"Latvia" Former Soviet Union Military Bases
Yakovlev, Yak-1 Armament 
  • 1 × 20mm 0.8 inch" ShVAK Cannon,
  • 1 × 12.7mm "0.5 inch" Berezin UBS Machine Gun, 
  • One-second salvo weight of fire 2kg "4.4 pounds" with both the cannon and the machine gun using high-explosive ammunition 
ShVAK Cannon
                                                                 20mm 0.8 inches" ShVAK Cannon
The ShVAK "Russian: ШВАК: Шпитальный-Владимиров Авиационный Крупнокалиберный, Shpitalnyi-Vladimirov Aviatsionnyi Krupnokalibernyi, "Shpitalny-Vladimirov large-calibre for aircraft" was a 20mm autocannon used by the Soviet Union during World War II. It was designed by Boris Shpitalniy and Semyon Vladimirov and entered production in 1936. ShVAK was installed in many Soviet aircraft including Yakovlev Yak-1, Yakovlev Yak-3, Polikarpov I-153 and I-16, Lavochkin La-5 and La-7, LaGG-3, early Ilyushin Il-2, and Soviet-modified Hawker Hurricane aircraft as well as T-38 and T-60 tanks.
The ShVAK 20 mm auto cannon is a large-caliber version of the 12.7mm ShVAK machine gun. Plant INZ-2 began production of 12.7mm of ShVak machine guns in 1935. During 1935-1936 12.7mm ShKAS machine gun was re-chambered to a 20mm caliber round and serial production was launched. Some months later the 12.7mm version has been removed from manufacture altogether. 
The autocannon version differed only in the caliber. It is a gas-operated disintegrating link ammunition belt fed weapon with either cable or pneumatic charging in remote applications. ShVAK ammunition consisted of a mix of fragmentation-incendiary and armor piercing-incendiary rounds. By 1944 ShVAK was supplanted by the 20mm development of the Berezin UB 12.7mm machine gun "UBS', the Berezin B-20, which offered the same performance as 20mm ShVAK but with the advantage of being significantly lighter. 
  • Caliber: 20mm
  • Cartridge: 20×99R
  • Rate of fire: 700–800 rounds/minute
  • Muzzle velocity: 750–790 m/s "2,460-2,592 ft/s"
  • Weight: 88 pounds "40kg" without ammunition for the wing version
  • Length: 66.1 inches "1679mm" for the wing version
Ammunition Specifications 
Berezin UB 12.7mm "0.5 inches" Berezin UBS Heavy Machine Gun 
                                                       12.7mm "0.5 inche" Berezin UBS Machine Gun
                      12.7mm 0.5 inch Shell
Berezin UB "УБ - Универсальный Березина, Universalni Berezina, Berezin's Universal" was a 12.7mm caliber Soviet aircraft Heavy Machine Gun widely used during World War II. 12.7mm "0.5 inches" Berezin UBS Machine Gun, One-second salvo weight of fire 2kg "4.4 pounds" with both the cannon and the machine gun using high-explosive ammunition.  
In 1937, Mikhail Yevgenyevich Berezin began designing a new large caliber aircraft machine gun chambered to the 12.7mm round used by infantry machine guns. The new design passed factory trials in 1938 and was accepted into service in 1939 under the designation BS "Березин Синхронный, Berezin Sinkhronniy, "Berezin Synchronized". The rate of fire made it well suited for use as defensive armament in aircraft. While a successful design, BS was not without its faults, the biggest being its cable-operated charging which required considerable physical strength. Continued development resulted in the improved UB which came in three versions: UBK "Kрыльевой, Krylyevoi, for the wings", UBS Синхронный, "Sinkhronniy Synchronized", and UBT "Турельный, Turelniy, for the turret", with UBS and UBK charged by compressed air. The UB was accepted into service on 22 April 1941, just two months before the start of the 
German-Soviet War.
The Berezin UB is a gas-operated air-cooled machine gun chambered to the Soviet 12.7x108mm infantry machine gun round. Ammunition is supplied via a disintegrating link belt with a unique system in which each new round helps to extract the spent cartridge. Another unusual feature is that the belt is advanced during the return of the moving portion of the gun and not during the recoil. Turret installations were charged manually, while wing and synchronized versions utilized pneumatic charging.
The UB in all variants was used by the vast majority of Soviet military aircraft of World War II.
Production History
  • Designer: Mikhail Yevgenyevich Berezin
  • Designed: 1937–1939
  • Weight: 21.5 kilograms "47.4 pounds"
  • Cartridge: 12.7x108mm
  • Action: Gas
  • Rate of Fire: 800-1050 RPM
  • Muzzle Velocity: 814–850 m/s "2,670–2,800 ft/s"
  • Feed System: Belt 
  • Sights: Iron 
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Revised: 01/28/2013 – 19:33:13