de Havilland DH98 Mosquito Prototype

image001The de Havilland Aircraft Museum has received £41,000 from the Heritage Lottery Fund (HLF) to complete the restoration of the de Havilland Mosquito Prototype fighter-bomber.

Aircraft Overview:

The fast, high-flying Mosquito was for much of the War able to roam almost at will over enemy-occupied territory. Built of non-strategic materials (i.e. wood), it was designed for speed and range as a two-seat unarmed light bomber, unarmed reconnaissance aircraft and long range fighter. Its performance derived from a combination of;

  • careful packaging,
  • an aerodynamically clean shape,
  • a high wing loading,
  • and high power from two supercharged liquid-cooled V-12 Merlin engines.

For minimum frontal area, the engines are forward-mounted in closely tailored nacelles, and the intakes and ducts for the cabin heater, coolant radiators and oil coolers are built into the inboard wing leading edges. The fuselage is largely of balsa/plywood sandwich formed on moulds in left and right halves. The wing pair, of wood spars and stringers with plywood webs and skinning, is built as a single unit, mounted above the bomb bay. The Mosquito was built in 43 marks for a variety of roles, with a total production of 7,781 aircraft.

Aircraft Specifications:

Power Unit: Two 1,460 hp Rolls Royce Merlin 21

Wing Span: 54 ft 2 in (16.5 m)

All-up Weight (A.U.W): 19,670 lb (8,922 kg)

Max Speed: 382 mph (615 kph)

Ceiling: 35,000 ft (10,670 m)

Range: 2,180 miles (3,500 km)

On Display at the Museum:

This aircraft is the only surviving World War II prototype to be preserved in the World.

Designed and built at Salisbury Hall, the initial DH.98 design was presented to the Air Ministry in September 1938.Development was hampered by continued Air Ministry interference who tried to impose defensive armament-two rearward firing machine guns and provision for torpedoes to be carried for a maritime strike role. However de Havilland disregarded these potential changes believing that their design for a fighter and fighter-bomber roles were the best configuration for the Mosquito.

The company suffered repeated rejections from the Air Ministry, Air Marshall Freeman was not convinced that the type would outperform a Spitfire or German fighters that would be deployed in the forthcoming war.

Finally ,in November 1938 an order to develop a Mosquito Prototype was granted but de Havilland were instructed that priority was to be given to the production of Tiger Moth Trainers, Rapide light Transports (called Dominies by the RAF) and essential variable speed Airscrews for several other aircraft manufacturers.

The Air Ministry persisted with their demands for defensive armament suggesting that the more powerful Griffon engine might permit the installation of a four gun turret without compromising top speed, but as neither Griffons nor turrets were available only mock ups were built.

Finally on 12th December 1939 a prototype was ordered, but only for a photo –reconnaissance aircraft as the then Bomber Command chief, Sir Edgar Ludlow-Hewitt did not favour an unarmed bomber.

The prototype was to have a maximum speed of 397mph at 23,700 feet and cruise at 327mph at 26.600 feet. Range was to be 1,480 miles at 24,900 feet and a maximum ceiling of 32,100 feet.

The Dunkirk emergency held up detail design and construction as all Merlin Engines was need for fighters, and none could be spared for the prototype. Eventually Lord Beaverbrook intervened and made Merlin’s available for the prototype.

The de Havilland team at Salisbury worked through the Battle of Britain but E-0234, the bomber/reconnaissance prototype fitted with Merlin 21’s was moved by road to de Havilland’s factory on 3rd November 1940.

It was painted overall yellow and rolled out on November 19, 1940, just 10 months and 26 days after its inception.

The Mosquito prototype’s first flight was on 25th November 1940 piloted by Geoffrey de Havilland, Jr, accompanied by John Walker, designer of the engine installation.

Following a demonstration to Lord Beaverbrook and other senior Government Ministers at Langley on 29th December an order for 150 aircraft was given to de Havilland.

Renumbered W4050,the prototype reached an altitude of 22,000ft on 17th January 1941 and was delivered to Boscombe down on 19th February with camouflaged upper surfaces and yellow under surfaces for initial service trials.

On the 24th February while taxying on the rough surface of the airfield the tailwheel jammed and the fuselage fractured around the starboard access hatch. The damage was serious enough for the fuselage to be changed and the fuselage of the following prototype W4051 was used.

DH98 Mosquito Prototype at The de Havilland Museum, London Colney, UK. #DH98 #Mosquito #prototype #ww2 #history #restoration #theta360 – Spherical Image – RICOH THETA