Sturmgeschütz IV für 15 cm Sturmhaubitze 43

The effort to obtain an offensive self-propelled gun reaches the first battles of World War II. The first attempt was lafetation 15 cm s.I.G.33 Sfl. on Pz.Kpfw. I ohne Aufbau Ausf.B, followed by 15 cm s.I.G. 33 on vehicle Pz. Kpfw. II (Sf). After these self-propelled guns of open construction, a self-propelled gun Sturminfanteriegeschütz 33 was developed, which was characterized by a fully enclosed combat area, which perfectly protected the crew from small arms fire and artillery shells. Even the medium tank platform Pz.Kpfw.III was not suitable for mounting a heavy howitzer. At the end of 1942, the company Alkett developed and submitted for approval to Adolf Hitler the concept of a new Sturmpanzer on the platform Pz.Kpfw.IV. He produced 40-60 assault works with 15 cm s.I.G. approved. The company Alkett based on the experience with Sturminfanteriegeschütz 33 developed a superstructure with a sloping frontal armor up to 100 mm thick. The ceiling of the superstructure was also tilted for better observation. The driver's window came from the design of a heavy tank VK 45.01 (P). The development of the main weapon 15 cm StuH 43 L/12 was entrusted to the company Skoda, Plzen. The production of this self-propelled gun was not to be ensured by standard series production in any of the factories, but was to take place as part of repairs to tank platforms Pz.Kpfw.IV in Heeres-Kraftfahrzeug-Werkstatt (army) repair warehouse) in Vienna. The production of the first 40 vehicles was promised until May 12, 1943, so that they were ready for the planned summer offensive at Kursk. In 2/1943, a wooden model was built and the construction of a prototype immediately followed. The prototype was built in the form of a command vehicle (additional long-range radio station and star antenna). In 3/1943 the company Skoda delivered to the Waffenamt first six 15 cm howitzer StuH 43 L/12. Delivery of another 40 howitzers took place in 4/1943 and the remaining 14 pieces in 5/1943. The team was fulfilled the first order for 60 weapons. The assembly of the first 20 pieces of self-propelled parts took place in 4/1943, the remaining 40 pieces in 5/1943. For the first time to Adolf Hitler this vehicle was presented on 13.5.1943-15.5.1943 in Rastenburg during the presentation of new combat equipment.
The following 80 vehicles of this type were produced again at the Heeres-Kraftfahrzeug-Werkstatt (army repair depot) in Vienna.
Interestingly, thanks to the lobbying of Generaoberst Ernst Guderian at Adolf Hitler, these machines were classified as tank destroyers and thanks to In this classification, the vehicles were assigned to tank units and not artillery.


On May 4, 1943, this self-propelled cannon was officially named "Sturmpanzer". The well-known name of this machine as "Brummbär" is not its official name. The nickname "Grizzley Bear" was mentioned in a US intelligence report dated 9/1944. It was the name of a captured vehicle from the French Caen. This name in the German transcription "Brummbär" was later used in the British intelligence report and in post-war journalism gained a mark of officiality. The correct designation of this machine is Sturmgeschütz für 15cm Sturmhaubitze 43 (Sd.Kfz.166) Ausf.I-IV or Sturmpanzer Ausf.I-IV.






Characteristic features of individual series:


Sturmpanzer Ausf.I
Only versions Pz.Kpfw.IV Ausf.E, Pz.Kpfw.IV Ausf.F[/url) were used for conversions ] a [url=/topic/view/6418] Pz.Kpfw.IV Ausf.G. Older versions have been modified to the standard version Pz.Kpfw.IV Ausf.G (new drive, tension and castors, 400 mm wider belts). The 50 mm thick frontal armor was reinforced with an additional 50 mm thick armor (100 mm in total) and the 30 mm thick lower frontal armor was reinforced with an additional 30 mm thick armor. The fastening was performed by screwing, when holes for drilling screws were drilled into the base armor. The vehicles, of course, had refurbished engines Maybach HL 120. The driver's window came from the design of a heavy tank VK 45.01 (P). Details were added, such as ventilation holes on the hatches to the couplings (older versions of tanks did not have them), etc. On the rear body of the hull were carriers for two spare wheels. The tool box was on the right side of the engine part of the body. The fire extinguisher was on the right front fender. On the rear armor on the sides were armored boxes for antenna outlets. Ausf.I had a pair of antennas. In the case of the command vehicle, the right standard rod antenna was replaced by a star antenna.


Sturmpanzer Ausf.II
The lower part of the driver's window received 50 mm additional armor protection. On the rear body of the hull were doubled carriers for a total of four spare wheels. A projectile deflector was welded to the ceiling of the superstructure in front of the commander's hatch. Schurzens and their holders were modified (triangular handles). The sight cover was reshaped and guided/protected by screwed rails/deflectors. A flue gas fan was mounted on the ceiling directly above the howitzer. The front cover of the charger/machine gunner had a welded profile (?). The Ausf.II series vehicles were both refurbished Ausf.I vehicles and new vehicles. In the case of new vehicles, these were the platforms of the new version of the tank Pz.Kpfw.IV Ausf.H. These new vehicles had modified sides of the superstructure, where in addition to the original shooting port for the crew's personal weapons located in the angled side armor, the same shooting port was in the rear of the side armor on both sides of the superstructure. The version of the platform Pz.Kpfw.IV Ausf.H with a homogeneous 80 mm thick armor eliminated the need to install additional armor. However, the front lower body of the hull still had a 30 mm additional armor mounted. The vehicles had Filzbag air filters mounted on the right side of the engine section.The enlarged tool box has moved to the left side of the engine compartment. the fire extinguisher moved from the right front fender to the engine ceiling just behind the rear of the body on the left. A crowbar was placed next to a wooden pad under the jack on the front left fender. Zimmerite antimagnetic paste was applied on machines manufactured from 9/1943. On the rear armor on the sides were armored boxes for antenna outlets. However, Ausf.II had only one antenna on the right. The vehicles had all-metal support rollers. The new machines had a modified (lightweight construction) howitzer StuH 43/1 with a conical mouth, mainly (approx. 12/1943-1/1944). The company Škoda has developed a new type of ammunition with a longer range. Compared to the original ammunition 15 cm Jgr.38 m less weight (38 kg vs. 27 kg), and about 45% greater range (standard range of the new ammunition was 5,000 meters, maximum 6,200 meters).


Sturmpanzer Ausf.III
Instead of the driver's window used from the heavy tank VK 45.01 (P), the driver had an armored booth with a rotating observation periscope on its ceiling. The body was made of armor with a lock. The rear part of the bottom of the body was not angled, but straight and connected to the modified rear body armor. Filzbag air filters have stopped being installed. Massive armored boxes for antenna outlets have been removed. One small base for the rod antenna on the rear body armor on the right has become standard. On the left side of the rear body of the superstructure was the preparation for the installation of an additional antenna in the case of conversion of the vehicle to the command. The antenna mount protected the armored cover. The hinges of the rear two-part escape hatch on the rear of the superstructure have been modified.


Sturmpanzer Ausf.IV
The final appearance of the Sturmpanzer had a changed superstructure. The front armor of the superstructure did not have a broken shape, the ceiling was lowered and angled. The lower edge of the front shell of the superstructure has shifted about 45 mm backwards. Instead of the commander's hatch, a turret made of a self-propelled gun StuG III Ausf.G with a fully revolving ring (360 °) for an anti-aircraft machine gun was mounted instead of the commander's hatch. In the upper left front part of the frontal armor was an armor protrusion with a machine gun Kugelblende, in which the machine gun was mounted MG 34. On its ceiling was mounted another fan designed to extract the flue gases generated by firing from a machine gun. A massive protrusion with a two-part hatch was also created in the rear side of the superstructure. Instead of the original massive double lid of the charger, there were two small hinged lids on the ceiling. The vehicle was manufactured on a tank platform Pz.Kpfw.IV Ausf.J. Due to the significantly increased weight of this self-propelled vehicle exceeding the maximum design weight of the tank platform Pz.Kpfw.IV (25 tons), the vehicles in this series used all-metal wheels. In the first serial vehicles of the 4th series, all-metal wheels replaced all the original wheels with a rubber band. Later, they were mounted only on the first trolley, or the first pair of trolleys (2-4 pieces on each side), the rest were of the original construction with a rubber bandage. Changes introduced for type Pz.Kpfw.IV Ausf.J were also introduced for Sturmpanzers. Only three support rollers were installed, a pair of tubular exhausts began to be installed instead of the original cylindrical exhaust muffler. From 9/1944, the antimagnetic paste zimmerite ceased to be applied.


On January 19, 1944, it was planned to move the assembly of the new Sturmpanzers from Vienna to the Nibelungenwerke factory. In Heeres-Kraftfahrzeug-Werkstatt, the repair of tank destroyers was to begin Ferdinand/Elefant. However, the decision of 21 January 1944 decided to repair the tank destroyers in Nibelungenwerke and the production of new Sturmpanzers was to be moved to the Werk Stahlindustrie in Duisburg. In the period from 6/1944 to 3/19945, a total of 162 vehicles were produced here.In German documents dated 15.11.1944, information was found that every fifth Sturmpanzer produced was to be equipped with an optical rangefinder "Entfernungsmesser 0,9 m Raumbild".
At a meeting with Adolf Hitler on November 12, 1944, it was decided to stop the production of tanks weighing 25 tons ( Pz.Kpfw.IV ). Production of all types of vehicles was to focus on the platforms Pz.Kpfw.38 (t), Panther and Tiger. However, Albert Speer's notes state that Sturmpanzer production on the Pz.Kpfw.IV platform should continue with using the machines that were to be sent for repair.
In the post-war report of the Werk Stahlindustrie company dated 30 August 1945, it is stated that the conversion of the three Sturmpanzers into training and repair vehicles was to take place (in 10/1944).
For the needs of supplying Sturmpanzer ammunition, a small series of ammunition tanks was created.

Hillary Louis Doyle, Lukas Friedli, Thomas L. Jentz - Panzer Tracts No.8-1, Sturmpanzer (Sturminfanteriegeschutz 33, Sturmpanzer and Munitionspanzer development and production from 1942 to 1945), year of publication 2014
Thomas L. Jentz, Hillary Louis Doyle - Panzer Tracts No.8 - Sturmgeschuetz s.Pak to Sturmmoerser, year of publication 1999, ISBN 1-892848-04-X
https://www.panzerworld.net/facts.html