This weapon was manufactured by Rheinmetal-Borsig and was essentially a longer barrel version of the Army 3.7 cm Flak 36. This new gun was a great improvement over the older 3.7 cm/83 SK C/30 and had a much higher rate of fire. Recoil operated, air cooled and used five-round ammunition strips.
These were the first German light anti-aircraft guns to have shields, a surprising shortcoming of earlier weapons.
The design of this gun emphasized ease of manufacturing. Constructed of a monobloc barrel which was connected to the breech ring by a bayonet joint to allow easy replacement. Used a vertical sliding breech block, hydraulic brake and spring recuperator.
|Designation||3.7 cm/69 (1.5") Flak M42|
|Ship Class Used On||U-boats, Emden, destroyers and minesweepers|
|Date Of Design||1942|
|Date In Service||1944|
|Gun Weight||240 lbs. (109 kg)|
|Gun Length oa||N/A|
|Barrel Length||100.79 in (2.560 m)|
|Rifling Length||90.1 in (2.289 m)|
|Grooves||(20) 0.0217 in deep x 0.150 in (0.55 mm x 3.81 mm)|
|Lands||0.087 in (2.2 mm)|
|Twist||Uniform RH 1 in 25.6|
|Chamber Volume||16.5 in3 (0.270 dm3)|
|Rate Of Fire||250 rounds per minute cyclic|
|Weight of Complete Round||HE tracer: 3.0 lbs. (1.36 kg)
HE incendiary: 3.02 lbs. (1.37 kg)
AP tracer: 3.31 lbs. (1.50 kg)
|Projectile Types and Weights||HE tracer: 1.40 lbs. (0.635 kg)
HE incendiary: 1.42 lbs. (0.640 kg)
AP tracer: 1.54 lbs. (0.700 kg)
|Bursting Charge||HE tracer: N/A
HE incendiary: N/A
AP tracer: N/A (probably solid bullet)
HE incendiary, complete round: 14 in (355 mm)
|Propellant Charge||0.386 lbs. (0.175 kg) RPC/38N
Cartridge: 1.0 lbs. (0.51 kg)
|Muzzle Velocity||HE tracer: 2,838 fps (865 mps)
HE incendiary: 2,772 fps (845 mps)
AP tracer: 2,674 fps (815 mps)
|Working Pressure||18.7 tons/in2 (2,950 kg/cm2)|
|Approximate Barrel Life||7,000 rounds|
|Ammunition stowage per gun||2,000 rounds 1|
The sources below differ in many areas for this weapon. The figures given in this table come mainly from "Naval Weapons of Word War Two."
- ^Minesweeper outfits were half AP tracer and half HE tracer. Outfits on other ships was intended to be two-thirds HE incendiary and one-third AP tracer.
- "Naval Weapons of World War Two" by John Campbell
- "German Warships 1815-1945" by Erich Gröner
- "Das Buch der Deutschen Kriegsmarine" by Jak P. Mallmann Showell
- "German Destroyers of World War Two (2nd Edition)" and "German Cruisers of World War Two" both by M.J. Whitley
Special help by Dave Krakow