The de Havilland DH 112 Venom is a British post-war single-engined jet aircraft developed and manufactured by the de Havilland Aircraft Company. Much of its design was derived from the de Havilland Vampire, the firm's first jet-powered combat aircraft; it was initially referred to as the Vampire FB 8 prior to the adoption of the Venom name.Gunston 1981, p. 52.
The Venom was developed during the late 1940s to fulfil Air Ministry Specification F.15/49, under which the aircraft was intended to be operated as an interim solution, lying between the first generation of British jet fighters – straight-wing aircraft powered by centrifugal flow engines such as the Gloster Meteor and the Vampire – and later swept wing, axial flow-engined combat aircraft, such as the Hawker Hunter and de Havilland Sea Vixen. In comparison with the Vampire, it had a thinner wing and a more powerful de Havilland Ghost 103 turbojet engine, making the aircraft more suitable for high altitude flight. Both the Royal Air Force (RAF) and the Royal Navy took interest in the type; in order to suit the needs of the latter, a specialised derivative, the Sea Venom, was produced; it was a navalised model of the aircraft that was suitable for carrier operations. A dedicated model for aerial reconnaissance was also procured by the Swiss Air Force. On 2 September 1949, the first Venom prototype, VV612, performed its maiden flight.
The Venom entered service with the RAF in 1952, where it was operated as both a single-seat fighter-bomber and two-seat night fighter. Despite the type's relatively short service life with the RAF, British Venoms flew on operations on several occasions, including the Suez Crisis, the Malayan Emergency, and the Aden Emergency. It was withdrawn from front line operations by the service in 1962 following the introduction of more capable aircraft. The Venom had also proved to be popular on the export market, having been sold in substantial numbers to Iraq, New Zealand, Sweden, Switzerland and Venezuela. The Swiss Air Force was the final operator to use the type in an active military role, finally retiring their last examples during 1983. Large numbers of ex-military Venoms have since been acquired by private entities and several have continued to fly, performing displays at various air shows, while many examples have been preserved in static display conditions in museums and as gate guardians.
Development Origins
During 1948, the British aircraft manufacturer de Havilland proposed a development of the Vampire, furnished with a thinner wing and a more powerful engine, to serve as a high altitude fighter, designated as the 'Vampire FB 8' ("fighter bomber Mark 8"). The design gradually shifted, with company designation DH 112, in order to fulfill Air Ministry requirement OR.277, defined in Specification F.15/49, which sought a fast, manoeuvrable and capable fighter-bomber to replace the Royal Air Force's (RAF) existing Vampires in that capacity.Birtles 1999, p. 61. From the onset, the envisioned role had been intended as an interim fighter-bomber, while the development of aircraft capable of even greater performance had already been anticipated by the service.
Although generally similar in appearance to the preceding Vampire, sharing the distinctive twin-boom tail and composite wood/metal structure, the Venom was a completely new design.Thetford 1962, p. 186. As originally designed, it was powered by the de Havilland Ghost 103 turbojet engine, which was capable of generating 4,850lb of thrust, considerably more powerful than the earlier de Havilland Goblin that had been used on the Vampire. The Venom adopted a wing designed with a leading edge sweepback of 17.6 degrees, a minimised thickness/chord ratio reduced from 14 per cent to 10 per cent, while the trailing edge was straight; a pair of optionally-fitted wing tip tanks were also designed to be fitted without any negative impact on the aircraft's overall combat manoeuvring capability.
A single Vampire F 1 had flown with the new Ghost engine in 1947. On 2 September 1949, the first Venom prototype, VV612, performed its maiden flight at Hatfield, Hertfordshire, piloted by John Derry.Birtles Air Pictorial July 1971, p. 242.Birtles 1999, p. 63. In May 1950, following the end of company trials, the prototype was delivered to RAF Boscombe Down for official trials by the Aeroplane and Armament Experimental Establishment (A&AEE). In the course of these trials, the aircraft proved capable of satisfactory performance, including the besting of some contemporary fighters during mock combat, while some minor faults were also uncovered. On 23 May 1950, the second prototype, VV613, officially joined the development programme; it was delivered to the A&AEE for further trials on 3 April 1951.
The first six production Venom also participated in trials performed by both de Havilland and the A&AEE.Birtles 1999, p. 64. On 21 April 1952, the first delivery of a production-standard Venom, a single-seat fighter-bomber, was made to the Central Fighter Establishment, where it was used for a full service evaluation prior to the type being cleared for active service. During 1952, the initial production model entered operational service with the RAF as the 'Venom FB 1'.Birtles Air Pictorial July 1971, p. 243. A total of 375 of this initial model were constructed.
Further development
On 22 August 1950, an improved Venom, the NF.2 night fighter, performed its first flight, piloted by John Derry. de Havilland had developed it from the single seat ground attack-oriented Venom to serve as a replacement for the Vampire NF 10. For this variant, the fuselage was redesigned to accommodate a two-man crew, (pilot and navigator/radar operator), seated in a side-by-side configuration, and an aircraft interception radar installed in the extended nose.Birtles 1999, p. 72. During late 1953, the Venom NF.2 entered squadron service, after being delayed to resolve minor problems that had been discovered.Birtles Air Pictorial August 1971, pp. 281–282. Specifically, preliminary handling trials had revealed unsatisfactory performance in poor weather conditions.Birtles 1999, pp. 72–73.
The Venom NF.2 was modified after being involved in several accidents in which pilots had difficulty making night-time approaches. Changes included the adoption of jettisonable clear canopies and alterations to the flight control surfaces, and the altered aircraft were re-designated NF.2As.Birtles 1999, pp. 73, 75. The Venom NF.2 was soon followed by the NF 3, which was the ultimate night fighter variant of the Venom. It incorporated further improvements, including power-actuated ailerons and an improved air interception radar.Birtles 1999, p. 75. In 1953, the Venom NF 3 performed its first flight; it entered operational service with the RAF during June 1955.Birtles 1999, pp. 75–76.
The final Venom model developed for the RAF was the single-seat FB.4, which first flew on 29 December 1953.Birtles Air Pictorial July 1971, p. 244. It entered service in 1955 and 250 were built. The FB.4 was powered by a single 4,850 lbf (21.6 kN) thrust de Havilland Ghost 103 engine. It was the first Venom to be fitted with an ejector seat, as well as being furnished with redesigned tail surfaces and hydraulically powered ailerons.The British Fighter since 1912 p. 363.Aircraft of the Royal Air Force since 1918 pp. 235–236.Pilot's Notes Venom FB Mk 4: 2nd edition A.P.4335D pp. 9, 37. The new rudder design prevented excessive yaw and eliminated incidents of rudder locking at low speeds. The FB 4 variant was the first to be compatible with the underwing fuel tanks.
The majority of the type's production was conducted by de Havilland themselves. Following the completion of an initial batch of 15 production Venoms, manufacturing was transferred from de Havilland's Hatfield facility to their larger production plant at Hawarden Airport.Birtles 1999, p. 65. On 26 July 1952, the first Hawarden-built Venom was delivered to the RAF. In addition, the construction effort was augmented by numbers of Venom FB.1, FB.4 and NF.51 aircraft that were produced by Fairey Aviation at Manchester (Ringway) Airport.Scholefield 1998, p. 38.Birtles 1999, pp. 65, 68. At one point, the production of further Venoms at the Bristol Aeroplane Company's Filton facility was considered but was ultimately not pursued. During the early 1950s, the prospects for Italian aircraft manufacturer Fiat Aviazione producing the type under license were explored; these did not materialise however.
On account of substantial demand for the type from the Swiss Air Force, a licensed production arrangement was established with a consortium of Swiss aviation manufacturers in 1953, who did produce large numbers of Venoms.Birtles 1999, p. 71. In the early 1970s, Swiss Venoms were equipped with a new extended nose to add space for the addition of a ultra high frequency (UHF) radio, an Identification friend or foe (IFF) transponder and a SAAB BT-9K ballistic computer that was used in conjunction with ground attack ordnance.
Design The de Havilland Venom was a jet-propelled combat aircraft, featuring a distinctive twin-boom tail and composite wood/metal structure. Originally developed as a ground-attack fighter, it served as an interceptor as well.Birtles 1999, pp. 61, 65–66. It possessed a favourable rate of climb and other positive characteristics that lent itself well to combat operations, and represented a significant advance over the preceding Vampire.Birtles 1999, pp. 65–66. It was a sound ground attack aircraft, possessing good manoeuvrability, steadiness, endurance, handling, and a range of compatible stores. The Venom's manoeuvrability even gave it an edge against many dogfighters of the era, although its limited top speed proved to be a weakness in this role. Early issues, such as a rear spar weakness and flash fires due to the ingestion of vented fuel by the engine air intakes under some conditions, were quickly identified and overcome.Birtles 1999, p. 67.
The Venom FB 1 was armed with four nose-mounted 20 mm (.79 in) Hispano Mk V autocannon and could carry either two 1,000 lb (approx 450 kg) bombs1,000 lb was the nominal weight of these Medium Capacity bombs or eight RP-3 "60 lb" air-to-ground rocket projectiles – the heavier bombs being an improvement over the Vampire FB 5. For additional range, each of the wing tips could be fitted with a fuel tank, freeing up the underwing stores positions for other stores and munitions, these tanks could not be jettisoned during flight. When installed, the tip tanks also had the effect of improving the aircraft's roll rate, which was lower than many of its contemporaries. Early production Venoms commonly suffered from weaknesses within the wing structure, leading to flight limitations and warning markings being applied to distinguish them from typical aircraft.
The Venom FB 1 was powered by a single 4,850 lbf (21.6 kN) thrust de Havilland Ghost 48 Mk.1 turbojet engine; later marks were equipped with increasingly powerful models. The engine was ignited using explosive cartridges, known as Coffman engine starters; at the time, many operators were not previously familiar with such means of start up. Early production models lacked ejection seats, which was subject to official criticism and in response, they were fitted in later production models.Birtles 1999, pp. 64–65. The airframe itself had a relatively short life in UK service as it had been designed as a short term interim aircraft pending development of what would become the Hawker Hunter but in Swiss service, where the type was subject to a lengthy service life, several strengthening modifications were performed to more than double its viable lifespan.Birtles 1999, pp. 70–71. It was known for its simplicity in construction and relative cost-effectiveness, which contributed to its popularity to export customers.
Operational history