De Havilland Mosquito
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The de Havilland
De Havilland
The de Havilland Aircraft Company was a British aviation manufacturer founded in 1920 when Airco, of which Geoffrey de Havilland had been chief designer, was sold to BSA by the owner George Holt Thomas. De Havilland then set up a company under his name in September of that year at Stag Lane...

 DH.98 Mosquito was a British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 multi-role combat aircraft that served during the Second World War and the postwar era. It was known affectionately as the "Mossie" to its crews and was also nicknamed "The Wooden Wonder". It saw service with the Royal Air Force
Royal Air Force
The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...

 (RAF) and many other air forces in the European theatre
European Theatre of World War II
The European Theatre of World War II was a huge area of heavy fighting across Europe from Germany's invasion of Poland on September 1, 1939 until the end of the war with the German unconditional surrender on May 8, 1945...

, the Pacific theatre of Operations
Pacific War
The Pacific War, also sometimes called the Asia-Pacific War refers broadly to the parts of World War II that took place in the Pacific Ocean, its islands, and in East Asia, then called the Far East...

 and the Mediterranean Theatre
Mediterranean Theatre
The Mediterranean Theatre is the war zone covering the Mediterranean Sea. It has seen at least two wars spanning the whole of the sea:*Mediterranean theatre of World War I*Mediterranean, Middle East and African theatres of World War II...

.

Originally conceived as an unarmed fast bomber, the Mosquito was adapted to many other roles during the air war, including: low to medium altitude daytime tactical bomber
Tactical bomber
A tactical bomber is a bomber aircraft with an intended primary role of tactical bombing—attacking tactical targets, such as enemy's troops and military equipment. This implies that either aircraft's range or ordnance is insufficient to use it effectively as a strategic bomber.All light bombers,...

, high-altitude night bomber, pathfinder
Pathfinder (RAF)
The Pathfinders were elite squadrons in RAF Bomber Command during World War II. They located and marked targets with flares, which a main bomber force could aim at, increasing the accuracy of their bombing...

, day
Day fighter
A day fighter is a fighter aircraft equipped only to fight during the day. More specifically, it refers to a multi-purpose aircraft that does not include equipment for fighting at night , although it is sometimes used to refer to some interceptors as well.Examples of planes that were classified as...

 or night
Night fighter
A night fighter is a fighter aircraft adapted for use at night or in other times of bad visibility...

 fighter
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...

, fighter-bomber
Fighter-bomber
A fighter-bomber is a fixed-wing aircraft with an intended primary role of light tactical bombing and also incorporating certain performance characteristics of a fighter aircraft. This term, although still used, has less significance since the introduction of rockets and guided missiles into aerial...

, intruder, maritime strike aircraft, and fast photo-reconnaissance aircraft. It was also used by the British Overseas Airways Corporation
British Overseas Airways Corporation
The British Overseas Airways Corporation was the British state airline from 1939 until 1946 and the long-haul British state airline from 1946 to 1974. The company started life with a merger between Imperial Airways Ltd. and British Airways Ltd...

 (BOAC) as a transport.

When the Mosquito entered production in 1941, it was one of the fastest operational aircraft in the world. Entering widespread service in 1942, the Mosquito supported RAF strategic night fighter defence forces in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 from Luftwaffe
Luftwaffe
Luftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....

 raids, most notably defeating the German aerial offensive Operation Steinbock
Operation Steinbock
Operation Steinbock was the nocturnal Second World War Luftwaffe offensive operation to destroy British military and civilian targets in southern England, between January and May 1944. The attacks were mainly in and around the Greater London area...

 in 1944. Offensively, the Mosquito units also conducted nighttime fighter sweeps in indirect and direct protection of RAF Bomber Command
RAF Bomber Command
RAF Bomber Command controlled the RAF's bomber forces from 1936 to 1968. During World War II the command destroyed a significant proportion of Nazi Germany's industries and many German cities, and in the 1960s stood at the peak of its postwar military power with the V bombers and a supplemental...

's heavy bombers to help reduce RAF bomber losses in 1944 and 1945. The Mosquito increased German night fighter losses to such an extent the Germans were said to have awarded two victories for shooting one down. As a bomber, it took part in "special raids", such as pinpoint attacks on prisoner-of-war camp
Prisoner-of-war camp
A prisoner-of-war camp is a site for the containment of combatants captured by their enemy in time of war, and is similar to an internment camp which is used for civilian populations. A prisoner of war is generally a soldier, sailor, or airman who is imprisoned by an enemy power during or...

s (to aid escapes), Gestapo
Gestapo
The Gestapo was the official secret police of Nazi Germany. Beginning on 20 April 1934, it was under the administration of the SS leader Heinrich Himmler in his position as Chief of German Police...

 or German intelligence and security force bases, as well as tactical strikes in support of the British Army
British Army
The British Army is the land warfare branch of Her Majesty's Armed Forces in the United Kingdom. It came into being with the unification of the Kingdom of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army incorporated Regiments that had already existed in England...

 in the Normandy Campaign
Normandy Campaign
The Battle of Normandy or Normandy Campaign includes the following:* Operation Overlord - The Western Allied campaign in France from June 6 - August 25, 1944...

. Some Mosquitos also saw action in RAF Coastal Command
RAF Coastal Command
RAF Coastal Command was a formation within the Royal Air Force . Founded in 1936, it was the RAF's premier maritime arm, after the Royal Navy's secondment of the Fleet Air Arm in 1937. Naval aviation was neglected in the inter-war period, 1919–1939, and as a consequence the service did not receive...

 during the Battle of the Atlantic, attacking Kriegsmarine
Kriegsmarine
The Kriegsmarine was the name of the German Navy during the Nazi regime . It superseded the Kaiserliche Marine of World War I and the post-war Reichsmarine. The Kriegsmarine was one of three official branches of the Wehrmacht, the unified armed forces of Nazi Germany.The Kriegsmarine grew rapidly...

 U-Boat
U-boat
U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...

 and transport ship concentrations, particularly in the Bay of Biscay
Bay of Biscay
The Bay of Biscay is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the western coast of France from Brest south to the Spanish border, and the northern coast of Spain west to Cape Ortegal, and is named in English after the province of Biscay, in the Spanish...

 offensive in 1943 in which significant numbers of U-boats were sunk or damaged.

The Mosquito was also used in the Mediterranean and Italian
Italian Campaign (World War II)
The Italian Campaign of World War II was the name of Allied operations in and around Italy, from 1943 to the end of the war in Europe. Joint Allied Forces Headquarters AFHQ was operationally responsible for all Allied land forces in the Mediterranean theatre, and it planned and commanded the...

 theatres, as well as being used by the RAF in the CBI Theatre, and by the RAAF
Royal Australian Air Force
The Royal Australian Air Force is the air force branch of the Australian Defence Force. The RAAF was formed in March 1921. It continues the traditions of the Australian Flying Corps , which was formed on 22 October 1912. The RAAF has taken part in many of the 20th century's major conflicts...

 based in the Halmaheras
Maluku Islands
The Maluku Islands are an archipelago that is part of Indonesia, and part of the larger Maritime Southeast Asia region. Tectonically they are located on the Halmahera Plate within the Molucca Sea Collision Zone...

 and Borneo
Borneo
Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....

 during the Pacific War
Pacific War
The Pacific War, also sometimes called the Asia-Pacific War refers broadly to the parts of World War II that took place in the Pacific Ocean, its islands, and in East Asia, then called the Far East...

.

Design and development

Earlier designs

Throughout the 1930s, de Havilland established a reputation for developing innovative high-speed aircraft such as the DH.88 Comet
De Havilland DH.88
The de Havilland DH.88 Comet was a twin-engined British aircraft that won the 1934 MacRobertson Air Race, a challenge for which it was specifically designed...

 racer. The potential of their construction techniques could also be seen in the design of the DH.88, which heavily influenced the Mosquito, while the DH.91 Albatross
De Havilland Albatross
|-See also:...

 airliner also successfully employed the composite wood construction that the Mosquito would later use. The construction of their aircraft compensated for the low power of engines generally available at the time. The 22-passenger Albatross was capable of cruising at 210 miles per hour (338 km/h) at 11000 feet (3,352.8 m). The wooden construction and stressed skin covering not only saved weight and compensated for the low power engines, but simplified production and enabled a fast construction rate.

On 8 September 1936, the British Air Ministry issued Air Ministry specification P.13/36, which called for a twin-engined medium bomber capable of carrying a 3000 pounds (1,360.8 kg) bomb load for 3000 miles (4,828 km) with a maximum speed of 275 miles per hour (442.6 km/h) at 15000 feet (4,572 m); a maximum bomb load of 8000 pounds (3,628.7 kg) which could be carried over shorter ranges was also specified. Major aviation firms entered heavy designs with new high-powered engines and multiple defensive turrets, but de Havilland felt that a smaller aircraft could do the same job. The firm had little experience of working with the Air Ministry
Air Ministry
The Air Ministry was a department of the British Government with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964...

, and their all-wood construction was considered to be out of keeping with official policy, which was then concentrating on promoting heavily armed bombers with all-metal construction. P.13/36 would eventually lead to the Avro Manchester
Avro Manchester
|-See also:-References:NotesCitationsBibliography* Buttler, Tony. British Secret Projects: Fighters and Bombers 1935–1950. Hickley, UK: Midland Publishing, 2004. ISBN 978-1857801798....

 and Handley Page Halifax
Handley Page Halifax
The Handley Page Halifax was one of the British front-line, four-engined heavy bombers of the Royal Air Force during the Second World War. A contemporary of the famous Avro Lancaster, the Halifax remained in service until the end of the war, performing a variety of duties in addition to bombing...

.

Concept and design

In 1937 the concept of a fast unarmed bomber that included a design comparable to P.13/36, was put before the Air Ministry by George Volkert of Handley Page. Within the RAF it had support as an idea worth pursuing, although concerns were raised that the economic benefits over conventional bombers were marginal given the limited operational role it could play. The Ministry was also considered the maximum use of non-strategic materials for aircraft production, that lead to the development of the Albemarle medium bomber
Armstrong Whitworth Albemarle
The Armstrong Whitworth A.W.41 Albemarle was a British twin-engine transport aircraft that entered service during the Second World War.Originally designed as a medium bomber that could be built by non-aviation companies without using light alloys, the Albemarle never served in that role, instead...

 which was largely constructed from spruce and plywood attached to a steel tube frame.

Geoffrey de Havilland strove to surpass the original P.13/36 specifications, and at first considered the adaptation of existing designs, such as the Albatross airliner, to the RAF's requirements. In April 1938 de Havilland considered the performance of a twin Merlin
Rolls-Royce Merlin
The Rolls-Royce Merlin is a British liquid-cooled, V-12, piston aero engine, of 27-litre capacity. Rolls-Royce Limited designed and built the engine which was initially known as the PV-12: the PV-12 became known as the Merlin following the company convention of naming its piston aero engines after...

 engined Albatross, armed with three gun turrets and a six-man crew. It would carry 6000 pounds (2,721.6 kg) of bombs to Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...

 and return at 11000 feet (3,352.8 m). It had a total weight of 19000 pounds (8,618.3 kg), a top speed of 300 miles per hour (482.8 km/h) and cruise speed of 268 miles per hour (431.3 km/h) at 22500 feet (6,858 m). On 7 July, Geoffrey de Havilland sent a letter to Air Marshal
Air Marshal
Air marshal is a three-star air-officer rank which originated in and continues to be used by the Royal Air Force...

 Wilfred Freeman, the Air Council's member for Research and Development, discussed the specification and argued that the weight to strength ratio of wood to that of duralumin
Duralumin
Duralumin is the trade name of one of the earliest types of age-hardenable aluminium alloys. The main alloying constituents are copper, manganese, and magnesium. A commonly used modern equivalent of this alloy type is AA2024, which contains 4.4% copper, 1.5% magnesium, 0.6% manganese and 93.5%...

 or steel, and that a different approach to designing a high-speed bomber would be better. Freeman gave the plans the green light. On 27 July 1938, de Havilland distanced themselves further by stating the P.13/36 specification could not be met by a two Merlin engine aircraft unless the Air Ministry only wanted half of the 4000 pounds (1,814.4 kg) bomb load, otherwise a larger and slower bomber would be needed.

Eventually, after examining concepts based on the Albatross and the new DH.95 Flamingo
De Havilland Flamingo
|-See also:-References:NotesBibliography* Bain, Gordon. De Havilland: A Pictorial Tribute. London: AirLife, 1992. ISBN 1-85648-243-X.* Green, William and Gordon Swanborough. "De Havilland's War Orphan." Air Enthusiast. Number 30, March-June 1996, pp. 1—10. Bromley, Kent, UK: Pilot Press.*...

, de Havilland settled on a completely new design. It would be aerodynamically clean and powered by the Rolls-Royce Merlin
Rolls-Royce Merlin
The Rolls-Royce Merlin is a British liquid-cooled, V-12, piston aero engine, of 27-litre capacity. Rolls-Royce Limited designed and built the engine which was initially known as the PV-12: the PV-12 became known as the Merlin following the company convention of naming its piston aero engines after...

 which, in 1939, offered huge promise. The concept behind what became known as the DH.98 Mosquito was that it would have to be faster than enemy fighter aircraft
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...

, and would therefore not need defensive armament: heavy, drag producing gun turrets would simply slow it down and make interception more likely, plus they were no defence against anti-aircraft guns. Instead high-speed and good manoeuvrability would make it easier for the design to evade both fighters and ground fire. In turn the lack of turrets meant that production would be easier and faster, with a delivery rate far in advance of any competing designs. Without armament, the crew could be reduced to two, a pilot and a navigator. This was in complete opposition to contemporary RAF design philosophy, which required well-armed heavy bombers - the Mosquito was much more akin to the German schnellbomber
Schnellbomber
A Schnellbomber is a high-speed bomber. The concept developed in the 1930s when it was believed that a very fast bomber could simply outrun its enemies....

 concept.

Eric Bishop
Ronald Eric Bishop
Ronald Eric Bishop CBE FRAeS was the chief designer of the de Havilland Mosquito, one of the most famous aircraft of the Second World War.Bishop also designed the de Havilland Comet.-Career:...

, de Havilland's chief designer, worked out the design of the Mosquito at Salisbury Hall.. The design also made provision for the addition of 20 mm cannon installed under the nose. This heavy forward-firing armament proved very successful in wartime. In September 1938, during the Munich Crisis, de Havilland presented their new design to the Air Ministry.

The DH.98 was deemed too radical by the Air Ministry and was rejected several times. The priority given to speed was emphasised - one basic design able to combine medium bomber capability with reconnaissance and "general purpose" classes. The aircraft was also to be capable of maritime strike, so specifications for torpedo carrying equipment were to be part of this new design. In addition, the Ministry suggested two forward and two rear firing machine guns for defence. The Air Council then applied further requirements, such as remotely controlled guns, and a top speed of 275 miles per hour (442.6 km/h) at 15000 feet (4,572 m) on two-thirds engine power and a range of 3000 miles (4,828 km) with a 4000 pounds (1,814.4 kg) bomb load.

In October 1938, still sceptical about the idea of a wooden aircraft and the concept of the unarmed bomber, the Ministry again rejected de Havilland's proposal, and instead asked whether de Havilland would consider building wings for another bomber as sub-contractors. To appease the Air Ministry, de Havilland built a series of mock-ups, with a two machine gun armed turret installed in the fuselage just aft of the cockpit. Apart from this compromise de Havilland refused to change the fundamentals of the design.

Although Freeman was supportive, and agreed to the lack of armament, he was still doubtful over de Havilland's claims that a wooden twin engined bomber could fly 1500 miles (2,414 km) and be able to fly faster than a Spitfire: it was also thought in the Air Ministry that the Germans would produce fighters which were faster than expected. There was also still strong opposition to a two crew bomber and the Air Ministry wanted at least a third crewman to reduce the workload of the others on long flights. At a meeting considering de Havilland's, Blackburn's and Bristol's fast bomber ideas in November, Freeman directed de Havilland to produce a fast aircraft powered firstly with Merlin engines with options to use progressively more powerful engines - firstly Griffons, then Napier Sabre
Napier Sabre
The Napier Sabre was a British H-24-cylinder, liquid cooled, sleeve valve, piston aero engine, designed by Major Frank Halford and built by Napier & Son during WWII...

s.

Throughout October and November 1939, de Havilland were experimenting with using different engines and considering the effects of defensive armament on their designs. By using more powerful Griffon
Rolls-Royce Griffon
The Rolls-Royce Griffon is a British 37-litre capacity, 60-degree V-12, liquid-cooled aero engine designed and built by Rolls-Royce Limited...

 engines it was thought a four-gun turret could be installed without compromising the top speed. The Ministry were still supportive of the aircraft for development purposes, but unavailability of engines and turrets meant that only prototypes could be constructed.

On 12 December 1939, the Vice-Chief of the Air Staff
Vice-Chief of the Air Staff (United Kingdom)
The British Vice-Chief of the Air Staff was the post occupied by the senior Royal Air Force officer who served as a senior assistant to the Chief of the Air Staff. The post was created during World War II on 22 April 1940 and its incumbement sat on the Air Council...

, Director General of Research and Development, Air Officer Commanding-in-Chief
Air Officer Commanding
Air Officer Commanding is a title given in the air forces of Commonwealth nations to an air officer who holds a command appointment. Thus, an air vice marshal might be the AOC 38 Group...

 (AOC-in-C) of RAF Bomber Command
RAF Bomber Command
RAF Bomber Command controlled the RAF's bomber forces from 1936 to 1968. During World War II the command destroyed a significant proportion of Nazi Germany's industries and many German cities, and in the 1960s stood at the peak of its postwar military power with the V bombers and a supplemental...

 met to thrash out the details of the design and its uses for future strategy. The AOC-in-C would not accept an unarmed bomber, but insisted it would be suited for reconnaissance missions with F24 cameras. On that day, the Air Council ordered the DH.98 prototype built under specification B.1/40.

After more talks between the company and Air Ministry and operational commands, on 29 December 1939, the project received official backing when the Air Ministry asked for a "basic" bomber requirement for a bomber capable of carrying a 1000 pounds (453.6 kg) bomb load and with a range of 1500 miles (2,414 km). Finally, on 1 January 1940, a further meeting, chaired by Wilfrid Freeman, took place involving Geoffrey de Havilland, John Buchanan, Deputy of Aircraft Production and John Connolly, Buchanan's chief of staff. Claiming the Mosquito was the "fastest bomber in the world", de Havilland added "it must be useful". Freeman supported its production for RAF service and ordered a single prototype for an unarmed bomber variant to specification B.1/40/dh, powered by two Merlin engines. The aircraft was to have a speed of 397 miles per hour (638.9 km/h) at 23700 feet (7,223.8 m) and a cruising speed of 327 miles per hour (526.3 km/h) at 26600 feet (8,107.7 m) with a 1480 miles (2,381.8 km) range at 24900 feet (7,589.5 m) on full tanks. Maximum service ceiling was to be 32100 feet (9,784.1 m). On 1 March 1940, Air Marshal
Air Marshal
Air marshal is a three-star air-officer rank which originated in and continues to be used by the Royal Air Force...

 Roderic Hill
Roderic Hill
Air Chief Marshal Sir Roderic Maxwell Hill KCB, MC, AFC & Bar, RAF was a senior Royal Air Force commander during World War II, and a past Rector of Imperial College...

 ordered a contract, again under Specification B.1/40, for 50 DH.98 aircraft, including the prototype.

Project Mosquito

The design and construction of the prototype was able to begin almost immediately, but work was cancelled again after the Battle of Dunkirk
Battle of Dunkirk
The Battle of Dunkirk was a battle in the Second World War between the Allies and Germany. A part of the Battle of France on the Western Front, the Battle of Dunkirk was the defence and evacuation of British and allied forces in Europe from 26 May–4 June 1940.After the Phoney War, the Battle of...

, when it was decided there was no production capacity for aircraft like the DH.98, which was not expected to be in service until early 1941. This was mostly as a result of the shortage of Merlin engines which were needed in fighter aircraft. Instead production was to focus on existing types, namely the Supermarine Spitfire
Supermarine Spitfire
The Supermarine Spitfire is a British single-seat fighter aircraft that was used by the Royal Air Force and many other Allied countries throughout the Second World War. The Spitfire continued to be used as a front line fighter and in secondary roles into the 1950s...

, Hawker Hurricane
Hawker Hurricane
The Hawker Hurricane is a British single-seat fighter aircraft that was designed and predominantly built by Hawker Aircraft Ltd for the Royal Air Force...

, Vickers Wellington
Vickers Wellington
The Vickers Wellington was a British twin-engine, long range medium bomber designed in the mid-1930s at Brooklands in Weybridge, Surrey, by Vickers-Armstrongs' Chief Designer, R. K. Pierson. It was widely used as a night bomber in the early years of the Second World War, before being displaced as a...

, and Bristol Blenheim
Bristol Blenheim
The Bristol Blenheim was a British light bomber aircraft designed and built by the Bristol Aeroplane Company that was used extensively in the early days of the Second World War. It was adapted as an interim long-range and night fighter, pending the availability of the Beaufighter...

.

The Mosquito was only reinstated as a priority in July 1940 after de Havilland promised Lord Beaverbrook 50 machines by December 1941; although de Havilland knew this was unlikely. Only 20 Mosquitos were built that year. During this time Beaverbrook, as Minister for Aircraft Production, asked Air Marshall Freeman to cease work on the project. Freeman did not issue such an order but it seemed the project would be shut down when the design team were denied the materials with which to build their prototype. Only when Beaverbrook was satisfied that work would not divert effort from the repairing of Merlin engines and production of Tiger Moth
Tiger moth
Tiger moths are moths of the family Arctiidae.Tiger moth may also refer to:*de Havilland Tiger Moth, an aircraft; an aerobatic and trainer tailwheel biplane*de Havilland DH.71 Tiger Moth, an earlier monoplane produced by de Havilland...

 trainers, was it allowed to continue.

The prototype was being built during the Battle of Britain
Battle of Britain
The Battle of Britain is the name given to the World War II air campaign waged by the German Air Force against the United Kingdom during the summer and autumn of 1940...

 and nearly a third of factory time was lost because the workers took cover in the factory's bomb shelters. Nevertheless, the original day bomber prototype, which initially wore the factory serial
United Kingdom aircraft test serials
United Kingdom aircraft test serials are used to externally identify aircraft flown within the United Kingdom without a full Certificate of Airworthiness...

 E-0234, was rolled out on 19 November 1940, and first flew on 25 November, only 10 months after the go-ahead. By January 1941 the prototype was carrying the military serial number W4050
United Kingdom military aircraft serials
In the United Kingdom to identify individual aircraft, all military aircraft are allocated and display a unique serial number. A unified serial number system, maintained by the Air Ministry , and its successor the Ministry of Defence , is used for aircraft operated by the Royal Air Force , Fleet...

. The original estimates were that as the Mosquito prototype had twice the surface area and over twice the weight of the 1940 Spitfire Mk II
Supermarine Spitfire (early Merlin powered variants)
The British Supermarine Spitfire was the only fighter aircraft of the Second World War to fight in front line service, from the beginnings of the conflict, in September 1939, through to the end in August 1945. Post-war the Spitfire's service career continued into the 1950s...

, but also with twice its power, the Mosquito would end up being 20 miles per hour (32.2 km/h) faster. Over the next few months, W4050 surpassed this estimate, easily beating the Spitfire Mk II in testing at RAF Boscombe Down in February 1941, reaching a top speed of 392 miles per hour (630.9 km/h) at 22000 feet (6,705.6 m) altitude, compared to a top speed of 360 miles per hour (579.4 km/h) at 19500 feet (5,943.6 m) for the Spitfire. It also surpassed the Spitfire at low to medium altitude, some 6000 feet (1,828.8 m).

The Air Ministry was still not happy with the concept of the unarmed bomber. Nevertheless, in the aftermath of the Battle of Britain, interest in long-range heavy fighter and bomber destroyers began. The original 50 prototype order was changed to 20 bomber variants and 30 fighters; it was still uncertain whether the fighter version should have dual or single controls or should carry a turret so three prototypes were required. This caused some delays as half built wing components had to be strengthened for the expected higher combat load requirements. The nose sections also had to be altered, from clear perspex, to solid noses designed to hold heavy air-to-air combat weapons.

Prototypes and test flights

On 3 November 1940, the aircraft, still coded E-0234, was transported by road to Hatfield
Hatfield, Hertfordshire
Hatfield is a town and civil parish in Hertfordshire, England in the borough of Welwyn Hatfield. It has a population of 29,616, and is of Saxon origin. Hatfield House, the home of the Marquess of Salisbury, is the nucleus of the old town...

, where it was placed in a small blast-proof assembly building, where successful engine runs were made on 19 November. Two Merlin 21 two-speed single-stage supercharged engines were installed driving de Havilland Hydromatic constant-speed, three-blade airscrews. On 24 November 1940, taxiing trials were carried out by Geoffrey de Havilland, who was the company's chief test pilot
Test pilot
A test pilot is an aviator who flies new and modified aircraft in specific maneuvers, known as flight test techniques or FTTs, allowing the results to be measured and the design to be evaluated....

 and responsible for maiden flights. The tests were successful and the prototype was subsequently readied for flight testing, making its first flight, piloted by Geoffrey de Havilland, on 25 November. The flight was made 11 months after the start of detailed design work, a remarkable achievement considering the conditions of the time.

For this maiden flight E-0234 took off from a 450 feet (137.2 m) field beside the shed it was built in. John E. Walker, Chief Engine Installation designer, accompanied de Havilland. The takeoff was "straight forward and easy" and the undercarriage was not retracted until a considerable height was obtained. The aircraft reached 220 mph (98.3 m/s), and the only problem was that the undercarriage doors - which were operated by bungee cord
Bungee cord
A bungee cord , also known as a shock cord, is an elastic cord composed of one or more elastic strands forming a core, usually covered in a woven cotton or polypropylene sheath...

s which were attached to the main undercarriage legs - remained open by some 12 inches (304.8 mm) at the maximum speed obtained. This problem persisted for some time. Another teething problem was the inability of the tailwheel to caster
Caster
A caster is an undriven, single, double, or compound wheel that is designed to be mounted to the bottom of a larger object so as to enable that object to be easily moved...

 properly, which caused the airframe in the rear fuselage to fracture during tests at the Aeroplane and Armament Experimental Establishment
Aeroplane and Armament Experimental Establishment
The Aeroplane and Armament Experimental Establishment was a research facility for British military aviation from 1918 to 1992.-History:...

 (A&AEE) in 1941. This problem was solved in June–July 1941 by the fitting of a Dowty
Dowty Group
Dowty Group was a leading British manufacturer of aircraft equipment. It was listed on the London Stock Exchange and was once a constituent of the FTSE 100 Index but was acquired by TI Group in 1992.-History:...

 unit. The left wing of E-0234 had a tendency to drag to port slightly, so a rigging adjustment was carried out before further flights.

On 5 December 1940 the prototype, now using the serial number W4050, experienced tail buffeting at speeds between 240 miles per hour (107.3 m/s) and 255 miles per hour (114 m/s). The pilot noticed this most in the control column, and handling became more difficult. During testing on 10 December wool tufts were attached to the suspect areas to investigate the direction of airflow: the conclusion was that the airflow separating from rear section of the inner engine nacelle
Nacelle
The nacelle is a cover housing that holds engines, fuel, or equipment on an aircraft. In some cases—for instance in the typical "Farman" type "pusher" aircraft, or the World War II-era P-38 Lightning—an aircraft's cockpit may also be housed in a nacelle, which essentially fills the...

s was disturbed, leading to a localised stall
Stall (flight)
In fluid dynamics, a stall is a reduction in the lift coefficient generated by a foil as angle of attack increases. This occurs when the critical angle of attack of the foil is exceeded...

 and the disturbed airflow was striking the tailplane, causing the buffeting. In an attempt to alleviate the buffeting the company experimented with special aerodynamic slots
Leading edge slot
A leading edge slot is an aerodynamic feature of the wing of some aircraft to reduce the stall speed and promote good low-speed handling qualities. A leading edge slot is a span-wise gap in each wing, allowing air to flow from below the wing to its upper surface...

 fitted to the inner engine nacelles and to the leading edge of the tailplane to smooth the air flow and deflect it from striking the tailplane with such force. These slots, and wing root fairings fitted to the forward fuselage and leading edge of the radiator intakes, stopped some of the vibration experienced by the pilot but failed to cure the tailplane buffeting. In February 1941 the buffeting was eliminated by incorporating triangular fillets on the trailing edge of the wings and lengthening the nacelles, the trailing edge of which curved up to fair into the fillet some 10 in (25.4 cm) behind the wing's trailing edge: this meant the flap
Flap (aircraft)
Flaps are normally hinged surfaces mounted on the trailing edges of the wings of a fixed-wing aircraft to reduce the speed an aircraft can be safely flown at and to increase the angle of descent for landing without increasing air speed. They shorten takeoff and landing distances as well as...

s had to be divided into inboard and outboard sections.

With teething problems largely solved, John Cunningham
John Cunningham (RAF officer)
Group Captain John "Cat's Eyes" Cunningham CBE, DSO & Two Bars, DFC & Bar, , was a British Royal Air Force night fighter ace during World War II and a test pilot, both before and after the war...

 flew W4050 on 9 February 1941. He was greatly impressed by the "lightness of the controls and generally pleasant handling characteristics". Cunningham concluded that when the type was fitted with radar, it would be a perfect replacement for the Beaufighter.

During its trials on 16 January 1941, W4050, in a bomber/reconnaissance configuration, the prototype outpaced a Spitfire at 6000 ft (1,828.8 m). On 19 February official trials began at the A&AEE based at Boscombe Down
MoD Boscombe Down
MoD Boscombe Down is an aircraft testing site located at Idmiston, south of Amesbury, in Wiltshire, England. It is run and managed by QinetiQ, the company created as part of the breakup of the Defence Evaluation and Research Agency in 2001 by the UK Ministry of Defence...

, although de Havilland's representative was surprised by a delay in starting the tests. On 24 February, as W4050 taxied across the rough airfield, the tailwheel jammed leading to the fuselage fracturing: this was replaced by the fuselage of the Photo Reconnaissance prototype W4051 in early March. In spite of this problem the Initial Handling Report 767 issued by the A&AEE stated "The aeroplane is pleasant to fly....Aileron control light and effective..." The maximum speed reached was 388 mph (173.5 m/s) at 22000 ft (6,705.6 m), with an estimated maximum ceiling of 33900 ft (10,332.7 m) and a maximum rate of climb of 2880 ft/min at 11400 ft (3,474.7 m).

On 20 April 1941, it was demonstrated to Lord Beaverbrook, the Minister of Aircraft Production
Minister of Aircraft Production
The Minister of Aircraft Production was the British government position in charge of the Ministry of Aircraft Production, one of the specialised supply ministries set up by the British Government during World War II...

. The Mosquito made a series of flights, including one rolling climb on one engine. Also present were US General Henry H. Arnold
Henry H. Arnold
Henry Harley "Hap" Arnold was an American general officer holding the grades of General of the Army and later General of the Air Force. Arnold was an aviation pioneer, Chief of the Air Corps , Commanding General of the U.S...

 and his aide Major
Major
Major is a rank of commissioned officer, with corresponding ranks existing in almost every military in the world.When used unhyphenated, in conjunction with no other indicator of rank, the term refers to the rank just senior to that of an Army captain and just below the rank of lieutenant colonel. ...

 Elwood Quesada who wrote "I...recall the first time I saw the Mosquito as being impressed by its performance, which we were aware of. We were impressed by the appearance of the airplane that looks fast usually is fast, and the Mosquito was, by the standards of the time, an extremely well streamlined airplane, and it was highly regarded, highly respected."

During testing, it was found that W4050 had the power and internal capacity to carry four times the 1000 lb (453.6 kg) of bombs originally specified. In order to better support the higher loads the aircraft was capable of, the wingspan was increased, on later prototypes and production aircraft, from 52 in 6 in (16 m) to 54 in 2 in (16.51 m). It was also fitted with a larger tailplane in comparison to later production types, an improved exhaust system, and lengthened nacelles that improved stability. These modifications became standard across the production versions. The skin on the tail surfaces was all wood and plywood covered, while the rudder
Rudder
A rudder is a device used to steer a ship, boat, submarine, hovercraft, aircraft or other conveyance that moves through a medium . On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane...

 and elevators
Elevator (aircraft)
Elevators are flight control surfaces, usually at the rear of an aircraft, which control the aircraft's orientation by changing the pitch of the aircraft, and so also the angle of attack of the wing. In simplified terms, they make the aircraft nose-up or nose-down...

 were made of aluminium, and the elevators fabric covered. In 1943, the elevators were covered in metal to increase speed in dives.

The trials set up future production plans between Britain, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. The Americans did not pursue their interest. It was thought the Lockheed P-38 Lightning could handle the same duties just as easily. Arnold felt the design was being overlooked, and urged the strategic personalities in the United States Army Air Force to learn from the design if they chose not to adopt it. The USAAF then requested one airframe to evaluate on 12 December 1941, several days after the attack on Pearl Harbor
Attack on Pearl Harbor
The attack on Pearl Harbor was a surprise military strike conducted by the Imperial Japanese Navy against the United States naval base at Pearl Harbor, Hawaii, on the morning of December 7, 1941...

, and the USAAF entered the war without a fast dual-purpose reconnaissance machine.

W4051 was to be the second prototype, but an airframe fracture in W4050 meant that W4051's airframe was used as a replacement. W4051 received a production standard fuselage and actually saw combat operations. W4050 flew on 10 June 1941, the third Mosquito after W4052, which flew on 15 May 1941. W4055 flew the first operational Mosquito flight on 17 September 1941.

During the flight testing, the Mosquito was fitted with a number of innovations. W4050 was fitted with a turret behind the cockpit for drag tests. It was not adopted and the idea was abandoned in July 1941. W4052 had the first version of the Youngman Frill airbrake fitted to the fighter prototype. The frill was opened by bellows and venturi effect
Venturi effect
The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section of pipe. The Venturi effect is named after Giovanni Battista Venturi , an Italian physicist.-Background:...

 to provide rapid deceleration during interceptions and was tested between January - August 1942, but was abandoned when it was discovered that lowering the undercarriage had the same effect.

Construction of a fighter prototype, W4052 was carried out at the secret Salisbury Hall facility. The new prototype differed from its bomber brethren in a number of ways. It was powered by an upgraded variant of the Merlin 21 of
1460 hp, and also had a flat bullet-proof windscreen. It was tested with powerful armament such as 40 mm cannon and other modifications, bomb racks, fuel drop tanks, barrage balloon
Barrage balloon
A barrage balloon is a large balloon tethered with metal cables, used to defend against low-level aircraft attack by damaging the aircraft on collision with the cables, or at least making the attacker's approach more difficult. Some versions carried small explosive charges that would be pulled up...

 cable cutters in the leading edge of the wings, Hamilton airscrews and braking propellers, as well as drooping aileron systems which enabled steep approaches, and a larger rudder tab. The prototype continued to serve as a test machine until it was scrapped on 28 January 1946.

W4050 continued to be used for long and varied testing programs. In late October 1941 it was taken back to the factory to be fitted with Merlin 61s
Rolls-Royce Merlin
The Rolls-Royce Merlin is a British liquid-cooled, V-12, piston aero engine, of 27-litre capacity. Rolls-Royce Limited designed and built the engine which was initially known as the PV-12: the PV-12 became known as the Merlin following the company convention of naming its piston aero engines after...

, the first production Merlins fitted with a two-speed, two-stage supercharger. The first flight with the new engines was on 20 June 1942. W4050 recorded a maximum speed of 428 mph (191.3 m/s) at 28500 ft (8,686.8 m) (fitted with straight-through air intakes with snowguards, engines in F.S gear) and 437 mph (195.4 m/s) at 29200 ft (8,900.2 m) without snowguards. It was used to eliminate problems on W4052. Most of this related to the former's exhaust and armament systems. Flash eliminators had to be fitted to the NF.II to prevent the crew from being blinded by muzzle flash during the firing of the weapons. The cooling intake shrouds that were to cool the exhausts overheated after a while. Flame dampers prevented the exhaust glow on night operations, but they had an effect on performance. Multiple ejector and open-ended exhaust stubs configuration solved the problem and were used in the PR.VIII, B.IX and B.XVI variants. This increased speed performance in the B.IX alone by 10–13 mi (16.1–20.9 km)per hour.

By the time testing was over and the Air Ministry had authorised mass production plans to be drawn up on 21 June 1941, the aircraft was the world's fastest operational aircraft. The Air Ministry authorised 19 PR. models and 176 fighters. A further 50 were unspecified. In July 1941, the Air Ministry confirmed these would be unarmed fast bombers. Using two-stage Merlin 77s, it reached 439 miles per hour (706.5 km/h) in December 1943.

By the end of January 1942, contracts had been awarded for 1,378 Mosquitos of all variants, including 20 T.III trainers and 334 FB.VI bombers. Another 400 were to be built by de Havilland Canada
De Havilland Canada
The de Havilland Aircraft of Canada Ltd. company was an aircraft manufacturer with facilities based in what is now the Downsview area of Toronto, Ontario, Canada...

.

Basic design (based on the FB Mk VI)

The Mosquito was a mid-wing (or shoulder-wing) aircraft powered by two Merlin engines. The most produced variant, designated
British military aircraft designation systems
British military aircraft designations are used to refer to aircraft types and variants operated by the armed forces of the United Kingdom.Since the end of the First World War, aircraft types in British military service have generally been known by a name British military aircraft designations are...

 the FB.VI (Fighter-bomber Mark 6), was powered by two Merlin Mk 23 or Mk 25 engines driving three-bladed hydromatic propellers.

Construction

The oval-section fuselage was a frameless monocoque
Monocoque
Monocoque is a construction technique that supports structural load by using an object's external skin, as opposed to using an internal frame or truss that is then covered with a non-load-bearing skin or coachwork...

 shell built in two halves being formed to shape by band clamp
Band clamp
A band clamp is a type of clamp which allows the clamping of items where the surfaces to be clamped are not parallel to each other; where there are multiple surfaces involved; or where clamping pressure is required from multiple directions at once.Examples of when a band clamp may be used...

s over a mahogany or concrete mould, each holding one half of the fuselage, split vertically. The shell halves were made of sheets of Ecuadorean balsa
Balsa
Ochroma pyramidale, commonly known as the balsa tree , is a species of flowering plant in the mallow family, Malvaceae. It is a large, fast-growing tree that can grow up to tall. It is the source of balsa wood, a very lightweight material with many uses...

wood sandwiched between sheets of Canadian birch
Birch
Birch is a tree or shrub of the genus Betula , in the family Betulaceae, closely related to the beech/oak family, Fagaceae. The Betula genus contains 30–60 known taxa...

, but in areas needing extra strength—such as along cut-outs—stronger woods replaced the balsa filler. The join was along the vertical centre line. This spilt construction greatly aided the assembly of the internal equipment as it allowed the technicians easy access to the fuselage interior. While the casein
Casein
Casein is the name for a family of related phosphoprotein proteins . These proteins are commonly found in mammalian milk, making up 80% of the proteins in cow milk and between 60% and 65% of the proteins in human milk....

-based glue in the plywood dried, carpenters cut a sawtooth joint into their edges while other workers installed the controls and cabling on the inside wall. When the glue was completely dried, the two halves were glued and screwed together. The fuselage construction joints were made from balsa wood and plywood strips with the spruce
Spruce
A spruce is a tree of the genus Picea , a genus of about 35 species of coniferous evergreen trees in the Family Pinaceae, found in the northern temperate and boreal regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...

 multi-ply being connected by a balsa V joint, along with the interior frame. The spruce would be reinforced by plywood strips at the point where the two halves joined to form the V joint. Located on top of the joint the plywood formed the outer skin. During the joining of the two halves ("boxing up"), two laminated wooden clamps would be used in the after portion of the fuselage to act as support. A covering of doped
Aircraft dope
thumb|right|[[United Kingdom military aircraft serials|2699]] a [[World War I]] [[Royal Aircraft Factory B.E.2]] finished in a clear dopeAircraft dope is a plasticised lacquer that is applied to fabric-covered aircraft...

 Madapolam
Madapolam
Madapolam is a soft cotton fabric manufactured from fine yarns with a dense pick laid out in linen weave. Linen weave is the simplest and thickest interlaced, reversible basic weave, in which the appearance of the face and back of the woven fabric is the same. Its smallest repeat is 2/2, where two...

 (a fine plain woven cotton) fabric was stretched tightly over the shell and a coat of silver dope was applied, after which the exterior camouflage was applied. The underside was cut to allow for wing assembly. The fuselage could be made in a week by six technicians.

The fuselage was separated by seven bulkheads made up of two plywood skins parted by spruce blocks, which formed the basis on each half for the outer shell. Each bulkhead was a repeat of the spruce design for the fuselage halves; a balsa sheet sandwich between two plywood sheets/skins. Among the glues used was Casein
Casein
Casein is the name for a family of related phosphoprotein proteins . These proteins are commonly found in mammalian milk, making up 80% of the proteins in cow milk and between 60% and 65% of the proteins in human milk....

 resin plus many other screws and flanges (made of various woods) which held the structure together.

The all-wood wing was installed into the roots by means of four large attachment points. The wing was built as a one-piece structure and was not divided into separate construction sections. It was made up of two main spars, spruce and plywood compression ribs, stringers
Longeron
In aircraft construction, a longeron or stringer or stiffener is a thin strip of wood, metal or carbon fiber, to which the skin of the aircraft is fastened. In the fuselage, longerons are attached to formers and run the longitudinal direction of the aircraft...

, and a plywood covering. The outer plywood skin was covered and doped like the fuselage. The engine radiators were fitted in the inner wing, just outboard of the fuselage on either side. These gave less drag. The radiators themselves were split into three sections: an oil cooler section outboard, the middle section forming the coolant radiator and the inboard section serving the cabin heater. The wing contained metal framed and skinned ailerons, but the flaps were made of wood and were hydraulically controlled. The nacelles were mostly wood, but the engine mounts were all metal as were the undercarriage parts (for strength). Engine mounts of welded steel tube were added, along with simple landing gear oleos filled with rubber blocks. Wood was used to carry only in-plane loads, with metal fittings used for all triaxially loaded components such as landing gear, engine mounts, control surface mounting brackets, and the wing-to-fuselage junction. The outer leading wing edge had to be brought 22 inches (55.9 cm) further forward to accommodate this design. The main tail unit was all wood built. The control surfaces, the rudder
Rudder
A rudder is a device used to steer a ship, boat, submarine, hovercraft, aircraft or other conveyance that moves through a medium . On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane...

 and elevator
Elevator (aircraft)
Elevators are flight control surfaces, usually at the rear of an aircraft, which control the aircraft's orientation by changing the pitch of the aircraft, and so also the angle of attack of the wing. In simplified terms, they make the aircraft nose-up or nose-down...

 were aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

 framed and fabric covered. The total weight of metal castings and forgings used in the aircraft was only 280 lb (127 kg).

In November 1944, several crashes occurred in the Far East
Far East
The Far East is an English term mostly describing East Asia and Southeast Asia, with South Asia sometimes also included for economic and cultural reasons.The term came into use in European geopolitical discourse in the 19th century,...

. At first, it was thought these were as a result of wing structure failures. The casein glue, it was said, cracked when exposed to extreme heat. This caused the upper surfaces to "lift" from the main spar. During the ensuing investigation it was concluded that there were construction defects found at two plants; at Hatfield and Coventry. The gluing there left “much to be desired”. However, the main reason for the failures, the Air Ministry concluded on 1 January 1945, was the weather conditions in Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

, thereby endorsing the view of Major Hereward de Havilland, leading the investigation. To solve the problem, a sheet of plywood was set along the span of the wing to seal the entire length of the skin joint along the main spar.

The casein glue was replaced by "Aerolite
Aerolite (adhesive)
Aerolite is a urea-formaldehyde gap filling adhesive which is water and heat resistant. It is used in large quantities by the chipboard industry and also by wooden boat builders for its high strength and durability. It is also used in joinery, veneering and general woodwork assembly...

", a synthetic urea-formaldehyde
Urea-formaldehyde
Urea-formaldehyde, also known as urea-methanal, named so for its common synthesis pathway and overall structure, is a non-transparent thermosetting resin or plastic, made from urea and formaldehyde heated in the presence of a mild base such as ammonia or pyridine...

 adhesive developed by Dr. Norman de Bruyne
Norman de Bruyne
Norman Adrian de Bruyne FRS was born in Punta Arenas Chile on November 8, 1904, baptized on March 19, 1905 at the Anglican Church St. James Church, by the Rev. Edwin Aspinall. His father was Dutch and his mother English. He grew up in England, studied science at the University of Cambridge and...

 at Aero Research Limited
Aero Research Limited
Aero Research Limited was a British company that pioneered several new adhesives, intended initially for the aeronautical industry.Formed in 1934 by Norman de Bruyne at Duxford, Cambridgeshire from an earlier company of his, the Cambridgeshire Aeroplane Construction Company, ARL started a...

 (ARL), which was better able to resist deterioration in high humidity conditions. The de Havilland company also pioneered the use of radio frequency (RF) heating to accelerate curing of the adhesive.

Fuel, landing gear, electrical power and armament systems

The main landing gear were housed in the nacelles behind the engines. These were raised and lowered hydraulically. The main landing gear shock absorbers were of the rubber in compression type with twin pneumatic brakes for each wheel. The Dunlop-Marstrand tailwheel was retractable.

The fuel systems allowed the light Mosquito frame to obtain a considerable range. There were nine fuel tanks. The two in the outer wing, the "outer tanks", each contained 58 gallons (263.7 l) of fuel. The two inner wing fuel tanks, located between the wing root and engine nacelle contained 143 gallons (650.1 l) each. The central tank mounted in the fuselage between bulkhead number two and three aft of the cockpit, consisted of two 25 gallons (113.7 l) fuel tanks. The total fuel load of 452 imp gal (2,054.8 l) was initially deemed appropriate for the type. The range could be increased further; the Mk 6 could have larger fuselage tanks, increasing the capacity of the fuselage from 50 to 63 imp gal (227.3 to 286.4 L). Two 100 gallons (454.6 l) fuel cells were added under the wings to increase the total to 715 imp gal (3,250.5 l). Both the inner wing, and fuselage tanks are listed as the "main tanks".
The central and inner wing tanks were pressurised to reduce fuel vaporisation at high altitude, a feature needed in the photographic reconnaissance variants. The pressure venting cock located behind the pilot's seat controlled the pressure valve; as the altitude increased the valve increased the volume applied by a pump. This system was extended to include field modifications of the fuel tank system.
The engine oil tanks were in the engine nacelles. Each nacelle contained a 15 gallons (68.2 l) oil tank, including a 2.5 imp gal (11.4 l) air space. The oil tanks themselves had no separate coolant controlling systems. The coolant header tank was in the forward nacelle, behind the propeller. The remaining coolant systems were controlled by the coolant radiators shutters in the forward inner wing compartment, in between the nacelle and the fuselage and behind the main engine cooling radiators which were fitted in the leading edge. Electric-pneumatic operated radiator shutters directed and controlled airflow through the ducts and into the coolant valves to predetermined temperatures.
Electrical power came from a 24 volt DC generator on the starboard (No. 2) engine and an alternator on the port engine which supplied AC power for radios. The radio shutters, superchargers, gun camera, bomb bay, bomb/rocket release and all the other crew controlled instruments were powered by a 24 volt battery. The radio communication devices included VHF
Very high frequency
Very high frequency is the radio frequency range from 30 MHz to 300 MHz. Frequencies immediately below VHF are denoted High frequency , and the next higher frequencies are known as Ultra high frequency...

 and HF communications, GEE navigation
GEE (navigation)
Gee was the code name given to a radio navigation system used by the Royal Air Force during World War II.Different sources record the name as GEE or Gee. The naming supposedly comes from "Grid", so the lower case form is more correct, and is the form used in Drippy's publications. See Drippy 1946....

, and IFF and G.P devices.

The electric generators also powered the fire extinguishers. Located on the starboard side of the cockpit, the switches would operate automatically in the event of a crash. In flight, a warning light button would flash to indicate a fire, should the pilot not already be aware of it. In later models, presumably to save liquids, the fire extinguisher was changed to semi-automatic triggers.

The design of the Mark VI allowed for a provisional long-range fuel tank to increase range for action over enemy territory, for the installation of bomb release equipment specific for depth charge
Depth charge
A depth charge is an anti-submarine warfare weapon intended to destroy or cripple a target submarine by the shock of exploding near it. Most use explosives and a fuze set to go off at a preselected depth in the ocean. Depth charges can be dropped by either surface ships, patrol aircraft, or from...

 explosives for strikes against enemy shipping, or for the simultaneous use of rocket projectiles and a 100 gallons (454.6 l) drop tank under each wing for a supplement to the main fuel cells. The FB.VI had a wingspan of 54 foot, a length (over guns) of 41 in 2 in (12.55 m). It had a maximum speed of 378 miles per hour (608.3 km/h) at 13200 feet (4,023.4 m). Maximum take-off weight was 22300 pounds (10,115.1 kg) and the range of the aircraft was 1120 miles (1,802.5 km) with a service ceiling of 26000 feet (7,924.8 m).

Its armament was four Browning .303 machine guns and four 20 mm Hispano cannons for air and soft ground targets. Its bomb load consisted of 2000 pounds (907.2 kg) of bombs or eight RP-3 unguided rockets.

Pilot's notes and characteristics

Because of its design and light frame, the Mosquito had a low stall speed of 105 knots (205.8 km/h) with undercarriage and flaps raised. When both were lowered, the stall speed decreased to 90 - 100 knots (196 km/h). Stall speed at normal approach angle and conditions was 90 - 95 knots (186.2 km/h). Warning of the stall was given by buffeting and would occur 10 knots (19.6 km/h) before stall was reached. The conditions and impact of the stall were not severe. The wing did not drop unless the control column was pulled back. The nose drooped gently and recovery was easy.
For cruising the maximum speed for obtaining maximum range was 170 knots (333.2 km/h) at 17000 lb (7,711.1 kg) weight.
The design was noted for having light and effective control surfaces which allowed for good manoeuvrability. It was noted that the rudder should not be used aggressively at high speeds and the poor aileron control at low speeds when landing and taking off was also a problem for inexperienced crews. For flying at low speeds, the flaps had to be set at 15°, speed reduced to 175 knots (201 mph) and rpm
Revolutions per minute
Revolutions per minute is a measure of the frequency of a rotation. It annotates the number of full rotations completed in one minute around a fixed axis...

 set to 2,650. The speed could be reduced to the acceptable 130 knots (254.8 km/h) for low speed flying.

Prototypes

Three prototypes were built, each with a different configuration. The first to fly was the bomber prototype W4050 on 25 November 1940, followed by the night fighter model on 15 May 1941 and the photo-reconnaissance model on 10 June 1941.

Photo-reconnaissance aircraft

The photo-reconnaissance prototype became the basis for the Mosquito PR Mk I. The first operational sortie
Sortie
Sortie is a term for deployment or dispatch of one military unit, be it an aircraft, ship, or troops from a strongpoint. The sortie, whether by one or more aircraft or vessels, usually has a specific mission....

 by a Mosquito was made by a PR Mk I on 17 September 1941 (the Bomber Mk IV entered service in May 1942 with No. 105 Squadron
No. 105 Squadron RAF
No. 105 Squadron was a flying squadron of the Royal Air Force, active for three periods between 1917 and 1969. It was originally established during the First World War as a squadron of the Royal Flying Corps and disbanded after the war. Reactivated shortly before the Second World War, it was...

). On the very first mission, the unarmed Mosquito PR.I outpaced three Messerschmitt Bf 109
Messerschmitt Bf 109
The Messerschmitt Bf 109, often called Me 109, was a German World War II fighter aircraft designed by Willy Messerschmitt and Robert Lusser during the early to mid 1930s...

s that attempted to engage the aircraft at 23000 feet (7,010.4 m). The PR Mk I had a maximum speed of 382 miles per hour (614.8 km/h), a cruise speed of 255 miles per hour (410.4 km/h), ceiling of 35000 feet (10,668 m), a range of 2180 nautical miles (4,037.4 km), and a climb rate of 2850 feet (868.7 m) per minute.

The Mosquito PR Mk IV was 27 Mosquito B Mk IV bombers, converted into two-seat photo-reconnaissance aircraft. The type first flew in April 1942.
The Mosquito PR Mk VIII was the next photo-reconnaissance version. It was to fill as an interim solution until PR.IX and PR.XVI models were available in large numbers. The VIII was based on the IV but it was powered by two Rolls-Royce Merlin 61 engines in place of Merlin 21/22s. It first flew on 20 October 1941. The four built were converted from B.IVs. The PR Mk VIII had a maximum speed of 436 mph (700 km/h), a cruise speed of 258 mph (415 km/h), ceiling of 38,000 ft (11,580 m), a range of 2,550 nm (4,100 km), and a climb rate of 2,500 feet per minute (760 m).

The Mosquito PR Mk IX was another unpressurized version without any armament. It first flew on 24 March 1943; 54 were built in total. It was based on the Mosquito B Mk IX bomber aircraft. Powered by two 1,680 hp (1,253 kW) Merlin 72/73 or 76/77 engines. It could carry either two 50 gallons (227.3 l), two 100 gallon (455 litre) or two 200 gallon (910 litre) droppable fuel tanks. In total 90 were built.

The Mosquito PR Mk XVI had a pressurised cockpit and three additional fuel tanks in the bomb bay. It was powered by two Rolls-Royce Merlin 72/73 or 76/77 piston engines. A total of 435 of the PR Mk XVI were built. The PR Mk XVI had a maximum speed of 415 mph (668 km/h), a cruise speed of 250 mph (402 km/h), ceiling of 38,500 ft (11,730 m), a range of 2,450 nm (3,942 km), and a climb rate of 2,900 feet per minute (884 m).

The Mosquito PR Mk 32 was a long-range, high-altitude pressurized photo-reconnaissance version. It was powered by a pair of two-stage supercharged 1,960 hp (1,260 kW) Rolls-Royce Merlin 113 and Merlin 114 piston engines, the Merlin 113 on the starboard side and the Merlin 114 on the port. First flown in August 1944, only five were built and all were conversions from PR.XVIs.
The Mosquito PR Mk 34 and PR Mk 34A was a very long-range unarmed high altitude photo-reconnaissance version. The fuel tank and cockpit protection armour were removed. Additional fuel was carried in a bulged bomb-bay: 1,192 gallons which was the equivalent of 5419 miles (8,721 km). A further two 200 gallon (910 litre) drop tanks under the outer wings gave a range of 3,600 miles (5,800 km) cruising at 300 mph (480 km/h). Powered by two 1,690 hp (1,259 kW) Merlin 114s first used in the PR.32. The port Merlin 114 drove a Marshal cabin supercharger. A total of 181 were built including 50 built by Percival Aircraft Company at Luton
Luton
Luton is a large town and unitary authority of Bedfordshire, England, 30 miles north of London. Luton and its near neighbours, Dunstable and Houghton Regis, form the Luton/Dunstable Urban Area with a population of about 250,000....

. The PR.34's maximum speed (TAS) was 335 mi/h at sea level, 405 mi/h at 17000 ft (5,181.6 m) and 425 mi/h at 30000 ft (9,144 m).
All PR.34s were installed with four split F.52 vertical cameras, two forward, two aft of the fuselage tank and one F.24 oblique camera. Sometimes a K.17 camera was used for air surveys. In August 1945 the PR.34A was the final photo-reconnaissance variant with one Merlin 113A and 114A each delivering 1,710 hp (1,274 kW).

Colonel Roy M. Stanley II, USAF (RET) wrote; "I consider the Mosquito the best photo reconnaissance aircraft of the war".

Bombers

On 21 June 1941 the Air Ministry ordered that the last 10 Mosquitoes, ordered as photo-reconnaissance aircraft, should be converted to bomber use. These 10 machines were part of the original 1 March 1940 production order. These became the B.IV Series I. Aircraft W4072 was to be the prototype. It flew for the first time on 8 September 1941. The 50 B.IV series II bombers differed from the series I in having a larger bomb bay to increase the payload to four 500 lb (226.8 kg) bombs instead of four 250 lb (115 kg) bombs of Series I. This was made possible by shortening the stabilizer of the 500 lb (230 kg) bomb so that these four larger weapons could be carried.

The bomber prototype led to the B Mk IV, of which 273 were built. The B Mk IV could accommodate four 500 lb (226.8 kg) bombs, or a 2,000 lb (920;kg) total load in the bomb bay. Some of these variants were later converted for special operations with the Highball
Bouncing bomb
A bouncing bomb is a bomb designed specifically to bounce to a target across water in a calculated manner, in order to avoid obstacles such as torpedo nets, and to allow both the bomb's speed on arrival at the target and the timing of its detonation to be pre-determined...

 anti-shipping weapon. A B.IV was used a trials aircraft for the bomb. In RAF Bomber Command
RAF Bomber Command
RAF Bomber Command controlled the RAF's bomber forces from 1936 to 1968. During World War II the command destroyed a significant proportion of Nazi Germany's industries and many German cities, and in the 1960s stood at the peak of its postwar military power with the V bombers and a supplemental...

 54 B.IVs were modified to have bulged bomb bays to carry a 4,000 lb (1,812 kg) High explosive bomb to operate as a light night-striking force. The B Mk IV had a maximum speed of 380 mph (611 km/h), a cruising speed of 265 mph (426 km/h), ceiling of 34,000 ft (10,360 m), a range of 2,040 nm (3,280 km), and a climb rate of 2,500 feet per minute (762 m).

Other bomber variants of the Mosquito included the Merlin 21 powered B Mk V high-altitude version. Trials with this configuration were made with W4057 which had the wings strengthened and an addition of two fuel tanks. Alternatively, two 500 lb (227 kg) bombs. This design was not produced in Britain, but formed the basic design of the Canadian-built B.VII. Only the W4057 was built in prototype form. The Merlin 31 powered B Mk VII was built by de Havilland Canada. It was based on the B.V and first flown on 24 September 1942. It only saw service in Canada and only 25 were built. Six were handed over to the United States Army Air Force. B Mk IX (54 built) was powered by either the Merlin 72,73, 76 or 77. The two-stage Merlin variant was based on the PR.IX. The prototype was converted from a PR.VIII. Prototype DK 324 was first flown on 24 March 1943.
The B Mk IX had a maximum speed of 408 mph (656 km/h), a cruising speed of 250 mph (402 km/h), ceiling of 36,000 ft (10,970 m), a range of 2,450 nm (3,940 km), and a climb rate of 2,850 feet per minute (869 m). The IX could carry a maximum load of 2-4,000 lb (910-1,810 kg) of bombs. A Mosquito B.IX holds the record for the most combat operations flown by an Allied bomber in the Second World War. LR503, known as "F for Freddie" because of its squadron code letters, GB*F, first served with 109 and subsequently 105 Squadron of the RAF. It flew 213 sorties during the war, only to crash at Calgary airport during the 8th Victory Loan Bond Drive on 10 May 1945, two days after Victory in Europe Day
Victory in Europe Day
Victory in Europe Day commemorates 8 May 1945 , the date when the World War II Allies formally accepted the unconditional surrender of the armed forces of Nazi Germany and the end of Adolf Hitler's Third Reich. The formal surrender of the occupying German forces in the Channel Islands was not...

, killing both the pilot, Flt. Lt. Maurice Briggs, DSO, DFC, DFM and navigator Fl. Off. John Baker, DFC and Bar.

The B.XVI was powered by the same variations as the B.IX. The two-stage powerplants were added along with a pressurised cabin. DZ540 first flew on 1 January 1944. The prototype was converted from a IV (402 built). The next variant, the B.XX, was powered by Packard Merlins 31 and 33s. It was the Canadian version of the IV. Altogether, 245 were built.

The B.35 was powered by Merlin 113 and 114As. Some were converted to TT.35s (Target Tugs) and others were used as PR.35s (photo reconnaissance). The B Mk XVI had a maximum speed of 408 mph (656 km/h), a cruising speed of 245 mph (394 km/h), ceiling of 37,000 ft (11,280 m), a range of 1,485 nm (2,390 km), and a climb rate of 2,800 feet per minute (853 m). The type could carry 4,000 lb (1,810 kg) of bombs. The B.35 had a maximum speed of 422 mph (679 km/h), a cruising speed of 276 mph (444 km/h), ceiling of 42,000 ft (12,800 m), a range of 1,750 nm (2,820 km), and a climb rate of 2,700 feet per minute (823 m).

Fighter aircraft

Developed during 1940, the Mosquito F Mk II was developed and the first prototype was completed on 15 May 1941. These aircraft were fitted with four 20 mm (.79 in) Hispano cannon
Hispano-Suiza HS.404
The Hispano-Suiza HS.404 was an autocannon widely used as both an aircraft and land weapon in the 20th century by British, American, French, and numerous other military services. The cannon is also referred to as Birkigt type 404, after its designer. Firing a 20 mm caliber projectile, it delivered...

 in the fuselage belly and four .303 in (7.7 mm) Browning machine gun
M1919 Browning machine gun
The M1919 Browning is a .30 caliber medium machine gun that was widely used during the 20th century. It was used as a light infantry, coaxial, mounted, aircraft, and anti-aircraft machine gun by the U.S. and many other countries, especially during World War II, the Korean War, and the Vietnam War...

s mounted in the nose. This fit required the movement of the crew ingress/egress door from the bottom to the right side of the nose. The aircraft also featured a modified windscreen, with flat bulletproof panels in front.

The aircraft was made largely out of wood, the majority of it being plywood. Notable features were the leading edge radiators and the use of compression rubber blocks in the undercarriage legs. The type was also fitted with a gun camera in a compartment above the weapons themselves in the nose. The aircraft was also fitted with exhaust flame dampers to handle the Merlin XX's fumes. The machine had a wing aspect ratio of seven.

Night fighter aircraft

The first production night fighter
Night fighter
A night fighter is a fighter aircraft adapted for use at night or in other times of bad visibility...

 Mosquitos were designated Mosquito NF Mk II. A total of 466 were built with the first entering service with No. 157 Squadron
No. 157 Squadron RAF
No. 157 Squadron RAF was a Royal Air Force Squadron that was active as a night fighter unit in World War II.-Formation and World War I:No. 157 Squadron Royal Flying Corps was formed on 14 July 1918 at RAF Upper Heyford and was eventually equipped with Salamander aircraft for ground support duties,...

 in January 1942, replacing the Douglas Havoc. These aircraft were similar to the F Mk II, but were fitted with the AI Mk IV metric wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...

 radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...

. The herring-bone transmitting
Transmitter
In electronics and telecommunications a transmitter or radio transmitter is an electronic device which, with the aid of an antenna, produces radio waves. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating...

 antenna
Antenna (radio)
An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...

 was mounted on the nose and the dipole receiving
Receiver (radio)
A radio receiver converts signals from a radio antenna to a usable form. It uses electronic filters to separate a wanted radio frequency signal from all other signals, the electronic amplifier increases the level suitable for further processing, and finally recovers the desired information through...

 antennae were carried under the outer wings. A number of NF IIs had their radar equipment removed and additional fuel tanks installed for use as night intruders. These aircraft, designated NF II (Special) were first used by 23 Squadron
No. 23 Squadron RAF
No. 23 Squadron was a squadron of the Royal Air Force. Until October 2009, it operated the Boeing Sentry AEW1 Airborne Warning And Control System aircraft from RAF Waddington, Lincolnshire.-First World War:...

 in operations over Europe in 1942. No. 23 Squadron was then deployed to Malta on 20 December 1942, and operated against targets in Italy.

Ninety-seven NF Mk IIs were upgraded with centimetric AI Mk VIII radar and these were designated Mosquito NF Mk XII. The Mosquito NF Mk XIII, of which 270 were built, was the production equivalent of the Mk XII conversions. The centimetric radar sets were mounted in a solid "thimble" (Mk XII / XIII) or "bull nose" (Mk XVII / XIX) radome, which required the machine guns to be dispensed with. The other night fighter variants were the Mk XV, Mk XVII (converted Mk IIs), Mk XIX and Mk 30. The last three marks mounted the U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

-built AI Mk X radar.
  • Mosquito NF Mk X: Unbuilt night fighter version.
  • Mosquito NF Mk XI: Unbuilt night fighter version.
  • Mosquito NF Mk XIV: Unbuilt night fighter version.
  • Mosquito NF Mk XV: This designation was given to five Mosquito B Mk IV bombers, which were converted into two-seat high-altitude night fighters.
  • Mosquito NF Mk XVII: Designation for 99 NF.II conversions, with single-stage Merlin 21, 22, or 23 engines, but British AI.X (US SCR-720) radar.
  • Mosquito NF Mk XIX: Improved version of the Mosquito NF XIII night fighter aircraft. It could be fitted with American or British AI radars; 220 built.
  • Mosquito NF Mk 30: High-altitude night fighter version. Powered by two 1,710 hp (1,275 kW) Roll-Royce Merlin 76 piston engines, enabling a 424 mph (682.4 km/h) top speed at 26500 ft (8,077.2 m). It also carried early electronic countermeasures
    Electronic countermeasures
    An electronic countermeasure is an electrical or electronic device designed to trick or deceive radar, sonar or other detection systems, like infrared or lasers. It may be used both offensively and defensively to deny targeting information to an enemy...

     equipment. 526 built.
  • Mosquito NF Mk 31: Unbuilt night fighter version.


After the war, two more night fighter versions were developed, the NF Mk 36 and the NF Mk 38.
  • Mosquito NF Mk 36: Similar to the Mosquito NF Mk 30, but fitted with the American-built AI.Mk X radar. Powered by two 1,690 hp (1,260 kW) Roll-Royce Merlin 113/114 piston engines; 266 built. Max level speeds (TAS) with flame dampers fitted were 305 mi/h at sea level, 380 mi/h at 17000 ft (5,181.6 m), and 405 mi/h at 30000 ft (9,144 m).
  • Mosquito NF Mk 38: Similar to the Mosquito NF Mk 30, but fitted with the British-built AI Mk IX radar. 50 built. Type had a VNE of 370 knots (425 mph) without under wing add-ons and within the altitude of seal level to 10000 ft (3,048 m). From 10,000 to 15000 ft (4,572 m) the fell to 348 knots (400 mph). As the height increased other recorded speeds are as follows; 15,000 to 20000 ft (6,096 m) speed was 320 knots (368 mph); 20,000 to 25000 ft (7,620 m), speed was 295 knots (339 mph); 25,000 to 30000 ft (9,144 m), 260 knots (299 mph); 30,000 to 35000 ft (10,668 m), speed was 235 knots (270 mph). With two added 100 gallon fuel tanks this performance falls; between sea level and 15,000 feet 330 knots (379 mph); between 15,000 to 20000 ft (6,096 m) it drops to 320 knots (368 mph); 20,000 to 25000 ft (7,620 m), speed was 295 knots (339 mph); 25,000 to 30000 ft (9,144 m), 260 knots (299 mph); 30,000 to 35000 ft (10,668 m), speed was 235 knots (270 mph). Little difference is noted in speed above 15000 ft (4,572 m).


Mosquito night intruders of No. 100 Group RAF
No. 100 Group RAF
No. 100 Group was a special duties group within RAF Bomber Command.It was formed on 11 November 1943 to consolidate the increasingly complex business of electronic warfare and countermeasures within one organisation. The group was responsible for the development, operational trial and use of...

, Bomber Command, were also fitted with a device called "Serrate
Serrate radar detector
Serrate was an Allied radar detection and homing device, used in Allied nightfighters to track German night fighters equipped with the earlier UHF-band BC and C-1 versions of the Lichtenstein radar during World War II....

" to allow them to track down German night fighters from their Lichtenstein
Lichtenstein radar
Lichtenstein radar was a German airborne radar in use during World War II. It was available in at least four major revisions, the FuG 202 Lichtenstein B/C, FuG 212 Lichtenstein C-1, FuG 220 Lichtenstein SN-2 and FuG 228 Lichtenstein SN-3.- FuG 202 Lichtenstein B/C :Early FuG 202 Lichtenstein B/C...

 B/C and SN-2 radar emissions, as well as a device named "Perfectos" that tracked German IFF
Identification friend or foe
In telecommunications, identification, friend or foe is an identification system designed for command and control. It is a system that enables military and national interrogation systems to identify aircraft, vehicles, or forces as friendly and to determine their bearing and range from the...

 signals.

Fighter-bomber aircraft

The most numerous Mosquito variant was the FB Mk VI fighter-bomber of which 2,298 were built, some one-third of Mosquito production. The prototype was converted from a B.VI first flew in February 1943.

The FB Mk VI was powered by two 1,460 hp (1,088 kW) Merlin 21s or 1,635 hp (1,218 kW) Merlin 25s. It first flew on 1 June 1942. Some 19 that were built by Airspeed Ltd were eventually modified to be completed as FB.XVIIIs. Two were converted to TR.33 maritime assault prototypes. The variant was generally armed with four 20 mm cannon and four .303 (7.7 mm) machine guns for hitting soft ground targets. The main hitting power came from the two 250 lb (115 kg) bombs enclosed in the bomb bay plus more and was later plus two RP-3 "60 lb" rockets
RP-3
The RP-3 , was a British rocket used in the Second World War. Though primarily an air-to-ground weapon, it saw limited use in other roles. Its 60 lb warhead gave rise to the alternative name of the "60 lb rocket"; the 25 lb solid-shot armour piercing variant was referred to as the "25 lb rocket"...

 to carry out anti-shipping strikes. Other variations of armament fixtures could have entailed eight 60 lb (27 kg) rockets in place of any other internal load. Later the main bomb load was upgraded to two 500 lb (230 kg) bombs. Alternatively, a third option could have been an aerial mine or depth charge
Depth charge
A depth charge is an anti-submarine warfare weapon intended to destroy or cripple a target submarine by the shock of exploding near it. Most use explosives and a fuze set to go off at a preselected depth in the ocean. Depth charges can be dropped by either surface ships, patrol aircraft, or from...

 for attacking German submarines. All-out level speed is often given as 368 mi/h, however this speed applies to aircraft fitted with saxophone exhausts. The test aircraft (HJ679) fitted with stub exhausts was found to be performing below expectations. It was returned to de Havilland at Hatfield where it was serviced. Its top speed was then tested and found to be 384 mi/h, in line with expectations.

The FB Mk VI proved durable in dogfights with single-engine fighter aircraft
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...

. Retaining the forward-firing armament, Mosquito FB Mk VIs of No. 143 Squadron RAF were engaged by 30 Focke-Wulf Fw 190
Focke-Wulf Fw 190
The Focke-Wulf Fw 190 Würger was a German Second World War single-seat, single-engine fighter aircraft designed by Kurt Tank in the late 1930s. Powered by a radial engine, the 190 had ample power and was able to lift larger loads than its well-known counterpart, the Messerschmitt Bf 109...

s from Jagdgeschwader 5
Jagdgeschwader 5
Jagdgeschwader 5 Eismeer was a Luftwaffe fighter Wing that served during World War II. As the name Eismeer implies, it was created to operate in the far North of Europe, namely Norway, Scandinavia and northern parts of Finland, all nearest the Arctic Ocean...

 on 15 January 1945. In the ensuing battle five Mosquitos were lost but five Fw 190s were shot down in return as well as sinking an armed trawler and two merchant ships.

Other fighter-bomber variants were the Mosquito FB Mk XVIII (sometimes known as the Tsetse
Tsetse fly
Tsetse , sometimes spelled tzetze and also known as tik-tik flies, are large biting flies that inhabit much of mid-continental Africa between the Sahara and the Kalahari deserts. They live by feeding on the blood of vertebrate animals and are the primary biological vectors of trypanosomes, which...

) of which 18 were built and a total of 27 were made by converting Mk VIs. These were fitted with a Molins "6-pounder Class M" cannon, a modification of the QF 6-pounder (57 mm) anti-tank gun
Ordnance QF 6 pounder
The Ordnance Quick-Firing 6-pounder 7 cwt, or just 6 pounder, was a British 57 mm gun, their primary anti-tank gun during the middle of World War II, as well as the main armament for a number of armoured fighting vehicles...

 weighing 1,580 lb (716 kg) fitted with an auto-loader to allow both semi- or fully automatic fire, in the nose, along with two .303 in (7.7 mm) sighting machine guns. The cannon was later deleted. The Air Ministry
Air Ministry
The Air Ministry was a department of the British Government with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964...

 initially suspected that this variant would not work, but tests proved otherwise. Although the gun provided the Mosquito with yet more anti-shipping firepower for use against U-boats it required a steady, and hence vulnerable, approach-run to aim and fire the gun. In comparison, rockets were more effective, especially because the 6-pounder was a significant weight penalty. The aircraft carried 24 rounds for the 6 pounder which had a muzzle velocity of 2,950 ft/s (900 m/s). The gun had an excellent range, some 1,800 - 1,500 yards (1,650 - 1,370 m). It was sensitive to sidewards movement and an attack required a dive from 5,000 ft (1,520 m) at a 30° angle with the Turn and bank indicator
Turn and bank indicator
In aviation, the turn and bank indicator shows the rate of turn and the coordination of the turn. The rate of turn is indicated from a rate gyroscopically and the coordination of the turn is shown by either a pendulum or a heavy ball mounted in a curved sealed glass tube. No pitch information is...

 on centre. A move during the dive could jam the cannon.
The prototype was converted from a FB.VI and was first flown on 8 June 1943.

The effect of the new weapon was demonstrated on 10 March 1944 when four Mk VIs escorting XVIIIs from 248 Squadron engaged a German convoy of one U-Boat and four destroyers, protected by 10 Ju 88s. Three of the Ju 88s were shot down. Pilot Tony Phillips destroyed one Ju 88 with four shells, one of which tore an engine off the Ju 88. The U-Boat was damaged. On 25 March, U-976 was sunk by Molins-equipped Mosquitos. On 10 June, U-821 was abandoned in the face of intense air attack from No. 248 Squadron, and was later sunk by a Liberator
B-24 Liberator
The Consolidated B-24 Liberator was an American heavy bomber, designed by Consolidated Aircraft of San Diego, California. It was known within the company as the Model 32, and a small number of early models were sold under the name LB-30, for Land Bomber...

 of No. 206 Squadron. On 5 April 1945 Molins Mosquitos again demonstrated their value and attacked five German surface ships in the Kattegat
Kattegat
The Kattegat , or Kattegatt is a sea area bounded by the Jutland peninsula and the Straits islands of Denmark on the west and south, and the provinces of Västergötland, Scania, Halland and Bohuslän in Sweden on the east. The Baltic Sea drains into the Kattegat through the Øresund and the Danish...

 and set all of them on fire and sinking. The Sperrbrecher
Sperrbrecher
A Sperrbrecher , was a German auxiliary ship of the Second World War that was intended to serve as a type of minesweeper, by sailing ahead of other vessels through minefields, intending to detonate any mines in their path...

 was lost with all hands, with some 200 bodies being recovered by Swedish
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

 vessels. Some 900 German soldiers died in total. On 9 April German U-Boats U-804
German submarine U-804
German submarine U-804 was a Type IXC/41 U-boat of the German Kriegsmarine during World War II. U-804 was ordered on 7 December 1940, and was laid down on 1 December 1942 at Deutsche Schiff- und Maschinenbau AG, Bremen as 'werk 362'...

, U-843 and U-1065
German submarine U-1065
German submarine U-1065 was a Type VIIC/41 U-boat of the German Kriegsmarine during World War II.She was ordered on 14 September 1941, and was laid down on 23 September 1943 at Krupp Germaniawerft, Kiel, as 'werk 702'...

 were spotted in formation heading for Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

. All were sunk. U-251 and U-2359 followed on the 19 April and 2 May 1945.

Despite the preference for rockets, a further development of the idea was carried out using the even larger 32-pounder
Ordnance QF 32 pounder
The Ordnance QF 32 pounder or ' was a British 94 mm gun, developed as a replacement for the Ordnance QF 17 pounder anti tank and tank gun....

, a gun based on the QF 3.7 inch AA gun
QF 3.7 inch AA gun
The 3.7-Inch QF AA was Britain's primary heavy anti-aircraft gun during World War II. It was roughly the equivalent of the German 88 mm FlaK but with a slightly larger calibre of 94 mm and superior performance. It was used throughout World War II in all theatres except the Eastern Front...

 designed for tank use, the airborne version using a novel form of muzzle brake
Muzzle brake
Muzzle brakes and recoil compensators are devices that are fitted to the muzzle of a firearm or cannon to redirect propellant gases with the effect of countering both recoil of the gun and unwanted rising of the barrel during rapid fire...

. Developed to prove the feasibility of using such a large weapon in the Mosquito, this installation was not completed until after the war when it was flown and fired in a single aircraft without problems before being scrapped. The FB Mk 26 and FB Mk 40, based on the Mk VI, were built in Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

 and Australia and were powered by later versions of the Packard
Packard
Packard was an American luxury-type automobile marque built by the Packard Motor Car Company of Detroit, Michigan, and later by the Studebaker-Packard Corporation of South Bend, Indiana...

-built Merlin engines. The FB.26 was the Canadian variant version of the VI and improved from the FB.21. Two 1,620 hp (1,207 kW) single stage Packard built Merlin 225s. Some 300 were built and another 37 converted to T.29 standard. 212 FB.40s were built by versions of FB.VI were produced by de Havilland Australia. Six were converted to PR.40; 28 to PR.41s one to FB.42 and 22 to T.43s tactical assault aircraft. Most units were powered by Packard-built Merlin 31 or 33s.

All the fighter variants shared a number of common features. They had a flat, single-piece armoured windscreen
Bulletproof glass
Bulletproof glass is a type of strong but optically transparent material that is particularly resistant to being penetrated when struck by bullets, but is not completely impenetrable. It is usually made from a combination of two or more types of glass, one hard and one soft...

 and the pilot was provided with a fighter-style control stick rather than a wheel. The guns in the nose also meant that the bomber variants' entry hatch in the nose had to be relocated to a door on the starboard side, forward of the leading edge.

Training aircraft

The Mosquito was also built as a trainer
Trainer (aircraft)
A trainer is a class of aircraft designed specifically to facilitate in-flight training of pilots and aircrews. The use of a dedicated trainer aircraft with additional safety features—such as tandem flight controls, forgiving flight characteristics and a simplified cockpit arrangement—allows...

.
  • Mosquito T Mk III : Two-seat training version. Powered by two Rolls-Royce Merlin 21 piston engines. A total of 348 of the T Mk III were built for the RAF and Fleet Air Arm
    Fleet Air Arm
    The Fleet Air Arm is the branch of the British Royal Navy responsible for the operation of naval aircraft. The Fleet Air Arm currently operates the AgustaWestland Merlin, Westland Sea King and Westland Lynx helicopters...

    . de Havilland Australia
    De Havilland Australia
    De Havilland Aircraft Pty Ltd was part of de Havilland, then became a separate company. It was purchased by Boeing and is now Hawker de Havilland Aerospace Pty Ltd, a subsidiary of Boeing Australia Ltd-Early Years and WWII:...

     built 11 T Mk 43 trainers, similar to the Mk III.

Torpedo-bomber aircraft

To meet specification N.15/44 for a navalised Mosquito for Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 use as a torpedo bomber, de Havilland produced a carrier-borne
Aircraft carrier
An aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...

 variant. A Mosquito FB.VI was modified as a prototype designated Sea Mosquito TR Mk 33 with folding wings, arrester hook, thimble nose radome, Merlin 25 engines with four-bladed propellers and a new oleo-pneumatic landing gear rather than the standard rubber-in-compression gear. An order for 100 TR.33s was placed although only 50 were built at Leavesden. Armament was four 20mm cannon, two 500lb bombs in the bomb bay, (another two could be fitted under the wings) eight 60lb rockets (four under each wing) and a standard torpedo under the fuselage. The first production TR.33 flew on the 10 November 1945. These were followed by six Sea Mosquito TR Mk 37s, which differed in having ASV Mk. XIII radar instead of the TR.33's AN/APS-6.

Target tug aircraft

The Royal Navy also operated the Mosquito TT Mk 39 for target towing. A number of B Mk XVIs bombers were converted into TT Mk 39 target tug aircraft. The RAF's target tug version was the Mosquito TT Mk 35 which were the last aircraft to remain in operational service, finally being retired in 1956.

Canadian-built aircraft

A total of 1,133 (to 1945) Mosquitos were built by De Havilland Canada at Downsview Airfield in Downsview Ontario (now Downsview Park in Toronto Ontario).
  • Mosquito B Mk VII : Canadian version based on the Mosquito B Mk V bomber aircraft. Powered by two 1,418 hp (1,057 kW) Packard Merlin 31 piston engines; 25 built.
  • Mosquito B Mk XX : Canadian version of the Mosquito B Mk IV bomber aircraft; 145 built, of which 40 were converted into F-8 photo-reconnaissance aircraft for the USAAF.
  • Mosquito FB Mk 21 : Canadian version of the Mosquito FB Mk VI fighter-bomber aircraft. Powered by two 1,460 hp (1,089 kW) Rolls-Royce Merlin 31 piston engines, three built.
  • Mosquito T Mk 22 : Canadian version of the Mosquito T Mk III training aircraft.
  • Mosquito B Mk 23 : Unused designation for a bomber variant.
  • Mosquito FB Mk 24 : Canadian fighter-bomber version. Powered by two 1,620 hp (1,208 kW) Rolls-Royce Merlin 301 piston engines; two built.
  • Mosquito B Mk 25 : Improved version of the Mosquito B Mk XX Bomber aircraft. Powered by two 1,620 hp (1,208 kW) Packard Merlin 225 piston engines; 400 built.
  • Mosquito FB Mk 26 : Improved version of the Mosquito FB Mk 21 fighter-bomber aircraft. Powered by two 1,620 hp (1,208 kW) Packard Merlin 225 piston engines; 338 built.
  • Mosquito T Mk 27 : Canadian-built training aircraft.
  • Mosquito T Mk 29 : A number of FB Mk 26 fighters were converted into T Mk 29 trainers.

Australian-built aircraft

  • Mosquito FB Mk 40 : Two-seat fighter-bomber version for the RAAF. Powered by two 1,460 hp (1,089 kW) Roll-Royce Merlin 31 piston engines. A total of 178 built in Australia.
  • Mosquito PR Mk 40 : This designation was given to six FB Mk 40s, which were converted into photo-reconnaissance aircraft.
  • Mosquito FB Mk 41 : Two-seat fighter-bomber version for the RAAF. A total of 11 were built in Australia.
  • Mosquito PR Mk 41 : Two-seat photo-survey version for the RAAF. A total of 17 were built in Australia.
  • Mosquito FB Mk 42 : Two-seat fighter-bomber version. Powered by two Rolls-Royce Merlin 69 piston engines. One FB Mk 40 aircraft was converted into a Mosquito FB Mk 42.
  • Mosquito T Mk 43 : Two-seat training version for the RAAF. A total of 11 FB Mk 40s were converted into Mosquito T Mk 43s.

Highball

A number of Mosquito IVs were modified by Vickers-Armstrongs to carry Highball
Bouncing bomb
A bouncing bomb is a bomb designed specifically to bounce to a target across water in a calculated manner, in order to avoid obstacles such as torpedo nets, and to allow both the bomb's speed on arrival at the target and the timing of its detonation to be pre-determined...

 and were allocated Vickers Type numbers:
  • Type 463 - Prototype Highball conversion of Mosquito IV DZ741.
  • Type 465 - Conversion of 33 Mosquito IVs to carry Highball.

Details

In England, fuselage shells were mainly made by the furniture companies Ronson, E. Gomme
G-Plan
G-Plan was a pioneering range of furniture in the United Kingdom, produced by E Gomme Ltd of High Wycombe.In 1943, during World War II, furniture was part of rationing in the United Kingdom; the Board of Trade set up the Utility scheme which limited costs and the types of furniture on sale. A small...

, Parker Knoll
Parker Knoll
Parker Knoll is a British furniture manufacturing company, originally formed by Frederick Parker, a British furniture manufacturer, and Willi Knoll, a German inventor of a new form of sprung furniture. With roots in the manufacture of high-quality furniture, the brand concentrated on mass-market...

 and Styles & Mealing. The specialized wood veneer
Wood veneer
In woodworking, veneer refers to thin slices of wood, usually thinner than 3 mm , that are typically glued onto core panels to produce flat panels such as doors, tops and panels for cabinets, parquet floors and parts of furniture. They are also used in marquetry...

 used in the construction of the Mosquito was made by Roddis Manufacturing in Marshfield, Wisconsin
Marshfield, Wisconsin
Marshfield is a city in Marathon and Wood counties in the U.S. state of Wisconsin. It is the largest city in Wood County. The small portion of the city that extends into Marathon County is part of the Wausau Metropolitan Statistical Area. The population was 18,800 at the 2000 census. Marshfield is...

, United States. Hamilton Roddis had teams of dexterous young women ironing the (unusually thin) strong wood veneer product before shipping to the UK. Wing spars were made by J.B. Heath and Dancer & Hearne. Many of the other parts, including flaps, flap shrouds, fins, leading edge assemblies and bomb doors were also produced in High Wycombe, Buckinghamshire, which was well suited to these tasks because of a well-established furniture-manufacturing industry. Dancer & Hearne processed much of the wood from start to finish, receiving timber and transforming it into finished wing spars at their High Wycombe
High Wycombe
High Wycombe , commonly known as Wycombe and formally called Chepping Wycombe or Chipping Wycombe until 1946,is a large town in Buckinghamshire, England. It is west-north-west of Charing Cross in London; this figure is engraved on the Corn Market building in the centre of the town...

 factory.

About 5,000 of the 7,781 Mosquitos made contained parts made in High Wycombe. In Canada, fuselages were built in the Oshawa, Ontario
Oshawa, Ontario
Oshawa is a city in Ontario, Canada, on the Lake Ontario shoreline. It lies in Southern Ontario approximately 60 kilometres east of downtown Toronto. It is commonly viewed as the eastern anchor of both the Greater Toronto Area and the Golden Horseshoe. It is now commonly referred to as the most...

 plant of General Motors
General Motors
General Motors Company , commonly known as GM, formerly incorporated as General Motors Corporation, is an American multinational automotive corporation headquartered in Detroit, Michigan and the world's second-largest automaker in 2010...

 of Canada Limited. These were shipped to De Havilland
De Havilland
The de Havilland Aircraft Company was a British aviation manufacturer founded in 1920 when Airco, of which Geoffrey de Havilland had been chief designer, was sold to BSA by the owner George Holt Thomas. De Havilland then set up a company under his name in September of that year at Stag Lane...

 Canada in Toronto for mating to fuselages and completion. As a secondary manufacturer, de Havilland Australia started construction in Sydney. These production lines added 1,076 from Canada and 212 from Australia.

Total Mosquito production was 7,781 of which 6,710 were built during the war. The ferry operation of the Mosquito from Canada to the war front was problematic, as a small fraction of the aircraft would mysteriously disappear over the mid-Atlantic. The theory of "auto-explosion" was offered, and, although a concentrated effort at de Havilland Canada to address production problems with engine and oil systems reduced the number of aircraft lost, it was unclear as to the actual cause of the losses. The company introduced an additional five hours flight testing to "clear" production aircraft before the ferry flight. By the end of the war, nearly 500 Mosquito bombers and fighter-bombers were delivered successfully by the Canadian operation.

In total, both during the war and post war, de Havilland exported 46 FB.VIs and 29 PR.XVIs to Australia, two FB.VI and 18 NF.30s to Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

, approximately 205 FB.26, T.29 and T.27s to Nationalist China, 19 FB.VIs to Czechoslovakia
Czechoslovakia
Czechoslovakia or Czecho-Slovakia was a sovereign state in Central Europe which existed from October 1918, when it declared its independence from the Austro-Hungarian Empire, until 1992...

 in 1948, 6 FB.VIs to Dominica
Dominica
Dominica , officially the Commonwealth of Dominica, is an island nation in the Lesser Antilles region of the Caribbean Sea, south-southeast of Guadeloupe and northwest of Martinique. Its size is and the highest point in the country is Morne Diablotins, which has an elevation of . The Commonwealth...

, a few B.IVs, 57 FB.VIs, 29 PR.XVIs and 23 NF.XXXs to France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

. Some T.IIIs were exported to Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...

 along with 60 FB.VIs, and at least five PR.XVIs and 14 naval versions. Four T.IIIs, 76 FB.VIs, one FB.40 and four T.43s were exported to New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

. Three T.IIIs were exported to Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

, and 18 FB.VIs which were later converted to night fighter standard. South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

 received two F.II and 14 PR.XVI/XIs and Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

 received 46 NF.XIXs. Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...

 received 96 FB.VIs and several T.IIIs, and Yugoslavia
Yugoslavia
Yugoslavia refers to three political entities that existed successively on the western part of the Balkans during most of the 20th century....

 had 60 NF.38s, 80 FB.VIs and three T.IIIs delivered.

Production sites

Production
Producer and site Number built
de Havilland Hatfield, Hertfordshire
Hatfield, Hertfordshire
Hatfield is a town and civil parish in Hertfordshire, England in the borough of Welwyn Hatfield. It has a population of 29,616, and is of Saxon origin. Hatfield House, the home of the Marquess of Salisbury, is the nucleus of the old town...

3,326
de Havilland Leavesden, Hertfordshire 1,476
Standard Motor Company
Standard Motor Company
The Standard Motor Company was founded in Coventry, England in 1903 by Reginald Walter Maudslay . The Standard name was last used in Britain in 1963, and in India in 1987.-1903–1914:...

, Coventry
Coventry
Coventry is a city and metropolitan borough in the county of West Midlands in England. Coventry is the 9th largest city in England and the 11th largest in the United Kingdom. It is also the second largest city in the English Midlands, after Birmingham, with a population of 300,848, although...

1,066
Percival Aircraft Company, Luton
Luton
Luton is a large town and unitary authority of Bedfordshire, England, 30 miles north of London. Luton and its near neighbours, Dunstable and Houghton Regis, form the Luton/Dunstable Urban Area with a population of about 250,000....

245
Airspeed Aircraft, Portsmouth
Portsmouth
Portsmouth is the second largest city in the ceremonial county of Hampshire on the south coast of England. Portsmouth is notable for being the United Kingdom's only island city; it is located mainly on Portsea Island...

122
de Havilland Hawarden
Hawarden Airport
Hawarden Airport , is a small airport in Hawarden situated in North East Wales close to the border with England and west southwest of the city of Chester. The airport is owned and operated by BAE Systems. A long term tenancy agreement has been signed with Airbus UK, giving rights as the sole...

, Chester
Chester
Chester is a city in Cheshire, England. Lying on the River Dee, close to the border with Wales, it is home to 77,040 inhabitants, and is the largest and most populous settlement of the wider unitary authority area of Cheshire West and Chester, which had a population of 328,100 according to the...

96
de Havilland Canada
De Havilland Canada
The de Havilland Aircraft of Canada Ltd. company was an aircraft manufacturer with facilities based in what is now the Downsview area of Toronto, Ontario, Canada...

, Toronto
Toronto
Toronto is the provincial capital of Ontario and the largest city in Canada. It is located in Southern Ontario on the northwestern shore of Lake Ontario. A relatively modern city, Toronto's history dates back to the late-18th century, when its land was first purchased by the British monarchy from...

1,076
de Havilland Australia
De Havilland Australia
De Havilland Aircraft Pty Ltd was part of de Havilland, then became a separate company. It was purchased by Boeing and is now Hawker de Havilland Aerospace Pty Ltd, a subsidiary of Boeing Australia Ltd-Early Years and WWII:...

, Sydney
Sydney
Sydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...

212

Operational history

The de Havilland Mosquito operated in many roles during the Second World War. Mosquito-equipped squadrons were asked to perform medium bomber
Medium bomber
A medium bomber is a bomber aircraft designed to operate with medium bombloads over medium distances; the name serves to distinguish them from the larger heavy bombers and smaller light bombers...

, reconnaissance
Aerial reconnaissance
Aerial reconnaissance is reconnaissance that is conducted using unmanned aerial vehicles or reconnaissance aircraft. Their roles are to collect imagery intelligence, signals intelligence and measurement and signature intelligence...

, tactical strike, anti-submarine warfare and shipping attack and Night fighter
Night fighter
A night fighter is a fighter aircraft adapted for use at night or in other times of bad visibility...

 duties, both defensive and offensive, until the end of the war. The Mosquito was first announced publicly on 26 September 1942 after the Oslo Mosquito raid
Oslo Mosquito raid
The Oslo Mosquito raid was a British air raid on Oslo, Norway, during World War II. The target of the raid was the Victoria Terrasse building, the headquarters of the Gestapo...

 of 25 September.

Mosquitos were widely used by the RAF Pathfinder Force
Pathfinder (RAF)
The Pathfinders were elite squadrons in RAF Bomber Command during World War II. They located and marked targets with flares, which a main bomber force could aim at, increasing the accuracy of their bombing...

, which marked targets for night-time strategic bombing
Strategic bombing
Strategic bombing is a military strategy used in a total war with the goal of defeating an enemy nation-state by destroying its economic ability and public will to wage war rather than destroying its land or naval forces...

. Despite an initially high loss rate, the Mosquito ended the war with the lowest losses of any aircraft in RAF Bomber Command
RAF Bomber Command
RAF Bomber Command controlled the RAF's bomber forces from 1936 to 1968. During World War II the command destroyed a significant proportion of Nazi Germany's industries and many German cities, and in the 1960s stood at the peak of its postwar military power with the V bombers and a supplemental...

 service. Post war, the RAF found that when finally applied to bombing, in terms of useful damage done, the Mosquito had proved 4.95 times cheaper than the Lancaster
Avro Lancaster
The Avro Lancaster is a British four-engined Second World War heavy bomber made initially by Avro for the Royal Air Force . It first saw active service in 1942, and together with the Handley Page Halifax it was one of the main heavy bombers of the RAF, the RCAF, and squadrons from other...



Special Luftwaffe
Luftwaffe
Luftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....

 units (Jagdgeschwader 25 and Jagdgeschwader 50) were formed to combat the Mosquito attacks, though they were rather unsuccessful. Hermann Göring ordered the formation of the units in response to the "political humiliation" in April 1943. JG 25 and JG 50 were to be commanded by Oberstleutnant
Oberstleutnant
Oberstleutnant is a German Army and Air Force rank equal to Lieutenant Colonel, above Major, and below Oberst.There are two paygrade associated to the rank of Oberstleutnant...

 Herbert Ihlefeld
Herbert Ihlefeld
Herbert Ihlefeld was a German World War II fighter ace who served in the Luftwaffe from 1936 until the very end of World War II in May 1945. He was also a recipient of the Knight's Cross of the Iron Cross with Oak Leaves and Swords...

 and Major
Major
Major is a rank of commissioned officer, with corresponding ranks existing in almost every military in the world.When used unhyphenated, in conjunction with no other indicator of rank, the term refers to the rank just senior to that of an Army captain and just below the rank of lieutenant colonel. ...

 Hermann Graf
Hermann Graf
Colonel Hermann Graf was a German Luftwaffe World War II fighter ace. A flying ace or fighter ace is a military aviator credited with shooting down five or more enemy aircraft during aerial combat. He served on both the Eastern and Western Fronts...

. The units were "little more than glorified squadrons and achieved little against the elusive RAF aircraft". To cover the Luftwaffe's impotence the units were given great propaganda value by German propaganda. Walter Grabmann
Walter Grabmann
Walter Grabmann was a German World War II Luftwaffe Generalmajor. He was also a recipient of the Knight's Cross of the Iron Cross...

 stated that the units were not worth the expenditure in light of the results they obtained.

The Mosquito operated in both defensive and offensive operations for the duration of the war. The Mosquito flew its last official European war mission on 21 May 1945, when Mosquitos of 143 Squadron and 248 Squadron RAF were ordered to continue to hunt German submarines that might be tempted to continue the fight. Only passive E-Boats were encountered.

Some of the most successful RAF pilots flew the Mosquito. Night fighter pilots Wing Commander
Wing Commander (rank)
Wing commander is a commissioned rank in the Royal Air Force and the air forces of many other Commonwealth countries...

 Branse Burbridge
Branse Burbridge
Wing Commander Branse Burbridge, DSO & Bar, DFC & Bar , was the top scoring Allied night fighter pilot of World War II.Born in East Dulwich, Burbridge lived in Knebworth when the Second World War broke out in September 1939, working as an insurance clerk...

 claimed 21 kills; Bob Braham
Bob Braham
John Randall Daniel 'Bob' Braham DSO & Two Bars, DFC & Two Bars, AFC, CD, was a British pilot and one of the most highly decorated airman of the RAF in World War II. He claimed 29 enemy aircraft destroyed, probably destroyed one more, and damaged 6 in 318 operational flights...

 claimed around a third of his 29 kills in a Mosquito. John Cunningham claimed 19 of his 20 victories at night in his Mosquito, "Cat's Eyes".

One Mosquito is listed as belonging to German secret operations unit Kampfgeschwader 200, which tested, evaluated and sometimes clandestinely operated captured enemy aircraft during the war. The aircraft was listed on the order of battle
Order of battle
In modern use, the order of battle is the identification, command structure, strength, and disposition of personnel, equipment, and units of an armed force participating in field operations. Various abbreviations are in use, including OOB, O/B, or OB, while ORBAT remains the most common in the...

 of Versuchsverband OKLs, 2 Staffel, Stab Gruppe on 10 November and 31 December 1944. However, on both lists, the Mosquito is listed as unserviceable.

Göring's comments on the Mosquito

The Mosquito famously annoyed the Commander in Chief of the Luftwaffe, Reichsmarschall
Reichsmarschall
Reichsmarschall literally in ; was the highest rank in the armed forces of Nazi Germany during World War II after the position of Supreme Commander held by Adolf Hitler....

 Hermann Göring
Hermann Göring
Hermann Wilhelm Göring, was a German politician, military leader, and a leading member of the Nazi Party. He was a veteran of World War I as an ace fighter pilot, and a recipient of the coveted Pour le Mérite, also known as "The Blue Max"...

, when, on 20 January 1943, the 10th anniversary of the Nazis' seizure of power, a Mosquito attack knocked out the main Berlin broadcasting station, putting his speech off air. Göring complained about the high speed of the aircraft and its wooden structure, built by a nation he considered to have large metal reserves, while Germany had shortages of such materials and could not produce such a design.

Operators

 Myanmar
 Canada

 South Africa
 United States


Survivors

The last airworthy Mosquito, a T3 RR299 G-ASKH "HT-E", was destroyed in an airshow accident at Barton, Manchester, England, on 21 July 1996, in which both aircrew were killed. In 1959 RR299 was based at Exeter Airport serving in the CAACU (Civilian Anti-aircraft Cooperation Unit) located there. There are approximately 30 non-flying examples around the world with several under restoration. In 1963 aircraft collector Lynn Garrison
Lynn Garrison
Lynn Garrison is a Canadian pilot and political adviser. He was an RCAF fighter pilot from the 403 City of Calgary Squadron, commercial pilot, film producer, director and mercenary...

 purchased a B.35 (RS700)(CF-HMS) from Spartan Air Services for display in Calgary, Alberta. The largest collection of Mosquitos is at the de Havilland Aircraft Heritage Centre
De Havilland Aircraft Heritage Centre
The de Havilland Aircraft Heritage Centre, formerly the Mosquito Aircraft Museum, is a volunteer-run aviation museum in London Colney, Hertfordshire, England...

, which owns three aircraft. Three additional aircraft are currently under restoration to fly including one owned by Jerry Yagen, being restored by Glynn Powell in Auckland
Auckland
The Auckland metropolitan area , in the North Island of New Zealand, is the largest and most populous urban area in the country with residents, percent of the country's population. Auckland also has the largest Polynesian population of any city in the world...

, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

.

DH.98 Mosquito F Mk II

DH.98 Mosquito B Mk XVI

See also

External links

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