keskiviikko 13. tammikuuta 2016

Petljakov Pe-8 / TB-7

The Petlyakov Pe-8 was a Soviet heavy bomber designed before World War II, and the only four-engine bomber the USSR built during the war. Produced in limited numbers, it was used to bomb Berlin in August 1941. It was also used for so-called "morale raids" designed to raise the spirit of the Soviet people by exposing Axis vulnerabilities. Its primary mission, however, was to attack German airfields, rail yards and other rear-area facilities at night, although one was used to fly the People's Commissar of Foreign Affairs (Foreign Minister) Vyacheslav Molotov from Moscow to the United States in 1942.

Originally designated the TB-7, the aircraft was renamed the Pe-8 after its primary designer, Vladimir Petlyakov, died in a plane crash in 1942. Supply problems complicated the aircraft's production and the Pe-8s also had engine problems. As Soviet morale boosters, they were also high-value targets for the Luftwaffe's fighter pilots. The loss rate of these aircraft, whether from mechanical failure, friendly fire, or combat, doubled between 1942 and 1944.

By the end of the war, most of the surviving aircraft had been withdrawn from combat units. After the war, some were modified as transports for important officials, and a few others were used in various Soviet testing programs. Some supported the Soviet Arctic operations until the late 1950s.

General characteristics
Crew: Eleven
Length: 23.2 m 
Wingspan: 39.13 m 
Height: 6.20 m 
Wing area: 188.66 m²
Empty weight: 18,571 kg 
Loaded weight: 27,000 kg 
Max. takeoff weight: 35,000 kg 
Powerplant: 4 × Mikulin AM-35A liquid-cooled V12 engine, 999 kW (1,340 hp) each
Maximum speed: 443 km/h 
Range: 3,700 km 
Service ceiling: 9,300 m 
Rate of climb: 5.9 m/s 
Wing loading: 143 kg/m² 
Power/mass: 140 W/kg 
Armament: 2 x 20-millimeter (0.79 in) ShVAK cannons (dorsal and tail turrets)
2 x 12.7-millimeter (0.50 in) UBT machine guns (engine nacelles)
2 x 7.62-millimeter (0.300 in) ShKAS machine guns (nose turret)

Bombs: Up to 5,000 kg 
Petljakov Pe-8 oli neuvostoliittolainen, nelimoottorinen raskas pommikone, jota valmistettiin vuosina 1936–1944. Kone tunnettiin myös nimellä TB-7, ja se oli ainut nelimoottorinen Neuvostoliiton toisen maailmansodan aikana valmistamista pommikoneista. Konetta rakennettiin prototyypit mukaan lukien 93 kappaletta.

Projektinimellä ANT-42 tunnetun koneen suunnittelu aloitettiin Tupolevin lentokonesuunnittelutoimistossa kesäkuussa 1934, pääsuunnittelijana toimi Vladimir Petljakov. Mikulin AM-34FRN -moottoreilla varustetun aseistamattoman prototyypin ensilento lennettiin 27. joulukuuta 1936, ohjaajana Mihail Gromov. Kone vaurioitui ensilennon laskuvaiheessa pahoin, johtuen prototyyppiasteella olevan moottorityypin alitehoisuudesta. Suunnittelua kuitenkin jatkettiin, ja parannetun, Mikulin AM-34 -moottoreilla varustetun toisen prototyypin ensilento lennettiin 28. kesäkuuta 1938.

Toinen prototyyppi rakennettiin vastaamaan muun muassa aseistuksen ja varustelun osalta tuotantosarjan koneita. Sarjavalmistus aloitettiin vasta vuonna 1940, johtuen muun muassa moottorien toimitusvaikeuksista ja pääsuunnittelijan vankeustuomiosta. Ensimmäinen sarjakone nimellä TB-7 toimitettiin toukokuussa 1940, viimeiset vuoden 1944 aikana. 

Sarjatuotannon ollessa kesken, moottorityypiksi vakiintui Shvetsov ASh-82FN -moottori, joita vaihdettiin myöhemmin jo valmistuneisiinkin koneisiin. Petljakovin kuoltua lento-onnettomuudessa tammikuussa 1942 konetyyppi nimettiin Petljakov Pe-8:ksi.
Konetyyppi osallistui Neuvostoliiton ensimmäiseen poliittiseksi tarkoitettuun Neuvostoliiton ensimmäiseen pommituslentoon Berliiniin 8. elokuuta 1941.
When Operation Barbarossa began on 22 June 1941, only the 2nd Squadron of the 14th Heavy Bomber Regiment (Russian: Tyazholy Bombardirovochnyy Avia Polk—TBAP), based at Boryspil was equipped with Pe-8s, but was not ready for combat. Two of its nine Pe-8s were destroyed by German air strikes shortly after the war began, before the Pe-8s were withdrawn out of reach in Kazan. Stalin ordered that the squadron be reformed into a regiment, and that it strike targets deep inside German territory. 

Theoretically, this tactic would boost Soviet morale by demonstrating the vulnerability of the enemy. The squadron was re-designated on 29 June as the 412th TBAP and began training for long-range missions. On or about 27 July it was again renamed, this time as the 432nd TBAP. On the evening of 10 August, eight M-40-engined Pe-8s of the 432nd TBAP, accompanied by Yermolaev Yer-2s of the 420th Long-Range Bomber Aviation Regiment (DBAP), attempted to bomb Berlin from Pushkino Airfield near Leningrad. 

One heavily loaded Pe-8 crashed immediately upon take off, after it lost an engine. Only four managed to reach Berlin, or its outskirts, and of those, only two returned to their base. The others landed elsewhere or crash-landed in Finland and Estonia. The aircraft of the commander of the 81st Long-Range Bomber Division, Combrig Mikhail Vodopianov, to which both regiments belonged, was attacked mistakenly by Polikarpov I-16s from Soviet Naval Aviation over the Baltic Sea and lost an engine; later, before he could reach Berlin, German flak punctured a fuel tank. He crash-landed his aircraft in southern Estonia.

Five more Pe-8s were lost during the operation, largely due to the unreliability of the M-40s. Seven Pe-8s were lost during the month of August alone, rendering the regiment ineffective. During this period, the surviving aircraft were re-equipped with AM-35As, which gave them a shorter range, but a more reliable engine.
By 1 October 1941, the regiment mustered fourteen Pe-8s after having been replenished by new aircraft from the factory. It spent the rest of the year conducting night raids on Berlin, Königsberg, Danzig and as well as German-occupied cities in the Soviet Union. The regiment was re-designated as the 746th Separate Long-Range Aviation Regiment (Russian: Otdel'nyy Avia Polk Dahl'nevo Deystviya—OAPDD) on 3 December. No aircraft were reported on hand two days later after this designation, but eleven were on strength on 18 March 1942.
During the winter of 1941–42, the regiment was assigned the destruction of 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. This was a test run for a flight carrying Soviet Foreign Minister Molotov and his delegation from Moscow to London and then to Washington, D.C. and back, for negotiations to open a second front against Nazi Germany (19 May–13 June 1942). The flight crossed German-controlled airspace on the return trip without incident. 

From August 1941 to May 1942, the regiment flew 226 sorties and dropped 606 tonnes (596 long tons; 668 short tons) of bombs. In the course of these missions, they lost 14 bombers, five in combat, and the rest from engine malfunction. The regiment received 17 Pe-8s as replacements. Sixteen aircraft were on hand on 1 May 1942, but the number had only increased to seventeen two months later; the regiment was losing aircraft almost as fast as they were being replaced.

The 890th Long-Range Aviation Regiment (Russian: Avia Polk Dahl'nevo Deystviya—APDD) was formed on 15 June 1942 and both regiments were used to bomb German-held transportation centers of, among others, 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. By the eve of the Soviet counterattack at Stalingrad, Operation Uranus, on 8 November the regiments had fourteen Pe-8s on hand. Under the command of the 45th Long-Range Bomber Aviation Division (Russian: Dal'nebombardirovochnaya Aviatsionnaya Diviziya—DBAD), they did not participate in the Stalingrad air attacks.

In 1943, from the division's primary airfield at Kratovo, southeast of Moscow, the regiments bombed transportation centers, airfields and troop concentrations. The railroad yard at Gomel was a favorite target and the regiment dropped approximately 606 tonnes (596 long tons; 668 short tons) of bombs there between February and September 1943. It is not clear if these sorties were made by Pe-8s alone or in combination with other aircraft. In addition, the regiment dropped the first FAB-5000 bomb on Königsberg in April 1943, continuing the pin-prick attacks against targets deep in the German rear. In May 1943, efforts shifted to disrupt the German concentration of forces for the Battle of Kursk. In one sortie, the 109 bombers of the 45th DBAD struck the rail junction at Orsha during the evening of 4 May, most of which were not Pe-8s; the German High Command reported the destruction of 300 rail wagons and three ammunition trains.
By 1 July, the regiment had 18 Pe-8s for deployment during the early phase of the Battle of Kursk. The long-range aviation units continued to attack targets in the German rear areas at night, supporting the Soviet ground offensive in the Orel Bulge, called Operation Kutuzov, that began on 12 July. The Germans had transferred the nightfighters of the Fourth Group of Nightfighter Wing 5 (IV./Nachtjagdgeschwader 5), flying a mix of Junkers Ju 88 and Dornier Do 217 aircraft, to counter the Soviet raids near the Orel area. Initially, the night fighters were ineffective against the Soviet raids, until the deployment of their ground radar "eyes". 

Once the Germans had use of their radar, after the night of 17–18 July, Soviet losses increased sharply. Although the Germans flew only fourteen sorties that night, they claimed eight kills. On the night of 20–21 July, Captain (Hauptmann) Heinrich Prinz zu Sayn-Wittgenstein, commander of IV./NJG 5, shot down three himself. 
The exhaust plume of the ASh-82 engine may have been a contributing factor; the engines lacked flame dampening exhausts, making their plume visible from a distance. Despite its losses, the 746th was re-designated as the 25th Long-Range Guards Aviation Regiment (GAPDD) on 18 September 1943 in recognition of its achievements.

The loss of Pe-8s to all causes—mechanical, combat, friendly fire—had steadily increased from one aircraft per 103 flights in 1942 to one per 46 sorties in 1944. Despite the losses, production kept pace with need. The number of aircraft belonging to the 45th DBAD continued to rise; 20 were on hand on 1 January 1944 and 30 on 1 June. The Pe-8s flew 276 sorties in 1944 against such targets as Helsinki, Tallinn and Pskov. Aviation historian Yefim Gordon maintains that the Pe-8 flew its last mission on the night of 1–2 August 1944, but the Statistical Digest of the VVS contradicts this claim, showing 31 Pe-8s assigned to 45th DBAD on 1 January 1945 and 32 on hand on 10 May 1945. However, during this period the 45th DBAD only had three regiments, none of which used the Pe-8 as their primary aircraft, so while the 45th DBAD may have had Pe-8s, these may not have been in use as the primary combat aircraft.

The 890th began to fly Lend-Lease B-25 Mitchells in the spring of 1944 and was itself re-designated as the 890th Bomber Aviation Regiment on 26 December 1944.[24] 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 the Lend-Lease Mitchells.

After the war, the Pe-8 was used extensively 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 mother ship for the experimental rocket-engined Bisnovat 5 in 1948–49. Aeroflot received several of the surviving Pe-8s for polar exploration. Their military equipment removed, they had additional fuel tanks installed, were painted orange, and had their engines upgraded to either ASh-82FNs or Shvetsov ASh-73s. One landed at the North Pole in 1954[15] and others helped to monitor the drift ice stations NP-2, NP-3 and NP-4 during the late 1950s.

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