Tank suspensions; fight!

[Juha3]

The Germans would have been better off skipping all the Tigers, Panthers, Elefants, and casemate tank destroyers and instead taken the same money and resources to produce 10x as many 7.5 cm KwK 40 L/43 armed Panzer IVs, with earlier introduction of the Ausf. H with its better armour and longer, high velocity 7.5 cm KwK 40 L/48 gun. With the right AP round this gun will kill any T-34 or Sherman at reasonable range.


View: https://m.youtube.com/watch?v=NhDPhtuWxU0&pp=ygUJUGFuemVyIGl2

In fact Panther was not much more expensive than Pz IV. A Panther tank cost 117,100 Reichsmark to produce. This compared with 103,462 RM for the Panzer IV with its old fashioned leaf spring suspension. These figures did not include the cost of the armaments and radio. Of course weighting twice as much brought many problems. A Tiger I cost some 2.4 times more than a Pz IV but nowhere near 10 times.
The video goes wrong right from the start, the Germans started planning to build tanks as early as 1923 and had the Kama tank school in Kazan in the Soviet Union until 1933, the year Hitler came to power. The video shows briefly the Lichttractor, of which only 4 prototypes were built and tested in Kazan. The Rheinmetall version was selected for production in 1928 but the order for 289 vehicles was cancelled the same year. Six larger Grosstractors were built in 1928-9, which were secretly transported to Kazan for testing and training vehicles.

 

[Admiral Beez]

I read that one reason why the Sherman was the way it was, that is narrow, short and high, was that it allowed them to pack more of them into transport ships. That being said, a rear drive version with torsion bars wouldn't have necessarily changed that basic constraint, although it would have allowed it to be somewhat lower profile.

I think the main reason that the M2-M4 had bogie suspension was that's what its locomotive manufacturers were used to. As for rear drive, it just seems that other than Christie, no one in the US gave it a go. Which to me is an odd thing, as the by the 1930s the French, British and Soviets had several tanks with rear drive.

 

[z42]

Here's a video from the British tank museum in Bovington which touches on the proposed replacements to the T-34, first the T-34M and later the T-43.


View: https://www.youtube.com/watch?v=azjAmD0f_Ck

Both featured torsion bar suspension and a new three man turret. However, the T-34M was abandoned in favor of trying to increase production of the existing T-34 model. And similarly the T-43 was changed to use the 85mm gun, and the turret was adapted to the T-34 resulting in the T-34-85, and the T-43 was canceled.

From the front view comparing the T-34 and T-43 one can see how the use of the torsion bar suspension instead of Christie enabled the T-43 to be much narrower (assuming internal volume is roughly the same).

 

[bf109xxl]

Both featured torsion bar suspension and a new three man turret. However, the T-34M was abandoned in favor of trying to increase production of the existing T-34 model.

Not only for this reason. In general, the T-34M project was Morozov's initiative and was created in a great hurry. It was not sufficiently developed for mass production.

And similarly the T-43 was changed to use the 85mm gun, and the turret was adapted to the T-34 resulting in the T-34-85, and the T-43 was canceled.

The T-34-85 turret was developed separately - only the prototype had the T-43 turret. The T-43 project had many shortcomings that made it more vulnerable than the T-34 despite its thicker armor.

From the front view comparing the T-34 and T-43 one can see how the use of the torsion bar suspension instead of Christie enabled the T-43 to be much narrower (assuming internal volume is roughly the same).

View attachment 846736

Is a difference of 250 mm that much?

 

[z42]

Not only for this reason. In general, the T-34M project was Morozov's initiative and was created in a great hurry. It was not sufficiently developed for mass production.

It does seem like the T-34M project was largely a clean sheet design, retaining very little from the T-34, perhaps suggesting that the name was more a "marketing" thing rather than the minimum changes required for switching to torsion bars and a bigger turret.

Is a difference of 250 mm that much?

Just eyeballing from the picture I provided. Admittedly the wider turret on the T-43 might be deceiving the eye.

(From looking at pictures of the T-34 suspension, I'd estimate the suspension would eat up something like 30cm per side. Though they had fuel tanks and stuff in the space between the spring boxes, so it wasn't all wasted.)

A Soviet note suggesting that switching to torsion bars would increase internal volume by 20% and reduce suspension weight by 300-400kg, among other benefits:

Torsion Bars for the T-34

A blog about World War II era archive documents, primarily dealing with armoured warfare.

www.tankarchives.com

 

[bf109xxl]

It does seem like the T-34M project was largely a clean sheet design, retaining very little from the T-34, perhaps suggesting that the name was more a "marketing" thing rather than the minimum changes required for switching to torsion bars and a bigger turret.

The customers (military) and developers themselves persisted in calling it a "major modernization", but I'm probably more in agreement with your opinion.

Just eyeballing from the picture I provided. Admittedly the wider turret on the T-43 might be deceiving the eye.

I used data from the most comprehensive book (in my opinion, of course) on this topic:

A Soviet note suggesting that switching to torsion bars would increase internal volume by 20% and reduce suspension weight by 300-400kg, among other benefits:

That was the customer's estimation. But the military wanted to strengthen the armor, as a result, the T-34M was to be much heavier than the T-34, for example, the track width was supposed to be reduced from 550 to 450 mm. The problem was the V-5 engine, which was never mastered in mass production, although it could have been produced with the V-2. Kolomiets considers the main problem to be the insufficient capacity of the equipment required for production - in particular, the presses for stamping the turrets.

 

[Shortround6]

So basically (based on the internet) they changed.
The track (narrower)
The number of roadwheels (6)
the Suspension (torsion bars)
The engine (higher powered version or different?)
The transmission (6 speed?)
The shape of the hull just about everywhere.
The size and shape of the turret.
The number of crew.
The amount of the fuel.

They kept
The main gun.
The two machine guns.
The radio?

Yep, it looks like just a modified T-34 to me

 

[z42]

In their defense though, changing from Christie to torsion bars is quite a major change to the hull, and even if you keep the same basic layout most of the hull plates are probably going to be somewhat different in shape. And similarly a new bigger turret is, well, a new and bigger turret. Presumably also requiring a bigger turret ring, more powerful electric/hydraulic(?) motor for rotating it etc.

Though I guess they could have retained more of the equipment. Tracks, roadwheels, engine, transmission, they could have kept all these I suppose.

 

[Elan Vital]

There were two iterations of the T-34M in 1941, the version that bf109xxl posted which was the latest one considered for production, and an earlier one which was more extensive and was rejected as a result (and due to design flaws).

The T-34M was picked up again in a different form 1942 and grew into the early T-43.

Even if it was cancelled, the T-34M did feed the T-34 production program as improved items like the wheels, gearbox and air filters were put into production.

 

[bf109xxl]

Even if it was cancelled, the T-34M did feed the T-34 production program as improved items like the wheels, gearbox and air filters were put into production.

This is a fundamentally misconception. All the listed improvements of the T-34 were made completely independently of the development of the T-34M, which can be confirmed by documents (references to them can be found in the book by Kolomiets). Moreover, according to Kolomiets, the development of the T-34M delayed the introduction of these innovations on the T-34 by a few months.

 

[yosimitesam]

Attached is an interesting article about the U.S. development history of torsion bars. It's from the March-April 2002 issue of ARMOR magazine. The title in the article is:
"The Origins of Torsion Bar Tank Suspensions"
"Did the U.S. just copy a German design?"

It's a 3-page PDF from the magazine. Interesting reading.