The Museum is now closed for the winter – reopening on 11th February 2018
Donations by Text – Text DHAM15 £10 to 70070


De Havilland History

The de Havilland Aircraft Company

Sir Geoffrey de Havilland, founder of the de Havilland World Enterprise, one of the first global manufacturing companies, was one of Britain’s aviation pioneers. Geoffrey and his colleague, Frank Hearle had designed and built their first aircraft, powered by an engine designed by Geoffrey, and neither of them had even seen an aircraft before. The first example crashed on the initial attempt at flight in December 1909, due to instability and lack of experience by the novice pilot. The engine was salvaged and the wreck taken back to the workshop in Fulham where a more successful aircraft was constructed and flown by Geoffrey on 10 September 1910 at the remote site of Seven Barrows near Newbury. With funds nearly depleted, Geoffrey was able to sell the aeroplane to the Royal Aircraft Factory at Farnborough for £400, at the same time gaining work for himself and Frank.

At the Royal Aircraft Factory Geoffrey was responsible for the design and test flying of his own aircraft, the most significant being the BE.2, which he flew to a height record of 10,560 feet with a passenger on 12 August 1912. With the outbreak of WWI, Geoffrey and Frank joined the Aircraft Manufacturing Company (Airco) at Hendon where the D.H series of designs was started with the DH.1, the most successful type being the DH.4 two seat day bomber, which was faster than many of the contemporary fighters. During WWI, Airco also produced fighters, trainers and the DH.10 twin engine bomber, all designed by Geoffrey de Havilland.

With the end of WWI, the expected boom in aviation was not realised, and Airco was sold to BSA, with Geoffrey forming the de Havilland Aircraft Company at Stag Lane Aerodrome in Edgware on 15 September 1920, employing around 60 personnel from Airco. Business was maintained by overhaul and spares support of surplus DH.4s and DH.9s and the operation of the Aeroplane Hire Service. It was the development of the DH.60 Moth, first flown by Geoffrey on 22 February 1925, which commenced the highly successful series of light touring and training aircraft throughout the 1930s, including the DH.82 Tiger Moth, which became the standard RAF elementary trainer during WWII. The Moth types lead to what became known as the de Havilland World Enterprise, one of the first global manufacturing organisations, with factories set up in Canada and Australia, as well as assembly in India, New Zealand, South Africa and the USA, and representation for sales and support world-wide. De Havilland Canada was formed in March 1928, followed by the Australian company, both of which contributed to Mosquito production during WWII.

With the congestion at Stag Lane Aerodrome, due to production and development test flying, private Moth owners and training, a move was made to a new site at Hatfield on farm land, where flying training started in June 1930. Stag Lane Aerodrome closed to flying in 1934 to allow development of the site for building, raising funds for the construction of a new factory on the Hatfield Aerodrome site. In 1934 another significant aircraft was designed for the MacRobertson Air Race from London (Mildenhall) to Melbourne, three DH.88 Comet Racers being entered for the event. Apart from one Comet winning the race, the significance was the semi-monocoque stressed wooden construction with exceptional aerodynamic cleanliness, which was later developed for the Mosquito. This was the first de Havilland aircraft with a retractable undercarriage, and the specially developed Gipsy racing engines drove de Havilland developed variable pitch propellers.

From the Moth series of light aircraft, the logical development was a series of small local service airliners, starting with the DH.84 Dragon, a biplane with an enclosed cabin, capable of carrying up to eight passengers and powered by two Gipsy Major engines, similar to used to power the Tiger Moth. From this was developed the improved and more powerful Dragon Rapide and four engine DH.86. These airliners used the traditional wooden structure with fabric covering, but the DH.90 Dragonfly used the stressed skin semi-monocoque structure in a biplane layout with low drag and a very smooth finish. This was followed by the much larger four engine DH.91 Albatross airliner, the fuselage of which was stressed skin wooden monocoque structure consisting of inner and outer layers of preformed birch ply, with a balsa wood stabilising sandwich in between. This form of construction is similar to the modern composite structures, although de Havilland used natural material. The Albatross featured a one piece wing, the fuselage being lowered on to it in assembly, giving a low drag smooth finish, the entire surface of this very graceful airliner being covered with a light fabric doped on to resist damp, and finally painted.

For the DH.95 Flamingo, a twin engine high wing airliner, de Havilland introduced metal overall construction for the first time, giving greater structural resilience to climatic effects, but production of both the Flamingo and Albatross were cut short prematurely by the outbreak of WWII. De Havilland ceased production and development of civil aircraft, but Hatfield was kept busy with Tiger Moth production, which had been adopted by the RAF as the standard basic trainer. Many battle damaged Hurricanes were brought to Hatfield for repair and return to service and 150 Oxford twin engine trainers were produced on behalf of Airspeed during 1939, but the de Havilland Board were keen to make a more positive contribution to the war effort.

The design office needed a project to keep the factory busy, the main thoughts being around a high speed unarmed bomber.   The design team moved to the isolated Salisbury Hall near London Colney on 5 October 1939, and began work on the concept of a four engine metal structure armed bomber as a starting point. The team led by Ronald Bishop reasoned that the defensive armament was only effective against hostile fighters, but not ground fire, and the weight and drag of the guns, turrets, armour plating and extra crew could be saved. This resulted in a smaller twin Rolls-Royce Merlin powered aircraft, with two crew and fast enough to outrun the hostile fighters. Wooden construction would use non-strategic materials and labour, providing lower drag and more efficient smooth finish. The airframe would be more resilient to damage and easier to repair.

With the help and enthusiasm of Sir Wilfred Freeman, Director of Research an initial contract was received for 50 unarmed bombers on 1 March 1940, design having commenced in October 1939. Even with this contract, the government was concentrating all capacity on existing aircraft, even though many were already obsolete and ineffective. As a result de Havilland was unable to obtain much needed materials. By arguing that the project was occupying very little manpower, and demands for special materials were very small, the project was reinstated in July, providing it did not interfere with the work in hand.

Preparations were made for production at Hatfield despite delays caused by bombing in the area when time was lost by employees going in shelters when an air warning sounded. Bombs fell within a mile of the Hatfield factory one day in every five, but there was only one direct hit on 3 October 1940 when a low flying Ju.88 dropped four bombs on the old 94 Shop, killing 21 people and injuring a further 70. An anti-aircraft gun on the administration building roof damaged the aircraft sufficiently for it to crash land at Hertingfordbury, the crew being taken prisoner. Amongst the wreckage was eighty percent of Mosquito work in progress, and as a result all Mosquito work was widely dispersed to avoid further disruption due to enemy attack. Amongst the sub contractors were major members of the furniture and coach building industry who would not otherwise have been able to contribute to the war effort. Production lines were set up at Hatfield mainly for bomber assembly and a new factory at Leavesden for fighter versions.

The yellow prototype Mosquito was completed at Salisbury Hall in a barn like hangar on the other side of the moat, and moved to Hatfield on 3 November 1940 where it was reassembled in a remote hangar, emerging on 19 November for engine runs, ready for Geoffrey de Havilland Jnr, the chief test pilot, with John Walker, the engine installation designer to make the maiden flight on 25 November 1940, only eleven months from the start of detailed design. The prototype soon proved itself during flight testing and on 20 April 1941 was demonstrated to Lord Beaverbrook – Minister of Aircraft Production, and General Arnold, Head of the U S Army Air Force, resulting in additional production lines being set up in Canada and later Australia.

Meanwhile at Salisbury Hall the fighter prototype was complete and ready to fly. To save a month of dismantling the aircraft, transporting it to Hatfield and reassembly, it was decided to fly it out of an adjacent field at Salisbury Hall on 15 May 1941 by Geoffrey de Havilland Jnr, followed later by two more Mosquitos built at Salisbury Hall.

The first deliveries were made to the RAF in July 1941and as the demand grew for this outstanding combat aircraft, a whole range of variants were produced in addition to unarmed bombers, including night fighters, intruders, ship-busting, ground attack, unarmed photo reconnaissance, courier for urgent freight and eventually naval strike and target towing. Bomber development included the carriage of a 4,000 lb bomb in a bulged bomb-bay, which was equivalent to the load carried by the USAAF B-17 Flying Fortress. A total of 4,444 Mosquitos were built at Hatfield and Leavesden up to 15 August 1945, with other British production at Standard Motors at Coventry, Percival at Luton and Airspeed at Christchurch building over 1,000 more.

Although the Hatfield design department was busy on progressive development of the Mosquito, mainly with the installation of more powerful Merlins, the major developments were the DH.103 Hornet twin Merlin long range fighter for service in Asia and the Vampire, the first de Havilland jet fighter. The Hornet made its first flight on 28 July 1944, and construction was based on the Mosquito, but the wings were a composite of wooden structure with ply skins on the top surface and aluminium for the lower skin. The aircraft entered service with both the RAF and FAA as a day fighter and all weather fighter.

Development of the Vampire was continuing in parallel with the de Havilland Goblin jet engine developed by Major Frank Halford and his team, the aircraft being flown for the first time by Geoffrey de Havilland Jnr on 20 September 1943, 16 months after the go-ahead, achieving 500 mph in 1944, although by the time production was established, the war was over. The Vampire featured a twin fuselage boom layout with the tail across the rear, to allow a more efficient short jet pipe, maintaining as much thrust as possible.

As early as 1943 preparations were being made towards the requirements for commercial aviation after the end of the war. The Brabazon Committee was formed under the chairmanship of Lord Brabazon to define the best range of civil aircraft to be developed, in particular avoiding direct competition with the already advanced American airliner developments. Amongst the proposed projects was the Type 5B specification for a light transport capable of carrying up to eight passengers. This fitted neatly into the class of local service airliners produced by the company in the 1930s, resulting in work starting on what was to become the Dove in late 1944. The Dove was an all metal low wing design powered by two Gipsy Queen piston engines, suitable as a feederliner, air ambulance, air taxi, executive transport, survey and aircrew trainer. This was the first all metal aircraft to use Redux bonding to join metal, saving weight, and the hand built prototype was first flown on 25 September 1945, the 25th anniversary of the formation of the de Havilland Aircraft Company. Initial production of the Dove, Vampires and Canadian designed Chipmunks was at Hatfield, but all were moved to the major factory at Broughton, near Chester, where Vickers Armstrong had produced Wellington bombers in WW2. A scaled up version of the Dove was the 14 seat, four engine Heron with a range of up to 1,500 miles, the prototype making its first flight on 10 May 1950. A total of 544 Doves and 149 Herons were built at Hatfield and Broughton.

The de Havilland Aircraft of Canada Chipmunk was the first original design from then Canadian company and was an all metal two seat basic trainer to replace the biplane Tiger Moth.. 217 were built in Canada, with a first flight on 22 May 1946 and a further 1,000 were built at Hatfield and Broughton for the RAF and overseas air forces.

The Vampire was progressively developed, not only for the RAF, but for export widely, over 1,500 being built mainly be English Electric at Preston and de Havilland at Broughton. As well as British production, Vampires were built under license in Switzerland, Italy, India, France and Australia.   A Vampire was the first jet aircraft to land on an aircraft carrier, when Lt Cdr Eric ‘Winkle’ Brown landed and took off from HMS Ocean on 3 December 1945.

Hatfield’s major development of the Vampire, was the two-seat Night Fighter, which first flew on 28 August 1949, and like all Vampires and the later Venoms, had a wooden fuselage pod with similar construction to the Mosquito, with the remainder of the structure aluminium. The Vampire Night Fighter was produced as an inexpensive aircraft for export and was initially ordered by Egypt. Unfortunately, the British Government imposed an arms embargo on Egypt at about this time, and the majority of the production served with the RAF as an interim night fighter, replacing Mosquitos. The other development was the two-seat side-by-side advanced jet trainer, with design and production at the old Airspeed factory at Christchurch. The Government ordered 610 for service with the RAF and FAA, with a further 412 exported.

The major development of the Vampire was the Venom family, which had a similar overall layout and construction, but was fitted with the more powerful DH Ghost engine developing 5,300lb thrust. It had a thinner wing with swept back leading edges and removal wing tip fuel tanks. The Venom flew from Hatfield for the first time in its single seat ground attack configuration on 2 September 1949, and the development followed similar lines to the Vampire, with a two-seat AI radar equipped Night Fighter which first flew on 22 August 1950 and a two-seat all weather naval fighter for the Fleet Air Arm, featuring folding wings and an arrester hook.

One of the major challenges of the early jet age was the penetration of the Sound Barrier, or exceeding Mach 1, the speed of sound. The de Havilland challenge to this phenomena was the DH.108, with three experimental prototypes built of this swept wing tailless aircraft using the wooden Vampire fuselage nacelle as a basis. The purpose was to test the layout for a proposed jet airliner, and Geoffrey de Havilland Jnr made the first flight of the low speed prototype from the long runway at RAF Woodbridge on15 May 1946. The high speed second prototype had the potential of breaking the existing absolute world speed record of 616 mph achieved in a Gloster Meteor. During practice flights, Geoffrey reached 637 mph at 9,000 feet, but during a low level practice on 26 September 1946, tragedy struck and the aircraft broke up over the Thames Estuary, killing the elder son of the founder. The third prototype was also designed for high speed, and on the power of 3,750lb thrust Goblin engine, became the first aircraft outside America to exceed the speed of sound in a dive on 6 September 1948 flown by John Derry.

With the loss of Geoffrey de Havilland, John Cunningham, the WW2 night fighter ace was appointed as chief test pilot, and made the first flight of the DH.110 prototype on 26 September 1951, this experimental aircraft later being developed into the Sea Vixen, all weather naval fighter. Sea Vixen development and initial production was at the old Airspeed site at Christchurch and was a complete redesign from the original DH.110 and powered by a pair of Rolls-Royce Avon 208 jet engines. The long delayed production order was placed in January 1955 for an initial batch of 78 Sea Vixens, including 21 pre-production aircraft to be used for the development programme of what was in effect a weapons system. The airframe was about 80 percent redesigned from the DH.110, and it featured hydraulically folding wings, a new offset to port cockpit canopy, arrester hook and the latest A.I radar under a pointed nose radome. The Sea Vixen was the first British jet fighter not armed with guns, the armament being Firestreak guided missiles. In addition 28 2in rocket projectiles were carried in a retractable ventral pack, with more carried under the wings.

The first production Sea Vixen made its maiden flight on 20 March 1957 from Hurn Airport, which had a longer runway than at Christchurch, the aircraft being towed on the road to the flight test centre and was later used for the initial deck trials on HMS Ark Royal. Following intensive service trials with 700Y Squadron at Yeovilton, the unit was commissioned as 892 NAS on 2 July 1959 as the first FAA squadron. Two aircraft were taken off the Christchurch production and converted into the FAW.2 configuration at Hatfield, and production was transferred from Christchurch to Broughton after 118 had been produced. One FAW.1 was built there, before converting to FAW.2 standard when a further 29 were produced, the last one flying on 3 February 1966. Many of the serving FAW.1s were also converted to the FAW.2 standard both a Broughton and Sydenham. The departure of the Sea Vixen from FAA service commenced with the disbandment of 892 NAS in October 1968 with the final 899 NAS disbanding on 23 January 1972.

In addition to aircraft, the de Havilland World Enterprise produced aero engines, propellers, guided missiles and space rockets. From the 1930s de Havilland had diversified within the aerospace industry, initially producing piston engines, and then developed variable pitch propellers for its own designs. This diversification allowed many other aircraft manufacturers who had a need for these engines and propellers, creating a worldwide market for aerospace equipment and systems. Also by being in control of their own engine production, difficulties were avoided with the supply of other manufacturers engines, and their continued support.

In the early weeks of 1941, the decision was made to begin jet propulsion development with Government financial support. The first drawings of what was to become the Goblin were issued to the workshops in August 1941 and 248 days later, on 13 April 1942, the prototype of this revolutionary form of power was started up in great secrecy in the special test chamber within the Halford Laboratory at Hatfield. Within two months the engine was running at full power and by 25 September, when nearly 200 hours of bench testing had been completed, type approval was granted for 25 hours flight.

While piston engine development and production continued, the Goblin was the power plant for the Vampires and a more powerful development was the Ghost which in its military form powered the Venoms, and as the world’s first commercial jet engine was the power plant for the Comet airliner, with civil approval achieved on 28 June 1948. The de Havilland Engine Company led by Major Frank Halford went on to develop the more efficient Gyron turbo jet, which did not enter production, but from it was developed the Gyron Junior two of which powered the Blackburn Buccaneer S.1 low level naval strike aircraft. In parallel with jet engine development, the Engine Company also designed rocket engines, initially the Sprite as a booster for heavily loaded bombers, which ran at Hatfield for the first time in November 1949. The Spectre variable power rocket was designed for mixed power plant fighters as a defence against high flying hostile nuclear bombers, giving the fighter an instant rapid climb to combat altitude, leaving the Gyron engine to continue with the cruise. With the detection of high flying bombers by radar, they came down to low level to stay below radar coverage, and the mixed power plant concept was abandoned.

With the start of research into early missile systems towards the end of the war, de Havilland began to look at the possibilities of future air launched missiles. In 1951 the work commenced with government contracts for turbo alternators and development of an infra-red heat seeking missile seeker system. The following year the Propeller Company received a contract to develop the infra-red heat seeking Firestreak, Britain’s first air-to-air missile, which was used to arm the early marks of Lightning and Sea Vixen FAW.1s. The Firestreak was followed into service by the all-aspect higher performance Red Top, used to arm the later Lightning F.6s and Sea Vixen FAW.2s.

In the mid 1950s de Havilland commenced development of an intercontinental ballistic missile to give Britain an independent nuclear deterrent. Known initially as ‘Project 3000’ the stainless steel spot welded structure was fabricated in a secure building, known as the 3000 store. On completion, each structure was pressurised to retain its strength, and lifted into the vertical position for functions and tests in an adjacent tower. In the late 1950s a special test tower was erected on the Manor Road site where ground launch systems separation was developed, the local residents believing the rocket was being fired up, when it was only surplus fuel being burnt creating a glow in the sky. The development of the intercontinental missile were cancelled by the Government in 1960, but Blue Streak, as it had been named, formed the basis of the first stage for a satellite launcher, the total system being called Europa, with the upper two stages supplied by France and Germany. Blue Streak made successful launches from Woomera in Australia and later Kourou in French Guiana, but the programme suffered a number of setbacks with failures of the upper stages, and was cancelled in 1972. The experience gained continues in the Ariane European Space programme, which is supported by Airbus Space and Defence in Stevenage, where the payloads are produced.

The de Havilland factory at Hatfield had a rich heritage of jet airliner pioneer development, commencing with the Comet. The Comet was conceived to meet the Brabazon Type IV Specification for a high speed transatlantic mail plane. The Ministry of Supply placed an order for two all metal prototypes with four engines in a modestly swept back low wing in March 1945, which by then had become a 36 premium level comfort passengers over the Commonwealth routes. There were many challenges to be overcome, including pressurisation and air conditioning the cabin at over 30,000ft, coping with navigation at much higher speeds and having docile flying characteristics for approach and landing. The Comet was as much a technical challenge as the supersonic Concorde two decades later, but at much less cost. During the design and development, considerable research was done on structures, insulation and the new jet engines, the two prototypes being hand built in the Hatfield Experimental department. John Cunningham took the Comet on its maiden flight on 27 July 1949, and following a comprehensive flight development programme, the first of eight Comet 1s for BOAC made its inaugural jet passenger service from Heathrow to Johannesburg on 2 May 1952.

This gave Britain a lead of four to five years in the commercial jet airliner market, export orders soon received from Canada and France. The Comet 1 was very much an interim solution to gain operational experience, until the more powerful and efficient Rolls-Royce Avon was available for the improved Comet 2. BOAC and a number of overseas airliners placed orders for Comet 2s, followed by the stretched Comet 3 with greater range and capacity. There were two accidents where Comet 1s stalled on the ground on take-off, and one broke up after take-off from Calcutta in a violent storm, leading to the development of weather radar. Then came the major blow to the Comet programme when two disintegrated over the Mediterranean after take-off from Rome, the first one falling off Elba on 10 January 1954, and after precautionary modifications G-ALYY feel off Stromboli on 8 April. As a result of a detailed inquiry, with much of the wreckage recovered from the sea bed, it was found that the Comets suffered from metal fatigue in the cabin, particularly caused by overstressing in the corners of the square windows.

With the knowledge gained, the Comet 3 was developed into the Comet 4 with 19 being ordered by BOAC, the first of which was flown by John Cunningham from Hatfield on 27 April 1958. Comet 4s were sold world-wide, and served with the RAF, later being developed into the Nimrod maritime patrol aircraft.

In 1956 de Havilland formed a consortium with Hunting and Fairey to produce the DH.121, later to be known as the Trident, the first second generation airliner. The Trident was ordered by BEA, but it was delayed when the airline requested a reduction in size due to a modest passenger reduction forecast. Government policy at the time was that there should be mergers of the diverse manufacturers and at the end of 1959, de Havilland became part of Hawker Siddeley Aviation. Trident design and development continued with John Cunningham making the maiden flight on 9 January 1962, this advanced airliner being the fastest in service with a cruising speed of 600 mph and triplicated systems for improved safety and allowing it to become the first airliner to be capable of fully automatic landings in all weathers. Trident Series 1s were also sold to Middle East airlines and significant numbers of the developed Trident 2s and 3s to CAAC of China, the last being delivered on 13 September 1978.

Following the Trident was a mini jet airliner designated the DH.125 business jet, with the main production linen at Broughton. The DH.125 was first flown by Chris Capper on 13 August 1962, and probably some 1,000 have been built, both in the UK and USA, although it is no longer in production.

The final airliner from Hatfield was under the control of British Aerospace, which was formed when the British aerospace industry was nationalised by the Government in March 1977, allowing the BAe.146 to go ahead in July 1978. The BAe.146 was a high wing feeder jet powered by four ALF 502 jet engines which was first flown from Hatfield by Mike Goodfellow on 3 September 1981. The BAe.146 was built in three versions, the 70-seat -100, the 85-seat 146-200 and the stretched 146-300 which could carry 100 passengers. Assembly lines for the BAe.146 were set up at Hatfield and later Woodford, to where all assembly was transferred on 12 February 1992. As a result, it was announced on 23 September 1992 that all design and production at Hatfield would cease at the end of 1993, with the airfield and site closed in the spring of 1994, and developers taking over.

The de Havilland World Enterprise included the de Havilland Engine Company and de Havilland Propeller Company. The Engine Company, led by Major Frank Halford, a gifted engineer who led the design of the Gipsy series of engines, pioneered jet turbine development and produced rocket engines. The Propeller Company developed variable pitch propellers, many of which were fitted to Hurricanes and Spitfires, and other combat aircraft in WWII, as well as post war development of air-to-air guided missiles. The de Havilland companies therefore produced aircraft from basic trainers to jet airliners and supersonic fighters: piston, jet and rocket engines; propellers, missiles and space rockets. This was an achievement unequalled by any other aerospace manufacturer world-wide.

Philip Birtles, President of the de Havilland Aircraft Museum – January 2016