As the German Luftwaffe (German Air Force) lost control over the skies of Germany in the second half of the Second World War; it could no longer provide sufficient protection against Allied aircraft. Panzer divisions were especially affected by the lack of cover from fighter aircraft because they were always at the center of the most intense fighting. While the Germans already had copious amounts of half-tracked Self-Propelled Anti-Aircraft Guns of different calibers and weights (Sd.Kfz.10/4, Sd.Kfz.6/2, Sd.Kfz.7/1, etc), these had the significant flaw of being vulnerable to the planes they themselves were meant to protect against.
A tank-based anti-aircraft vehicle (German: Flakpanzer) could solve this problem, but little effort was done in this direction. The first attempt was the Flakpanzer I, which was built only in limited numbers and was more an improvisation of an existing design rather than a purpose-built vehicle. The later 20 mm armed Flakpanzer models (Flakpanzer 38(t)) and the Wirbelwind) were built in some numbers but were considered unsuccessful, mostly due to the weak fire power of the 2cm Flak 38 by this late stage of the war.
Larger caliber 37 mm (Möbelwagen and the Ostwind, based on the Panzer IV) armed models proved to be somewhat better vehicles but were not without flaws. The Mobelwagen required a long time to prepare for action, and the Ostwind was built in limited numbers and too late to have any influence on the War. Even the famous 88 mm anti-aircraft guns were installed on some fully-tracked and tank chassis’, but again only in very limited number. These anti-aircraft vehicles’ main problem was the lack of a fully enclosed crew compartment. This issue was to be solved by the production of a new vehicle with a fully enclosed turret, the Leichte Flakpanzer IV 3 cm but mostly known by as ‘Kugelblitz’.
A period scale model of the Leichte Flakpanzer IV 3 cm and shows how the real vehicle would have looked like. Photo: panzernet.net
The history of the Leichte Flakpanzer IV 3 cm began with the creation of a different project design to provide German U-Boats (submarines) with an adequate anti-aircraft system. This project was carried out by Altmärkische Kettenwerke G.m.b.H (Alkett), starting in January 1944. The idea was to test a new design of a fully enclosed oblate spheroid turret armed with two 3 cm Mk 303 cannons. This project was never implemented as originally intended, but it would instead inspire a development of a fully protected Flakpanzer with similar armament.
One of the major shortcomings of all German Flakpanzers was the lack of a fully enclosed fighting compartment. As all were open top (because of the easier construction, guns exhaust gases and the need to produce them as fast as possible) it made the gun crews exposed to air attacks.
In May 1944, several Flakpanzer projects were showed to the Generalinspekteur of German Armored units, General Heinz Guderian. One of these was Oberleutnant Josef von Glatter-Gotz Leichte Flakpanzer IV 3 cm sketch project. On the insistence of General Heinz Guderian, the design and realization of a fully protected Kugelblitz began in late 1944. For design and production of this vehicle the Daimler-Benz company was chosen, and for its weapons, Rheinmetall.
The vehicle was designed by Oberleutnant Josef von Glatter-Gotz, who represented his Kugelblitz sketch project to General Heinz Guderian in May 1944. This is a sketch possibly made after the war. Photo: SOURCE
By November 1944, plans for the new Flakpanzer were presented to the German Army General Staff. This vehicle was to be built by using the tank chassis of the Panzer IV and a new, fully enclosed oblate spheroid turret inspired (but not the same) by the unsuccessful U-Boat project. At the beginning of 1944, Alkett tested the original U-Boat oblate spheroid turret on an unmodified Panzer IV, but due to problems with the 3 cm MK 303 gun (it never went into production) and the complicated turret (possibly too difficult for production), this project was abandoned.
The version of Panzer IV chosen for this modification is unknown. Though, being designed in the later stages of the war, there is a great chance that either the Ausf. H or the Ausf. J versions were used (according to author Marcus Hock, the Ausf. J was used). The Panzer IV tank chassis was chosen simply as it was available in large numbers and it was becoming obsolete as a main frontline combat tank. It is also likely that the tanks used for this modification would not have been a newly built model, but instead, one returned to a factory for repairs or salvaged from the front. Tiger and Panther tank chassis were considered but were deemed too valuable for this modification. The main armament was to be two 3 cm cannons, but the option of two 2 cm guns was considered to be used as a temporary solution.
The serial production was to start in late 1944, but due to Allied bombing raids over German territory, many factories were not at full capacity. As a result of these delays, the serial production only commenced at the beginning of 1945, with few produced vehicles. It is possible that at least one complete prototype was built in late 1944. In one photograph dated October 16th 1944 taken during a demonstration of different anti-aircraft weapons designs near Kummersdorf, a Kugelblitz can be seen in the background. This could only be a wooden mock-up, but it is hard to say with certainty and it could likewise be a real vehicle. It was hoped that by January 1945 pre-serial production would begin, but these plans were never realized.
This is a photograph of a Kugelblitz taken in Kummersdorf. But the question arises, is this a real vehicle or just a wooden mock-up? Photo: SOURCE
By direct orders from Hitler, in November 1944, works on a similar project began. Instead of a standard Panzer IV tank chassis, the experimental Panzer 38(d) (or by using the Jagdpanzer 38(t) according to some sources) would be used as a base. It was to be equipped with the same oblate spheroid turret, but armed with both two 2 cm MG 151/20 and two 3 cm MK 103/38 cannons, though none was ever built.
Depending on the sources, this vehicle is known under a few different designations. It is usually called the Flakpanzerkampfwagen IV (Thomas L. Jentz), Flakpanzer IV (Heiner F. Duske) or Leichte Flakpanzer IV (Peter Chamberlain and Hilary L.Doyle). Frequently, the ‘3 cm’ label is added to the name in order to differentiate it from other anti-aircraft vehicles based on the Panzer IV chassis. The nickname ‘Kugelblitz’ is used in many sources in reference to this vehicle. But if this nickname is a German or a post-war designation is hard to say. In this article, the ‘Kugelblitz’ name has and will be used, if only for the sake of simplicity. ‘Kugelblitz’ can be translated as ball lightning.
Production Plans and Number Built
Original plans for the Kugelblitz production predicted that the first five vehicles would be built by September 1944. Then it was to increase production to up to 30 vehicles by December 1944, and by early 1945, around 100 operational vehicles where to be built. The initial vehicles were to be built by Daimler-Benz (also in charge of producing two prototypes) and Deutsche Eisenwerke (three prototypes). For many reasons, including lack of resources and Allied bombing raids, production began only in early 1945. By the end of January 1945, planned monthly production was (sources give different numbers): 10 in January, 10 (30) vehicles in February, 10 (30) in March and a last batch of 40 in April. Because of the chaotic state Germany was in at this point of the War, it is difficult to determine the exact number of produced vehicles, but it probably did not match the planned production.
Production numbers are hard to find. Some sources state that at least one complete model was built, in addition to possibly a few more turrets, but other sources vary from up to five or even seven vehicles being completed. ‘Panzer Tracts No.12, Flak selbstfahrlafetten and Flakpanzer’, written by Thomas L. Jentz, cites several examples: According to Ing. Ebel (he worked at the Daimler-Benz) only three were fully completed. Mostly as the main supplier and builder of some of the vehicle’s parts, the Deutsche Eisenwerke plant (near the city of Duisburg, West Germany), was captured (at the beginning of 1945) by the Allied forces. According to Rudolf Spolders, the director of Deutsche Eisenwerke, only two turrets were completed, which were sent to Berlin to be possibly used as static anti-aircraft emplacement. Additionally, Jentz affirms that one complete vehicle was ready in October 1944 and that two more vehicles were built in March 1945. According to Walter J. Spielberger, five were built by February 1945. Bryan Perrett quotes that “half a dozen or so” were built. According to Duško Nešić, one prototype was built in November 1944, and two more in February 1945. According to some internet websites up to 7 were built. What can be said with certainty though is that at least two fully operational vehicles were built, as there is evidence of their existence (photographs and remains of one turret).
As already mentioned, the Kugelblitz was built by using the Panzer IV (possibly Ausf. H or J) tank chassis. The suspension and running gear were the same as those of the original Panzer IV, with no changes to its construction. It consisted of eight small road wheels (on both sides) suspended in pairs by leaf-spring units. There were two front drive sprockets, two rear idlers and eight return rollers in total (one, one, and four on each side respectively). The design of the engine compartment was also unchanged. The engine was the Maybach HL 120 TRM (water cooled) 265 hp with 2.600 rpm.
The maximum armor of the lower frontal glacis was 80 mm thick, the sides were 30 mm, the rear 20 mm and the bottom armor was only 10 mm.
Most parts of the upper tank hull were unchanged from the original Panzer IV. The driver’s front observation hatch and the ball-mounted hull machine gun remained. The turret ring was replaced with a one taken from the Tiger I (with a diameter of 1900 mm). This was necessary because of the wider size of the newly designed turret. Because of this, the two hull crew hatch doors (for the driver and radio operator) were repositioned so as to not disturb this new installation. The front hull, directly above the driver and radio operator positions, was totally straight and level with engine deck. This differs substantially from standard Panzer IV hull as this part was slightly sloped. The front armor of the upper hull was 80 mm, the sides were 30 mm, and the rear armor that protected engine compartment was only 20 mm.
The biggest change in the design was the new enclosed oblate spheroid turret (with a fully 360° traverse) armed with two 3 cm cannons. Some sources (Marcus Hoch and Walter J. Spielberger) describe it as spherically (or simply as ball-shaped) shaped, but due to flattened sides and irregular top shape, the oblate spheroid is a more convenient designation. This newly designed turret was fully enclosed (suspended by using gimbals) and protected by a rounded protective mantlet (which had a shape like a shortened cone). The mantlet was made by welding three curved steel plates. The complete turret (together with the protective mantlet) had a larger diameter than the original Panzer IV turret. The oblate spheroid turret had a very compact construction with a diameter of only 60 cm. At least, in theory, it could be easily adapted to be operationally used in any other German armored vehicle. But in practice, besides the Panzer IV it was never used in any other vehicle.
The turret mantlet had 30 mm of armor, the inner enclosed oblate spheroid turret 20 mm, the rear part was 30 mm, with 10 mm on the top. This relatively thin armor offered protection from most machine guns and grenades.
Dimensions of the Kugelblitz were: length 5.92 m, width 2.95 m, and the height 2.3-2.4 m (depending on the source). The weight was around 23 to 25 t, again, depending on the source used.
Parts of the 3 cm cannons were protected by an armored casing, as can be seen here. On the front mantlet, the place where the two armored plate are welded together, it is visible. Photo: SOURCE
The main weapon consisted of two 3 cm MK 103/38 cannons. These cannons were already in use by the German Air Force (under the designation MK 103), mostly for ground attacks. But as the 2 cm calibers anti-aircraft gun began to become obsolete by 1944, the 3 cm MK 103 was reused for the role of a new ground anti-aircraft weapon (usually under the designation 3cm Flak 38 or 103/38). In addition to the better firepower, the compact size and belt-feed ammunition system proved to be ideal for the use in an enclosed turret. The main gun was placed in a box-shaped armored causing, but it was not gas-tight although it is possible that it was planned to be gas-tight in the future. Due to the fact that when used in action these canons produced a lot of powder smoke, installation of good extractor fans was important. The elevation of the 3 cm MK 103/38 was from – 7° to +80° (with other sources specifying -4° to +80° or -5° to +70°) with the whole ball moving up and down like an Oscillating Turret. The gun was activated by a trigger chain connected to the commander’s foot pedals (one for each gun). Initially, the manual traverse was tested by using reduction gears, but it proved to be a slow process. The traverse speed was only 10° per second and the elevation only 7º to 8° per second. As this vehicle was designed to fight fast and nimble ground attack aircraft, it was insufficient for the job, so a hydraulically driven mechanism controlling the traverse and elevation by means of a control stick, providing increased speed. The maximum rotating speed was 60° per second.
The maximum rate of fire was 250 rounds per minute, but 150 rpm was the more practical rate. The total ammunition load for this weapon was 1,200 rounds. The discharged cases fell into canvas bags placed under the guns. The order for redesigning and installing the new 3cm cannons in the turret was given to the Ostbau-Sagan in September 1944.
External parts of the two 3 cm canons barrels were protected by an armored casing and held in the center by three screws on each side. Besides their personal weapons, the crew could use the ball-mounted hull MG 34 machine gun for self-defense.
Illustration showing the crew movements in unison with the turret movement. Photo: SOURCE
The Flakpanzer Kugelblitz, painted in the ‘Dunkelgelb’ colour. Illustration by Mr. C. Ryan, funded by our Patron Golum through our Patreon Campaign.
Crew & Their Positions
The crew consisted of the commander/gunner, two gunner assistants, driver, and a radio operator. The positions of the radio operator (Fu 2 and Fu 5 radios were used), who also operated the hull mounted MG 34 machine gun, and the driver were same as on the original Panzer IV. The remaining three crew members were positioned in the new turret. The commander/gunner was position in the middle, behind the main guns, whilst the gunner assistants were placed on the left and right side in front of him. The crewmembers situated left of the gun were responsible for the turret’s movements, and the one on the right side was responsible for loading the guns. The spare ammunition was located on the right side. In some sources (like the Valka internet site), the left side crew operator was the gunner, but as the position of the foot pedals is behind the gun, this is incorrect. Each of these three crew members had hatch doors which they could use to enter or exit the vehicle. The gunner assistants’ hatch doors had a small round shaped hatch, which was also used for sighting devices. The commander had a small observation cupola on top of the new turret, equipped with a periscope for finding targets. The small size of these hatches made entering and exiting the vehicle difficult. On the turret rear, the mantlet was partially elevated, possibly for better rear protection of the commander when his hatch was open. But this, with combination of the position of the commander’s hatch, made any escape almost impossible when the turret was at high elevation. The turret crew moved together with the turret movements. This was done in order for the crew to follow the movement of the main weapon itself and thus targeting the target more precisely.
Photo of the turret where all three turret crew escape hatch doors are visible. Two on each side plus the additional rear two-part hatch door for the commander. Photo: SOURCE
3 cm Flugabwehrkanone 103/38 (3 cm Flak 38)
The 3 cm Flak 38 was made in late 1944 due to the weak firepower of the 2 cm Flak’s. It was built as a combination of the aircraft 3 cm MK 103 cannon and the 2 cm Flak 38 mounting, mostly to get it in operational service as soon as possible and to be cheap to produce. In mid-1944, Rheinmetall-Borsing was tasked with the production of some 2000 guns, in addition to 1000 gun that were to be built by Gustloffwerke, but only small numbers were produced by the end of the war. The similar four-barreled version of the 2 cm Flak 38 was also tested with the 3 cm MK 103, but it too was built in limited number only. The 3 cm Flak 38 was not a successful design, largely because of the strong vibration when firing which made the target aiming difficult and could cause some damage on the mounting itself. One innovation was the use of belt-fed system instead of the old magazine fed system. There are few designation for this gun, (depending on the source) the 3 cm Flugabwehrkanone 103/38 (simply Flak 38), Flak 103/38, 3 cm MK 103/38, or more aggressive ‘Jaboschreck’. The Jaboschreck word in essence can be translated as fast ground attack aircraft (Jagdbomber in German or just short Jabo) terror or fright (schreck).
The 3 cm Flak 38. Photo: SOURCE
The 3 cm Flak 38 was a gas-operated and fully automatic gun. With 360° traverse and -5° to +70° elevation. The rate of fire was around 450 rpm, but the more practical rate of fire was 250 rpm. Total weight of the gun was 619 kg. There where few different types of ammunition in use: the HE (815 gm), an experimental high-capacity HE rounds, AP with a muzzle velocity of 800 m/s. The maximum firing range was around 5.700 m.
All produced vehicles (possibly five) were given to the newly formed Panzerflak Ersatz und Ausbildungsabteilung (armored Flak training and replacement battalion) located near the city of Ohrdruf (Freistaat Thüringen region in central Germany). One company was divided into three platoons equipped with a mix of different Flakpanzers vehicles. The first platoon was equipped with the Wirbelwind, the second with Ostwind, and the third platoon was intended to be equipped with experimental vehicles, such as the Kugelblitz.
The fate of all produced Kugelblitz Flakpanzers is not known. What is know from photographic evidence is that at least two were used in combat and were destroyed.
One or more vehicles (in addition to possibly an unknown number of turrets) were sent to Berlin, and during the final Soviet assault on the German capital all were lost. A photo taken on 11th July 1945 shows one destroyed Kugelblitz in Berlin. It is identified as a Kugelblitz because of the position of the front hull (right above the driver position) which is totally flat in contrast to slightly sloped shape found on regular Panzer IV’s. Doyle states this to be a real Kugelblitz.
Destroyed Kugelblitz captured during the battle for Berlin. Photo: SOURCE
There is information about another Kugelblitz vehicle that was used in combat, but in this case against Allied forces on the West, more specifically during the battles for Hörschel, Spichra and Creuzburg by the end of March and beginning of April 1945. As the American forces advanced through central parts of Germany, they came to a small village named Spichra. This village was surrounded by the Werra River and the only way across was through a partly destroyed bridge connected to a power plant. This bridge was defended with few anti-tank guns, some Panzer IIIs (marked as training vehicles) and one Kugelblitz (from the Panzerflak Ersatz und Ausbildungsabteilung). All were located at Spatenberg Hill near this village. An American reconnaissance force was sent to investigate and to find a place where the river crossing could be possible. This unit came under German fire and was forced to pull out with some losses. The American response was to bomb the village and the nearby hill. In the following battle the Kugelblitz was destroyed and its remains were discovered in 1999.
By the end of the war, the Allies managed to capture one Kugelblitz turret. Until the seventies it was stored at Royal Military College of Science at Shrivenham, United Kingdom. It was eventually returned to Germany (in the late seventies) and can now be seen at the Anti-Aircraft School at Rendsburg (Schleswig-Holstein).
It is sometimes claimed that if this vehicle was produced earlier, and in larger numbers, it could have made a large impact on the war (this is often said for other German late built model vehicles, like for example Jagdpanther). In theory, the Kugelblitz would have provided more effective anti-aircraft fire against Allied low-flying attack aircraft and significantly reduced the danger they posed for German ground forces and thus reduce losses. They also note that the highly developed and advanced construction of this vehicle and its impact on later models built after the war. Claims about the potential impact of the Kugelblitz on the course of the war omit certain facts:
- The Kugelblitz was built only in limited numbers, possibly only a few prototype vehicles.
- It is important to notice that these were prototypes (pre-production) vehicles, and their combat potential thus was limited, having been hastily constructed and possibly not even properly tested.
- There is only a limited record of Kugelblitz combat use, and if it was effective against its primary targets (ground attack aircraft) is unknown.
- The claim that the Kugelblitz had a great impact on post-war anti-aircraft vehicle designs is questionable. A number of the first post-war anti-aircraft models had partially enclosed turrets, such as the American M42 Duster or the Soviet ZSU-57-2 design.
- The Allies were already using anti-aircraft vehicles (during the WW2) with a fully enclosed turret (based on the Crusader tank design), so they had some experience with this system, probably influencing post-war designs more strongly.
In conclusion, the Kugelblitz was definitely an improvement (in the case of crew protection) over previous Flakpanzers that were already in operational use. It had good firepower with its two 3 cm cannons, good mobility and solid protection. It had a much lower silhouette than the Wirbelwind Flakpanzer for example, making it a less visible target. As a design it was certainly impressive and innovative.
The biggest negative side was the fact that it was never properly tested to see if the whole Kugelblitz design was successful and efficient. Even if it was built in larger numbers, it was simply too little too late. By late 1944 and 1945, the war was already lost for Germany.
|Dimensions||5.92 x 2.88 x 2.3 m|
|Total weight, battle ready||23-25 tons|
|Crew||5 (Radio operator, two gunners, driver and commander)|
|Armament||2x 3 cm Mk 103/3 Auto-cannons|
1x MG 34
|Armor||Panzer IV hull 10-80 mm, turret mantlet 30 mm and the oblate spheroid part 10-30 mm|
|Propulsion||Maybach V12 gasoline HL 120 TRM|
(220 kW) 300 bhp@2500 rpm
|Speed on /off road||38 km/hr, 20 km/hr|
|Range (road/off road)||200/130 km|
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