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The Junkers Ju 288, originally known within the Junkers firm as the EF 074, was a German bomber project designed during World War II, but which only ever flew in prototype form. The first of 22 development aircraft flew on 29 November 1940. ==Development== Prior to the opening of World War II, the Luftwaffe bomber force was primarily aircraft of limited performance, some originally developed with civilian uses in mind as well. The only truly modern design in the inventory was the Ju 88, the first purposed-designed schnellbomber. Although it outperformed the collection of other designs in service, it had numerous problems of its own. Perhaps most notable among these was its very small internal bomb bay that forced it to carry some of its load externally, slowing performance. Junkers had been experimenting on paper in its engineering departments with a variety of improved models of the Ju 88 since 1937, powered by the planned Jumo 222 multibank gasoline engine, or Jumo 223 inline multibank diesel of greatly increased power of at least 1,500 kW/2,000 HP apiece. No serious work was undertaken on these versions, but after Heinrich Hertel left Heinkel and joined Junkers in 1939, the EF 074 design was submitted to the RLM in May 1939 as the Junkers corporate entry in the RLM's ''Bomber B'' design competition. The EF 074 entry was essentially a scaled-up Ju 88, sharing its general layout and most of its fuselage and wings with extensions in various places. The nose was completely redesigned to follow the strongly developing preference (as with the He 111P and -H's revised cockpits) in German aviation firms for a more streamlined "stepless cockpit", having no separate windscreen panels for the pilot and co-pilot. This layout allowed cabin pressurization to be more easily implemented. All of the defensive armament was meant to be remotely controlled — (in one proposal ), comprising a remotely operated rear-facing dorsal turret at the rearmost end of the cockpit glazing, and two remotely operated "flank" turrets on the rearwards sides of the fuselage just forward of the empennage, otherwise each resembling the FDSL 131 units of the Me 210 – the exclusive use of remotely operated turrets for the Ju 288's defensive firepower allowed them to be located in useful positions, as well as eliminating "breaks" in the fuselage pressurization. The fuselage was expanded along its length to allow for a much longer bomb bay — somewhat as had been done with the Dornier Do 217 then in development itself — that would allow for an 3,630 kg (8,000 lb) payload to be carried internally, eliminating the need to carry ordnance on outside hardpoints. Performance would be greatly improved over the Ju 88, both due to the all-internal bombload and the greatly improved power. Accordingly the RLM sent out the specifications for Bomber B in July 1939, the Ju 88 retroactively becoming the second aircraft to be designated Bomber A in the ''Luftwaffe''s existence. (The original usage, dating from June 3, 1936, was the specification for what became the He 177). The Bomber B program aimed at replacing all of the medium bombers in the ''Luftwaffe'' inventory with a new design based on the EF.74 or something with equal performance. Bomber B was intended to have even better speed than the Ju 88, high-altitude cruising with a pressurised cockpit, heavier defensive armament, range allowing it to cover any point in the British Isles, and a massive 4,000 kg (8,820 lb) warload, double that of the earlier generation bombers. A number of companies returned proposals, but these were to some extent a formality, the EF.74 had already been selected as the winner, and of the rest of the designs submitted, only the Focke-Wulf Fw 191 and Dornier Do 317 progressed even as far as prototypes, with the Henschel Hs 130 even coming under consideration as a late entrant. Work began on building prototypes soon after, and the first example was completed by mid-1940. Power was supposed to be supplied by two 24-cylinder Jumo 222 six-bank, four cylinders per bank, over-1,500 kW output class powerplants, but problems with 222 development — as with almost every new concept for over-1,500 kW output piston-engined aircraft engines then underway — meant the first prototypes flew with BMW 801 radial engines, instead. The first flight-quality 222s did not arrive until October 1941, and even at this point it was clear they were nowhere near ready for full-scale production. When it became apparent the 222 was not likely to become a viable powerplant, in May 1942, Junkers proposed replacing them with the much heavier Daimler Benz DB 606s instead, the very same 1.5 tonnes-apiece, twin-crankcase "welded-together engines" that ''Reichsmarschall'' Hermann Göring complained about some three months later, regarding the He 177's own endless powerplant troubles — this was on top of a troublesome main landing gear design, (possessing twin vertical members directly behind a single oleo strut ) for each pair of twinned wheels mounted to a forward-projecting lever-action lower arm (similar to that on the He 177A), causing trouble from collapsing on touchdown. As these technical difficulties were being addressed, the lack of a well-defined strategic bombing doctrine — which effectively ceased to exist within the ''Luftwaffe'' by June 1936, with the untimely death of ''General'' Walther Wever, the main proponent for such a capability — meant the mission and purpose of the Ju 288 remained nebulous throughout its development. As an interim measure, RLM ordered the Junkers Ju 188, which was a fairly minor upgrade of the original Ju 88 incorporating the basic cockpit design of the never-produced Ju 88B. Work continued on the 288 throughout, but in 1944 the project was finally abandoned as ''Luftwaffe'' priorities became more intensely focused on homeland defence. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Junkers Ju 288」の詳細全文を読む スポンサード リンク
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