Source: Yuri Pasholok’s blog
Hello everyone,
an interesting thing appeared on Yuri Pasholok’s blog. On the example of the IS-4, Yuri Pasholok demonstrates, how much can various projections differ from reality. He states that if someone claims some vehicle to be modelled after “factory drawings”, you don’t have to take that claim too seriously, because – if I understood what he wrote correctly, there is not only a significant difference between various book drawings and the final product, there is also a difference between the general factory drawings and the final product.
Basically, production plans consist of series of detailed partial drawings, by which the vehicle parts are created. General drawings however (as in, general overview, even though created by the same factory) tend to be much less accurate (this is apparently the reason why for example Wargaming preferred the partial IS-3 turret plans to the general model in the recent IS-3 turret changes).
Here is a comparison, made by Yuri Pasholok:
The photograph above is of the serial IS-4 vehicle. Red lines belong to the drawing published by well-known Russian author Michael Svirin, blue lines represent the general drawing of the IS-4M (Drawing 701 – Sb.3 from April 1952). As you can see, both the general factory projection and Svirin’s projection (from the book) are different from reality.
To compare, here is a comparison of a partial turret drawing from IS-4M (701-157-Sb.3) with the real life tank:
As you can see, it fits much better than the general drawing, demonstrating the superior accuracy of partial drawings.
Is this the same for Germans or were they a bit more accurate in producing the same tank they drew? :D
Roughly the same, but sometimes worse. Panther frontal armor angles were not exactly unified and sometimes they were off by a degree or two. Or various thickness of plates. During wartime anyway – peace-time tanks were very precise.
You know, maybe that’s because Panther front armor angles weren’t to be primary dimensions but result of production, with other ones as primary instead? Just a guess, but i wouldn’t be surprised.
More likely that the assembly jigs were not always used, as a time-saving effort when at full production.
The explanation is very easy (strange seeing that it’s not a common knowledge ;) , but that’s probably my technical weirdo mind).
“General” drawings (assemblies) are for showing how the machine works, how parts fit together, how everything “looks like”. If there are any dimensions on it, they are only for that reason (eg. how much space in garage you need :P of if you bang your head on the roof).
Parts’ drawings are for production purposes, with all dimensions and other “stuff” taking into account the way the part is made and how to check if it’s bad or good afterwards. If they are proper drawings, anyway ;) , you get as many bad designers as bad programmers or bad PR guys.
enjoy reading
http://en.wikipedia.org/wiki/Engineering_tolerance
I don’t need to. And seems to me that this turret is well within tolerances set by designers.
Always the most important part that must be in tolerance is where the major assemblies meet. These interfaces would be the items set to the tightest tolerance, and as such would require a post-casting machining process. The outer armour thickness probably isn’t even on a general drawing tolerance – a result of the production ability of the time when dealing with hollow sand castings.
Still nice to see a fellow Engineer’s drawing from times past though :)
Hmm I have always wondered about that. Nice :). Still is it not easier to find real-life examples of the vehicles and measure those ? :P
Also, did the IS-3 not have 122mm of frontal armour according to measurments?
As far as I remember, someone said not so long ago that this was either a myth from some book, or some measuring error. Either way IS-3 is fine the way it is now, according to WG.
IRC it was on the Russian forums during open EU beta testing. Right before they buffed IS-7 turret armour to 240mm and nerfed its diamond shaped side plate to 100( was 150 before that). On the same page, where they measured the IS-7, there were also IS-3 measurements.
IS-3 has completely wrong lower plate angles compared to RL version. In game it’s retardedly sloped under extreme angle while in RL it wasn’t nowhere near as much as angled.
is3′s hull was the one that was on game before the change they did to so called historical adjusment
they only thing they did which is historical is the turret the hull mustn’t have been changed at all
why they bother going into this unessesary change on the hull??
I cant say really. Maybe you are right, maybe you are not. The hull was also made a little longer.
Turret was nerfed though. No one was shooting next to the mantlet anyway. Side armour can be fel though.
What was IS-4′s actual armoring ? I’m struggling to find accurate numbers anywhere, and WoT’s values are vastly inaccurate IIRC.
They are not inaccurate, they correspond to factory values.
C’mon already, fix the IS-4, the ST-I has like 3-4 degrees better sloping on the UHP which makes about 20mm more effective armor on the ST-I. Also the ST-I doesn’t suffer from the weak turret top, and IS4 has that weak turret top along with the IS-3.
agree, i sold my ST-I only to find out the IS-4 is tier 9 tank… they have no respect to Russian Tanks, they mess it up, IS-4 should be Invisible.
PS – it’s very good if you can side scrap, but still they should buff it’s frontal armor badly and give it 500 moar HP.
They should give it that 60 degree frontal armor, not 500 more HP, but more HP and maybe better mobility.
IS-4 frontal armour is at 61 degrees.
Only buffs I can imagine are mobility and maybe turret top buffs
Yes, but ST-I’s armor is at 64 degrees when IS-4′s is at 60.
The IS4 would be just fine if they gave it slightly better mobility and gun depression of -8… the same as ST1. HP is fine and giving it even more is not the solution. If you look at the new ratings charts, IS4 is one of the most under performing tier 10 tanks, and driving it makes it feel like an underdog, far more than the IS7.