The Flakpanzer IV Kugelblitz ("ball lightning") was a German self-propelled anti-aircraft gun developed during World War II, which was still at the prototype stage at the end of the war. Unlike earlier self-propelled anti-aircraft guns, it had a fully enclosed, rotating turret.
The need for a specialised self-propelled anti-aircraft gun, capable of keeping up with the armoured divisions, had become increasingly urgent for the German Armed Forces, as from 1943 on the Ger-man Air Force was less and less able to protect against enemy fighter bombers.
Therefore a multitude of improvised and specially designed self-propelled anti-aircraft guns were built, many on the Panzer IV chassis, starting with the Flakpanzer IV Möbelwagen and progressing through the Wirbelwind and Ostwind models. The Kugelblitz was the final development of the Flakpanzer IV.
The first proposal for the Kugelblitz envisioned mounting a modified anti-aircraft turret developed for U-boats on the Panzer IV chassis, which was armed with dual 30 mm MK 303 Brunn guns (a configura-tion known as Doppelflak, "dual flak"). This was however abandoned as unpractical, as the perform-ance of the MK 303 was less than desired and in any case the entire production run of this gun turret was reserved for the German Navy.
Instead, the 30 mm twin gun Zwillingsflak ("twin flak") 103/38 was used, which had also been fitted to such planes as the Henschel Hs 129 and Dornier Do 335. The rate of fire of the twin 30 mm guns was 450 rounds a minute.
The Kugelblitz had the chassis and basic superstructure of the Panzer IV tank, on which a newly de-signed turret was mounted. This turret was fully enclosed, with overhead protection and 360° traverse.
Service
The Kugelblitz was not yet out of development when the war ended. Several evaluation vehicles had been built, but it is unclear how many. It is also unclear what happened to the few Kugelblitzes which were built; some sources say that they ended up being used in the Battle for Berlin.