We’re back in Kubinka, this time in front of the IS-4.
Develoment of IS-4 started in November of 1943, although production didn’t start until 1946: It missed the war.
The idea was to try to take into account any defects or improvements from IS-2, and to incorporate any captured enemy technology.
As a result, you’re going to see a few things which do link to IS-2,
but you’ll also see some very novel features which don’t exist on any other Soviet vehicles of the era.
We’re going to do this in the typical fashion, exterior first, have a look at the suspension,
go around up to the engine deck, move forward onto the turret and then move inside.
We should get a pretty good overview of the vehicle that way.
One of the first differences you’re going to notice with IS-2 is the front slope.
IS-2 had a sort of stepped front slope, with an almost vertical driver’s port, this was deemed something of a weak point.
Part of the design parameters for IS-4 was that it was supposed to withstand the German 8.8 L/71 cannon.
So what they did was made a single glacis, they added additional armor protection for the driver,
and that was deemed sufficient.
Other features on the front slope, nothing too unusual, you have the standard service light and horn.
The two little plates in between the tow hooks, those are, I’m told, service markings.
Every time the tank went in for service or modification, they would engrave the update onto that.
The only other last thing to note is that the fenders are spring loaded,
you can actually lift them up and they’ll hold in position, which seems to be a bit of an excess to me, but what the hey.
So, the fenders. Soviet over-engineering at its finest.
You undo a latch here,
and simply they get locked into position.
Now, why exactly they felt the need to put this particular creature comfort on the tank I’m not entirely sure.
I have to say, if I was going to put life improvements,
spring loaded fenders would probably not be number one on my list of priorities.
No particular surprises when you get to the running gear.
You basically take an IS-2 and add an extra set of roadwheels, we now have seven pair per side.
Torsion bar, again.
A point to note, the bump stops do exist like other torsion bar vehicles, but unlike, say,
an American vehicle, there are no shock absorbers or friction snubbers to stop the rocking effect of the torsion bar.
They simply rely on mass.
The wheels themselves, they have cast serial numbers so you know who made them.
Lubrication, they’ve actually pulled off a bolt on this one, that’s how you add your oil, put the bolt back in and away you go.
Track tension, similar again to the other ISs, there’s a locking plate, you kick the locking plate out of the way,
you then get your big wrench and crank the screw forwards or backwards to extend the idler wheel forwards or backwards.
Track: The same as pretty much everything else on the IS series,
the only difference here is that we now have a center guide on every individual track link instead of the more typical alternating version.
Single pin, kept in place by a clip and a couple of washers.
The last thing to point out is that the sideskirts are a mid-life modification, they were added in the 50s,
and unlike, say, the IS-3, the side hull doesn’t angle out to the side, it’s a simple, angular step.
There is absolutely nothing of interest on this side of the tank whatsoever
because they had to leave room for the unditching log, which would be mounted here.
Moving to the rear of the tank, things get a little more interesting again.
Each fender could hold two cylindrical 90-litre fuel tanks, side by side.
These are not attached to the fuel system, they are simply to be pumped or siphoned into the internal fuel tanks.
To the rear center are the mounting points for the MDH smoke generators.
MDH, I’m told, stands for “Small Naval Generator”. Simple enough.
They are equipped with a quick-detach for the driver, he can just pull a lever and the things will fall off,
if, for some reason, he needs to.
To the front of that is the large access port for the transmission housing.
It looks like to open it up, you have to do a lot of unbolting of bolts,
and it’s a big piece of metal and it looks like you need two or three lads to open it up
Seems very inconvenient to me, I wouldn’t want to be doing it routinely.
The gun travel lock, of course, for holding the gun.
You’d spin the turret to the rear if you were, say, undertaking railheading
Spinning the turret to the rear performs two functions: Firstly it reduces the overhang so the overall length of tank is reduced,
and secondly, it’s a good crutch, it stops the excess of load on the elevation mechanism
due to bumps or whatever as they’re simply locked in place.
As you move to the rear, we have the convoy lights, marker lights, and not much else.
As we come to the left hand side of the tank, we now have room for two stowage boxes: No log.
Exhaust, one on each side, of course, you may have noticed as we went around the far side. And then we move up onto the turret.
Turret has mounting points for gun maintenance equipment, lots and lots of handles for the tank riders:
Tank riders were the infantry that would ride on the tank, and then when they got into combat they’d bail off to the side and go on on foot.
We suspect that this is the intercom system for the infantry commander to speak with the tank crew
as the tank crew would likely have been buttoned up.
Which does beg the question, if it’s dangerous enough for the tank crew to be buttoned up,
why in God’s name would you be riding on the outside of the tank.
However, I don’t get paid to make those decisions, next stop, engine deck.
As you get up on the engine deck, the obvious thing that you’ll see here are the circular radiator fans, shamelessly stolen from the Germans.
Outside of that, not too much.
There is the central port here for the cooling.
There are two fuel tanks.
The left fuel tank is 295 gallons, the right is 115, giving you a grand total of 410, which will get you about 170 kilometers.
If you traverse the turret to one side, there is an access port for the engine itself,
you can lift it up, it hinges sideways, and you can see the top of the V12.
Moving forward, casting mark on the turret, and again the loader’s 12.7 mm Dshka,
which goes to quite a significant angle of elevation very easily.
Blade sight, optical sight.
I’m told 60 rounds in the magazine.