De Havilland Mosquito
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The de Havilland Mosquito ("The Wooden Wonder", also known as "The Timber Terror") was a military aircraft that excelled in a number of roles during World War II. It was a twin-engine aircraft with the pilot and navigator sitting side by side. Unorthodox in design, it used a plywood structure of spruce and balsa in a time when wooden construction was considered outdated. It was powered by a pair of Rolls-Royce Merlin engines.
The Mosquito was conceived as a fast day bomber that could outrun fighter defences and hence dispensed with defensive armament; however, owing to its speed, agility and its exceptional durability due to its wooden design, it was also used as a fighter. The fighter versions used a flat windshield to aid sighting. Its various roles included tactical bomber, pathfinder, day or night fighter, fighter-bomber, intruder, maritime strike or photo-reconnaissance aircraft. It served with the RAF, RAAF, RCAF, RNZAF, USAAF and Israeli Air Force, plus the air forces of Belgium, Burma, China, Czechoslovakia, France, Norway, South Africa, the Soviet Union, Sweden, Turkey, Yugoslavia and the Dominican Republic.
"In 1940 I could at least fly as far as Glasgow in most of my aircraft, but not now! It makes me furious when I see the Mosquito. I turn green and yellow with envy.
The British, who can afford aluminium better than we can, knock together a beautiful wooden aircraft that every piano factory over there is building, and they give it a speed which they have now increased yet again. What do you make of that?
There is nothing the British do not have. They have the geniuses and we have the nincompoops. After the war is over I'm going to buy a British radio set - then at least I'll own something that has always worked."
Hermann Göring, January 1943
The Mosquito inspired a German imitation, the Focke Wulf Ta 154 Moskito, which, like the original, was constructed of wood.
Construction
The genius of the aircraft's construction lay in the innovative and somewhat unorthodox use of seemingly commonplace materials and techniques. The bulk of the Mosquito was made of plywood. Stronger and lighter than most grades of plywood, this special plywood was produced by a combination of 3/8" sheets of Ecuadorean balsawood sandwiched between sheets of Canadian birch plywood. Like a deck of cards, sheets of wood alternated with sheets of a special casein-based (later formaldehyde) wood glue.Forming the fuselage was done in concrete moulds. Left and right sides of the fuselage were fitted with bulkheads and structural members separately while the glue cured. Reinforcing was done with hundreds of small brass wood screws. This arrangement greatly simplified the installation of hydraulic lines and other fittings, as the two halves of the fuselage were open for easy access by workers. The two halves of the fuselage were then glued and bolted together, and covered with doped Madapolam fabric.
The wings were also made of wood. To increase strength, the wings were made as one single assembly, onto which the fuselage, once both halves had been mated, was lowered and attached.
Metal was used sparingly in the construction of structural elements. It was mostly used in engine mounts and fairings, control surfaces, and of course, brass screws.
The glue used was initially casein-based. It was changed to a formaldehyde-based preparation when the Mosquito was introduced to fighting in semi-tropical and tropical climates, after some unexplained crashes led to the suspicion that the glue was unable to withstand the climate. De Havilland also developed a technique to accelerate the glue drying by heating it using radio waves.
The specialized wood veneer used in the construction of the Mosquito was made by Roddis Manufacturing in Marshfield, Wisconsin, United States. Hamilton Roddis had teams of dexterous young women ironing the (unusually thin) strong wood veneer product before shipping to the UK.
History
De Havilland conceived the idea of a wooden aircraft to take advantage of the underused resources and skills of the furniture industry at a time of great pressure on the conventional aircraft industry, and shortages of steel and aluminium. The Air Ministry was not interested; de Havilland designed the Mosquito on a speculative basis, only interesting the Ministry when they saw the performance of the prototype.The original Mosquito design dated from 1938 but it was not until March 1940 that there was sufficient interest in the aircraft for construction to commence. Three prototypes were built, each with a different configuration. The first to fly was the bomber prototype W4050 on November 25 1940 followed by the night fighter model on May 15, 1941 and the photo-reconnaissance model on June 10 1941.
The outstanding feature of the Mosquito was its speed, faster than any other aircraft of the time—so much so that defensive armament was not fitted as the Mosquito could outrun any pursuer.
The photo-reconnaissance model became the basis for the PR Mk.I Mosquito while the bomber model became the B Mk.IV, of which 273 were built. The first operational sortie by a Mosquito was made by a PR Mk.I on September 20 1941. The Mk.IV entered service in May 1942 with No. 105 Squadron. The B Mk.IV could accommodate 4 × 500 lb. (227 kg) bombs in the bomb bay, and either two drop tanks or two additional 500 lb. bombs on wing hardpoints.
The Mk.IX was a high-altitude bomber variant but the most numerous bomber version was the Mk.XVI of which about 1,200 were built. The Mosquito bombers could carry a 4,000 lb. (1 816 kg) "blockbuster" bomb in their internal bomb bay. This required a bulged bomb bay which could alternatively accommodate up to 6 × 500 lb. bombs on an Avro carrier. Mosquitos were widely used by the RAF Pathfinder Force which marked targets for night-time strategic bombing. Despite an initially high loss rate the Mosquito ended the war with the lowest loss rate of any aircraft in RAF Bomber Command service. The RAF found that when finally applied to bombing, it had proved 4.5 times cheaper than the Lancaster in terms of useful damage done, and they have never specified a defensive gun on a bomber since. Special Luftwaffe units formed to fight the Mosquito attacks were rather unsuccessful, and the Luftwaffe considered the Mosquito a superior implementation of their own "Schnellbomber" concept.
The first production night fighter Mosquitos were designated the NF Mk.II and 466 were built with the first entering service with No. 157 Squadron in January 1942, replacing the Douglas A-20 Havoc. They were armed with four 20 mm Hispano cannons mounted in the lower front fuselage and four .303 in (7.7 mm) Browning machine guns in the nose as well as an AI Mk.IV radar. The success of these night fighters, and the need to conceal the existence of radar, resulted in a degree of notoriety for pilot John "Cat's Eyes" Cunningham; he and other pilots were said untruly to have phenomenally acute night vision due to eating carrots (this was due to a British disinformation campaign arising from the aforesaid need to hide the development of radar from the Germans).
Ninety-seven NF Mk.IIs were upgraded with a centrimetric AI Mk.VIII radar and these were designated the NF Mk.XII. The NF Mk.XIII, of which 270 were built, was the production equivalent of the Mk.XII conversions. They also dispensed with the machine guns in the nose. 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 US-built AI Mk.X radar. After the war, two more night fighter versions were developed, the NF Mk.36, powered by the Merlin 113/114 engine, and the NF Mk.38 using the British-built AI Mk.IX radar. To warn German night fighters that they were being tracked by these radars, the Germans introduced Naxos ZR radar detectors.
Mosquito night intruders of 100 Group RAF, Bomber Command, were also fitted with a device called "Serrate" to allow them to track down German night fighters from their Lichtenstein B/C and SN2 radar emissions, as well as a device named "Perfectos" that tracked German IFF.
Variants
The most numerous Mosquito variant was the FB Mk.VI fighter-bomber of which 2,718 were built. Originally converted from a Mk.II, the Mk.VI first flew in February 1943. Designed for a fighter-bomber role, the Mk.VI could carry two 250 lb (110 kg) or 500 lb (230 kg) bombs in the internal bomb bay as well as two more bombs under the wings. From early 1944, Coastal Command operated Mk.VIs armed with eight 60 lb (27 kg) rockets to carry out anti-shipping strikes.
Other fighter-bomber variants were the FB Mk.XVIII (Tsetse) of which 27 were made by converting Mk.VIs. These were fitted with a Molins 57 mm cannon, a 6 pounder (2.7 kg), 7 cwt (356 kg) anti-tank gun modified 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. This variant was first suspected to not work by the Air Ministry, but mock tests proved otherwise. Although the gun provided the Mosquito with yet more anti-shipping firepower to put against U-boats, it required a steady and vulnerable bombing run to aim and fire the gun, thus making rockets more effective, especially because Mosquitos without the 6 pounder didn't suffer the weight penalty of the gun. The FB Mk.26 and FB Mk.40, based on the Mk.VI, were built in Canada and Australia and were powered by Packard-built Merlin engines.
The Mosquito was also built as a trainer; 348 of the T Mk.III were built for the RAF and Fleet Air Arm. de Havilland Australia built 22 T Mk.43 trainers, similar to the Mk.III.
de Havilland produced a carrier-borne variant to meet the Royal Navy's specification N.15/44. This resulted in 50 of the TR Mk.33 which featured folding wings, a nose thimble radome and fuselage hardpoints for mounting torpedoes. The navy also operated the TT Mk.39 for target towing. The RAF's target tug version was the TT Mk.35 which were in fact the last aircraft to remain in operational service, finally being retired in 1956.
Numbers produced
Total Mosquito production was 7,781 of which 6,710 were built during the war. De Havilland accounted for 5,007 aircraft built in three factories in the United Kingdom. Mosquitos were also built by Airspeed Ltd, Percival Aircraft Company and Standard Motors. The Canadian and Australian arms of de Havilland produced 1,134 and 212 aircraft respectively. Mosquito movement from Canada to the war front was unreliable, as a small fraction of the aircraft would mysteriously explode in transit over the mid-Atlantic. The cause for this auto-explosion was never found.The last Mosquito was completed in November 1950; a NF Mk.38 built at Chester.
The Canadian Historical Aircraft Association based out of Windsor, Ontario is building a Mosquito from scratch. Glyn Powell located in Papakura, New Zealand has built a mould for the wooden fuselage and CHAA bought the very first one ever sold. They have two unused engines still in the crates and some parts retrieved from a crash up in the arctic.
Operations
The Mosquito was used most frequently as part of the Light Night Striking Force (LNSF), carrying out high-speed night raids with precision aiming and navigation. Their mission was two-fold: first, they would target small but vital installations; and second, they would act as a diversion from the raids of the heavy bombers, simulating large formations through the use of chaff. On nights when no heavy bomber raid was planned, the LNSF would often strike so the German air defences would not get a rest.One of the most daring uses of the Mosquito was Operation Jericho, the mission to destroy the walls and guards' quarters of Amiens prison to allow the escape of members of the French resistance. It also raided a Nazi rally in Berlin, giving the lie to the speaker's (Reichmarschall Hermann Göring's) claim that such a mission was impossible. Another spectacular raid involved a very low altitude bombing raid on the Gestapo headquarters in Copenhagen, Denmark, destroying their records and freeing a large number of prisoners.
Mosquitos took part in many bombing missions as pathfinders, marking targets very accurately with flares for attack by massive formations of less accurate heavy bombers. In service with Bomber Command Mosquitoes flew over 28,000 operations, dropping 35,000 tons of bombs, and losing just 193 aircraft in the process (a loss rate of 0.7%, compared to a 2.2% loss rate for the four engined heavies). It has been calculated that a Mosquito could be loaded with a 4,000 lb. "cookie" bomb, fly to Germany, drop the bomb, return, bomb up and refuel, fly to Germany again and drop a second 4,000 lb bomb and return, and it would still land before a Stirling (the slowest of Bomber Command's four-engined bombers) which left at the same time armed with two 4,000 lb bombs.
Between 1943 and the end of the war, Mosquitos were also used as transport aircraft on a regular route over the North Sea between Leuchars in Scotland and Stockholm. Lockheed Hudsons and Lodestars were also used but these slower aircraft could only fly this route at night or in bad weather to avoid the risk of being shot down. During the long daylight hours of summer, the Mosquito was the only safe alternative.
Because Sweeden was neutral, the aircraft carried civilian markings and were operated by Norwegan officers, who were nominally 'civilian employees' of BOAC. They carried small, high value cargos such as precision ball bearings and machine-tool steel. Occasionally, important passangers were carried in an improvised cabin in the bomb bay.
A Mosquito also holds the record for the most missions flown by an Allied bomber in World War II. F for Freddie, first with 109 and subsequently 105 Squadron, flew 213 sorties during the war, only to crash on May 10 1945, two days after VE Day at the Calgary airport, likely owing to pilot error.
Mosquitos flying with the Israeli Air Force saw action during the Suez Crisis of 1956.
Notable pilots
- Sidney Cotton – Australian spy and photographic reconnaissance pioneer
- John Cunningham – British night-fighter pilot
- Guy Gibson – British 617 Sqn commander; killed when his Mosquito crashed in the Netherlands during a mission. (It has been speculated that this was the result of overstressing of the spar, during a dive-bombing run, to mark a target.) However, this speculation does not stand up when it is known that Gibson was returning to England after target marking. He was heard to give the crews a 'pat on the back' after the raid.
- Keith Miller – Australian international cricketer, regarded by many as the greatest Australian all-rounder. In later life when asked how he dealt with pressure on the cricket field, Miller replied: "Pressure is [having] a Messerschmitt up your arse, playing cricket is not."
- Bob" John Randall Daniel Braham –The highest decorated RAF airman of WW2 and a top Night fighter ace.
- Kirk Kerkorian – Worked as a ferry pilot for Mosquitos from Canada to Britain and elsewhere during WWII. The North Atlantic route was dangerous; the pay was high, $1000 per trip. [link] with a section of the Las Vegas Review-Journal book, The Top 100, citing a 1974 biography by Dial Torgerson Kerkorian, An American Success Story.
Preservation
There are believed to be around 30 preserved examples at various collections including the Royal Air Force Museum at Hendon. The wooden construction makes restoration difficult.As of 2004 the original W4050 aircraft was undergoing complete restoration in the de Havilland Aircraft Heritage Centre in Hertfordshire, UK. It was designed to carry four 250 lb. bombs but tests with 500 lb. bombs with shortened fins indicated that four 500 lb bombs could be carried.
A beautifully restored example is currently on display at the National Museum of the United States Air Force. The aircraft is a British-built B. Mk. 35 manufactured in 1946 and was later converted for towing targets. It is similar to the P.R. Mk. XVIs used by the AAF. The aircraft was flown to the Museum in February 1985, suffering several breakdowns along the way and taking many months to arrive. This Mosquito has been restored to a Mk. XVI configuration and painted to represent a weather reconnaissance aircraft of the 653rd Bomb Squadron, 25th Bomb Group, based in England in 1944-45. It is currently displayed in the Museum's WWII gallery.
Another Mosquito is currently under restoration in a hangar at the RAAF Museum at Point Cook, Victoria, Australia.
The last Mosquito known to be airworthy (designated RR299), a T Mk.III built sometime between October 1944 and July 1945, crashed on 21 July, 1996 with the loss of both crew after stalling during a banked turn at an airshow at the Barton Aerodrome near Barton, Greater Manchester. Several potential restorations to airworthiness exist, although the wooden construction makes this difficult. A replica is under construction in New Zealand.
The Mosquito B.35 held in the Experimental Aircraft Association, Oshkosh, Wisconsin, USA was airworthy when Kermit Weeks, the owner, loaned it to the museum. Whether it is considered so now is a matter for discussion.
Specifications (DH.98 Mosquito B Mk. XVI)
References
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External links
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