De Havilland Mosquito |
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Great Britain |
By late 1942 the Mosquito was becoming operational in ever increasing numbers, and its unique qualities of very high speed and long range were clearly ideal for many missions. |
It is one of the paradoxes of aircraft development that some of the world's
greatest aeroplanes have achieved their fame doing jobs other than the one for
which they were originally designed. No better example of this could be found
than the Mosquito, which, conceived as a bomber, became one of the war's most
potent fighters. More than this, indeed, it was probably the most successfully
versatile of any twin-engined type built between 1939 and 1945. It excelled in
all the widely varied roles. Its duties included the duties of low-level and
high-attack day and night bomber, long-range photo-reconnaissance, mine layer,
pathfinder, high-speed military transport, long-range day and night fighter, and
fighter-bomber. It served in Europe, the Middle and Far east and on the Russian
front. In fact the ubiquitous Mosquito reigned supreme among General Purpose
types; and of the grand total of 7,781 Mosquitos built, 6,710 were delivered
during the war years.
On March 1, 1940, the first contract was placed, for fifty D.H.98 bombers
(including prototypes) to be built to specification B.1/40 which had been
written around De Havilland's proposals, and the name Mosquito was approved. The
period was an inauspicious one for the Initiation of so radical a design; with
the war going against Britain the tendency was to concentrate on existing
designs. With the fall of France and the Dunkirk evacuation the Mosquito was
actually dropped from Ministry of Aircraft Production programs at one stage,
setting back the ordering of materials. But permission to proceed was later
given again, although De Havillands were told that their Tiger Moth and Oxford
production were to take priority. Had it not been that the Mosquito used
"non-strategic" molded
plywood for its construction, it might well never have been reinstated.
Construction of the prototype was pressed ahead through the difficult months of
1940, while the "Battle of Britain" was fought out overhead; bombs
fell within a mile of the Hatfield factory on one day in every five, and nearly
25 per cent of the working hours, day and night, were spent in air-raid
shelters. Despite all these vicissitudes, the prototype (W4050) made its first
flight on November 25, 1940, only ten months and twenty-six days after detailed
design work had commenced. The pilot was Geoffrey De Havilland, Jnr. Meanwhile,
inevitably, requirements had been changing. There was some loss of confidence in
the high-speed bomber, while the heavily armed long range fighter grew in favor.
The contract was, therefore, changed to twenty bombers and thirty fighters,
necessitating the modification of a number of parts already manufactured.
Construction of a fighter prototype proceeded at Salisbury Hall, London Colney,
which served as a dispersal for the Hatfield design office and experimental
shop. Two days before this prototype (W4052) was ready to fly, a German agent
was dropped by parachute close to Salisbury Hall, in plain clothes and with a
portable radio. He was captured next day, and the day after, May 15, 1941,
Geoffrey De Havilland flew the fighter prototype from a 450-yard field beside
the shed in which it had been built.
The prototype made its first flight on November 25,1940. This was only ten months and twenty-six days after detailed design work had commenced. |
The first Mosquito sortie was made on September 20,1941, when a single
aircraft made a reconnaissance flight over France. At home, the Mosquito night
fighter, carrying A.I Mk IV airborne radar, began to take over from the Bristol
Blenheim. By late 1942 the Mosquito was becoming operational in ever increasing
numbers, and its unique qualities of very high speed and long range were clearly
ideal for a particular mission then being planned.
It had been decided that an attack should be made on the German Gestapo
headquarters in Oslo, Norway, which contained records of members of underground
resistance organizations. Such a mission would, if successful, help protect
those who were supplying Britain with secret information. Therefore, on
September 25,1942, Mosquitos carried out a long range attack on the HQ,
accurately bombing the building and then returning home at high speed.
The basic fighter Mosquito introduced into squadron service in 1942 was the
N.F.Mk.II, equipped primarily as a night-fighter and used for home defense
alongside the Bristol Beaufighter. Its armament comprised four 20 mm cannon in
the front fuselage belly and four 0.303 in. Browning machine-guns in the extreme
nose. It carried AI Mk.IV or A.I.Mk.V "arrowhead" radar and a G-45
machine gun. Its matt-black overall finish, incidentally, reduced its maximum
speed by 16 mph. Power was provided either by two Merlin 21 engines giving 1,280
hp for takeoff and 1,480 hp at 12,250 feet, or two Merlin 23 engines giving
1,390 hp for takeoff and the same maximum power at 12,250 feet.
On the night of May 28-29,1942, Mosquito N.F.IIs scored their first
"probable," and in the following three years Mosquito night-fighters
racked up a score of approximately 600 enemy aircraft over the British Isles,
and also destroyed 600 flying bombs in a two month period. They later operated
in the bomber support role, their task being to defend the main heavy bomber
streams over enemy territory. Of the 466 Mark II Mosquito fighters produced,
some of the later aircraft had day-fighter finish and, with the AI radar
removed, operated over Malta, Italy, Sicily and North Africa from the end of
1942 onwards.
Operational experience with the Mosquito II in its day-fighter and intruder
roles led to the development of the F.B.VI, a potent fighter-bomber which came
into service during the early months of 1943. It had been discovered that the
Mosquito was able to accommodate a much greater warload than that for which it
had been designed, and thus the Mark VI, with a strengthened wing for external
loads which later became known as the "basic" wing, carried a full
complement of cannon and machine-guns, two 500-lb. bombs in the rear half of the
bomb bay (the front half containing the cannon breeches) and two 500 lb bombs
under the wings. Actually, the full 2,000 lb bomb load was only carried by the
Mark VI Series 2 which took advantage of the 1,620 hp available from the Merlin
25 for takeoff, the first 300 machines being F.B.VI Series 1 Mosquitos with
Merlin 21s or 23s and carrying two 250 lb bombs internally.
The prototype night fighter with a circular segmented air brake installation. |
Later, in mid-1943, the Mosquito FB Mk VI was becoming operational. As well
as the usual RAF duties, it was used by Coastal Command as an anti-shipping
aircraft, armed with eight 60 lb rocket projectiles. More unusual weapons
carried by some Mosquitos included a 57 mm cannon for ground attack (this
devastating gun was capable of destroying any armored vehicle), and the 4,000 lb
'block-buster' bomb. Even with this bomb on board, the Mosquito could out fly
most German night fighters, and on numerous occasions it attacked far-off Berlin
and German V1 flying-bomb sites.
An entirely separate line of development from the Mosquito N.F.II produced a
series of night-fighting variants which were primarily used for home-defense
purposes. The first of these was the N.F.XII, plans to produce the N.F.VI with
Merlin 21s and the "basic" wing, and the N.F.X with Merlin 61s and the
"basic" wing, having been abandoned. The Mosquito N.F.XII became the
first British aircraft to carry centimetric AI radar. This form of radar
introduced the spinning-dish scanner with greatly improved performance compared
with the earlier "arrow-head" type, but it resulted in some singularly
unattractive nose contours on the aircraft in which it was carried. The
centimetric radar supplanted the four machine guns in the fuselage nose,
reducing the armament to four 20 mm Hispano cannon. To expedite its service
debut, the Mosquito XII was based directly on the Mark II and ninety-seven
machines were converted by the installation of the new radar.
Of the Mosquitos built in Canada, the F.B.26 was one of the chief variants, the
design of which was based upon that of the F.B.VI. With the same armament as its
British counterpart, it had Packard Merlin 225 engines and weighed 21,473 lb.
The sole F.B.24 was similar but had Packard Merlin 69s, while the F.B.21, of
which only three were built, had Packard Merlin 31 or 33 engines. Australian
production was also based initially on the fighter-bomber, the F.B.40 being
similar to the F.B.VI but having Packard Merlin 31 (first hundred production
machines) or 33 (last seventy-eight) engines. One F.B.40 was re-engined with
Packard Merlin 69s and redesignated Mosquito F.B.42, but no production of this
version was undertaken.
No fewer than twenty-seven different versions of the Mosquito went into service
during the war years, and some of the most spectacular operations of the air war
stood to its credit. The Mosquito carried phenomenal loads over extremely long
distances, performing feats out of all proportion to the specification
originally envisaged by its designers. In short, the Mosquito was an outstanding
warplane on every count.
Mosquitos were active on D-Day, and right up to the end of the war. Others were
license built in Canada and Australia. Production did not end in Britain until
late 1950.
A De Havilland Mosquito Mk. B-4 . |
Specifications: | |
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De Havilland D.H.98 Mosquito N.F.XIX | |
Dimensions: | |
Wing span: | 54 ft. 2 in. (16.5 m) |
Length: | 41 ft. 2 in. (12.54 m) |
Height: | 15 ft. 3 in. (4.64 m) |
Weights: | |
Empty: | 15,970 lb (7,243 kg) |
Normal: | 20,600 lb. (9,344 kg) |
Max Gross: | 21,750 lb. (9,865 kg) |
Performance: | |
Maximum Speed: | 378 mph (608 km/h) @ 13,200 ft. (4,023 m) |
Cruise Speed: | 295 mph (474 km/h) @ 20,000 ft. (6,096 m) |
Service Ceiling: | 28,000 ft. (8,534 m) |
Range: | 1,400 miles (2,253 km) (with 453 Imp.
gal.) 1,905 miles (3,065 km) (with 616 Imp. gal., including two 50-gal. droptanks) |
Powerplant: | |
Two Rolls-Royce Merlin
25 twelve-cylinder 60ø Vee liquid-cooled engines each providing
1,620 hp (1,208 kw) @ takeoff and 1,500 hp (1,118 kw) @ 9,500 ft. (2,895 m). |
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Armament: | |
Four 20-mm. British Hispano cannon |