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  20. de Havilland 100: “Far better than we thought”
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  25. By GREG BAUGHEN 10th September 2020
  27. Mosquito’s early days
  29. That the Mosquito was among the finest British designs of the Second World War was not immediately obvious to the Air Staff when the prototype first took to the air. Indeed, the Air Ministry was not quite sure what to do with it. One of the roles lined up was target-towing for the Admiralty. But, eventually, its outstanding qualities became obvious
  31. img_46-10.jpg
  32. The second Mosquito prototype, W4051, was in fact the third to fly, taking to the air in June 1941. An official air-to-air shoot with it, also involving a photographer from The Aeroplane, took place the following month.
  34. img_47-2.jpg
  35. First prototype W4050 in another guise, at Hatfield with experimental identity E0234. It flew twice as such prior to being painted yellow and given serial W4050.
  37. Early in 1938, the increasing cost of the Air Ministry’s bomber programme was becoming a serious problem. To reduce expenditure, Air Marshal Wilfrid Freeman, the air member for research and development, suggested building less sophisticated bombers that did not use expensive alloys, and which could be produced by semi-skilled labourers in companies with no previous experience of aircraft production.
  39. The idea was for a simple aeroplane, with hand-held gun positions rather than turrets. It would carry 1,000lb of bombs and have a range of 1,500 miles. Alternative, cheaper construction techniques included steel tubes covered with plywood, which Armstrong Whitworth was developing, and all-wood construction, which de Havilland had used successfully with the likes of the DH88 Comet and DH91 Albatross.
  41. The Chief of the Air Staff, ACM Sir Cyril Newall, did not think it was worth developing a bomber that could only take a 1,000lb bomb load. He believed it had to carry at least 3,000lb of bombs. Nor was he happy with hand-held guns; the aircraft would have to have a tail turret. This rather undermined the idea of keeping it small and cheap. de Havilland proposed a twin-Rolls-Royce Merlin-engined bomber development of its Albatross, which, the company claimed, would have a bomb load of 4,000lb, a range of 1,500 miles and a top speed of 260mph. However, Freeman was more impressed with the composite steel-tube/plywood approach and gave the contract to Armstrong Whitworth. de Havilland’s first attempt at a wooden bomber suffered the indignity of being rejected in favour of the ill-starred Albemarle.
  43. However, de Havilland would get a second chance. In the autumn of 1939 ACM Edgar Ludlow-Hewitt, air officer commanding-in-chief of Bomber Command, wanted a high-speed, lightly armed bomber to replace the Bristol Blenheim. Its main role would be to follow up large-scale bomber raids with harassing ‘nuisance’ attacks. With enemy defences already alerted, the highest possible speed would be required. Higher-performance versions of the Bristol Beaufighter and Beaufort were among the possibilities considered. Freeman suggested a completely unarmed bomber that would be faster than any fighter. There was little support for the idea. Ludlow-Hewitt insisted the machine should have at least some defensive armament, if only to sustain crew morale. Freeman, however, was determined to pursue the unarmed approach. The latest offering from de Havilland was almost what he wanted.
  45. Soon after the outbreak of war de Havilland put forward a proposal for a bomber with a range of 1,500 miles and capable of carrying 1,000lb of bombs. It would not be completely unarmed, but would be, to quote company papers, “so outstanding little defensive equipment would be needed”. With two Merlins, a top speed of 405mph ought to be possible. If Napier Sabres could be used it would carry 4,000lb of bombs at the same speed. The Air Ministry thought these predictions rather optimistic and suggested 350mph as a more likely maximum speed. It also insisted on a rear turret. de Havilland came back with a bomber powered by two heavier and more powerful Rolls-Royce Griffons, the required four-gun tail turret and a claimed top speed of 390-400mph. Again, the Air Ministry thought this a little optimistic but agreed to purchase a couple of prototypes.
  47. img_47-1.jpg
  48. As the air member for research and development, Air Marshal Wilfrid Freeman was instrumental in the gestation of what became the Mosquito.
  49. img_48-2.jpg
  50. The all-yellow first prototype Mosquito landing at Hatfield on 10 January 1941.
  52. Freeman, however, had more ambitious plans. In November 1939 he met representatives from de Havilland, suggesting they removed all armament and concentrated on achieving the fastest bomber possible. Like Ludlow-Hewitt, Freeman only wanted a small number — no more than 50 — for harassing purposes. There was no question of it becoming an alternative to the heavy bombers on order.
  54. To ensure the bombers kept one step ahead of the fighters they were likely to encounter, he suggested de Havilland use all three engine types it had proposed. New powerplants would be introduced as they became available. With Merlins, at least 350mph ought to be possible. This would be followed by a Griffon-powered version that was expected to be capable of 370-380mph, Finally, in 1942, a Sabre-engined variant should push the type’s speed past 400mph. Each upgrade ought to provide a nine-to-12-month period in which the bomber ought to be able to outrun any enemy interceptor. It was a calculated gamble. The enemy might well develop a faster fighter sooner, but as only 50 of each type would be ordered, if it didn’t work, little would have been lost.
  56. de Havilland wanted the aeroplane to be as versatile as possible, but Freeman made it clear that no concessions were to be made for any other role. Nothing should stand in the way of achieving the fastest possible bomber. He was not after a multi-purpose aircraft. So worried was Freeman about others interfering with the project, he warned de Havilland sternly that, “the firm were to look to him as the authority on requirements, and were not to take instructions from anyone else.”
  58. With the heavy loss of Vickers Wellingtons on the December 1939 Wilhelmshaven raid, there was even more urgency about investigating alternative ways of bombing Germany. Ludlow-Hewitt believed there were two options: either adopt faster, lightly armed bombers, or operate only by night. Freeman obtained approval for the first batch of 50 Merlin-powered, unarmed DH98s, or Mosquitos, but they were seen very much as an interim measure. The Air Ministry was pinning its hopes on a longer-term prospect: a high-speed, streamlined version of the Avro Manchester, with no nose turret and Sabre engines. In January 1940 de Havilland received instructions to build 50 “high-speed bomber” aircraft.
  60. img_49-1.jpg
  61. An interim stage for the first Mosquito: now in yellow, but still carrying E0234 instead of its proper serial.
  63. img_49-2.jpg
  64. W4050 on the move at Hatfield. In February 1941, while undergoing service trials with the A&AEE at Boscombe Down, the aircraft suffered a fractured rear fuselage as a result of a jammed tailwheel while taxiing. It had to be replaced with a fuselage section intended for W4051.
  66. Interest, however, soon faded. Air Ministry opinion was hardening in favour of a switch to night operations and abandoning daylight raids altogether. Even Freeman was thinking of cancelling the contract. But the Assistant Chief of the Air Staff, Air Marshal Richard Peck, was anxious to keep the DH type for reconnaissance. In what was by all accounts a heated meeting, he persuaded Freeman not to cancel. However, the 50 on order were now seen primarily as reconnaissance aircraft, with just a secondary bombing capability.
  68. That July, de Havilland was asked to complete one of the aircraft on order as a fighter. There was not much expectation that it could be a success in this role. The speeds the designers were envisaging seemed to rule out, it was felt, even basic manoeuvring. Indeed, the Air Ministry found it difficult to imagine circumstances in which it would need to order any more Mosquitos. If it were possible to modify the type as a target tug, a further order might be justified, but beyond that it did not seem to have a future.
  70. On 25 November 1940. the prototype Mosquito, W4050, took to the air from Hatfield. The event probably passed unnoticed in Air Ministry circles. The aircraft handled well, was very fast and seemed promising, but none of this was influencing the ministry’s thinking. ACM Charles Portal had just taken over from Newall as Chief of the Air Staff and was reviewing all existing aircraft programmes. Early in December he sent a scathing assessment of the Mosquito to his Air Minister, Archibald Sinclair.
  72. The entire concept of a high-speed, unarmed bomber, he declared, was “based on fallacies”. It would never be so fast it could not be caught by a contemporary fighter. As a day fighter it would not be manoeuvrable enough. As a night fighter its landing speed would be too high, and it lacked a turret. This was considered essential at the time following the success of the Boulton Paul Defiant in the night fighter role. Photo-reconnaissance and target-towing seemed to be the only possible functions. Another 50 might be ordered in the event of a target tug conversion proving possible. In a covering letter to Lord Beaverbrook, in charge of the Ministry of Aircraft Production, Sinclair completed the demolition job by declaring the Mosquito “useless for the purpose for which it was designed.”
  74. img_50-1.jpg
  75. Mosquito production, probably in the Hatfield plant, during April 1943.
  77. In the meantime, however, Air Ministry talk of using it for target-towing had attracted the attention of the Admiralty. It was looking for a high-speed target tug and the Mosquito seemed ideal. As the Air Ministry did not seem to want the aircraft, perhaps a further 100 could be built for this purpose? The Air Ministry agreed, and added another 50 for RAF use. This version would have the Merlin II or III rather than the more valuable Merlin XX. de Havilland and the MAP were told to prepare the type for its new role. It was thought the conversion would be a relatively simple task.
  79. In fact, it soon transpired that it was far from straightforward. A hole would have to be cut in the bottom of the fuselage to deploy the winch for the towed targets. It would need a window for the winch operator to see backwards and downwards. A blister was necessary atop the fuselage to provide a rearwards view, together with further blisters for a cine camera and its operator. All these modifications might affect the structural integrity of the design. It was also feared that they could upset the centre of gravity, which might lead to even more extensive changes.
  81. While the MAP and de Havilland set about investigating the problems involved, there was the first sign that the Mosquito might have a more useful fighting role. In December 1940 the Blitz was at its height, Fighter Command was insisting it needed more night fighters, and the Air Ministry was worried that not enough Beaufighters could be built.
  83. To fill the gap, Portal wanted 30 of the original order of 50 Mosquitos converted into fighters, with more to follow if the prototype proved satisfactory. To have a long-term future as a night fighter it would need moveable guns, so two airframes were to be modified to carry a turret, armed with machine guns or cannon. Whether it be as a target tug or a night fighter, the Air Ministry seemed determined to spoil the lines of de Havilland’s graceful design.
  85. Even so, the aircraft was still not inspiring much confidence. At best it might make a reasonable substitute for the Beaufighter. The turning-point occurred a few weeks later. The Assistant Chief of the Air Staff, Air Marshal Philip Joubert de la Ferte, had a chance to take a “good look” at the Mosquito. The de Havilland team clearly did a good job of selling it. They rather optimistically claimed it had 10-12 hours’ endurance, which led Joubert de la Ferte to claim that, as a night fighter, “it could stay up all night”. Its high speed and endurance would also make it ideal as a long-range fighter. It would be particularly useful over the Atlantic and, with the addition of air-to-surface and air-to-air radar, “it becomes a really useful craft”. He suggested 50 long-range day fighters and 200 night fighters be ordered immediately. This seemed to be the first time anyone outside de Havilland had a good word to say about the Mosquito.
  87. Interest now snowballed. Official trials revealed the aircraft was pleasant to fly, manoeuvrable and had a top speed of 388mph. It was not just a reasonable alternative to the Beaufighter — it was clearly far better. In trials with a Spitfire V, it was faster below 24,000ft. ACM Richard Peirse, AOC-in-C of Bomber Command, wanted to try the aeroplane as soon as possible and was rather irritated that the night fighter version was getting priority. Suddenly everyone wanted the Mosquito.
  89. But what about those Admiralty target tugs? In January 1941, Freeman decided none of them would be built and the MAP was told the order for 150 should be completed as night fighters. However, it was one thing to make this decision, but quite another to implement it. The Admiralty had 100 on order and was expecting the MAP to deliver them. The Air Ministry seemed somewhat nervous about suggesting that towing targets was not the best use that could be made of Britain’s latest world-beating combat type. It was a “sensitive” issue and the navy was bound to feel “a little sore” about losing its Mosquitos. The MAP was still working on the modifications required in February 1941. Warning the Air Ministry of how extensive the task was, it confirmed no Mosquitos could be converted into target tugs until 1942.
  91. img_51-1.jpg
  92. After its part in the Mosquito flight test programme, PRI prototype W4051 served operationally with No 1 PRU at Benson.
  94. A ‘softly-softly’ approach seemed best. Rather than bring the matter up at the next production conference, the Admiralty would be told, informally, that “the Mosquito has turned out to be far better than we thought” and converting it into a target tug would take far too long. Hopefully the navy would accept something else.
  96. The tactic seemed to backfire. By late February, Freeman was under the impression that the Admiralty had accepted Blenheims instead of Mosquitos. Then it transpired that the Admiralty was only accepting them as an interim measure and was still expecting the new aircraft. Indeed, the MAP and de Havilland were still expending considerable effort on the project. In April 1941 a mock-up of the target tug version was being built, the problems of installing Merlin IIs investigated, and likely speeds with different-length winch cables calculated. When the Admiralty was finally persuaded it did not need Mosquito target tugs is not clear, but on 30 April a despairing Freeman was still pleading with the MAP to abandon any idea of building them.
  98. Given the desperate shortage of Mosquitos, it was just as well the Admiralty did not get its way. They were like gold dust. Arguably the type was never built in the numbers its usefulness justified. In 1943, US Army Air Forces chief of staff Gen ‘Hap’ Arnold needed a high-performance reconnaissance platform and the Mosquito looked ideal. Since the Americans were providing the British with thousands of aircraft under Lend-Lease, he thought perhaps they could spare them a few hundred Mosquitos. The scale of the request stunned Portal and the Air Ministry. At the time, the monthly production of all Mosquito variants rarely rose above 100. Portal rather grudgingly let the Americans have an initial two.
  100. ‘Freeman’s folly’ had not quite turned out as Freeman had intended. By chance, in the quest for a specialist high-speed, unarmed bomber, the Air Ministry had stumbled upon an extremely versatile warplane. It could not rescue the ailing bomber offensive on its own. It could never have been built in sufficient numbers to deliver the level of destruction types like the Lancaster could manage. But it was able to make a huge contribution to winning the war, used on nearly all fronts in almost every conceivable role.
  102. And it was even, eventually, used as a target tug. Somewhat ironically, of course, this was the role in which the last RAF Mosquitos — those of the contractor-operated No 3 Civilian Anti-Aircraft Cooperation Unit at Exeter — flew, when the type was finally retired in May 1963. What goes around comes around.
  104. img_51-2.jpg
  105. During the September 1946 SBAC show at Radlett, W4050 was displayed with some of the different armament and equipment fits the Mosquito had carried during wartime. This most historic example is, of course, today preserved by the de Havilland Aircraft Museum at Salisbury Hall, the type’s birthplace.
  107. img_52-2.jpg
  108. While the idea of using the Mosquito solely as a naval target tug thankfully fell by the wayside, it was in the targettowing role that the type bowed out of RAF service. TT35 RS719, here carrying the ML Type G winch, served with No 5 Civilian Anti- Aircraft Co-operation Unit at Woodvale prior to retirement in May 1958.
  112. March 1940
  114. Construction of DH98 prototypes begins
  116. 25 November 1940
  118. Maiden flight of first prototype E0234 (later W4050) from Hatfield, in hands of Geoffrey de Havilland Jr
  120. 15 May 1941
  122. Initial night fighter prototype, W4052, takes to the air
  124. 10 June 1941
  126. First photo-reconnaissance prototype, W4051, flies
  128. 13 July 1941
  130. RAF Mosquito deliveries begin, of PRI version to No 1 Photographic Reconnaissance Unit
  132. 17 September 1941
  134. Operational debut of type in photo-reconnaissance role, as W4055 of No 1 PRU conducts recce of Biscay ports
  136. 15 November 1941
  138. First delivery of Mosquito bombers — specifically MkIVs — to No 105 Squadron
  140. 30 May 1942
  142. Maiden victory for a Mosquito NFII night fighter, a No 151 Squadron aircraft shooting down a Dornier Do 217
  144. 25 September 1942
  146. No 105 Squadron attacks Gestapo HQ in Oslo, with four aircraft; Mosquito publicly revealed thereafter
  148. 31 December 1942-1 January 1943
  150. First use, by No 109 Squadron, of Mosquitos with Pathfinder Force using Oboe navigation system
  152. 30 January 1943
  154. Daylight missions to bomb Berlin by Nos 105 and 139 Squadrons, disrupting speeches by Göring and Goebbels
  156. 4 February 1943
  158. First BOAC Mosquito mission on ‘ball bearing run’ to Sweden, using MkIV G-AGFV
  160. 18 February 1944
  162. Operation ‘Jericho’, the Amiens prison raid by Mosquito FBVIs of Nos 21, 464 (Australian) and 487 (New Zealand) Squadrons
  164. 25 March 1944
  166. First Mosquito carrier landing, by Capt Eric ‘Winkle’ Brown in prototype Sea Mosquito TR33 aboard HMS Indefatigable
  168. 21 March 1945
  170. Same three squadrons that mounted Operation ‘Jericho’ attack Gestapo HQ in Copenhagen
  172. 20 August 1945
  174. After VJ-Day, No 110 Squadron FBVIs fly RAF’s final bombing mission of the war, supporting British ground forces against Japanese holding out in Burmese jungle
  176. 28 November 1950
  178. Final production Mosquito, NF38 VX916, emerges from DH factory at Hawarden, Chester; brings complete run to 7,781, including those built in Toronto and Sydney
  180. October-November 1956
  182. 115 Squadron, Israeli Air Force flies Mosquito PRXVIs and NF30s on type’s final offensive missions, during Suez crisis
  184. 9 May 1963
  186. No 3 Civilian Anti-Aircraft Co-operation Unit retires RAF’s last six Mosquitos — TT35 target tugs and a TIII trainer — at Exeter
  188. Topics
  189. Read more about de HavillandWorld War Two (1939-1945)Centenary
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  191. Originally published in Aeroplane Magazine
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