On 30 January 1943, the 10th anniversary of Hitler being made chancellor and the Nazis gaining power, a morning Mosquito attack knocked out the main Berlin broadcasting station while Hermann Göring was speaking, taking his speech off the air.

[11] Aviation firms entered heavy designs with new high-powered engines and multiple defensive turrets, leading to the production of the Avro Manchester and Handley Page Halifax.

[13] The ministry was also considering using non-strategic materials for aircraft production, which, in 1938, had led to specification B.9/38 and the Armstrong Whitworth Albemarle medium bomber, largely constructed from spruce and plywood attached to a steel-tube frame.

[14] Based on his experience with the Albatross, Geoffrey de Havilland believed that a bomber with a good aerodynamic design and smooth, minimal skin area, would exceed the P.13/36 specification.

[12] Still believing this could be improved, and after examining more concepts based on the Albatross and the new all-metal DH.95 Flamingo, de Havilland settled on designing a new aircraft that would be aerodynamically clean, wooden, and powered by the Merlin, which offered substantial future development.

[21] One design, completed on 6 September, was for an aircraft powered by a single 2,000 hp (1,500 kW) Napier Sabre, with a wingspan of 47 ft (14 m) and capable of carrying a 1,000 lb (450 kg) bomb load 1,500 mi (2,400 km).

[24] The Air Council added further requirements such as remotely controlled guns, a top speed of 275 mph (445 km/h) at 15,000 ft on two-thirds engine power, and a range of 3,000 mi (4,800 km) with a 4,000-lb bomb load.

Although estimates were presented for a slightly larger Griffon-powered aircraft, armed with a four-gun tail turret, Freeman got the requirement for defensive weapons dropped, and a draft requirement was raised calling for a high-speed, light-reconnaissance bomber capable of 400 mph (645 km/h) at 18,000 ft.[27] On 12 December, the Vice-Chief of the Air Staff, Director General of Research and Development, and the Air Officer Commanding-in-Chief (AOC-in-C) of RAF Bomber Command met to finalise the design and decide how to fit it into the RAF's aims.

Freeman supported it for RAF service, ordering a single prototype for an unarmed bomber to specification B.1/40/dh, which called for a light bomber/reconnaissance aircraft powered by two 1,280 hp (950 kW) Rolls-Royce RM3SM (an early designation for the Merlin 21) with ducted radiators, capable of carrying a 1,000 lb (450 kg) bomb load.

[29] Having the fighter variant kept the Mosquito project alive, as doubts remained within the government and Air Ministry regarding the usefulness of an unarmed bomber, even after the prototype had shown its capabilities.

[33] In June 1940, however, Lord Beaverbrook and the Air Staff ordered that production should concentrate on five existing types, namely the Supermarine Spitfire, Hawker Hurricane fighter, Vickers Wellington, Armstrong-Whitworth Whitley, and Bristol Blenheim bombers.

This was only after Beaverbrook was satisfied that Mosquito production would not hinder de Havilland's primary work of producing Tiger Moth and Airspeed Oxford trainers, repairing Hurricanes, and manufacturing Merlin engines under licence.

[3] On 19 February, official trials began at the Aeroplane and Armament Experimental Establishment (AAEE) based at Boscombe Down, although the de Havilland representative was surprised by a delay in starting the tests.

It was powered by 1,460 hp (1,090 kW) Merlin 21s, and had an altered canopy structure with a flat, bullet-proof windscreen; the solid nose had mounted four .303 British Browning machine guns and their ammunition boxes, accessible by a large, sideways hinged panel.

[58] W4052 was later tested with other modifications, including bomb racks, drop tanks, barrage balloon cable cutters in the leading edge of the wings, Hamilton airscrews and braking propellers, and drooping aileron systems that enabled steep approaches and a larger rudder tab.

[64][65] The ply-balsa-ply monocoque fuselage and one-piece wings with doped fabric covering would give excellent aerodynamic performance and low weight, combined with strength and stiffness.

Both principal spars were of ply box construction, using in general 0.25-in plywood webs with laminated spruce flanges, plus a number of additional reinforcements and special details.

An investigating team led by Major Hereward de Havilland travelled to India and produced a report in early December 1944 stating, "the accidents were not caused by the deterioration of the glue, but by shrinkage of the airframe during the wet monsoon season".

[nb 15] However, a later inquiry by Cabot & Myers firmly attributed the accidents to faulty manufacture and this was confirmed by a further investigation team by the Ministry of Aircraft Production at Defford, which found faults in six Mosquito marks (all built at de Havilland's Hatfield and Leavesden plants).

The Air Ministry forestalled any loss of confidence in the Mosquito by holding to Major de Havilland's initial investigation in India that the accidents were caused "largely by climate"[98] To solve the problem of seepage into the interior, a strip of plywood was set along the span of the wing to seal the entire length of the skin joint.

The main landing gear shock absorbers were de Havilland manufactured and used a system of rubber in compression, rather than hydraulic oleos, with twin pneumatic brakes for each wheel.

The de Havilland Mosquito operated in many roles, performing medium bomber, reconnaissance, tactical strike, anti-submarine warfare, shipping attacks and night fighter duties, until the end of the war.

VI wings flew close air support for the Allied armies in co-operation with other RAF units equipped with the North American B-25 Mitchell medium bomber.

105 and 139 Squadrons, on 30 January 1943, the 10th anniversary of the Nazis' seizure of power, a morning Mosquito attack knocked out the main Berlin broadcasting station while Luftwaffe Chief Reichsmarschall Hermann Göring was speaking, putting his speech off the air.

Particularly after the introduction of H2S (radar) in some Mosquitoes, these raids carrying larger bombs succeeded to the extent that they provided a significant additional form of attack to the large formations of "heavies.

[159] After the end of World War II Spartan Air Services used ten ex-RAF Mosquitoes, mostly B.35s plus one of only six PR.35s built, for high-altitude photographic survey work in Canada.

[179] Media related to De Havilland Mosquito NF at Wikimedia Commons At the end of 1940, the Air Staff's preferred turret-equipped night fighter design to Operational Requirement O.R.

[189] According to the Pilot's Notes and Air Ministry 'Special Flying Instruction TF/487', which posted limits on the Mosquito's maximum speeds, the NF Mk.38 had a VNE of 370 knots (425 mph), without under-wing stores, and within the altitude range of sea level to 10,000 ft (3,000 m).

Two ex-RAF FB.6s were converted to TT.6 standard at Manchester (Ringway) Airport by Fairey Aviation in 1953–1954, and delivered to the Belgian Air Force for use as towing aircraft from the Sylt firing ranges.

[220] When flight testing could no longer keep up, this was moved to the Central Aircraft Company airfield, London, Ontario, where the approved Mosquitoes left for commissioning and subsequent ferry transfer to Europe.