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WWII Tech Pubs Briefing
2cm Fliegerabwehrkanone 30 and
2cm Fliegerabwehrkanone 38
Written by
Frank Baldwin
Covering a crossing in northern France in May 1940,
German flak gunners take a terrible toll of Allied aircraft sent to destroy
this vital bridge.
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Country of Origin:
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Germany
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Manufacturer:
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Rheinmetall‑Borsig (2cm FlAK 30); Mauser
(2cm FlAK 38)
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Major Variants:
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2cm FlAK 30; 2cm FlAK 38, 2cm Flakvierling 38
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Role:
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Light anti-aircraft gun
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Operated by:
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Germany (army, navy, and air force), Netherlands, China
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First Manufacture:
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1934
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In Service:
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1935-45
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Number Built:
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15,985 barrels for Heer (German army) and 121,677
for Luftwaffe (German air force) in 1939-45
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Overview
By the end of World War I, German designers thought that
low-level air defence would require guns of 20-mm (0.79-in) calibre to
overcome the armour of the faster-moving ground-attack aircraft emerging
from this conflict. During the 1920s, the German firm of Rheinmetall-Borsig,
forbidden to manufacture anti-aircraft guns by the Versailles Treaty,
took over the Swiss firm of Solothurn and established it as a foreign
base of weapons design. Solothurn’s MK-ST-5 evolved from the concept of
an overgrown machine gun. Rheinmetall-Borsig shifted work on the gun to
its own facilities in Germany in the early 1930s with the introduction
of Germany’s re-armament policy. The Kriegsmarine (German navy)
adopted the gun in 1934 and within a year so had the Luftwaffe
(German air force). The Heer (German army) also ordered this design
once it started to raise flak units. Rheinmetall-Borsig mass-produced
the weapon as the 2cm Fliegerabwehrkanone (Aircraft Defense Cannon,
or FlAK) 30.
This recoil action gun was an effective
and robust weapon for the late 1930s. The carriage was a 360-degree turntable
towed on a light two-wheeled limber that allowed crew to easily transfer
the gun to and from the ground. This limber could also carry searchlights
and similar equipment. The gun could be used against infantry and light
vehicles while still mounted on the limber – attested by many action photographs.
The turntable was levelled with levelling screws. The 2cm FlAK 30 fired
a 120-g (4.23 oz) 20-mm HE projectile with a contact detonating fuse.
A pyrotechnic relay detonated the projectile after a set time as a safety
measure, limiting the effective ceiling to 2,200 m (7,200 ft). The 2cm
FlAK 30 was issued Panzergranate (Armour-Piercing Shell) 40 (PzGr40)
ammunition for antitank use until supplies of tungsten dwindled later
in the war. Ammunition came in 20-round box magazines. The gun’s original
fire control system used one of two available sights on each gun. One
was a complex Zeiss clockwork predictor and a reflecting mirror sight
called the Flakvisier (Flak Sight) 35, which required a constant
supply of range information from a crewmember operating a portable range
finder. The Linealvisier (Linear Sight) 21 was similar, but had
gunner’s reference markings for specific speeds instead of relying on
manual input for that quality. As the war progressed, these cumbersome
arrangements were simplified with a basic optical cartwheel sight and
corrections based on tracer observation.
A typical 2cm FlAK 30 detachment consisted of seven men,
although fewer men often crewed self-propelled installations. The Geschützführer
(Gun Leader) chose where to place the gun and how to camouflage it, and
was responsible for maintaining contact with other units. In action, he
selected targets and estimated their speed, calling it loudly to the rest
of the crew. Kanonier (Gunner) 1 aimed the gun with manual elevation
and traverse mechanisms. Kanonier 2 dialed the called target speed
and distance on the gunsight computer (when using the Flakvisier
35). Kanonier 3 dialed the target’s heading and altitude change
on the gunsight computer. Kanonier 4 fed ammuntion to the gun.
Kanonier 5 used the rangefinder and called out range to the target
in 200-m (220-yd) increments. The last crewman was a driver who took care
of the limber or vehicle, if the gun were towed
By the end of the 1930s, aircraft speeds had increased
to the point where the Germans considered the 2cm FlAK 30’s rate of fire
too slow to produce a reasonable chance of a hit or significant damage
to a modern target. Furthermore, the gun’s ammunition proved barely adequate
in both in muzzle velocity and explosive warhead content. It was also
prone to feed jams. The system required a redesign.
Rheinmetall-Borsig had plenty
to cope with, so the project passed to Mauser. Mauser’s refinement , the
2cm FlAK 38, kept many of the features and components of the 2cm FlAK
30, although the carriage required modification, which was done by Gustloff, in Suhl. To keep design changes
to a minimum, the ammunition and the 20-round ammunition boxes remained
the same. Minor changes to the bolt mechanism and spring return increased
the cyclic rate of fire by 25 percent to 450 rounds/min. Mauser produced
the 2cm FlAK 38 at six production centres.
After its introduction in 1939, the 2cm FlAK 38 became
the Germans’ principal light anti-aircraft weapon, but it never entirely
supplanted the 2cm FlAK 30, which served to war’s end. In September 1939,
the Luftwaffe had 6,072 assemblies of the two types, a number that
nearly tripled to 18,010 by May 1944.
The 2cm FlAK 38 provided a higher rate of fire than its
predecessor, but it did not entirely eliminate its drawbacks. To dramatically
increase rate of fire, Mauser engineered the radical solution of a multiple
gun platform, which increased firepower without compromising the investment
in ammunition production. The resulting 2cm Flakvierling (Flak
Quadruplet) 38 was a remarkable piece of engineering that featured four
2cm FlAK 38 barrels on a revised version of the standard carriage. Between
them, the four barrels produced 1,800 rounds/min. By February 1945, the
Luftwaffe had 3,768 2cm Flakvierling 38 in service.
German innovation led to several variants on these designs.
The 2cm Flakvierling 38/43F was a prototype with rangefinding radar,
originally produced for use on U-boats. The 2cm Gebirgsflak (Mountain
Flak) 38, intended for mountain troops, was mounted on a lightened fold-up
carriage that could be disassembled for manual transport. A further variant
could be carried underneath transport aircraft in support of Fallschirmjäger
(paratroops).
Many local field improvisations resulted in installations
on trucks, halftracks, and armoured trains, but not until late 1943 did
Germany begin mounting the guns on tracked, armoured vehicle chassis to
provide anti-aircraft armoured fighting vehicles. The first such armoured
carrier, the Flakpanzer (Armoured Anti-Aircraft Gun) 38(t) Gepard
(Cheetah), married a single 2cm FlAK 30 or 38 and a PzKpfw 38(t) chassis.
The PzKpfw IV chassis could carry the 2cm Flakvierling 38 instead.
A similar ordnance was used in many German armoured fighting
vehicles as the Kampfwagenkanone (Fighting Vehicle Gun; KwK) 30
and 38, which differed from the otherwise identical FlAK guns in barrel
length and role – they were used primarily to engage enemy troops and
light vehicles.
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Variants
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Type
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Number Built
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Remarks
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Ordnance
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2cm FlAK 30
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-
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Rheinmetall-Borsig original design firing 280 cyclical
rounds/min.
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2cm FlAK 38
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-
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Mauser redesign firing 450 cyclical rounds/min.
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Towed Mountings
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2cm FlAK 30 2cm FlAK 38
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-
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Single mount on two-wheeled carriage.
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2cm Flakvierling
38
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2,140 to March 1945
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Quadruple mounting based on a modified version of the
2cm FlAK 38.
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2cm Gebirgsflak 38
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-
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Lightweight mounting for 2cm FlAK 38
for mountain and airborne use.
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Static Naval Mountings
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2cm FlAK C30 2cm FlAK C38
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-
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2cm FlAK C30 and 2cm FlAK C38 installed in a C30 single
mounting, and 2cm FlAK C38 installed in C38 single, double, and
quadruple mountings.
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Self-Propelled AA Mountings
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2cm Flakvierling 38 auf schwerer geländegängiger
Lastkraftwagen 4.5t and other truck-mounted varieties
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-
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The 2cm FlAK 30 and 38 and the Flakvierling
were mounted on a variety of trucks with and without supplemental
armour. A one-ton 6x4 truck like the Krupp-Protze L 2 H 143,
which when equipped with a 2cm FlAK 30 or 38 was designated a Kfz
81, usually towed the gun carriage and stowed ammunition but occasionally
mounted the weapon right on the truck bed. Heavier trucks like the
4.5-tonne (5.0-ton) Mercedes-Benz L4500A found themselves
engaged in the 2cm Flakvierling 38 auf schwerer geländegängiger
Lastkraftwagen (on a heavy off-road truck) 4.5t, although these
more robust vehicles also employed single-barrel 20-mm guns.
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2cm FlAK 30 auf schwere gelände-gängiger
Einheits Personen-kraftwagen
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-
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A mounting of the 2cm FlAK 30 or 38 in the rear of
a wheeled 4x4 was designated “auf schwere geländegängiger
Einheits Personenkraftwagen” (on a heavy cross-country
passenger car). Many varieties of 4x4 were converted to carry
the FlAK guns.
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Mittlere Schützen-panzerwagen SdKfz 251
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Limited numbers
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Limited non-standard conversion of 2cm FlAK
30 or 38 on the generic SdKfz 251 mittlere Schützenpanzerwagen
(Medium Infantry Armoured Vehicle) halftrack.
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Leichte Panzerspähwagen
(2cm) SdKfz 222
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A 2cm FlAK 30 or 38 was mounted in a
small open turret to the rear of a 4x4 leichte Panzerspähwagen (Light Armoured Scout Car) SdKfz 222. Mainly
used by the Luftwaffe for convoy defence. Crew of three and
in production 1936-44.
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2cm FlAK 30 auf Fahrgestell Zugkraftwagen
1t SdKfz 10/4
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-
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Mounting of the 2cm FlAK 30 on the 1-tonne (1-ton)
Zugkraftwagen (Traction Vehicle) SdKfz 10 halftrack (sometimes
called a Demag after one of its original manufacturer):
“auf Fahrgestell” means “on chassis”. The sides of the vehicle
dropped down in action to enable 360-degree traverse. Spare ammunition
was carried in a two-wheeled towed limber. Detachment of seven.
Also called the leichte Selbstfahrlafette (Light Self-Propelled
Mount) 2cm FlAK 30 and in production in 1937.
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2cm FlAK 38 auf Fahrgestell Zugkraftwagen
1t SdKfz 10/5
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-
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Modified version of the SdKfz 10/4 introduced in 1941
with an armoured cab, gun shield, and 2cm FlAK 38. Sometimes called
the leichte Selbstfahrlafette 2cm FlAK 38.
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Mittlere Zugkraftwagen 8t SdKfz 7/1
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319
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This 8-tonne (9-ton) halftrack was mated to the 2cm
Flakvierling 38 in 1941. It had a crew of 10. Later variants
had armoured cabs. The vehicle was also called the Selbstfahrlafette
(Self-Propelled Gun Carriage) 2cm Flakvierling 38.
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Leichte Flakpanzer 38(t) SdKfz 140
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-
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The leichte Flakpanzer (Light Flak Tank) appeared
at the very end of 1943. This modified PzKfw 38(t) mounted a 2cm
FlAK 38 enclosed by an octagonal shield 10-mm (0.39-in) thick at
the rear of the chassis. The upper part of the shield could fold
outward. Crew of four.
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2cm Flakvierling auf Fahrgestell PzKpfw
IV Möbelwagen
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1
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The Möbelwagen (Moving Van), sometimes
called a Flakpanzer IV, was designed as a 2cm Flakvierling
38 platform on a PzKpfw IV chassis modified to include fold-down
armour surrounding the gun. The prototype was rejected in May 1943.
The Möbelwagen did see service eventually,
but armed with twin 3.7-cm (1.46-in) guns.
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2cm Flakvierling auf Fahrgestell
PzKpfw IV/3 Wirbelwind
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About 110
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Also called a Flakpanzer IV, the Wirbelwind
(Whirlwind) entered service at the end of 1943. It was based on
the unmodified chassis of the PzKpfw IV Ausf J. Unlike the Möbelwagen prototype, the 2cm Flakvierling 38 of the Wirbelwind
was mounted in a revolving open turret with 16 mm (0.63 in) of armour.
A crew of five tended the vehicle.
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Mittlere Schützen-panzerwagen
(2cm) SdKfz 251/17
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About 210
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Developed in 1944 as standard equipment to replace
field modifications. The gun is in a small, open, armoured turret
behind the driver’s compartnment. Crewed by four to six men.
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Predictors
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Flakvisier 35
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-
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The electronic Flakvisier (Flak Sight) 35
accepted the input values for target distance, speed, altitude change,
and heading.
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Linealvisier 21
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-
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The Linealvisier (Linear Sight) 21 accepted
the same input values as the Flakvisier 35 with the exception
of target speed. The sight had several markings for specific speeds
to help the gunner.
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Schwebekreis-visier 30
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-
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The Schwebekreisvisier (Floating Circle
Sight) 30 was a simplified optical “cartwheel” sight later introduced
for the FlAK 38.
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Specifications
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Model
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2cm FlAK
30
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2cm FlAK
38
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2cm Flakvierling
38
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Calibre
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20 mm (0.79 in)
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20 mm (0.79 in)
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20 mm (0.79 in)
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Width
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1.81 m (5.94 ft)
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-
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Height
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1.60 m (5.25 ft)
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-
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Overall Length (Gun and Mounting)
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4.08 m (14.11 ft)
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-
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-
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Length of Gun
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2,300 mm (90.55 in)
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2,252.5 m (88.68 in)
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2,252.5 m (88.68 in)
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Length of Barrel
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1,300 mm (51.18 in)
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1,300 mm (51.18 in)
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1,300 mm (51.18 in)
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Length of Rifling
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1,158 mm (45.59 in)
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1,158 mm (45.59 in)
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1,158 mm (45.59 in)
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Number of Rifling Grooves
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Eight
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Eight
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Eight
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Chamber Volume
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0.048 cu dm (2.93 cu in)
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0.048 cu dm (2.93 cu in)
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0.048 cu dm (2.93 cu in)
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Elevation
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-12° to +90°
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-20° to +90°
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-10° to +100°
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Traverse
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360°
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360°
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360°
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Mechanism
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Recoil-operated loading mechanism with 33-44 mm (1.30-1.73
in) of recoil.
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-
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- |
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Weight in Action
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450 kg (992 lb)
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405 kg (893 lb)
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1,509 kg (3,327 lb)
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Weight in Travelling Carriage/Mounting
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770 kg (1,698 lb)
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860 kg (1,896 lb)
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Unknown
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Muzzle Velocity (HE/T/SD)
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900 m/sec (2,953 ft/sec)
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900 m/sec (2,953 ft/sec)
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900 m/sec (2,953 ft/sec)
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Maximum Ceiling
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3,200m (10,500 ft)
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3,200m (10,500 ft)
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3,200m (10,500 ft)
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Effective Ceiling
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2,200 m (7,200 ft)
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2,200 m (7,200 ft)
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2,200 m (7,200 ft)
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Maximum Ground Range
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4,400 m (4,800 yd)
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4,400 m (4,800 yd)
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4,400 m (4,800 yd)
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Shell Weight
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120 g (4.23 oz)
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120 g (4.23 oz)
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120 g (4.23 oz)
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Rate of Fire
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Cyclic: 280 rounds/min
Effective: 100-120 rounds/min
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Cyclic: 450 rounds/min
Effective: about 180 rounds/min
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Cyclic: 1,800 rounds/min
Effective: about 800 rounds/min
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Rounds per Clip
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20-round box magazine
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20-round or 40-round box magazine, plus 50-round drum
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20-round box magazine
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Propelling Charges
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A duplex load
of 38-43 g (1.34-1.52 oz) of coarse-grained single-base powder with
0.5 g (7.7 grains) of fine-grained blackpowder contained in small
silk bags to the rear of the propellant as an initiator in German
and Italian cartridges and 0.30 g (4.6 grains) of PaPP powder in
Finnish cartridges. Produced a working pressure of 2,800 kg/sq cm
(17.8 ton/sq in).
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Ammunition
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Ammunition (all versions)
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20-mm (0.79-in) Long Solothurn. (Also known as
the 20x138B and the 20-mm Breda.) Rheinmetall-Borsig developed this ammunition in the early 1930s
and marketed it through the subsidiary Waffenfabrik Solothurn AG
of Switzerland. It was also adopted by Italy for use in a number
of Breda and Isotta-Fraschini anti-aircraft and air service guns,
by the Swiss for the Solothurn S18-1000 tank gun and S18-1100 anti-tank
rifle, and by Finland for the Lahti L39 anti-tank rifle.
Ammunition used brass or steel belted cases and percussion primers.
Ammunition can be subdivided into two basic classes: air type (2cm
FlAK 30/38), which was self-destroying, and ground type (2cm KwK
30/38). Both types of ammunition could be fired from either type
of gun, with minor variations to muzzle velocity due to differing
barrel lengths. The ammunition was continually developed; sources
differ as to when improved types became available. Practice,
experimental and specialised loadings are not provided.
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Air type
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Nose-mounted
contact-detonating fuse (except for the AP types, which had base-mounted
fuses). Self-destruct was either by tracer-initiated pyrotechnic
relay or by fuse actuation where tracer was not fitted. Self-destruct
was set to actuate at 2,200 m (7,200 ft) except for the AP/T/SD
which was intended to actuate at around 1,000 m (3,300 ft).
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HE/T/SD
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115 g (4.06 oz). Used a similar projectile to the 20x80RB FF/M. Penthrite/wax
HE charge in front body cavity and a tracer in rear body cavity,
with self-destroying relay. Tracer colour and duration unknown.
Used AZ5045 fuse. Muzzle velocity around 900 m/sec (2,953
ft/sec).
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HE/T/SD
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120 g (4.23 oz). A streamlined shell with penthrite/wax HE charge in front body cavity, and
6.0-sec green tracer in rear body cavity, with self-destroying relay.
Used AZ5045 fuse. Muzzle velocity of 900 m/sec (2,953 ft/sec).
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HE/I/SD
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120 g (4.23 oz). A streamlined shell with penthrite/wax/phosphorus HE/I charge in body cavity. Fuse actuated
self-destruction. Due to the lack of a tracer, this loading had
the greatest HE charge, of 20 g (0.71 oz). Muzzle
velocity of 900 m/sec (2,953 ft/sec).
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HE/I/T/SD
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116 g (4.09 oz). Used a similar projectile to the 20x80RB FF/M. Penthrite/wax/phosphorus HE/I charge in front body cavity, and a tracer
in rear body cavity, with self-destroying relay. Tracer colour and
duration unknown. Muzzle velocity around 900 m/sec (2,953
ft/sec).
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HE/I/T/SD
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120 g (4.23 oz). A streamlined shell with penthrite/wax/phosphorus HE/I charge in front body cavity, and tracer
in rear body cavity, with self-destroying relay. Tracer colour and
duration unknown. Muzzle velocity of 900 m/sec (2,953 ft/sec).
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HE/I
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109 g (3.84 oz). High-capacity Minengeschoss
(mine projectile), with 26 g (0.92 oz) penthrite/wax/phosphorus HE/I charge, versus 6-20 g (0.21-0.71
oz) for other types. Muzzle
velocity of 950 m/sec (3,117 ft/sec). Available from 1944.
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AP/HE/T/SD
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121 g (4.27 oz). Pointed steel shell with penthrite/wax
HE charge in the front section of body cavity and a tracer in rear
of body cavity, with self-destroying relay.
Tracer colour and duration unknown.
Muzzle velocity of 900 m/sec (2,953 ft/sec).
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AP/T/SD
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146 g (5.15 oz). Pointed steel shell with inert filling in the front section of body cavity
and a tracer in rear of body
cavity, with self-destroying relay. Tracer colour and duration unknown.
A pellet of penthrite/wax, initiated by a nitrocellulose/montan
wax pellet, was intended solely as a SD agent
and rested at the base of the inert filling. Muzzle
velocity of around 830 m/sec (2,723 ft/sec).
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AP/I/T/SD
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148 g (5.22 oz). Pointed steel shell with 2.7
g (0.095 oz) of white phosphorus contained within a light alloy
capsule in the front section of body cavity, and a tracer in rear
of body cavity, with the same self-destruct mechanism as the AP/T/SD.
Tracer colour and duration unknown. The
shell would break on impact, with the phosphorus burning through
the base of the shell. Muzzle
velocity of around 830 m/sec (2,723 ft/sec).
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Ground type
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Projectiles with a hardened nose section and
base-mounted fuses (except for APSV/T).
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AP/T
|
143 g (5.04 oz). Pointed steel shell with inert filling in the front section of body cavity
and 2.5-sec green tracer in rear of body cavity. Muzzle velocity of 830 m/sec (2,723 ft/sec).
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AP/I/T
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148 g (5.22 oz). Pointed steel shell with 2.7 g (0.095 oz) of white phosphorus contained
within a light alloy capsule in the front section of the body cavity.
The shell would break on impact, with the phosphorus burning
through the base of the shell. Muzzle
velocity of around 830 m/sec (2,723 ft/sec).
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AP/HE/T
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121 g (4.27 oz). Pointed steel shell with penthrite/wax
HE charge in the front section of body cavity and a tracer in rear
of body cavity. Tracer colour and duration unknown. Muzzle velocity of 900 m/sec
(2,953 ft/sec).
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APSV/T (PzGr40)
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101 g (3.56 oz). A tungsten carbide core within light alloy body, with a 1.5-sec tracer, white
changing to red. Muzzle velocity of 975 m/sec (3,199 ft/sec). Available
from 1940.
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|
Key
to Ammunition Types
|
| AP |
Armour-piercing |
| APSV |
Armour-piercing, super-velocity |
| HE |
High explosive |
| I |
Incendiary |
| SD |
Self-destroying |
| T |
Tracer |
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