FlaK30/38 and FlaKvierling

[David]

FlaK30/38 and FlaKvierling 38

Introduction

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Between the World Wars Germany, like other nations, realized that protecting it's ground troops from air attack was essential. Barred by the Treaty of Versailles from producing anti-aircraft guns on their own, several German companies bought foreign competition and developed weapons either in secret or for export. By the time Germany was re-militarized in 1933, they had a booming war industry with many capable designs. German war planners believed the 20mm cannon was more than capable for dealing with tactical attack aircraft as well as low-flying enemy fighters, and the FlaK30 was ordered into production in 1934.

The FlaK30/38 in it's deployed state.

By the end of the Spanish Civil War it was apparent that increasing aircraft speeds created the need for a FlaK gun with a greater rater of fire. The FlaK30's original producer, Rheinmetall Borsig, was busy enough with the war just starting, so they passed the job onto Mauser. Although a few adjustments were made, the FlaK38 was very similar to the FlaK30 but the newer gun could fire about 150% as many rounds per minute as it's predecessor. By 1939 FlaK30 production was winding down and replaced by the newer FlaK38, whose production went onto the end of the war in 1945. The FlaK38 was mounted on a Sd.Kfz.10 chassis and designated the Sd.Kfz.10/4 - Germany's first tracked self-propelled anti-aircraft gun.

The FlaKvierling 38 in it's deployed state.

The quest for a higher volume of fire didn't end with the FlaK38 though, and in 1940 the FlaKvierling was born. The FlaKvierling 38 was combination of 4 FlaK38 barrels on one mount, and it could fire a staggering 1800 rounds per minute. It had a gun shield to protect the crew, could be towed by most trucks and half-tracks, and could be set up very quickly. The FlaKvierling was mounted on various chassis including the Panzer IV and Sd.Kfz.7 half-track to create self-propelled anti-aircraft units.
For more information: German Light Anti-aircraft & Anti-tank Manual
Details

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	FlaK30	FlaK38	FlaKvierling 38
Caliber	20mm	20mm	20mm
Country	Germany	Germany	Germany
In Service Date	1935	1938	1940
Manufacturer	Rheinmetall Borsig	Mauser	Mauser
Total Built	8,000+	40,000+	3,768
In-Service (5/10/40)	6000+	3000+	127
Crew	7	7	8
Gunsight	Flakviser 35	Flakviser 38	Flakviser 40
Deployed Weight	450 kg	405 kg	1509 kg
Travel Weight	770 kg	860 kg	2100 kg
Ammunition	360	600	600 + 1800 (Trailer)
Ammunition Feed	20 round boxes	50 round drums	20 round drums
Cyclic Rate of Fire	280 RPM	450 RPM	1800 RPM
Effective Rate of Fire	120 RPM	180 RPM	800 RPM
Traverse	360°	360°	360°
Max Elevation	+90°	+90°	+100°
Max Depression	-12°	-20°	-10°
Muzzle Velocity	900m / Second	900m / Second	900m / Second
Max Ceiling	3200m	3200m	3200m
Projectile Name	HE/T/SD 138B	HE/T/SD 138B	HE/T/SD 138B
Projectile Weight	120 grams	120 grams	120 grams

Overview

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The FlaK30/38 and FlaKvierling were issued many types of ammunition, but for anti-aircraft duty they used the high-explosive, tracer, self-destructing (HE/T/SD) 20mm round. Most were also issued armor-piercing tracer rounds (AP/T) and armor-piercing super-velocity panzergranate 40 (Pzgr.40 or APSV.40) rounds with tungsten cores. When firing AP/T rounds the muzzle-velocity dropped to approximately 830m per second, but rose to 975m per second when firing APSV.40 ammunition, which could penetrate up to 49mm of armor within 300m. All these types of ammunition were available in quantity by the Battle of France, although the APSV.40 supply dried up after 1943 when Germany lost it's supply of tungsten.
The FlaK30/38 and FlaKvierling 38 were also converted for naval use with the designation FlaKC30 and FlaKC38. They were installed in single, double, and quadruple mounts, and they appeared on almost every type of warship including submarines. The Luftwaffe (Air Force), which was in charge of Germany's air defense, produced approximately 121,677 FlaK30/38 barrels and the Heer (Army) produced a further 15,985 barrels between 1939 and 1945.
Overall, the 20mm cannon was adequate at the beginning of the war, but after 1942 aircraft simply moved too fast and were too well armored for it to be truly effective. Some aircraft like the Russian IL-2 could absorb tremendous amounts of punishment before they were brought down. This is not to say the 20mm was useless, but it became clear that merely increasing the volume of firepower wasn't always the answer. Regardless, the 20mm units remained an essential part of Germany's air defense corps and were deadly when mixed with 37mm and 88mm FlaK guns.

Sights

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Flakvisier 35, 38, 40

The electronic Flakvisier (Flak Sight) was reflector sight that accepted the input values for target distance, speed, altitude change, and heading. After those values were input, all the gunner had to do was keep the cross-hairs on the target.

Linealvisier 21

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.

Schwebekreis-visier 30

The Schwebekreisvisier (Floating Circle Sight) 30 was a optical “cartwheel” sight later introduced for the FlaK 38. It was easier to produce and use at close ranges.

Self-Propelled 20mm FlaK

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FlaK Trucks

Many trucks were modified to carry the FlaK30 and FlaK38 cannons on their rear deck, including the Opel Blitz. There are too many variations to list, and just about every truck the German army used was fair game due to the Flak38's light weight, even civilian 4x4's.

Sd.Kfz.10/4

Germany's second tracked self-propelled anti-aircraft unit, it was the mating of a FlaK30 or FlaK38 on the chassis of a Sd.Kfz.10/4 half-track. Almost 1000 of these vehicles were issued to combat units before the invasion of France in May 1940.

Sd.Kfz.7/1

In 1940 German planners realized the need for more mobile firepower, and so a FlaKvierling 38 quad 20mm cannon was mounted on the chassis of a Sd.Kfz.7 half-track. About 22 of these conversions were ready by the Battle of France, and production increased dramatically during the war.

Sd.Kfz.251/17

A FlaK30 or FlaK38 was mounted on the back on a standard Sd.Kfz.251 half-track. It carried 600 20mm rounds and had a 360° traverse, but never went into production. Kits were issued to units to do field conversions, and an unknown number of this type were produced.

FlaKPanzer I

The result of mounting a FlaK38 20mm antiaircraft gun on the chassis of a Panzer I. The overloaded chassis lost its mobility and only 24 units were produced. They served on the Eastern Front until the last units were lost in the pocket of Stalingrad.

FlaKPanzer 38(t)

The installation of a FlaK38 20mm gun on the chassis of a Czech Panzer 38(t). It was overloaded in the rear and the member of the gun crew enjoyed no protection at all. The first units reached the frontline in January 1944, and only 141 were ever produced.

Wirbelwind

The first real German antiaircraft tank. The FlaKvierling 38's 4x 20mm antiaircraft guns were installed on the chassis of a Panzer IV. It proved efficient, but not enough to counter the crushing allied air superiority. The first of these units were ready for combat in mid-1944.