Friday 15 November 2013

Soviet Sight Testing

The life of KV-1S #15002 was no ordinary life. As its serial number might suggest, it was the second KV-1S built. Later on, it was converted into a KV-85. In a third and final experimental step, it was equipped with a PT-8 sight.

And shot at. CAMD RF 38-11369-64 tells us why:

"Trials of the tank turret by shooting

The tank's armour was tested with mount testing shells, in order to find out the reliability of the optical sight and its mounts.

Factory #100 performed a shelling of the tank with armour piercing shells in order to determine the reliability of various components of the tank. At the same time, this was used by our commission to test the sight.

The IS turret had a new 4x sight installed and carefully calibrated.

The tank as shot at with a 76 mm ZiS-5 gun from a distance of 300 meters. 10 shots were fired, 5 shots with mount testing shells, and 5 shots with armour piercing shells.

The mount testing shells were aimed at the area of the sight, with two shells impacting the shell on the level of the sight, and three in the mantlet on the same plane.

The armour piercing shells were used to test the sturdiness of various parts of the tank (driver's hatch, commander's cupola, etc). The hits were as follows:
  • Driver's hatch: one hit
  • Front armour: two hits
  • Commander's cupola: two hits"
Figure 7. Blue dots represent the mount testing shells. Red dots represent armour piercing shells.

"After shelling, the sight was examined externally and looked into. The result was as follows:
  1. The sight was free of deformations and defects.
  2. Sight adjustment and sharpness did not suffer.
  3. Calibration of the sight was not knocked off.
The support pole of the ocular portion of the sight, welded to the turret, fell off. The ocular part fell down, to the hydraulic turret traverse mechanism. This was a defect of the installation, and not the sight. Additionally, no defects or damages were caused by the falling of the sight. 

These tests show that the PT8-15 sight is sufficiently rugged and continues to function after numerous nonpenetrating hits. The sight mount is adequate. The only part that needs perfecting is the support pole for the ocular part of the sight."

"Figure 8. KV-85 tank with IS turret and PT8-15 sight after shelling. The white marks on the turret are results of the mount testing shells."

"Mount testing shells" are a special kind of shell, used for training. It is a homogeneous shell, with the same mass as the shell it's supposed to represent, but without things like an explosive filler. Obviously, these shells have lesser penetration than regular AP, but the IS turret withstood both types of shell from 300 meters, something Tigers weren't quite capable of

5 comments:

  1. Huh, didn't realise that Russian and German use basically the same word for "mount".

    ReplyDelete
  2. Another example of odd testing and even odder interpretation!

    Why are they shooting at the side of the turret? FIRE AT THE FRONT OF THE TURRET!!! Why not just use AP shells? Why a 'special' derated projectile.

    The picture seems to show that there are gouges on the frontal hits to the hull. looks like the drivers visor is gone. There are no gouges on the turret hits. Does this not make anyone question this whole procedure?

    The sight still fell down? But its still 'good'? Uh, in your world. I live in the real world, thanks.

    ReplyDelete
    Replies
    1. Yes, I'm sure you, an internet guy, knows how to best test tank sights. Also if you bothered reading the article instead of skipping right to outrage, you would have found out that they did, in fact, use AP shells. That's where the gouges came from. Also, the sight fell down due to an assembly screw-up and not any fault of the sight itself. Despite falling down, the sight sustained no damage.

      Delete
  3. Another example of odd testing and even odder interpretation!

    Why are they shooting at the side of the turret? FIRE AT THE FRONT OF THE TURRET!!! Why not just use AP shells? Why a 'special' derated projectile.

    The picture seems to show that there are gouges on the frontal hits to the hull. looks like the drivers visor is gone. There are no gouges on the turret hits. Does this not make anyone question this whole procedure?

    The sight still fell down? But its still 'good'? Uh, in your world. I live in the real world, thanks.

    ReplyDelete
    Replies
    1. I'm glad you were so outraged that you posted the same thing twice.

      Delete