P1040055 by
Jaap van der Kooij, on Flickr
So, Let’s add some info about the tank to make it a bit interesting.
Summery from wikipedia (combination of EN and RU):
In between the 2 world wars, Soviet military was looking at selfpropelled artillery to implement in the Red Army. One of the ideas was a turretless, fully armored vehicle designated for direct fire support to the infantry.
Early 1930’s, they ordered such a vehicle in Germany, as their own designers didn’t come up with a decent design. Unfortunately Daimler-Benz didn’t deliver what was promised according to the contract. So, the Soviets rejected this vehicle and later on Germany didn’t want to full fill it anymore.
The Wehrmacht received during the time of the invasion of France the STUG’s based on the Panzer III. As the Soviets noticed their success, the discussion of “assault guns” started again at the end of 1940. But it took till 1942 to take a decision on what kind of tank/assault gun this should be. Big influence on that decision was the fact that Germany invaded Russia and captured a large part of the Soviet production facilities. In principle, assault guns are easier and cheaper to design and produce (no turret, more space for a big gun in the fighting compartment). Which at that time was becoming increasingly more and more interesting for the soviets. The fact that there would be no turret, reduced labor and manufacturing by 27%.
Design started in April 1942 (with different types of guns, 76.2 ZIS 3, 122mm M-30 howitzers and 152mm ML-20 howitzers). The SU-122
Among others, they designed the SU-122 based on the T-34 chassis with the M-30 122mm howitzer. It had 45 mm thick frontal armor and the howitzer could be elevated or depressed between −3° and +26° and had 10° of traverse. The crew consisted of a driver, gunner, commander and two loaders. The design was finished somewhere in July/August of this year.
End of November 1942, the trails for the first prototype started till half of December. Several flaws and mistakes were found (not enough elevation, poor shell transfer mechanism, bad ventilation of the compartment). Furthermore it was very inconvenient that the commander had to assist in operating the gun, which prevented him from doing his other duties at the same time. Unfortunately they decided to take it into service as is, with the designation of SU-35, later changed to SU-122.
Later on during production these flaws were addressed and taken care of. In total there were 636 vehicles produced, they were used till the end of the war. At this moment there is only one surviving SU-122 in the Kubinka museum. I shared some pictures in this post:
viewtopic.php?p=319274&hilit=su+122#p319274
As a small addition, the blueprint: