Hello everyone, as you might have noticed, Wargaming recently added the SU-76i vehicle into the 8.10 test for supertesters: In addition, the game files contain one more vehicle, whose fate is not known, the SU-85i: Today, we are going to have a look at both of them in a bit more detail than what is written in the wikipedia article. History In the second year of the war, the Russian army was still coping with numerous problems of its vehicles. Despite the fact they managed to overcome the initial disaster of 1941, the war was still far from won and the Red Army still lacked the massive amounts of armor they would later throw at the Germans in 1944 and 1945. Other types of armor were problematic, such as the mass-produced SU-76. SU-76 as a self-propelled gun had two major flaws. One was the fact it was open-topped and the crew was not well protected from behind, earning it the nickname of “golozhopy Ferdinand” (“Ferdinand with bare ass”). Another major problem was the fact it actually had two engines. These would often get desynchronized, damaging the engine and transmission in the process. This issue became so prevalent it required a general factory solution, that took several months (it was one of Ginzburg’s worst screwups), during which a shortage of SPG’s appeared on the front. During this delay, the authorities (specifically the People’s Commissariat of Arms of the USSR (Народный комиссариат вооружения СССР or NKV), roughly an equivalent of the ministry of defense) turned their attention to captured vehicles, collected in various armor repair plants ever since the Fall of 1941. Most of these vehicles were the Panzer III tanks (called T-III by the Soviets) of various types, good medium tanks, quite popular amongst their German crews. One of the first ways to use this captured tech in 1942 was the proposal to install the 122mm D-30 gun on Panzer III chassis (designated SG-122(A)), but the gun proved to be too heavy and powerful for the suspension. A year later, on 3.2.1942, the NKV issued an order to create a 76,2mm assault gun project on Panzer III chassis. This task was assigned to the construction bureau under the leadership of A.N.Kashtanov, who earlier proposed to re-arm the SG-122(A) SPG with a ZIS-3 gun. After its evacuation to Sverdlovsk, Plant No.37 (in cooperation with Plant No.592) was tasked with converting 200 Panzer III tanks into 76,2mm self-propelled guns. The deadline was murderous: the prototype was to be ready until 1st of March 1943. At this point, the SPG recieved a designation of SU-76(T-III). The 76mm gun was chosen out of necessity – by that time, the 85mm D-5 gun was still tested and anything bigger simply couldn’t fit on the Panzer III chassis. Furthermore, since the F-34 and ZIS-5 76mm guns could use the 76mm field howitzer ammunition, logistics were made much simplier by this choice. In the end, the project – while resembling the earlier SG-122(A) – required some significant rework. The armored superstructure now recieved some slope for improved protection. The hull itself however remained pretty much unchanged from Panzer III. The vehicle was propelled by a 300hp 12-cylinder Maybach HL120 TRM with a Bosch 4 horsepower starter mini-engine. The vehicle had a mechanical Maybach SRG328145 transmission with semi-automatic hydraulic pre-selector. The suspension was identical to the original Panzer III one (Ausf.H and J – those were the most numerous ones in 1941 and 1942). Four armored hatches were added to the engine compartment in order to improve the access to the engine. The armor was fairly light, designed to protect the vehicle only from low-caliber cannons, AT rifles and HE shell fragments. The frontal hull armor was only 30mm thick, the sides were 30mm thick too and the rear was 20mm thick. The superstructure consisted of several sheets of rolled armor and in total the front was 35mm thick, sides were 25mm thick, the roof and the back was 15mm thick. The upper plate was riveted to the rest of the superstructure with bolts. There were also portholes for submachine and pistol fire created in the side armor. The two-wing door for the crew was located at the back of the superstructure. Compared to other Soviet SPG’s of the era, the SU-76(T-III) offered the crew good possibility to look out of it. The driver could either open a driver’s hatch to look out, or he could button up and use his periscope. Commander, loader and gunner could use the PTK-5 panoramatic devices to look out. These devices were installed in the sides and in the front plate of the superstructure and were protected by armored covers. The first variant of the SPG counted on using the ZIS-3Sh gun (Sh = Shturmovaya, ZIS-3 assault gun variant) used in SU-76, or the F-22USV. It wasn’t a bad choice, but it had its flaws, including poor mantlet protection and crew compartment issues. Thus in the end it was decided to use even more reasonable gun, the S-1, developed from the F-34 gun. Its advantage was the fact the trunnion pin took less space in the superstructure, allowing for more crew comfort. The installation of the gun itself was not a problem, but the new proposed mantlet was quite complicated. In order to avoid it, a team of engineers from UKZM and Plant No.592 designed new cast mantlet in only 5 days. This new mantlet, combined with the mount now allowed the gun to depress to -5 degrees, elevate to 15 degrees and move 10 degrees to each side from the axis. The sights (TMFD-7) were taken from the ZIS-3 gun. The vehicle carried a full complement of 48 76mm shells, including AP, HE, subcaliber AP tracer (BR-354P), HEAT (BP-353A) and several types of shrapnel and buckshot rounds. Although the original German Panzer III FUG5 radio was better than the Russian one, it was replaced with the 9R station in order to avoid signal confusion. But there were not enough radios to go around and only every third vehicle of the first series had them. The situation eventually improved in May-June 1943 and in the end almost every vehicle had one. Testing and Production Despite all the efforts, the design teams and plants could not keep up with the draconic schedules. On 15.2.1943, Simeon Ginzburg (director of the NKTP design bureau) reported that the prototype is being constructed, while in fact the workers began creating a prototype without the technical drawings and later, the designers in fact did make the technical drawings FROM the prototype by simply measuring it. In the end, the prototype was ready 5 days behind schedule (6.3.1943). The tests on Continue reading →

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