M3 Grant and M4 Sherman Family of Vehicles

[tomo pauk]

Grant with 3in 'stead of 75mm, 37 mm replaced with .50in. Surprise for Germans in 1942?

The 75mm was a better gun for infantry support and that was the primary purpose of US tanks.  US Armoured Doctrine had it that the job of tank hunting was that of the Tank Destroyers.  Tanks were to support infantry.

The flaw within the doctrine lays in assuming that enemy tanks will always encounter the tank destroyers first. That's called whishful thinking.

Good as it was, 75mm was getting replaced by 3in anyway by 1944.
M3 medium was used by Commonwelth forces & Soviets, too. I guess those would've like extra penetration & hit probability vs. what Germans were fielding from 1942.

[dy031101]

My scenarioes involving the M3 Medium are always like "forced into being substitute for M4 Sherman again" though  .

[dy031101]

HVSS is known for occupying less internal space and being easier to access for maintanence...... what is the closest equivalent within the rest of the Allies?  What is the closest equivalent within the Axis forces?

("Closest equivalents" in case there is no comparable schemes.)

[sotoolslinger]

Basically the Horstman and Christie are the most similar.

[jcf]

HVSS is known for occupying less internal space and being easier to access for maintanence...... what is the closest equivalent within the rest of the Allies?  What is the closest equivalent within the Axis forces?

("Closest equivalents" in case there is no comparable schemes.)

The US VVSS and HVSS are both examples of externally mounted suspension systems, which were common from the earliest
days of tank design. It was also the predominant style of suspension until the advent of internally mounted Christie-type and
torsion bar suspensions.

The Vickers Slow-motion suspension is one Brit example. Italian, French and Japanese tanks
used varying types of externally mounted suspension.

[sotoolslinger]

My bad. I always thought the Christie was an external design. I just went back and reread to discover that the spring arms are internally mounted.

[dy031101]

The US VVSS and HVSS are both examples of externally mounted suspension systems, which were common from the earliest
days of tank design. It was also the predominant style of suspension until the advent of internally mounted Christie-type and
torsion bar suspensions.

Is the leaf spring suspension as used by the Panzer IV an internally or externally mounted scheme?

[rickshaw]

Grant with 3in 'stead of 75mm, 37 mm replaced with .50in. Surprise for Germans in 1942?

The 75mm was a better gun for infantry support and that was the primary purpose of US tanks.  US Armoured Doctrine had it that the job of tank hunting was that of the Tank Destroyers.  Tanks were to support infantry.

The flaw within the doctrine lays in assuming that enemy tanks will always encounter the tank destroyers first. That's called whishful thinking.

Of course it was.  However, the US Army still designed and ordered vehicles to fulfil that doctrinal belief.

While it may have sounded silly, it was actually very similar to the doctrines utilised by the other combatants.  The British had their Infantry tank - Cruiser tank divide, the Soviets their Cavalry - "break through" tank - medium tank divide, the Germans started the war with an infantry/heavy tank - tank - Cavalry divide and ended up with Assault Gun - Tank Destroyer - Tank divide which was ignored by the end.

Good as it was, 75mm was getting replaced by 3in anyway by 1944.

But that is four years after the development of the M3 Medium Tank and even then, the 75mm armed Sherman was still predominate.

M3 medium was used by Commonwelth forces & Soviets, too. I guess those would've like extra penetration & hit probability vs. what Germans were fielding from 1942.

The Soviets definitely but for most of the Commonwealth forces, the main role of the tank was still actually infantry support and there the 75mm was sufficient.

[rickshaw]

My scenarioes involving the M3 Medium are always like "forced into being substitute for M4 Sherman again" though  .

Which it was capable of - as long as it did not encounter the more powerful versions of the Panzer III and IV or a Panther or Tiger.   Against the Italians and Japanese it was more than adequate.

[rickshaw]

HVSS is known for occupying less internal space and being easier to access for maintanence...... what is the closest equivalent within the rest of the Allies?  What is the closest equivalent within the Axis forces?

("Closest equivalents" in case there is no comparable schemes.)

For most, I'd suggest the various variations on the leaf-spring suspension which was utilised on many early tanks.   For more advanced suspensions, I'd suggest the Horstman system.  Another is the Belleville system used by the Japanese mediums and the various proposed (but never built) E series of Panzers.   The German system is the closest with individual suspension elements attached externally and able to be removed independently.   The Horstman and its variation the "slow-mo" Vickers system are a bit more complex.

The torsion bar and Christie suspension systems don't qualify as they were all internally mounted inside the hull.

[dy031101]

Which it was capable of - as long as it did not encounter the more powerful versions of the Panzer III and IV or a Panther or Tiger.

Which is why I'm thinking of either putting a 6-pounder in the turret (new/adopted design or modified originals) or putting a higher-velocity gun in the sponson to keep them serviceable.  Of course, that's with the understanding that the Panther or Tigers would be pushing it for tanks with just 6-pounder or US 76mm for an AT gun but not the level of armour protection sported by infantry tanks......  

[Joe C-P]

I had a couple other ideas, an M-4 upgunned, and an infantry support M-3.



The M-3 has a heavy MG in the turret, and a howitzer in the sponson. No hull MG.
The M-4 has a long-barrel 76mm, with a turreted light MG above and a short-barreled 35mm cannon in the hull.

[rickshaw]

Which it was capable of - as long as it did not encounter the more powerful versions of the Panzer III and IV or a Panther or Tiger.

Which is why I'm thinking of either putting a 6-pounder in the turret (new/adopted design or modified originals) or putting a higher-velocity gun in the sponson to keep them serviceable.  Of course, that's with the understanding that the Panther or Tigers would be pushing it for tanks with just 6-pounder or US 76mm for an AT gun but not the level of armour protection sported by infantry tanks......  

The 6 Pdr was actually pretty good for its calibre.  The first Tiger which the British encountered in Tunisia was knocked out by one...

[rickshaw]

My alternative armament proposals for the Grant/Lee, I've been toying some time with putting duel 6 Pdrs with autoloaders in the hull along the centreline, at the roof line and reducing the turret on top to something smaller with either twin MMGs or a single HMG and a stereoscopic rangefinder and moved to over where the sponson is now.

The M3 medium, despite being called a "tank" was really more an SP Gun, with its limited traverse main weapon, this would simply build on the idea and carry it to its full conclusion.  The traverse would be limited to about 22.5 degrees either side of the centre.  The gunner would be seated on the right, the driver on the left.  A cleft turret would allow the guns to depress allowing the tank to take up proper hull down positions - something the M3 couldn't.   The use of a stereoscopic rangefinder would confer greater accuracy at longer ranges.



Then, we have as an alternative the M3 Grant/Lee APC.  Enlarged side doors, a MMG armed turret. Steps to allow the grunts to climb in and out safely.   Such a vehicle would be able to carry 10 men easily.

[tomo pauk]

Good idea about that APC.

As for doctrine (rickshaw wrote):

Of course it was.  However, the US Army still designed and ordered vehicles to fulfil that doctrinal belief

Then why going with 37mm armament for M3 medium & M3 light? Either the doctrine was not such (ie. no anti-tank work for tanks), or they were building stuff that didn't went along the doctrine 

The other countries did make 'categories', tasks, but within tank arm itself.