The German 3.7-cm (1.457-in) Flakzwilling 43 was an attempt to increase the firepower of the basic Flak 43 by adding an extra barrel, but relatively few were produced as the weapon was rather high and awkward to emplace.

 

By 1942 the Allied air threat over all the various battlefields was reaching the point where there were never enough air defence weapons available. The 3.7-cm (1.457-in) guns were always in demand as they were the standard weapon against low-flying aircraft, and in 1942 Rheinmetall-Borsig was busy developing a gun to replace the existing costly and slow-to-make Flak 36/37 series. As ever, Rheinmetall-Borsig came up with a novelty, not in the gun or carriage design, but in the manner of manufacture: it decided to adopt methods already in use for small-arms production.

 

Rheinmetall-Borsig was in competition with Krupp for the new gun contract, and at one point the order was given to the Krupp gun, which used conventional production methods. But at the last moment the Krupp design developed weaknesses and Rheinmetall-Borsig got the award. This immediately resulted in the internal party and factional wrangling that often beset the German wartime industrial dream, so by the time Rheinmetall-Borsig was actually able to go ahead on a new production line well over a year had passed, Rheinmetall-Borsig was partially able to make up the leeway by the fact that its gun, known as the 3.7-cm Flak 43, was produced with stampings, weldings and simply fabricated components in the same way as sub-machine guns. The production time for a gun was cut by a factor of four, and the overall performance boosted by an increased rate of fire.

 

It was early 1944 before the first of the new guns was ready, and thereafter the type poured off the lines at Dürkopp. In service the Flak 43 proved very successful, but in the initial rush to get the new gun into production it had been decided to retain the original Flak 36/37 ammunition and barrel designs. Thus the Flak 43 was at a disadvantage from the start, for the increased speeds of low-flying aircraft and their increased degree of protection meant that a single strike from a Flak 43 did not always bring down the target aircraft. The only immediate answer to this was to multiply the number of barrels on a single carriage, and this led to the 3.7-cm Flakzwilling 43 with two barrels, one above the other, on a single mounting. This made a kill much more likely and the Flakzwilling became preferred over the single barrel version. In the event both were produced until the end of the war, and there were even plans for a four-barrel mounting at one stage. There was also a project on which the two barrels were mounted side-by-side.

 

The single- and twin-barrel Flak 43s were potent weapons, but the twin barrelled version was something of an unwieldy brute to get in and out of action because of its general top heaviness. Fortunately for Allied air crews, the number of Flak 43s was never enough to meet demands, especially regarding the Flakzwilling 43. By February 1945 there were 1,032 Flak 43s of both types in service, but of these only 280 were of the twin barrelled version. In action both types required six-man crews, and if a gun was to be maintained in action for any length of time more men were needed to supply ammunition to the gun.

 

Specification

Flak 43

Calibre: 37 mm (1,457 in)

Length of piece: 3.30 m ( 130 in)

Weight: in action 1392 kg (3,069 lb)

Elevation: -7.5° to +90°

Traverse: 360°

Muzzle velocity: 840 m (2,756 ft) per second

Maximum effective ceiling: 4800 m (15,748ft)

Rate of fire: (cyclic) 250 rpm

Projectile weight: 0.64 kg (1.41 lb)

 

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