Editing Petlyakov Pe-2 (section)

==Development==
In 1937, [[Vladimir Petlyakov]] was the leader of the Heavy Aircraft Brigade at the [[Tupolev]] [[OKB]] responsible for the development of the ANT-42 four-engined long-range bomber (which eventually entered service as the [[Petlyakov Pe-8|TB-7/Pe-8]]). However, that same year [[Joseph Stalin|Stalin]]'s [[Great Purge]] started, and none were spared suspicion; [[Andrei Tupolev]], the head of the OKB, was coerced into signing a "confession"  in October 1937 that he had formed an anti-Soviet group that included Petlyakov, and both men along with many others were arrested.<ref name="Smith pp. 9-10.">Smith 2003, pp. 9–10.</ref>

Too valuable to be simply executed, unlike many others arrested during the Great Purge, Petlyakov and other weapons designers were instead sent to ''[[sharashka]]s'', special prisons run by the [[NKVD]] where such valuable prisoners could continue their work under close scrutiny. In 1938, Petlyakov was tasked with leading the first Special Technical Department (STO — ''SpetsTekhOd'yel'') for aviation that also included other designers who became well-known such as [[Vladimir Mikhailovich Myasishchev|Vladimir Myasishchev]], a colleague of Petlyakov's at the Tupolev OKB.<ref name="Smith pp. 9-10.">Smith 2003, pp. 9–10.</ref>

=== VI-100 ===
Because the Russian word for "100"  is "sto"("сто"), the STO was later renamed KB-100, and there Petlyakov proposed the development of a twin-engine interceptor against high-altitude long-range bombers, particularly those being developed in Germany such as the [[Junkers Ju 86]]P and [[Henschel Hs 130]]. His proposal was accepted in March 1938, with the requirement that the first prototype be ready for its first flight before the end of 1939. The project was initially given the name '''''Samolyot''''' '''''100''''' ({{lit|Aircraft 100}}) and later called '''VI-100''' (''Vysotnyi Istrebitel'' — "High-Altitude Fighter").<ref name="Smith pp. 11.">Smith 2003, pp. 11.</ref>

The VI-100 project was an ambitious one for its time, with advanced features such as a pressurised cabin, all-metal construction, [[Turbosupercharged|turbo-superchargers]], and many electrically actuated systems. The performance requirements were also quite demanding: it was to be capable of reaching 630&nbsp;km/h (391 mph) at an altitude of 10,000&nbsp;m, a ceiling of 12,500&nbsp;m, and a range of 1,400&nbsp;km. The aircraft would also need a reinforced structure in order to withstand the Mach stresses of making diving attacks from high altitude against enemy bomber formations. In order to assist with the challenging development of the "100", other OKBs such as those of [[Alexander Sergeyevich Yakovlev|Yakovlev]], [[Artem Mikoyan|Mikoyan]] and [[Mikhail Gurevich (aircraft designer)|Gurevich]], and [[Pavel Sukhoi|Sukhoi]] were also enlisted. The first full-scale VI-100 mock-up was completed in May 1939, and the first flight of the prototype occurred on 22 December 1939.<ref name="Smith pp. 10-12.">Smith 2003, pp. 10–12.</ref>

The VI-100 was an all-metal [[low-wing]] [[cantilever]] monoplane powered by two [[Klimov M-105]]R engines, licence-built [[Hispano-Suiza 12Y]] engines that were the most advanced then available in the Soviet Union, driving VISh-42 three-blade [[Variable-pitch propeller (aeronautics)|variable-pitch propellers]], enhanced by two TK-3 turbo-superchargers fitted in the engine nacelles. Its primary armament were two [[ShVAK cannon|20&nbsp;mm ShVAK]] cannon and two 7.62&nbsp;mm [[ShKAS machine gun]]s, with another ShKAS in a fixed mounting in the tailcone for self-defence. The first prototype VI-100 was also designed to carry KS-76 (48 modified 76&nbsp;mm artillery shells with timed fuses) or KS-100 (96 AO-25 bomblets) cassettes in the fuselage for dropping on enemy bomber formations. The second prototype was instead fitted with external bomb racks for 1,000&nbsp;kg of bombs and internal bomb bays for 600&nbsp;kg of bombs.<ref name="Smith pp. 11-13.">Smith 2003, pp. 11–13.</ref>

The first VI-100 prototype was demonstrated publicly during the 1940 [[International Workers' Day|May Day]] parade, flown by [[Pyotr Stefanovsky|Maj. Stefanovsky]], as Petlyakov and his team watched on from the roofs of their ''sharashka''.<ref name="Smith pp. 15.">Smith 2003, pp. 15.</ref> During testing in 1940, the second prototype VI-100 suffered a cockpit fire due to an improperly tightened nut in the fuel supply, and crashed into a kindergarten, killing a group of young children and a teacher.<ref name="Smith pp. 14.">Smith 2003, pp. 14.</ref> Despite the loss of the second prototype and several defects being found in the first prototype, the VI-100 was judged satisfactory and suitable for further development. Its performance was superior to other Soviet high-altitude fighters such as the Mikoyan-Gurevich I-200 (the future [[Mikoyan-Gurevich MiG-3|MiG-3]]), and compared favourably with contemporary aircraft such as the [[Potez 630]], [[Messerschmitt Bf 110|Messerschmitt Bf 110 C]], and [[Bristol Beaufighter|Bristol Beaufighter Mk. I]].<ref name="Smith pp. 15-16.">Smith 2003, pp. 15–16.</ref> However, events led to substantial changes in the direction of the VI-100 project.

=== PB-100 ===
The value of tactical dive bombing had been proven by the [[Junkers Ju 87]] ''Stuka'' dive bombers of the ''[[Luftwaffe]]'' during the [[Blitzkrieg]] campaigns of 1939 and 1940, and the need for such an aircraft in the VVS-RKKA ([[Red Army|Workers & Peasants' Red Army Air Force]]) suddenly became very apparent. Furthermore, following the [[Molotov–Ribbentrop Pact|Molotov–Ribbentrop Non-Aggression Pact]], Soviet experts were able to visit German aircraft factories, where they discovered that Germany had no large-scale development of high-altitude long-range bombers underway. Existing aircraft were also judged to be within the capabilities of single-engined fighters like the I-200.<ref name="Smith pp. 17.">Smith 2003, pp. 17.</ref>

Consequently it was decided in May 1940 that a dive-bomber using the good aerodynamics of the VI-100 would be designed and put into production. The new aircraft, now designated the '''PB-100''' (''Pikiruyushchiy Bombardirovshchik'' — "Dive-Bomber"), was required to achieve a maximum speed of 535&nbsp;km/h at an altitude of 4800–4900&nbsp;m, a range of 1,600&nbsp;km at an altitude of 5,000&nbsp;m, and a ceiling of 8000&nbsp;m.<ref name="Smith pp. 17.">Smith 2003, pp. 17.</ref> Petlyakov and his team were instructed to redesign the two-seat high-altitude fighter into a three-seat dive-bomber within 45 days.<ref name="Khazanov and Medved pp. 8.">Khazanov and Medved 2013, pp. 8.</ref> In order to meet this deadline, Petlyakov's team were assisted by some 300 specialists from other OKBs.<ref name="Smith pp. 17.">Smith 2003, pp. 17.</ref>

The fuselage of the VI-100 had to be redesigned for the dive-bombing role. Initially, the PB-100 had three pressurised cabins for the three-man crew, but the VVS judged that pressurisation was an inessential luxury for the dive-bombing role, and was dropped. Furthermore, the high-altitude performance provided by the turbo-superchargers was also unnecessary, and these too were dropped. Extensive glazing was added to the lower portion of the nose to give the pilot maximum visibility during a dive-bombing attack. A bomb bay for a single 100&nbsp;kg bomb was added in each engine nacelle, while the engines remained the same. The wing was modified, with dive brakes added. The cockpit was redesigned, bringing the navigator and pilot together, and given extensive glazing, while a defensive machine gun was added in the ventral position, operated by a gunner.<ref name="Smith pp. 17.">Smith 2003, pp. 17.</ref>

The redesign was completed in time, and the PB-100 was ordered into production without the construction of a prototype (only static tests were conducted for new components such as the fuselage), with the first two series production PB-100s completed by Zavod 39 in the late autumn of 1940.<ref name="Smith pp. 18.">Smith 2003, pp. 18.</ref> The trials of the lead machine (No. 390101) began on 15 December 1940. In accordance with the new rules also adopted in December 1940, the aircraft was also redesignated '''Pe-2 2M-105'''.<ref name="Smith pp. 18.">Smith 2003, pp. 18.</ref>