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Petlyakov Pe-8

 
Wikipedia: Petlyakov Pe-8
Pe-8
Three-quarters view of a large four-engined parked aircraft with a conventional undercarriage with a group of people clustered in the left foreground and another on the other side of the fuselage in the background
Petlyakov Pe-8
Role Heavy bomber
National origin USSR
Manufacturer Factory No. 124
Designed by Vladimir Petlyakov
First flight 27 December 1936
Introduced 1940
Status Retired
Primary user VVS
Produced 1936–1944
Number built 93

The Petlyakov Pe-8, originally known as the TB-7, was a Soviet heavy bomber designed before World War II, the sole four-engined bomber the USSR built during the war. Produced only in small numbers, it bombed Berlin in August 1941 as well as other cities in Germany and Finland on so-called "morale raids" to raise the spirit of the Soviet people by exposing enemy vulnerabilities. Its primary mission, however, was to attack German airfields, rail yards and other rear-area facilities at night, although it also flew the People's Commissar of Foreign Affairs (Foreign Minister) Vyacheslav Molotov from Moscow to the United States in 1942. Sources disagree if the Pe-8 was withdrawn from combat operations in 1944 but, in any case, the surviving aircraft were withdrawn from service after the end of the war. Some aircraft were modified as VIP transports while others were used in various testing programs. Some were used in support of Soviet Arctic operations until the late 1950s.

Contents

Design and development

Development of the Pe-8 was initiated in response to a VVS requirement for a bomber that could carry 2,000 kg (4,400 lb) of bombs 4,500 km (2,800 mi) at a speed greater than 440 km/h (270 mph) from an altitude of 10,000 metres (32,808 ft) issued in July 1934 to replace the TB-3 heavy bomber.[1] The task was assigned to the Tupolev OKB where Andrei Tupolev handed the work to a team led by Vladimir Petlyakov and gave it the internal designation of ANT-42. The resulting aircraft was a four-engined, mid-wing cantilever monoplane that was designated as the TB-7 (Russian: Тяжёлый Бомбардировщик, Tyazholy Bombardirovschik, Heavy Bomber) by the VVS and owed more to the Tupolev SB than to the TB-3.[2] It was built mainly of duralumin, with two steel spars in the wings, although the ailerons were fabric-covered. The monocoque fuselage was pear-shaped which forced the pilots to sit in tandem, offset to the left with the flight engineer and radio operator sitting behind and below the pilots. The bombardier sat in the nose with a prominent chin gondola, nicknamed the 'beard', and a turret armed with a 20 mm (0.79 in) ShVAK cannon that covered a 120° cone ahead. The dorsal gunner sat at the rear of the ATsN fairing with a sliding hood covering a 7.62 mm (0.300 in) ShKAS machine gun and another ShKAS was mounted in a ventral hatch. The tail gunner had a powered turret with a ShVAK and, most unusually, there were manually operated ShVAK cannon mounted at the rear of each inner engine nacelle. Access to these positions was either through the wing or by a trapdoor in the upper wing surface. The large bomb bay had racks for up to 4,000 kg (8,800 lb) of bombs as well as external racks for a 500 kg (1,100 lb) FAB-500 bomb under each wing.[3][4] Space for a fifth engine, an auxiliary Klimov M-100 was reserved inside the fuselage, in a fairing above the wing spars and behind the pilots, driving a supercharger to supply pressurised air to the Mikulin AM-34FRN engines, with the installation designated ATsN-2 (Agregat tsentral'novo nadduva—central boosting unit).[5]

The maiden flight of the unarmed first prototype, without the ATsN installation, took place from Khodynka Airport on 27 December 1936 piloted by M. M. Gromov.[6] The ATsN system was installed during for the State acceptance trials in August 1937 and more powerful AM-34RNB engines were fitted during the tests.[7] The engine cooling system was revised to alleviate the problem with the aerodynamics of the outer engine nacelles by moving those radiators into deep ducts under the inner nacelles. The rudder was redesigned with a smooth skin and enlarged.[8]

A second prototype was begun in April 1936 incorporating lessons from the first aircraft and comments by the VVS. The fuselage was widened by 100 mm (3.9 in), the 'beard' was also widened, and the tail section was modified. The control system revised, an autopilot fitted and the electrical system was redesigned. The engines were changed to AM-34FRNVs and a redesigned undercarriage was fitted. The defensive armor system was revised and two more fuel tanks were added. The armament was revised and consisted of twin ShKAS guns in the nose, nacelle and tail turrets and a dorsal turret with a ShVAK; the ventral gun was eliminated. The bomb bay was modified to allow for a single 5,000 kg (11,000 lb) FAB-5000 bomb to be carried and provisions were added to carry VAP-500 or VAP-1000 poison gas dispensers under the wings.[8]

The arrests of Andrei Tupolev and Petlyakov in October 1937 during the Great Purge badly disrupted the program and the second prototype did not make its first flight until 26 July 1938.[9] The second prototype served as the base for the series aircraft, but further changes were made to the armament. The dorsal turret was changed to a MV-6 with a retractable ShVAK, another ShVAK in a KEB tail turret and a 12.7 mm (0.50 in) Berezin UBT machine gun in each ShU barbette in each inner engine nacelle. Other changes included the deletion of the 'beard' and the addition of another fuel tank.[9] Production was very slow for several reasons, not least the general disruption of the aviation industry by the Great Purge. Although preparations were made as early as 1937 at Factory No. 124 in Kazan the order to begin production wasn't given until 1939.[7]

Production of the ATsN system could not be organized in any systemic way and only the first four machines were equipped with it. The decision was made to proceed without it, but the supply of AM-34FRNV engines dried up when production of that engine ended during the second half of 1939 and only two or four TB-7s were equipped with them. The deletion of the Klimov M-100 engine of the ATsN-2 installation allowed a commander and radio operator to be carried in its place.[9] Factory No. 124 was ordered to shut down the TB-7 production line at the beginning of 1940 while alternative engines were evaluated.[10]

Cancelled Soviet 1 ruble stamp from 1945 of a Petlyakov Pe-8 in profile with a large bomb between the landing gear. CPA #989,
A wartime stamp illustrating a Pe-8 with inline engines

Six aircraft without engines were fitted with Mikulin AM-35A engines during 1940 and both the Charomskiy ACh-30 and Charomskiy M-40 aircraft diesel engines were evaluated. All eighteen TB-7s produced by the end of 1940 were re-engined with AM-35As. At least nine TB-7s were fitted with diesel engines in 1941, but neither diesel engine was satisfactory, despite greatly increasing the range of the aircraft, and all surviving TB-7s were re-engined with AM-35As by the end of 1941. Production continued at Factory No. 124, but at a very low rate, as most of the factory's resources were devoted to the higher-priority Petlyakov Pe-2. Most of these aircraft, redesignated as the Pe-8 after Petlyakov was killed in a Pe-2 crash on 12 January, were built with the AM-35A, although it had gone out of production the previous year in favor of the Mikulin AM-38 engine used in the Ilyushin Il-2.[11]

The 1,380 kW (1,850 hp) Shvetsov ASh-82 radial engine was proposed as a replacement to alleviate the shortage of engines and this was put into production in late 1942. The exhaust arrangements of the ASh-2 were not compatible with the guns in the rear of the engine nacelles and they were deleted. Another change at the end of 1943 was the deletion of the nose turret in favor of manually-operated ShKAS machine gun in a more streamlined nose. This version proved to have much the same range as the diesel-engined versions, but reliability was much improved. Total production of the TB-7/Pe-8 totaled 93.[12]

The last two or four Pe-8s were completed in 1944 as Pe-8ONs (Osobovo Naznacheniya—special-mission) with Charomskiy ACh-30B engines and a fillet at the base of the vertical stabilizer. These were special VIP transports with a seating capacity of twelve and a cargo capacity of 1,200 kg (2,600 lb).[13] Sources disagree if the armament, either partly or entirely, was removed.[14]

Wartime operational history

Pe-8 at snow-covered airbase
Pe-8 at snow-covered airbase.

When Operation Barbarossa began on 22 June 1941 only the 2nd Squadron of the 14th Heavy Bomber Regiment (TBAP—Tyazholy Bombardirovochnyy Avia Polk), based at Borispol[15] was equipped with nine TB-7s and it was not operational.[16][17] Two TB-7s were destroyed by German airstrikes shortly after the war began, before the TB-7s were withdrawn to Kazan. Stalin ordered that the squadron be reformed into a regiment so it could boost Soviet morale by striking targets deep inside Germany. The squadron was redesignated on 29 June as the 412th TBAP and began training for long-range missions.[15] About 27 July it was redesignated as the 432nd TBAP.[18] On the evening of 10 August eight M-40-engined TB-7s of the 432nd TBAP, accompanied by Yermolaev Yer-2s of the 420th DBAP, attempted to bomb Berlin from Pushkino Airfield near Leningrad. One heavily-loaded TB-7 crashed immediately after take off when it lost an engine. Only four managed to reach Berlin, or its outskirts, and only two TB-7s were able to return to their base, the others landing elsewhere or crash-landing in Finland and Estonia. The TB-7 of the commander of the 81st Long Range Bomber Division, Kombrig Mikhail Vodopianov, to which both regiments belonged, was attacked by Polikarpov I-16s from Soviet Naval Aviation over the Baltic Sea and then had one engine knocked out by flak before it reached Berlin. He was forced to turn around after a fuel tank was punctured and crash-landed in southern Estonia.[19] Five TB-7s were lost during the operation and the M-40s were proved to be totally unreliable.[20] A grant total of seven TB-7s were lost during the month of August, which rendered the regiment virtually useless. During this period the surviving aircraft were re-engined with AM-35As, which gave a shorter range, but were more reliable.[21]

By 1 October 1941 the regiment mustered fourteen TB-7s after having been replenished by new aircraft from the factory.[16] It spent the fall conducting night raids on Berlin, Königsberg, Danzig and as well as German-occupied cities in the Soviet Union. The regiment was redesignated as the 746th Separate Long-Range Aviation Regiment (OAPDD—Otdel'nyy Avia Polk Dahl'nevo Deystviya) on 3 December.[18] No aircraft were reported on hand two days later, but eleven were on strength on 18 March 1942.[16] During the winter of 1941–42 it was tasked with destroying a railroad bridge over the Volga River near Kalinin. In April 1942 one aircraft flew diplomatic personnel and mail on a non-stop flight from Moscow to Great Britain.[21] This was a test run for a flight carrying Soviet foreign minister Molotov and his delegation from Moscow to London and Washington, D.C. and back for talks on the opening of a second front against Nazi Germany (19 May 13 June 1942), crossing German-controlled airspace on the return trip without incident.[22] From August 1941 to May 1942 the regiment flew 226 sorties and dropped 606 tonnes (596 LT; 668 ST) of bombs. Fourteen bombers were lost, of which nine were non-combat losses, and seventeen TB-7s were received as replacements.[21] Sixteen aircraft were on hand on 1 May 1942, but this only increased to seventeen on 1 July.[16]

The 890th Long-Range Aviation Regiment (APDD—Avia Polk Dahl'nevo Deystviya) was formed on 15 June 1942[23] and both regiments were used to bomb transportation centers in the German rear area such as Orel, Bryansk, Kursk and Poltava. The pace of activity increased and the regiments flew as many missions in August as they had in the first ten months of the war.[24] By the eve of the Soviet counterattack at Stalingrad, Operation Uranus on 8 November the regiments had fourteen Pe-8s on hand,[16] although the regiments, now under the command of the 45th Long-Range Bomber Aviation Division (DBAD—Dal'nebombardirovochnaya Aviatsionnaya Diviziya), did not participate in the Battle of Stalingrad.[25]

In 1943 the division's primary airfield was at Kratovo, southeast of Moscow, and the regiments bombed transportation centers, airfields and troop concentrations in the first half of 1943. The railroad yard at Gomel was a favorite target and some 606 tonnes (596 LT; 668 ST) of bombs were dropped between February and September 1943, although it is not clear if these were all by Pe-8s. In addition the FAB-5000 bomb was first dropped on Königsberg in April 1943, continuing the pin-prick attacks against targets deep in the German rear.[24] In May 1943 efforts were shifted to attempt to disrupt the German buildup of forces for the Battle of Kursk. One example was when the 45th DBAD struck the rail junction at Orsha during the evening of 4 May with 109 bombers, most of which were not Pe-8s, destroying 300 rail wagons and three ammunition trains, as noted by the German High Command.[26]

During the early part of the battle, the long-range aviation units continued to strike targets in the German rear areas during the night, but this was focused in support of Soviet forces conducting their counterattack against the Orel Bulge, Operation Kutuzov, that began on 12 July. The Germans had transferred a group of nightfighters from Nachtjagdgeschwader 5 (IV./NJG 5), that flew a mix of Junkers Ju 88 and Dornier Do 217 aircraft, to the Orel area before the beginning of the battle to counter the constant raids against German railroad and other rear-area facilities, but these were virtually ineffective until their ground radars were deployed. This took until the night of 17–18 July and Soviet losses skyrocketed immediately as the Germans flew only fourteen sorties that night, but claimed eight kills. Three Pe-8s were lost on the night of 20–21 July, one to the guns of Hauptmann Heinrich Prinz zu Sayn-Wittgenstein, commander of IV./NJG 5.[27] This was a very high percentage of the eighteen that had been available on 1 July.[16] This may also have been because the exhausts of the ASh-82s were visible because they lacked flame dampening exhausts.[24] The 746th was redesignated as the 25th Long-Range Guards Aviation Regiment (GAPDD) on 18 September 1943 in recognition of its achievements.[18]

This was an omen as the loss rate, to all causes, for the Pe-8 had been steadily increasing from one aircraft per 103 flights in 1942 to one per 46 sorties in 1944.[28] Despite this the number of aircraft belonging to the 45th DBAD continued to climb; twenty being on hand on 1 January 1944 and 30 on 1 June.[16] The Pe-8s flew 276 sorties in 1944 against targets such as Helsinki, Tallinn and Pskov. Yefim Gordon maintains that the Pe-8 flew its last mission on the night of 1–2 August 1944,[28] but this is apparently contradicted by the Statistical Digest of the VVS which shows 31 Pe-8s assigned to 45th DBAD on 1 January 1945 and 32 on hand on 10 May 1945.[16] However, during this period the 45th DBAD only had three regiments, none of which used the Pe-8 as their primary aircraft.[29] The 25th GAPDD began to train flight crews in June 1944 on B-24 Liberator bombers that had been repaired after crash-landing in Soviet territory and the regiment was again redesignated as the 25th Guards Bomber Aviation Regiment on 26 December 1944.[18] The 890th had begun to fly Lend-Lease B-25 Mitchells in the spring of 1944 and was itself redesignated as the 890th Bomber Aviation Regiment on 26 December 1944.[23] The 362nd APDD was formed in early 1944 with four Pe-8s received from the other two regiments, but these were returned in the spring of 1944 when the regiment began to convert to B-25s.[30]

Post-war use

A number of Pe-8s were turned over to Aeroflot for polar exploration after the war. These had all military equipment removed and additional fuel tanks installed. They were painted orange and their engines were upgraded to either ASh-82FNs or Shvetsov ASh-73s. One aircraft landed at the North Pole in 1954[14] and others helped to monitor the drift ice stations NP-2, NP-3 and NP-4 during the late 1950s.[13] The Pe-8 was extensively used as a testbed for trials involving Soviet derivatives of the German V-1 flying bomb and it was designated as the Pe-8LL for prototype piston engine trials. It was also used as a mothership for the experimental rocket-engined Bisnovat 5 during 1948–49.[13]

Operators

 Soviet Union

Specifications (Pe-8/AM-35A)

Data from Gordon, Soviet Airpower in World War 2

General characteristics

  • Crew: Eleven
  • Length: 23.2 m (76 ft 0¼ in)
  • Wingspan: 39.13 m (128 ft 4 in)
  • Height: 6.20 m (20 ft 4 in)
  • Wing area: 188.66 m² (2,030.7 ft²)
  • Empty weight: 18,571 kg (40,941 lb)
  • Loaded weight: 27,000 kg (59,400 lb)
  • Max takeoff weight: 35,000 kg (77,000 lb)
  • Powerplant:Mikulin AM-35A liquid-cooled V12 engine, 999 kW (1,340 hp) each

Performance

Armament

See also

Comparable aircraft

References

Notes

  1. ^ Air International, p. 80
  2. ^ Gunston, Tupolev Aircraft, p. 98
  3. ^ Gunston, Tupolev Aircraft, pp. 98-99
  4. ^ Gunston, Osprey Encyclopedia, pp. 278–279
  5. ^ Air International, pp. 80–81
  6. ^ Gunston, Tupolev Aircraft, pp. 99–100
  7. ^ a b Gordon (2005), p. 75
  8. ^ a b Gunston, Tupolev Aircraft, p. 100
  9. ^ a b c Gunston, Tupolev Aircraft, p. 101
  10. ^ Gordon (2005), pp. 75–76
  11. ^ Gordon (2008), p. 393–94
  12. ^ Gunston, Osprey Encyclopedia, p. 281
  13. ^ a b c Gordon (2005), p. 76
  14. ^ a b Gunston, Tupolev Aircraft, p. 103
  15. ^ a b "14-й тяжелый бомбардировочный авиационный полк 14-й авиационный полк дальнего действия 11-й гвардейский Сталинский Краснознаменный авиационный полк дальнего действия 11-й гвардейский бомбардировочный Сталинский Краснознаменный авиационный полк" (in Russian). 07 July 2008. http://allaces.ru/cgi-bin/s2.cgi/sssr/struct/p/bap14.dat. Retrieved 16 December 2009. 
  16. ^ a b c d e f g h "Качественный состав боевых самолетов Дальней авиации на важнейшие даты Великой Отечественной войны 1941-1945 гг." (in Russian). http://ilpilot.narod.ru/vvs_tsifra/gl_3/3.118.html. Retrieved 30 October 2009. 
  17. ^ Gordon (2008), p. 395
  18. ^ a b c d "412-й тяжелый бомбардировочный авиационный полк 432-й тяжелый бардировочный авиационный полк 746-й отдельный авиационный полк дальнего действия 25-й гвардейский авиационный Орловский полк дальнего действия 25-й гвардейский бомбардировочный Орловский авиационный полк" (in Russian). 10 October 2009. http://allaces.ru/cgi-bin/s2.cgi/sssr/struct/p/bap432.dat. Retrieved 16 December 2009. 
  19. ^ "Водопьянов Михаил Васильевич" (in Russian). http://www.geroi.apifarm.ru/doc/first/34/1. Retrieved 24 October 2009. 
  20. ^ Bergstrom, Christer (2007). Barbarossa—The Air Battle: July-December 1941. Hersham, Surrey: Midland. p. 53. ISBN 1-85780-270-5. 
  21. ^ a b c Gordon (2008), p. 396
  22. ^ Air International, p. 101
  23. ^ a b "890-й Брянский авиационный полк дальнего действия" (in Russian). 22 December 2008. http://allaces.ru/cgi-bin/s2.cgi/sssr/struct/p/apdd890.dat. Retrieved 16 December 2009. 
  24. ^ a b c Gordon (2008), p. 397
  25. ^ Berstrom, Christer; Dikov, Andrey; Antipov, Vlad (2006). Black Cross/Red Star: Air War over the Eastern Front. 3: Everything for Stalingrad. Sundin, Claes. Hamilton, MT: Eagle Editions. ISBN 0-9761034-4-3. 
  26. ^ Bergstrom, p. 18
  27. ^ Bergstrom, p. 111
  28. ^ a b Gordon (2008), p. 398
  29. ^ "45-я Гомельская авиационная дивизия дальнего действия 45-я тяжелая бомбардировочная Гомельская авиационная дивизия" (in Russian). 30 March 2009. http://allaces.ru/cgi-bin/s2.cgi/sssr/struct/d/addd45.dat. Retrieved 16 December 2009. 
  30. ^ "362-й Рижский авиационный полк дальнего действия 362-й бомбардировочный Рижский авиационный полк" (in Russian). 15 August 2005. http://allaces.ru/cgi-bin/s2.cgi/sssr/struct/p/apdd362.dat. Retrieved 16 December 2009. 

Bibliography

  • Bergstrom, Christer (2007). Kursk—The Air Battle: July 1943. Hersham, Surrey: Classic Publications. ISBN 1-857802-388-1. 
  • Gordon, Yefim (2008). Soviet Airpower in World War 2. Hinckley, England: Midland Publishing. ISBN 978-1-85780-304-4. 
  • Gordon, Yefim; Rigamant, Vladimir (2005). OKB Tupolev: A History of the Design Bureau and its Aircraft. Hinckley, England: Midland Publishing. ISBN 1-85780-214-4. 
  • Gunston, Bill (1995). The Osprey Encyclopedia of Russian Aircraft 1875-1995. London: Osprey. ISBN 1-85532-405-9. 
  • Gunston, Bill (1995). Tupolev Aircraft since 1922. Annapolis, MD: Naval Institute Press. ISBN 1-55750-882-8. 
  • "Pe-8: Last of a Generation". Air International (Bromley, UK: Fine Scroll) 19 (2): 76–83, 101. August 1980. ISSN 0306-5634. 

External links

The initial version of this article was based on material from aviation.ru. It has been released under the GFDL by the copyright holder.


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