in April 1942, work began on an airframe to go around it the following month. Built to British Air Ministry specification E6/41, the prototype of the DH100 Spider Crab (LZ548/G) made its first flight from Hatfield airfield, Hertfordshire on September 20, 1943 with Geoffrey de Havilland Jnr at the controls. A further two prototypes were built, the last of which (MP838/G) was fitted with what was to become the aircraft's standard armament, four 20 mm Hispano cannons mounted under the nose. By the time the first production aircraft flew on April 20, 1945, the unofficial name of Spider Crab had been dropped and the aircraft became the DH100 Vampire F.1. It also became Britain's second operational military jet and first single-engine jet fighter.

Because the thrust of early turbojet engines was far from adequate, as low as one tenth of some current jet engines, the Vampire was designed to make the most of what was on offer. By keeping the jet intake ducts and exhaust nozzle as short as possible, power loss due to air friction was kept to a minimum. This led to the very distinctive short fuselage, twin-boom design of the Vampire. The construction of the monocoque fuselage was carried out in a manner very reminiscent to that used on the DH98 Mosquito. It was built in two halves and from the nose back to just aft of the cockpit (the point at which the engine was attached) was a composite of a layer of balsawood between two layers of moulded plywood. Although wooden construction on a jet fighter may have seemed archaic, especially when many piston engine fighters of the day were being made of metal, the end result was very strong and (more importantly) very lightweight. The mid mounted, cantilevered wing was of all metal construction built around a single spar and covered with a flush riveted Alclad (a heat-treated aluminium, copper, manganese, magnesium alloy) skin. The all-metal tail booms carried the twin vertical stabilisers and rudders and a single tailplane and elevator between them, mounted high enough to be clear of the jet exhaust. Retractable tricycle landing gear was fitted and, being jet powered and an aerodynamically clean design, wing mounted air brakes were installed to slow the aircraft for landing (normally a propeller provided enough drag to help slow an aircraft).

Even before the first prototype flew, the Royal Air Force had placed an order for 120 production aircraft. However, by the time deliveries of the Vampire F.1 began in March 1946, World War Two was over. The first 40 aircraft were used mainly for evaluation and testing with a number of improvements being made to the basic design, including the installation of the more powerful 3,100 lb thrust de Havilland Goblin 2 from the 40th Vampire onwards. Auxiliary underwing fuel tanks were also added and, from the 51st aircraft, a pressurised cockpit. Four Vampire Mk.IIs powered by a 4,500 lb thrust Rolls Royce Nene I turbojet engine were built to Air Ministry specification F.11/45 followed by the F.3 that entered service in April 1948. Powered by the same Goblin 2 engine as the F.1, the F.3 addressed the problem of short range suffered by its predecessors by enlarging the fuel tanks in the wings. This successfully added around 415 miles to the Vampire's range but caused stability problems, lowering and extending the chord of the tailplane and changing the shape of the vertical stabilisers and rudders soon cured this.

While development of the Vampire fighter progressed through a number of different variants, its potential as a ground attack aircraft had not been overlooked. As a result, the FB.5 made its first flight on June 29, 1948. Adapted from the F.1 and powered by the Goblin 2, this model had clipped and strengthened wings capable of carrying eight air to ground rockets or two 1,000 lb bombs. Longer stroke landing gear was installed to compensate for the extra weight and additional wing loading. Deliveries of production aircraft followed in 1949. A Vampire night fighter, the 3,350 lb thrust Goblin 3 powered DH113 NF.10, was introduced into service in July 1951. Built by de Havilland as a private venture, the fuselage was wider and longer than that of previous Vampires to enable a radar operator/navigator to be seated next to the pilot. To compensate for the changes to the fuselage, the tailplane was widened so it extended beyond the vertical stabilisers. Once again borrowing design ideas from the Mosquito, an American built A.I. Mk.10 radar, as used on the Mosquito NF.XVII night fighter, was installed in the NF.10's nose. The DH113 led to another private venture, the DH.115 T.11 trainer. Based on the NF.10, the radar and armament was removed, a second set of controls was installed and the Goblin 3 engine was replaced by a 3,500 lb thrust Goblin 35 turbojet. The prototype flew in November 1950 (15 months after the first flight of the NF.10) and entered service as a trainer for jet fighter operation. Several different variants of both the NF.10 and T.11 were subsequently developed, usually with minor detail changes or improvements, or experimentally for trials.

Developed from the third F.1 prototype (LZ551), a single example of the F.10 Sea Vampire was created for the Royal Navy. Fitted with new long-travel oleo shock absorbers, 40 percent more flap area and an arrestor hook, it became the first jet aircraft to land on an aircraft carrier when Lt. Commander E.M. Brown landed on HMS Ocean on December 3, 1945. Put into production as the F.20 Sea Vampire, it went on to become the first jet aircraft ever to see naval service. Based on the FB.5, the F.20 incorporated the features of the F.10 as well as extra structural strengthening to cope with the added strain of arrestor hook landings and enlarged air brakes and flaps. The DH115 T.11 was also adapted for use by the RN as the T.22 trainer and communications aircraft.

The RAF and RN were not the only users of the Vampire with various models, including those redesignated F.30 through to T.55 for export, seeing service in the armed forces of at least 30 different countries. Production under licence was also carried out in Australia (F.30, T.35), France (FB.5, SE-535 Mistral), India (T.55), Italy (F.52) and Switzerland (F.6). The type became the Royal New Zealand Air Force's first operational jet aircraft with a total of 58 being used between 1951 and 1972. The first 18 FB.52s (NZ5721-NZ5738) arrived during 1951 and 1952 and formed No.14 Squadron at Ohakea. Six T.55 trainers (NZ5701-NZ5706) arrived shortly after, followed by eight ex-RAF FB.5s (NZ5750-NZ5757) in 1953. The decision to withdraw the RNZAF P-51D Mustangs used by the Territorial Air Force and replace them with Vampires led to the arrival of the final batch of 21 ex-RAF FB.5s (NZ5758-NZ5778) and five T.11s by 1956. This idea was short-lived as the TAF was disbanded the following year and, combined with No.75 Squadron who were phasing out their Vampires and converting to the English Electric Canberra B (I) 12, large numbers of Vampires were placed in storage from 1959. During their time with the RNZAF, they served with a number of different squadrons and units before the last ones were finally replaced by aircraft such as the McDonnell Douglas A-4K Skyhawk and BAC167 Strikemaster Mk.88. By this stage, 21 Vampires had been written off due to accidents and others had been converted to instructional airframes. On their retirement, the remainder were sold to private owners or went the way of so many other surplus aircraft and were disposed of as scrap.

By the time production finally ended, 3,269 Vampires had been built at six aircraft factories in England and a further 1,067 built under licence abroad. For what was essentially a World War Two era design, the aircraft had surprisingly longevity with large numbers still in service in several air forces in the 1980s. The Swiss Air Force was the last Vampire user, retiring their sizeable fleet of FB.6s and T.55s from active service as late as 1990. It is now finding a new lease on life with growing numbers of privately owned Vampires appearing world wide including two on the New Zealand register. Approximately 18 other aircraft (or parts thereof) are also in the country at the time of writing, including nine still held by the RNZAF as museum pieces, on display or as gate guardians. The aircraft pictured here (ZK-RVM) is a former Swiss Air Force DH115 T.55. It was built in 1958 (c/n 985) and served with the Swiss Air Force as U-1225 until it's retirement in 1990. It went on the Swiss register as HB-RVM after being sold in 1991 before being imported into New Zealand in 1997. It now wears the colours of a No. 75 Squadron Vampire along with the (fictitious) RNZAF serial number NZ5712.

Text © 2002 Stuart Russell.

Specs.
Power plant:
One 14.9kN (3,350lb st) de Havilland Goblin D.Gn.3 turbojet
Wingspan:
11.58m (38ft)
Length:
9.37m (30ft 9in)
Max T-O weight:
5,620kg (12,390lb)
Max level speed:
869km/h (540mph)
Range:
1,963km (1,220miles)

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