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The PZL P.11 was a Polish fighter aircraft, designed in the early 1930s by PZL in Warsaw. It was briefly the most advanced fighter aircraft of its kind in the world.〔 The PZL P.11 served as Poland's primary fighter defence in the Polish campaign of 1939, but with the rapid advances in aircraft design in the late 1930s (seen in such fighters as the Messerschmitt Bf 109), it proved outclassed by its rivals at the onset of the war.〔 ==Design and development== The history of the PZL P.11 started in 1929, when a talented designer, Zygmunt Puławski, developed an all-metal, metal-covered monoplane fighter. While most of the world's forces were still using biplanes, the new P.1 used a high-mounted gull wing to give the pilot an excellent view. A second prototype, the P.6, was completed the next year. The design generated intense interest around the world, the layout becoming known as the "Polish wing" or "Puławski wing". A further improvement, the PZL P.7, was built for the Polish Air Force in a series of 150.〔 After designing the P.7, Puławski started further variants with larger engines, leading eventually to the P.11. The first P.11/I prototype flew in August 1931, after Puławski's death in an air crash. It was followed by two slightly modified prototypes, the P.11/II and the P.11/III. The first variant ordered by the Polish Air Force was the P.11a, considered an interim model and built in a series of 30. Otherwise similar to the P.7, it mounted the 575 hp (429 kW) Bristol Mercury IV S2 radial engine produced in Poland under licence.〔 The final variant for the Polish air force, the P.11c had a new, refined fuselage, with the engine lowered in the nose to give the pilot a better view. The central part of the wings was also modified. Production of the P.11c started in 1934 and 175 were produced. The first series of approximately 50 P.11c aircraft were fitted with Mercury V S2 of 600 hp (447 kW), the rest with Mercury VI S2 of 630 hp (470 kW).〔 Such limited production may appear irresponsible on the part of the Polish government, with the Red Army aviation reaching into thousands and Germany ramping up production at an unprecedented scale. Even without the new WP2 plant at Mielec, the PZL works could produce at least 10 fighters every month. However, the Lotnictwo Wojskowe (Military Aviation) command was still studying different concepts of the use of fighters and bombers, while the Polish design bureaus were developing very advanced designs. The untimely death of Zygmunt Puławski also complicated the matter.〔〔Symanowski and Hoffmann 2006, p. 1.〕 Apart from Poland, Romania showed interest in the new design. Even before the P.11a entered service with the Polish air force, 50 aircraft designated P.11b were ordered for the Romanian Air Force, while an agreement for licence production was agreed. Deliveries of Polish-built P.11bs to Romania commenced in October 1933. They were fitted with Gnome-Rhone 9Krsd ''Mistral'' engines, otherwise they were similar to the P.11a.〔Green and Swanborough 1985, p. 43.〕 After the P.11c had been developed, the Romanians decided to switch the licence production to the new model. As a result, from 1936 IAR built 70 aircraft as the IAR P.11f, powered by the Romanian-built IAR-K-9 engine, which was a heavily modified version of the Gnome-Rhone 9K giving .〔Green and Swanborough 1985, p. 44.〕 The Romanians then produced another Polish fighter, the PZL P.24, developed from the P.11 exclusively for export. Greece, Portugal, Yugoslavia, Turkey and Republican Spain were interested in buying the P.11, but finally Bulgaria, Greece and Turkey bought the P.24 instead.〔〔 When the P.11 entered service in 1934, as a contemporary of the British Gloster Gauntlet and German Heinkel He 51 it was arguably the most advanced fighter in the world.〔Winchester 2004, p. 219.〕 However, due to the quick progress in aircraft technology, the P.11 was obsolete by 1939, overtaken by cantilever designs with retractable landing gear such as the British Supermarine Spitfire and German Messerschmitt Bf 109.〔 Together with the older P.7, both remained the only Polish fighters in service, however, with about 185 P.11s available, distributed within six air regiments and the aviation school in Deblin. Although aware that the P.11 was outdated, the Polish Air Force had pinned their hopes on the new PZL.50 Jastrząb, which suffered extended delays. When it became apparent that the PZL.50 would not be in widespread service in time for a war that was clearly looming, consideration was given to producing an updated P.11 version with the 840 hp (626 kW) Mercury VIII and an enclosed cockpit, known as the P.11g ''Kobuz''. Only the prototype of the P.11g with a maximum speed increase to a still-slow 390 km/h (~240 mph) was flown before the war, in August 1939.〔 In light of the unavailability of PZL.50, the only hope of replacing the obsolete P.11 lay in acquiring modern fighters from abroad. In 1939, after receiving the necessary credits, Poland ordered from France 120 Morane-Saulnier M.S.406s, and from Britain, 14 Hurricane Is (the P.11's chosen replacement), plus one Spitfire I for testing, in addition to 100 Fairey Battle light bombers.〔("Polish Air Force." ) ''century-of-flight.net,'' 2003. Retrieved: 7 July 2011.〕 None of these aircraft were delivered to Poland before September 1939.〔 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「PZL P.11」の詳細全文を読む スポンサード リンク
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