Self-propelled unit Sturmgeschutz IV mit 15cm StuH 43 had strong reservations: front armor hull had a thickness of 80 mm front armor cuttings — 100 mm, 30-mm armor plates were installed on the sides of the body, which are further protected by the armor shields. Tank fire control panoramic and telescopic sights, which made it possible to conduct fire not only direct fire, and a closed position. Drawback of the 150-millimeter self-propelled "Brummbar" ("Grizzly Bear") was a big load and the chassis, which served as a prerequisite for the frequent breakdowns chassis. Batch creation of the installation was carried out in the period from 1943 to 1944 year, just did about 700 vehicles that were used in the self-propelled artillery units and Grenadier regiments in the mouth languid infantry guns.
First, in 1942 the company "Alkett" was given the task to create and begin creating a new assault tank, apart from the fact instructed to carry out works in cooperation with the company "Krupp". "Alkett" offered the car with a bulky bronerubkoy, which was mounted on the chassis of the tank PzKpfw IV, modified by "Krupp". In an oblique, flat head-chopping broneliste installed 150-mm howitzer assault. As in some previous projects, and self-propelled guns StuG 33 "Sturmhaubitze" 42 were considered "temporary measure." Albert Speer gave the order to design a "Sturmpanzer" IV, almost a direct predecessor of "Brummbar" ACS has StuG 33.
October 2, 1942 at the meeting Speer reported on the status of the hook "Sturmpanzer" IV. 10/14/1942 project presented to Hitler. Hitler gave the order to make the spring of 1943 40-60 of tanks. As the base of ACS took the chassis PzKpfw IV, and served as the main armament howitzer 150 mm StuH 43 L/12, which was the embodiment of a tank infantry gun slG 33 of Skoda. Hitler at this time he gave instructions to begin the development of a new version of self-propelled, having armed with 210 — or 220-mm mortar. However, the proposal Fuhrer life and not have realized. Skoda Company in February 1943 made a wood mock "Sturmpanzer" IV (Sturmpanzer 43). Self-propelled guns were given the designation "Sturmgeschutz" IV mit 15cm StuH 43 (Sd.Kfz.166).
The first 6 of 60 ordered tanks were ready in March 1943, before the end of April made another 40 machines. Last 14 assault tanks were delivered in May 1943. ACS is almost always going to based on the newly-built chassis, but there have been cars, modified from the ready-made tanks PzKpfw IV. Delivery of new chassis involved in the company "Nibelungenverke" (St. Valentine). 52 assault tanks from the first batch was done on the basis of new tanks PzKpfw IV chassis modification of G, for eight self-propelled guns were used reconditioned chassis PzKpfw IV modifications E and F. Later it was decided to use for the production of self-propelled guns are only available chassis. Final assembly of the assault tanks produced in Vienna Arsenal (Herreszeugamt Wien) in cooperation with the companies' Simmering-Graz-Pauker "and" Zaurerverke. " May 14-15 at the site in German East Prussia higher ranks third inspected the newest armored vehicles.
Batch creation of assault tanks "Brummbar" was to turn around at the end of May 1943, but the first production car was made in November 1943. Delay causes an acute shortage of tank chassis. Assembly "Brummbarov" at the Vienna arsenal led to May 1944. First "Sturmpanzer" IV were of overweight, because the weight of 150 — millimeter howitzer (1850 kg) was big for the chassis of a medium tank PzKpfw IV, recoil force was also unnecessary.
Other shortcomings in the middle of "Grizzly Bear" is necessary to emphasize the lack of engine power, unreliable box, and high consumption of fuel. The lack of machine-gun armament on the first series of ACS made the car defenseless against the threat from the anti-spec. The opposing team. The crew was the only means of self-propelled self-defense — sub-machine guns MP-40, of which it was possible to shoot through special loopholes, intended for fire. Loopholes have been made in cutting board sheets.
Usually, the crew of the tank assault consisted of 4 people, as did the loader duty radio operator in the event of separation of the functions of the crew consisted of 5 people. Place the driver on the first 150-mm "Brummbar" supervisory unit was equipped with "Fahrersehklappe-80." A similar device was put on the grave tank "Tiger I". In connection with the sabotage of Czech workers breakage occurred fur. parts of the supervisory unit. A huge number of the first batch of assault tanks lost during the battle of Kursk, under Zaporozhye and Kharkov.
In October 1943, decided to design a lightweight version bronerubki and guns, to reduce the total weight of the assault tank. The newest gun given the designation StuH 43/1 L/12. The new instruments were equipped with 80 machines second party, the establishment of which began in December 1943. Despite the decrease in the mass assault gun overcome "of overweight" chassis was only after reducing the thickness of the armor plates.
In the second batch of tanks assault unit "Fahrerschklappe-80" has been changed periscopic observation devices. In January 1944 machine "Sturmpanzer"IV was given a new official name -" Sturmpanzer "IV" Brummbar ". Also called self-propelled" Sturmpanzer "43.
The design of cutting assault gun "Brummbar" changed in the middle of 1944. Creating a machine lasted until March 1945: 166 cars were collected third and fourth parties. The last batch of machines are known under the title "Abschlusserie". Assault Tanks last parties were armed defensive MG-34 machine gun, mounted in the frontal cutting ball mount "Kugelblende". To reduce the weight of the machine changed the configuration of the upper part of cuttings guns and masks. In the roof of the cabin above the commander's cupola installed on assault gun StuG III modifications G, adapted to the assault weapons "Brummbar."
At the commander's turret could be mounted anti-aircraft machine gun. In addition tanks were equipped with the latest series protivokumulyativnymi screens, some have anti-magnetic tsimmeritnuyu the plaster. In the later 150-mm se
lf-propelled guns "Brummbar" a huge part of the "disease" was able to heal. Assault Tanks "Grizzly Bear" in Panzerwaffe units have proven to be reliable and the necessary system tools. To assemble the assault weapons used later editions of tanks PzKpfw IV chassis modifications H or J. PzKpfw IV chassis Ausf.N had one or two pairs of iron bearing rollers without rubber tires, all road wheels PzKpfw IV Ausf.J rubber tires did not have.
The only discrepancy that is not always possible to solve for the production of assault tanks "Brummbar" was the lack of internal volume bronerubki to accommodate the vast number of shots. When you load 38,150-mm shells (full ammunition), 5 person crew felt themselves in a very constrained. Weight shells ranged from 25 (anti-missile) to 38 kg (high explosive) kg. 150-mm howitzer was mounted in a head-armored sheet in a ball mask, and was slightly offset to the right of the longitudinal axis of the assault gun. Pointing angles in the horizontal plane is from — 15 to +15 degrees in the vertical plane of — 8 to +30 degrees.
The howitzer was armed with a telescopic sight Selbstfahrlafetten-Zielfemfohr 5×8 (Sfl.ZF la). The thickness of frontal armor plate — 100 mm. Bronekozhuh barrel on the machines of the first series was a small, compared with the machines later series. All assault tanks were equipped radios FUG2 USW, receiving and transmitting radio FuG5 power of 10 watts, tank intercom. The crew later releases — 5 people: Commander (workplace was located behind the instrument), two loaders, gunner and driver. Place the driver was located in the left frontal part of the body in the department of management.
In the period from March 1943 to March 1945 made the four parties "Sturmpanzer" IV and "Sturmpanzer" IV "Brummbar", in the amount of 298 pieces. (According to another disk imaging unit 306.). The assembly is made at the Vienna arsenal, and since June 1944 in Duisburg at the company "Deutsche Eyzenverke." "Heereszeugamt Wien" was supplied 140 assault weapons. "Deutsche Eisenwerke" — 166 "Brummbar". Components supplied by different companies.
Swoop tool "Sturmpanzer" IV "Brummbar" was created for joint action with the infantry units and was developed specifically for combat in the criteria of the cities. In practice it turned out that the instrument can be used perfectly for the destruction of various field fortifications — machine gun nests, bunkers, trenches and ditches. etc. Also, "Brummbary" were used for the specific fire support to infantry units and pantsergrenaderskih. Assault troops in tanks were nicknamed "Stupa".
A small amount of 150-mm self-propelled guns "Brummbar" middle and late batches used as command tanks installed on their additional antennas and radios. Company "Krupp" under the name Befehlsturmpanzcr IV (Bet.Stu.Pz.IV) made one experienced mock tank destroyer, armed with 88-millimeter cannon Rak43 L/71.
Now assault tanks "Sturmpanzer" IV "Brummbar" are part of the exhibition of French tank museum in Saumur, the German tank museum in Munster, South American Museum Aberdeen Proving Ground, also in Kubinka.
The performance properties of the self-propelled artillery "Brummbar":
Troop index — Sd.Kfz.166;
Model — SluPz IV "Brummbar";
Manufacturer — "Nibelungen", "Eisenverke";
Chassis — PzKpfw IV;
Combat weight — 28400 kg (later releases — more than 30050 kg);
Crew — 5 persons;
Road speed — 35 km / h;
Progress in store on the highway — 160 km;
Speed the lane — 8 km / h;
Progress in store on the ground — 100 km;
Fuel tank capacity — 470 l;
Length — 5930 mm;
Width — 2,880 mm;
Height — 2520 mm;
Ground clearance — 400 mm;
Track width — 400 mm;
The engine — HL120TRM "Maybach";
Power — 300 hp;
Gun — StuH 43;
Calibre — 150 mm;
Barrel length — 12 cal.;
The initial speed of the projectile fragmentation — 420 m / s;
Ammunition — 30 rounds;
Machinegun — MG-34 (in ACS first series was absent);
Caliber — 7.92 mm;
Ammunition — 600 rounds of ammunition;
Book — 20-100 mm.