We believe that we could produce a twin-engine bomber which would have a performance so outstanding that little defensive equipment would be needed.Geoffrey de Havilland - September 1939
The hugely versatile and high performance de Havilland DH.98 Mosquito was unquestionably the greatest contribution made by the de Havilland Aircraft Company to the success of the RAF in the Second World War.
Its innovative design made use of a wooden 'sandwich' construction, drawing upon the experience gained from the company's pre-war high-speed DH.88 Comet Racer, and the streamlined DH.91 Albatross airliner. Such was its popularity with pilots that it soon became affectionately known as ‘The Wooden Wonder’. Originally conceived as a high-flying, unarmed photo-reconnaissance aircraft, the Mosquito saw service in wide-ranging roles from bomber / fighter-bomber, night-fighter, anti-shipping strike, trainer, torpedo bomber and even as a target tug.
By 1938, the Air Ministry had started looking for a heavily-armed, multi-role aircraft, but at a meeting in October that year, the Ministry showed little interest in de Havilland’s Mosquito proposal and ordered the company to concentrate on building wings for other aircraft as a subcontractor
With the outbreak of war on 4th September 1939, British aircraft production became concentrated on fighters such as the Vickers Supermarine Spitfire and the Hawker Hurricane. New facilities were being created to meet the demand for these as well as heavy bombers like the Vickers Wellington and Armstrong-Whitworth Whitley.
As the conflict progressed however, raw materials were increasingly in short supply and the use of alternative non-strategic construction resources became more important. Additionally, greater significance was also placed on the requirement for new aircraft designs to have a multi-role capability. Both of these factors would have a favourable impact on the de Havilland Mosquito.
Despite their initial designs receiving a poor reception, de Havilland persevered and eventually the Air Ministry warmed to the concept of the Mosquito and a draft requirement was raised for a high-speed, light reconnaissance bomber capable of over 400 mph.
To maintain secrecy, the project team was based at Salisbury Hall, 6½ miles south of de Havilland’s main factory site of Hatfield. Without any government funding, the project was financed as a 'private venture', only finally receiving official backing with the eventual release on 1st March 1940 of Specification B.1/40, which called for 50 bomber/reconnaissance variants. This was supplemented in May 1940 by Specification F.21/40, calling for a fully-armed, long range fighter. As a result, de Havilland was authorised to build a fighter version of the Mosquito.
Construction of three prototypes began in March 1940, although work was cancelled soon after due to losses suffered at Dunkirk. Thankfully, the instruction issued by Lord Beaverbrook, Minister of Aircraft Production, was 'not very specific' and rather conveniently was largely ignored by Air Vice-Marshal Freeman (Vice-Chief of the Air Staff) who did not pass it on.
Despite this, development was very slow with the Design Team, led by Ron Bishop, experiencing severe shortages of basic materials to build prototypes.
The first prototype DH.98 Mosquito (W4050 - E0234) first flew at Hatfield on 25th November 1940, with Geoffrey R. de Havilland (Geoffrey Junior) at the controls, accompanied by John E. Walker, the chief engine installation designer. Painted in 'prototype yellow', take-off was reported as 'straightforward and easy' and the flight was relatively problem free, despite the undercarriage doors remaining slightly open.
Over the next test flights, various handling and performance issues were ironed out and during trials on 16th January 1941, the prototype outpaced a Vickers Supermarine Spitfire. The aircraft (W4050) has been preserved since 1959 at the de Havilland Aircraft Museum at Salisbury Hall, alongside the M25 motorway.
A second DH.98 Mosquito prototype (W4051) first flew as a photo-reconnaissance variant on 10th June 1941
The third prototype (W4052) was used for the development of the fighter variant with cannon and machine gun armament. It would also carry Airborne Interception (A.I.) equipment to enhance both its night and day fighter capabilities.
On entry into service, the ‘Mossie’ was an immediate success and became well-known for its bombing, pathfinder and precision, low-level strike capabilities. Wartime development resulted in a wide range of variants and a significant increase in bomb load capability and range after the incorporation of a larger bomb bay and auxiliary fuel tanks.
The major production was carried out in Britain by de Havilland Aircraft Company, Airspeed, the Standard Motor Company and Percival Aircraft Ltd with others being built overseas by de Havilland Canada and de Havilland Australia.
Numerous subcontractors were engaged in component manufacture, particularly wooden furniture companies as well as automotive coachbuilders.
The Mosquito saw glory on a number of operations, the most famous being Operation Jericho on 18th February 1944. Nine Mosquito FB.VI bombers, operating out of RAF Hunsdon in Hertfordshire, attacked the German-held prison at Amiens on the edge of the Somme Valley. Their skillful airmanship delivered low-level waves of bombs, first destroying the outer and inner prison walls, quickly followed by the guard house. A total of 255 allied prisoners escaped through the breaches in the buildings and walls although sadly 182 were soon recaptured.
Mosquitos flew their last wartime mission in the European theatre on 21st May 1945 when aircraft of 143, 235 and 248 Squadrons of RAF Costal Command joined the hunt for German submarines that may have been tempted to disobey the surrender order.
Ten Mosquitoes were also used by British national airline British Overseas Airways Corporation (B.O.A.C.) as high-speed, unarmed wartime transports for VIPs, operating flights to and from Sweden. Lastly, during their final days, a number of Mosquito TT.35 target towing Tugs flew with the RAF, some FB.VIs and T.IIIs being converted for this role by the Belgian Air Force.
The last operational flight by a Mosquito was in May 1963, when No.3 Civilian Anti-Aircraft Co-operation Unit retired its TT.35s.
A total of 7,781 DH.98 Mosquito aircraft were built, and, along with the RAF, the aircraft saw service in much of the main Allied air forces, including both the United States and Russia. Post-war, the aircraft was also operated by the air forces of France, Belgium, Turkey, Sweden, Dominica, South Africa, Yugoslavia, Australia, Canada, China, Czechoslovakia, Israel, New Zealand and Norway.