The Petlyakov Pe-2 ( — nickname «Пешка» (Pawn); NATO reporting name: Buck)Jane's All the World's Aircraft 1955-56 p. 188 was a Soviet twin-engine dive bomber used during World War II. One of the outstanding tactical attack aircraft of the war,Ethell 1996, p. 152. it also proved successful as a heavy fighter, as a night fighter (Pe-3 variant) and as a reconnaissance aircraft.Angelucci and Matricardi 1978, p. 234. The Pe-2 was, numerically, the most important Soviet bomber of World War II, at their peak comprising 75% of the Soviet twin-engine bomber force.Smith 2003, pp. 155. The Soviets manufactured Pe-2s in greater numbers (11,430 built) during the war than any other twin-engine combat aircraft except for the German Junkers Ju 88 and the British Vickers Wellington.Guston 1980, p. 173. Several Soviet bloc air forces flew the type after the war, when it became known by the NATO reporting name Buck.
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 TB-7/Pe-8). However, that same year 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.Smith 2003, pp. 9–10.
Too valuable to be simply executed, unlike many others arrested during the Great Purge, Petlyakov and other weapons designers were instead sent to sharashkas, 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 Myasishchev, a colleague of Petlyakov's at the Tupolev OKB.Smith 2003, pp. 9–10.
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 86P 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 () and later called VI-100 (Vysotnyi Istrebitel — "High-Altitude Fighter").Smith 2003, pp. 11.
The VI-100 project was an ambitious one for its time, with advanced features such as a pressurised cabin, all-metal construction, turbo-superchargers, and many electrically actuated systems. The performance requirements were also quite demanding: it was to be capable of reaching 630 km/h (391 mph) at an altitude of 10,000 m, a ceiling of 12,500 m, and a range of 1,400 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 Yakovlev, Mikoyan and Gurevich, and 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.Smith 2003, pp. 10–12.
The VI-100 was an all-metal low-wing cantilever monoplane powered by two Klimov M-105R 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 propellers, enhanced by two TK-3 turbo-superchargers fitted in the engine nacelles. Its primary armament were two 20 mm ShVAK cannon and two 7.62 mm ShKAS machine guns, 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 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 kg of bombs and internal bomb bays for 600 kg of bombs.Smith 2003, pp. 11–13.
The first VI-100 prototype was demonstrated publicly during the 1940 May Day parade, flown by Maj. Stefanovsky, as Petlyakov and his team watched on from the roofs of their sharashka.Smith 2003, pp. 15. 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.Smith 2003, pp. 14. 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 MiG-3), and compared favourably with contemporary aircraft such as the Potez 630, Messerschmitt Bf 110 C, and Bristol Beaufighter Mk. I.Smith 2003, pp. 15–16. 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 (Workers & Peasants' Red Army Air Force) suddenly became very apparent. Furthermore, following the 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.Smith 2003, pp. 17.
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 km/h at an altitude of 4800–4900 m, a range of 1,600 km at an altitude of 5,000 m, and a ceiling of 8000 m.Smith 2003, pp. 17. Petlyakov and his team were instructed to redesign the two-seat high-altitude fighter into a three-seat dive-bomber within 45 days.Khazanov and Medved 2013, pp. 8. In order to meet this deadline, Petlyakov's team were assisted by some 300 specialists from other OKBs.Smith 2003, pp. 17.
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 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.Smith 2003, pp. 17.
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.Smith 2003, pp. 18. 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.Smith 2003, pp. 18.
Design features The Pe-2 inherited the basic low-wing twin-engine monoplane configuration of the VI-100. It had an all-metal stressed-skin structure, with cloth only used to cover the ailerons and control surfaces. The tail had twin fins and rudders with a pronounced 8-degree dihedral on the tailplane; this had been added to the PB-100 to correct the poor lateral stability found on the VI-100 during testing.Smith 2003, pp. 27.
The wing design of the Pe-2 was also inherited from the VI-100, but this had been optimised for high altitude performance at the cost of lower lift at low altitude, resulting in suboptimal manoeuvreability and take-off and landing characteristics.Smith 2003, pp. 11. For example, while the Pe-2's flying characteristics were generally good once it was airborne, it took a good amount of force to pull the elevators up to rotate the plane for takeoff. Russian night bombing missions often flew with female pilots, and some of the women were not strong enough to get the airplane airborne by themselves. When such a situation occurred, the procedure was to have the navigator get behind the pilot's seat and wrap her arms around the control wheel and help the pilot pull the wheel back. Once the aircraft was airborne, the navigator returned to her duties and the pilot continued to fly the plane without assistance. In addition, the Pe-2 had a reputation for hard landings, as well as for its notorious "bounce" on landing due to the inadequate shock absorbers in the landing gear.Smith 2003, pp. 36. This could be fatal if the pilot was not prepared for it.Smith 2003, pp. 12.Smith 2003, pp. 94. As designed, the wings were also fitted with "Venetian blind"-type slatted dive brakes for the dive-bombing role.Smith 2003, pp. 28.
Pe-2s were equipped with an inert gas fire-suppression system for the self-sealing fuel tanks, which progressively filled the fuel tanks with nitrogen in order to reduce the risk of ignition when hit by enemy fire.Smith 2003, pp. 27.
Armament
The Pe-2 had an internal capacity for six 100 kg bombs, for a total of 600 kg; this was no better than that of the older Tupolev SB bomber. The internal capacity consisted of a fuselage bomb bay capable of carrying four 100 kg bombs or an additional fuel tank, with two small internal bomb bays in the rear of the engine nacelles for a single 100 kg bomb each.Smith 2003, pp. 28. This was supplemented by four external underwing racks. These were capable of carrying four 100 kg or 250 kg bombs, or two 500 kg bombs in overload configuration, giving a maximum bombload of 1,000 kg.Smith 2003, pp. 28. Only the bombs in the external racks could be used in a dive-bombing attack; the internally carried bombs had no dive release gear and could not be dropped in a steep dive.Smith 2003, pp. 21.
The offensive armament originally consisted of two 7.62 mm ShKAS fixed forward-firing machine guns in the nose.Smith 2003, pp. 28. The right ShKAS was replaced by the more powerful 12.7 mm UBK heavy machine gun from Series 13 production aircraft onwards.Smith 2003, pp. 100. From Series 32 onwards, provisions were made for underwing guide rails for up to ten RS-132 or RS-82 unguided rockets.
The defensive armament originally consisted of a single ShKAS machine gun in a dorsal TSS mounting, later MV-3 turret, manned by the navigator in the cockpit behind the pilot, and a ventral 7.62 mm ShKAS machine gun in a mounting in the fuselage behind the bomb bay aimed by a periscope.Smith 2003, pp. 12.Smith 2003, pp. 100. This defensive armament was found to be totally inadequate: from Series 13 onwards, the ventral ShKAS was replaced by one 12.7 mm UBT in an MV-2 mounting,Smith 2003, pp. 102. while the dorsal ShKAS was also replaced by a UBT in various different mountings, some modified in the field and others from the factory: MV-7 turret: Turret mounting tested in September 1941. Unsatisfactory and not adopted.