Was the IS Soviet Tank Line the Continuation of the KV Series?

Apr 2017
731
U.S.A.
#1
I've seen several descriptions that say the IS series developed from the KV series but how closely related were they? Was it the equivalent of the M26 to M48? Or the T-72 to T-90? Or was it a greater evolution?
 

Corvidius

Ad Honorem
Jul 2017
2,204
Crows nest
#2
IS was new but took on features from the KV series, and in that way was an evolution. Compare the first IS to the last KV, the 85, and it's easy to see where it comes from. Likewise while the T-55 was new, the T-44 neatly bridges the gap between it and the 34. The KV-85 has what is essentially a prototype for the IS turret and has the same type and style of road wheels and tracks. It's not an evolution in the sense that an existing model is upgraded, but that a new model is created using components tried and tested on the model it replaces. T-90 is a T-72, not an evolution of it. It started life as T-72BU and had a name change after Gulf War One to make a clear distinction between it and the "monkey models" that gave T-72 a bad reputation.
 
Apr 2017
731
U.S.A.
#3
IS was new but took on features from the KV series, and in that way was an evolution. Compare the first IS to the last KV, the 85, and it's easy to see where it comes from. Likewise while the T-55 was new, the T-44 neatly bridges the gap between it and the 34. The KV-85 has what is essentially a prototype for the IS turret and has the same type and style of road wheels and tracks. It's not an evolution in the sense that an existing model is upgraded, but that a new model is created using components tried and tested on the model it replaces. T-90 is a T-72, not an evolution of it. It started life as T-72BU and had a name change after Gulf War One to make a clear distinction between it and the "monkey models" that gave T-72 a bad reputation.
Interesting, then the main hull was different?
 
#5
The KV-1 was good when it first appeared in 1940 because its combat performance next to Soviet land-battleships (T-35, SMK, T-100) was vastly superior, and the early panzers used in Barbarossa had serious trouble piercing their armour. But their combat performance suffered next to the medium T-34 tanks, which had the same gun (76mm) but were much more mobile. The KV-1s allowed for more mobility at the expense of armour, but retained the same gun. The IS series would provide the Red Army with heavy tanks that had better armour and could fit a much more powerful gun (122mm). I think I remember reading that the IS-1 with its 85mm gun (like the KV-85) was (again like the KV-85) a stop-gap measure, thus why very few IS-1's were used.
 

Corvidius

Ad Honorem
Jul 2017
2,204
Crows nest
#6
Interesting, then the main hull was different?
Completely different hull. It's only the running gear that makes them look similar below the turret. What I meant by evolution in Soviet tanks is that while new tanks appear, in most cases they do not come out of thin air and there is a family tree to be followed back. T-10M to KV-1, T-55 to the Christie M1931 [a little contentious but certainly true up to the T-44]. It's tanks like the T-64 that really do come out of nothing more than the design bureau and have no pedigree.
 
Jul 2016
7,781
USA
#7
I've seen several descriptions that say the IS series developed from the KV series but how closely related were they? Was it the equivalent of the M26 to M48? Or the T-72 to T-90? Or was it a greater evolution?
Yes, continuation but new name because Kliment Voroshilov lost much of his political patronage with Stalin during the war.

Designed as a heavy breakthrough tank, it differed than the T26/M26, which was actually a medium tank, only for a short time was the T26 considered heavy before being redesigned as a medium, as was its later versions including the M48.

The T72 was a main battle tank designed as an update to the T62 and 64, being better and cheaper. Not a heavy tank, as the MBT concept was more a medium tank with mobility of light tank and firepower of heavy.
 

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