Part
|
Thickness (mm)
|
Plate Angle (deg)
|
Shell type
|
Angle
|
Impact velocity
|
Range (m)
|
Damage type
|
|
Caliber
|
Type
|
|||||||
Upper front plate
|
120
|
60
|
88
|
AP
|
0
|
965
|
350
|
No penetration
|
Upper front plate
|
120
|
60
|
122
|
AP
|
0
|
758
|
690
|
No penetration
|
Side with spaced armour
|
85/16
|
60/35
|
88
|
AP
|
90
|
982
|
150
|
No penetration
|
Side without spaced armour
|
85
|
60
|
88
|
AP
|
90
|
983
|
159
|
Limit of dangerous penetration
|
Side with spaced armour
|
85/16
|
60/35
|
75
|
Subcaliber
|
60
|
1051
|
100
|
No penetration
|
Side (upper belt)
|
100
|
0
|
75
|
AP
|
45
|
905
|
500
|
No penetration
|
Side (upper belt)
|
100
|
0
|
75
|
AP
|
60
|
720
|
1600
|
Penetration
|
Side (rear part)
|
60
|
0
|
75
|
AP
|
35
|
780
|
1500
|
Limit of rear plate
|
Bottom with spaced armour
|
20/30
|
60
|
75
|
AP
|
35
|
607
|
2200
|
Only spaced armour is penetrated
|
Bottom with spaced armour
|
20/30
|
60
|
75
|
AP
|
35
|
660
|
1900
|
Same
|
Resilience of main turret components
Part
|
Thickness (mm)
|
Angle of plate
|
Shell type
|
Impact velocity (m/s)
|
Range (m)
|
Damage type
|
|
Caliber
|
Type
|
||||||
Turret front
|
175
|
Sphere
|
88
|
AP
|
967
|
350
|
Penetration less than shell caliber
|
2nd belt
|
120
|
51
|
88
|
AP
|
900
|
1000
|
Penetration within +/- 15 degrees of normal
|
3rd belt
|
90-100
|
58
|
88
|
AP
|
900
|
1000
|
|
4th belt
|
175
|
15
|
88
|
AP
|
900
|
1000
|
|
2nd belt
|
120
|
51
|
88
|
AP
|
965
|
350
|
Penetration within +/- 30 degrees of normal
|
3rd belt
|
90-100
|
58
|
88
|
AP
|
966
|
350
|
|
4th belt
|
175
|
15
|
88
|
AP
|
975
|
300
|
|
Figure #35: Diagram of the damage to the turret.
Recommendations on improvement of the IS-3 tank design
Hull and turret
Figure #9: Diagram of the hull side armour.
2. Thicken the front part of the hull roof, not protected by the turret, to 45-60 mm.
3. Increase the thickness of the front of the turret to 230 mm.
4. Remove the sudden change from the fourth belt (175 mm) to the third belt (90 mm) by changing the slope of the fourth belt according to the attached diagram.
Figure #10. Diagram of the changes to the turret armour.
RGASPI 644-2-464
It's worth noting that the designers took the results of these trials seriously and upgraded the turret armour significantly,
It's worth noting that the designers took the results of these trials seriously and upgraded the turret armour significantly,
This is a very interesting document. It indirectly sheds light on the performance of cast armour in comparison to RHA as well.
ReplyDeleteGerman official penetration data based upon the G(D) criterium (5 out of 5 successes, no failures) indicates that the 88mm PzGr.39/43 does penetrate reliably only 80mm german RHA at 60° obliquity and 1000m/s.
The penetration data against the soviet cast turret show a somehow better performance:
at 59.2° compound netto obliquity (composed of 58° vertical at 15° horizontal component) the 8.8cm penetrates 90-100mm cast armour already at 900m/s.
at 62.3° compound netto obliquity (composed of 58° vertical and 30° horizontal component) the 8.8cm penetrates 90-100mm cast armour at 965m/s.
From this comparison it appears that either the WaPrüf penetration data of the 88mm are overly conservative, or alternatively, the soviet 100mm cast armour at high obliquity appear to be significantly inferior to their test RHA.
interesting, thanks for posting.
High hardness is a disadvantage at high obliquity impact. The harder the plate, and the lower the velocity, the more normalization occurs. At 60° the nose shape hardly ever is important because projectile break up occurs almost all the time, creating a rather blunt nose -if the projectile doesn´t shatter completely. More important is the deepness of the cap over the nose and it´s hardness, as it rightens up the projectile a bit, and digs out a piece of metal from the plate, allowing easier passage of whatever follows.
ReplyDeleteCast armour is certainly less effective than RHA due to the lack of cross rolling used to work out impurities and gas bubbles present in the cast.
Take also notice that german penetration definitions are harder. 0 out of 5 failures allowed can at high obliquity turn to significantly degrading results if a single projectile undergoes complete rather than nose-only break up.