As the Luftwaffe (German Air Force) lost control over the skies over 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.
The Germans already had copious amounts of half-tracked Self-Propelled Anti-Aircraft Guns (SPAAG) of different calibres and weights (Sd.Kfz.10/4, Sd.Kfz.6/2, Sd.Kfz.7/1, etc). As these vehicles had very limited or no armor, they were vulnerable to enemy fire either from ground or air. The crew needed better protection from small arms fire and artillery/mortar high explosive fragmentation shell shrapnel. A tank-based anti-aircraft vehicle (German: Flakpanzer) could solve this problem, as it would have sufficient armor to resist most ground attacks with the exception of larger caliber guns. They would also provide some protection against air attacks, but even tanks could be destroyed by air ground-attack fire.
Side view of the Flakpanzer 341. Source
Many designs based on different Panzer chassis and weapons were tested and built during the war. The most successful were the ones based on the Panzer IV chassis (Möbelwagen, Wirbelwind and Ostwind), which were built in some numbers but were too late to have a significant impact on the war. One of the major shortcomings of all German Flakpanzers was the lack of a fully enclosed fighting compartment. As all were open-topped (because of easier construction, easier exhaust of gun fumes and the need to produce them as fast as possible), the gun crews were exposed to air attacks.
By the end of the war, the Germans tried to solve this problem by designing and building new Flakpanzers with fully enclosed turrets. One of these was the Flakpanzer based on the Panther tank, best known today as the ‘Coelian’.
In May 1943, Oberleutnant Dipl.Ing von Glatter-Götz, responding to the orders of Inspectorate 6, initiated the development of a new series of Flakpanzers based on already existing chassis. The Panzer I and II were outdated or used for other purposes. The Panzer III tank chassis was used for the production of the StuG III and thus not available. The Panzer IV and the Panzer V Panther were considered next. The Panzer IV tank chassis was already in use for several German modifications, so it was decided to use it for the Flakpanzer program. The Panzer V Panther was considered in case even the Panzer IV chassis proved to be inadequate for the task.
The Germans formed a commission for the analysis of the effectiveness of enemy ground attack planes. The report (dated 31st June 1943) stated that, in the case of dive-bombing, the lowest point that the enemy plane reached was 1200 to 1500 m at an angle of 45-80°. Planes using larger caliber machine guns or cannons attacked at an altitude of around 150 to 300 m. The committee suggested that the best way to bring down enemy planes was using direct fire autocannons. To effectively fight the enemy planes, the future Flakpanzer would have to have a fully rotating turret with a high angle of fire and the caliber used should not be lower than 2 cm, with the more powerful 3.7 cm being preferred.
To give the crew the best protection possible and to meet any future Allied developments, the Panther-based Flakpanzer had to have a fully enclosed turret that could be armed with several different proposed weapon configurations. These included the 2 cm Flakvierling, 3.7 cm (either twin or triple configuration), 5.5 cm Flakzwilling and even an 88 mm caliber heavy flak gun. The first proposed design drawings (HSK 82827) were completed by Rheinmetall in late May 1943. The armament consisted of four 20 mm MG 151/20 mounted in a specially designed turret. The elevation of the four guns was -5° to +75°. This proposal was never implemented, mostly due to the weak armament by the standards of 1944.
On the 21st December 1943, a Panzerkommision was formed to examine the further development of a Flakpanzer based on the Panther tank chassis. It was decided that the main armament should consist of at least two 3.7 cm caliber anti-aircraft guns. This requirement was later revised to two 5.5 cm Gerät 58 guns. The development of this new weapon had begun in 1943, but due to its complicated design, problems developing the ammunition and the late start of the program, only 3 prototypes were completed by the war’s end.
For the construction of the new turret, Daimler-Benz was chosen. The new turret had to fulfill several set criteria like armor thickness and having an effective traversing mechanism. The armor protection of the turret was to be impressive, with 100 mm frontal armor and 40 mm on the sides. The turret was to be moved by using a hydraulic drive which was powered by the tank’s own engine. The new turret design was to be ready by the middle of 1944, but nothing came from this.
Rheinmetall’s proposed Flakpanzer turret armed with four 20 mm anti-aircraft guns. Source
The Rheinmetall-Borsig “341” design
Unfortunately, being more or less a project only, there is little known information about this Rheinmetall-Borsig design. What is known is that, by the end of 1943, Rheinmetall-Borsig (or its subsidiary, Vereingte Apparatebau AG, depending on the source) began working on its own design for the new Flakpanzer based on the Panther tank chassis. The first drawings of the new vehicle were completed by 23rd May, 1944. One mock-up turret was built and placed on a Panther D and presented to Wa Prüf 6 at Kummersdorf, possibly in early 1945. Due to many reasons, it never went into production and the whole 3.7 cm armed Flakpanzer based on the Panther tank chassis was cancelled in January 1945 in favour of the larger 5.5 cm weapons.
Only one mock-up with a wooden turret was ever built and presented to German army officials. It was never adopted for service, mostly due to the need to focus production on Panther tanks. Source
Depending on the source, there are different designations for this vehicle armed with 3.7 cm anti-aircraft guns. These include Flakzwilling 3.7 cm auf Panzerkampfwagen Panther, 3.7 cm Flakzwilling auf Panther Fahrgestell “341” or, simply, Flakpanzer 341. The designation 341 stands for the two main 3.7 cm guns (Flak or Gerät 341). This article will use the Flakpanzer 341 designation for the sake of simplicity.
It is also best known today under the ‘Coelian’ name. Coelian is actually the third name of Oberleutnant Dipl.Ing von Glatter-Götz, who was greatly involved in the development of the German Flakpanzer program. It is important to note that the Coelian designation was never used by the Germans and was possibly added after the war, like many similar German armored vehicle designations.
Front view of the Flakpanzer 341. The simple flat face of the lower part of the front turret and the angled upper part can be seen. Source: Unknown
Technical characteristics of the Flakpanzer 341
Due to a lack of information, the precise Flakpanzer 341 technical characteristics are not known in detail.
The Rheinmetall-Borsig Flakpanzer was meant to be built using a new turret designed by the company and mating it with a Panther tank chassis. While sources do not explicitly mention it, it is possible that the chassis used for the production would consist of damaged ones returning from the front for repairs or major overhauls (similar to the Wirbelwind and Sturmtiger) rather than using new ones. The armor of the Panther hull was 80 mm thick at the front and 40 mm on the side and rear. The overall Panther hull would most likely have had only some minor modifications in order to speed up production.
The lower front and side section of the turret had simple flat plates. The top armor was sloped, probably in order to increase protection against air attacks. The rear armor consisted of one large rounded plate. There were at least two hatches on the top and one on the turret rear. Additional ventilation ports would most likely have been added to avoid the accumulation of fumes from the guns. The turret armor thickness was 70 mm, the gun mantlet had 80 mm, while the sides and rear were 40 mm thick. This was less than the Daimler-Benz version with 100 mm of frontal armor. It is interesting to note that, on Hilary L. Doyle’s drawing from the book Panzer Tracts No.20-2 Paper Panzers (dated from May 1944), the turret has a much more angled front armor design. The built mock-up had flat front and side plates, probably as these were easier to build. The turret was to be operated by a hydraulic drive powered by the Panther’s own engine.
For the main armament, twin experimental 3.7 cm (L/77) Flak 341 guns were chosen. Some sources wrongly mention the 3.7 cm Flak 43 as the main armament. The 3.7 cm Flak 341 (3.7 cm Gerät 341) was an improved version of the same caliber anti-aircraft gun which was developed by Rheinmetall during 1944. The development process was too slow and only four prototypes were ever built. The Gerät 341 had a range of 4300 m, with a muzzle velocity of 1040 m per second and a rate of fire of 250 rounds per minute (or 400 to 500 depending on the source, but this was probably the maximum theoretical rate of fire of the two guns). The Flakpanzer 341 3.7 cm gun had a belt ammunition feed mechanism with some 1500 rounds of ammo for both guns. The ammunition would be stored beneath the turret, in the vehicle hull. The Flakpanzer 341 turret had a full 360° of traverse, and the gun could elevate between -5° and +90°. The total weight of the guns and the mount was around 470 kg. The secondary weapon would have been the radio operator’s ball-mounted MG 34 in the glacis plate, with one more possibly mounted on the turret roof.
The Flakpanzer 341 with the guns at high elevation. Source
The crew would consist of four to five crew members. While the sources do not specify the precise role of these crew members, we can assume that it would be more or less similar to other Flakpanzer vehicles. In the Panther hull, there were seats for the driver and radio operator / hull machine gun operator.
The two hatches on top of their positions were unchanged. The remaining crew members would be stationed in the new turret. One (or two) loaders would be positioned on either side of the guns. However, because these were belt-fed, their jobs were much easier than with the earlier magazine feed systems. The commander’s position was behind the gun, and he was also probably the gun operator.
The estimated combat weight was around 40 tonnes. The average weight of Panther tanks (depending on the model) was in the range of 44-45 tonnes. With its 700 hp strong Maybach engine, the Flakpanzer 341’s mobility would most likely have been better than that of the regular Panther tank.
The dimensions of the Flakpanzer 341 would also be similar to those of the regular Panther, with the same length of 6.87 m and width of 3.27 m. The height would be the only exception, at 2.8 m to the top of the turret.
The Daimler-Benz and Krupp Flakpanzer 44 design
During 1944, Daimler-Benz and Krupp were also working on a similar Panther-based Flakpanzer. Their turret design had 60 mm thick front armor. It was armed with two 3.7 cm Flak 44 anti-aircraft guns. This project is somewhat confusing for a few reasons. The existing drawings circulating online of the alleged Daimler-Benz and Krupp Flakpanzer 44 are actually of the Flakpanzer 341 according to Hilary L. Doyle. In addition, despite the best efforts of historians, no solid information about the existence of the above-mentioned Flak 44 anti-aircraft guns could be found. There were two different 3 cm Flak 44 projects, but they progressed very little. In addition, in some sources, the 3.7 cm Flakzwilling 43 is wrongly identified as the Flak 44. It is possible that this variation of the Flakpanzer 341 design was mistook after the war as a different project. Being developed during 1944/45, when Germany was in a state of chaos and due to the lack of documentation, the impression of another design having been developed could have formed easily. Of course, due to a lack of proper documentation, this is only an assumption at best.
This is the alleged drawing of the Flakpanzer 44. In fact, this is a Flakpanzer 341 with a modified turret. Source
Reasons for cancelling the project
While the idea of a Flakpanzer equipped with a fully enclosed turret, armed with two anti-aircraft guns, based on the Panther was certainly tempting, there were many reasons why this project would not have been very successful. A fully protected turret offered the crew much needed protection from ground and air fire but it also led to a number of issues that had to be resolved. These included potential problems with ammunition feed loading and removing the used shell cases at 90° angles. Due to the low quality of the German propellant in the late part of the war, during firing, a lot of powder smoke and fumes would be produced which could be dangerous for the crew. A dedicated and efficient ventilation system had to be installed.
The turret controls had to be designed and built to quickly respond to crew commands. The main armament was also problematic. Instead of using already produced weapons, the Rheinmetall-Borsig designers decided to use the experimental 3.7 cm Flak 341. which was never adopted for service. In January 1945, Wa Prüf 6 submitted a report in which the 3.7 cm caliber was deemed as insufficient for an anti-aircraft vehicle of the size of the Flakpanzer 341.
Another problem was the acquisition of air targets. In an open-topped turret, this could be easily achieved by the crew by simple observation. In a fully enclosed turret, a specially designed periscope and sights had to be added.
While the fully protected turret offered many potential advantages, it was not easy to successfully design and build one. While, during the war, the Allies used vehicles with fully enclosed turrets, most anti-aircraft vehicles built after the war were open-topped (like the ZSU-57-2 or M42 Duster).
The most obvious reason why the Flakpanzer 341 was canceled was the high demand for tanks on all fronts across Europe. Thus, sparing any Panther tank chassis for roles other than tank and anti-tank versions was out of the question for the Germans.
Despite this, the development of the Flakpanzer 341 continued up to the war’s end. It never received a high priority and only wooden mock-ups were ever built. Even if the war had continued for some time, there was a small chance (if any) that the Panther-based Flakpanzers would have ever been put into production.
This vehicle would have similar dimensions to those of the ordinary Panther tank. Source
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3.7 cm Flakzwilling auf Panther Fahrgestell “341” specifications
|Dimensions||6.87 x 3.27 x 2.8 m|
|Total weight, battle ready||Around 40 tons|
|Crew||4-5 (Gunner/commander, loaders, driver and radio operator)|
|Armament||Two 3.7 cm Flak 341 guns with 360 degree traverse|
|Armor||Hull front 80 mm, side and rear 40 mm,
Turret shield armor 80 mm, front armor front 70 mm side and rear 40 mm
|For information about abbreviations check the Lexical Index|