Tuesday 25 November 2014

85 mm Guns

Rival D-5 and S-31 guns might appear identical to the casual observer, but in reality, they had many subtle differences. The following data sheet contains the some data values regarding the KV-85 and IS-1 tanks that reveals some of them.



IS tank, S-31 gun
IS tank, D-5 gun
KV-1S tank, S-31
KV-1S tank, D-5
Tank length
8460
8420
8210
8450
Tank width
3060
3060
3270
3270
Height (gun horizontal)
2700
2700
2600
2600
Height (gun elevated)
3280
3160
2600
3365
Clearance
380
380
380
400
Width between tracks
3060
3060
3265
3265
Track in contact with ground, length
4540
4700
4600
4600
Track in contact with ground, width
650
650
650
650
Vertical gun angle
-2 to +21
-3.5 to +22
-3.5 to 15
-2.75 to 23
Horizontal gun angle
360
360
360
360
Bore axis height
1900
1945
2070
1965
Gun dead zone (m)
50
23
42
35
Shell mass
AP: 9.2 kg HE: 9.54 kg
Total round mass
AP: 15.85 kg HE: 16.2 kg
AP muzzle velocity
800
800
800
800
Muzzle energy (ton-meters)
300
300
300
300
Penetration at 1000 meters at a 30 degree angle
83-98 mm

As we can see, there are some differences in the size of the tanks that accommodate the gun, as well as various features, most notably gun depression. The IS can depress the D-5 more than the S-31, and even though the KV-85 can depress the S-31 slightly more, the higher bore axis gives that gun a much larger dead zone. Additionally, 15 degrees of gun elevation is quite unacceptable for a breakthrough tank that is expected to fight in urban conditions.

2 comments:

  1. Why is the gun depression for the D-5 different on both tanks, even though the turrets are ostensibly the same?

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