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 German Air Force was less and less able to protect itself 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. However, these designs were tall, open-topped designs with no protection for the crew. These flaws were to be eliminated in the Kugelblitz, 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 mmMK 303Brunn guns. This was however abandoned as impractical, as development of this gun had not yet been completed, and in any case the entire production run of this gun turret was reserved for Nazi Germany'sKriegsmarine. Instead, the Kugelblitz used the 30 mm MK 103 cannon in a Zwillingsflak 103/38 arrangement. The MK 103 had also been fitted in single mounts to such planes as the Henschel Hs 129 in a ventral gun pod, and to the twin-engined Dornier Do 335. The rate of fire of the twin 30 mm guns was 450 rounds a minute per gun. The Kugelblitz combined the chassis and basic superstructure of the Panzer IV tank with a newly designed oscillating turret. This turret was fully enclosed, with overhead protection and 360° traverse. Mass production was planned, but never happened due to the disruption by Allied bombing efforts. As production of the Panzer IV was about to be terminated further work was under way to change to the Jagdpanzer 38 Hetzer chassis which was in turn based on the Panzer 38. No prototypes based on Hetzer hulls were completed.
Service
The Kugelblitz was not yet out of development when the war ended. Only five prototypes were built. 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 of Berlin. One Kugelblitz was also involved in the fights near the town of, Thuringia, where it was destroyed and remained buried in the until its excavation in 1999.
Survivors
Today, one complete Kugelblitz turret is exhibited at the Lehrsammlung der Heeresflugabwehrschule, Rendsburg. An incomplete Kugelblitz cradle also exists, but is in a private collection.
