Karabin lotniczy wz. 37

The karabin lotniczy obserwatora wz. 37 (Polish for "observers aviation rifle pattern 1937") is an aerial machine gun, a development of the ręczny karabin maszynowy wz. 28. It was designed as a manually operated machine gun for defensive firing positions on board combat aircraft of Polish Military Aviation.

Karabin lotniczy obserwatora wz. 37
Type	aerial, flexible machine gun
Place of origin	Poland
Service history
In service	1937 to 1949
Used by	See Users
Wars	World War II
Production history
Designed	1937
Manufacturer	Państwowa Fabryka Karabinów
Produced	1937 to 1939
No. built	339-24,000
Specifications
Mass	7 kg (15 lb) (empty)
Length	1,110 mm (44 in)
Barrel length	611 mm (24.1 in)
Cartridge	8x57mm IS
Caliber	7.92mm
Action	gas operated
Rate of fire	1100 round/min
Muzzle velocity	853 m/s (2,800 ft/s)
Feed system	91 rounds

History

In the mid-1930s, Polish small arms designer Wawrzyniec Lewandowski was given the task of developing a flexible gun based on the rkm wz. 28 light machine gun. The desired changes included raising the cyclical rate of fire to 1100 rds/min, replacing the buttstock with a spade grip at the rear of receiver, moving the main spring under barrel and, most importantly, changing the feed system.

The gun's original 20 round box magazine was impractical with the gun's high rate of fire. A new feeding mechanism was added as a pack to the standard receiver. It contained a spring-loaded lever, which when cammed by the lock during locking would grab a round from a 91-round pan magazine located above the receiver and force the round into alignment to feed during unlocking. The weapon is the world's only specialised aerial flexible machine gun based closely on the Browning M1918, or "Browning Automatic Rifle". The wz. 37 was dubbed "Szczeniak" (Polish for "pup") due to its lightness and compactness compared to Vickers E and Vickers F machine guns it was intended to replace and the "barking" sound it made when shooting. During World War II the wz. 37 was used onboard PZL.37 Łoś bomber and LWS-3 Mewa reconnaissance aircraft.

This machine gun was also intended as a standard on-board weapon for other aircraft that did not manage to enter service before the outbreak of the war (PZL.46 Sum, PZL.48 Lampart, PZL.49 Miś).

Users

•  Germany
•  Poland
•  Romania
•  Soviet Union

Similar Weapons

• MG 42, Nazi Germany

References

1. Adam Popiel (1991). Uzbrojenie lotnictwa polskiego 1918-1939. Warsaw, SIGMA NOT. ISBN 83-85001-37-9.