Tank & AFV armament alternatives, 1935-45

[Jabberwocky]

The British were on the Path at least as well as anybody else. Then they went off the path and fell in the canal.

I get the feeling this was partially a result of the shuffling round of responsibility & oversight for British tank design in the 1936 to late 1941 period, plus the spreading around tank design/development efforts too much.

You had Nuffield, Vickers, Leyland, Harland & Wolf, Morris, Vauxhaul, Birmingham Railway, LMS Railway (and maybe a couple others as well) all involved in tank design up to 1942. It wasn't until the formation of the Tank Board in 1940 and then the introduction of the Directorate of Tank Design in 1941 that things started to get better.

Yes, you still ended up with run of the mill designs (Cromwell) and some outright poor designs (Challenger and Comet come to mind), but you also see a much better design-test-re-design cycle.

 

[z42]

Yes, you still ended up with run of the mill designs (Cromwell) and some outright poor designs (Challenger and Comet come to mind), but you also see a much better design-test-re-design cycle.

Hmm, what's so bad about the Comet? IMHO British tank design started to hit its stride with the Cromwell, which was ok-ish. Could have traded some of that speed for more armor though. Comet was basically Cromwell done right, with more armor and a better gun. And then leading to the Centurion, arguably the best all-round tank of its era.

That's the tragic irony of it, after muddling through the war with mostly sub-par (or worse) tanks, they then go on to design the best general purpose tank in the world, just in time to miss the war.

 

[bf109xxl]

Soviets don't have much in production, they skip over the sweet spots with the T-28 (way to big/complicated) and the BT-7 and T-26 good guns but 3 man crews have problems.

The Soviets developed the T-50 - the best light tank in 1941 (and maybe during the entire war) which was in production and should be produced in much greater numbers than the T-34. It was far better than any Soviet wartime improvisations, such as the T-70 and any Allied light tank. In this discussion, the existence of the T-50 is persistently ignored, even though it was the tank that was to become the Soviets' main tank.

The Early T-34s in 1940 have poor vision, poor radios (those that had them), had the BMG but that is were the 4th man was, not helping with the main gun which was the tanks reason for being.

In the hands of experienced crews, even the early T-34 with all its shortcomings was unequivocally more optimal in 1941 (excluding the T-50). Unfortunately, the Soviets could not ensure its adequate development during the war (in mass series) due to numerous technological problems. And huge losses due to non-technical reasons conceal the true effectiveness of the T-34 in the initial period of the war. The Soviets developed the most adequate tank design concept, but abominably realized it due to low technological level. All others had a much higher technological level, but conceptually created less suitable design, which was either too complicated to be produced in sufficient numbers or had insufficient characteristics / numerous flaws, etc.

Just slinging in a bigger gun doesn't solve any of these problems. Look at the early T-34s in Russia. They had stuffed 76mm guns in a turret designed for a 45mm gun. Yes they had the 76mm guns but they had a very bad rate of fire. 5 rpm on a test range? 2-3 rpm in actual combat?

Considering that no one could hit any target from a moving tank (perhaps with the exception of the Panther), this rate of fire on the battlefield was not a problem. The problem was to locate the target - the commander was distracted by cannon handling, and the quality of the observation equipment has already been mentioned.
I am not surprised at the persistence with which this discussion ignores the simple fact that the tank should not have been primarily designed to fight against its own kind - it is a common mistake. This - fighting against its own kind as primary combat role - was rather a specific feature of German tanks which were used in the second half of the war mainly as anti-tank self-propelled guns. But for the Soviets, and indeed for the Allies, this was not the primary combat role for tanks.

Summarizing: everybody needed the T-54 already in 1939 - with a better transmission and crew compartment isolation.

 

[yulzari]

Yes, you still ended up with run of the mill designs (Cromwell) and some outright poor designs (Challenger and Comet come to mind), but you also see a much better design-test-re-design cycle.

The Challenger was not a poor tank. Not wonderful but an excellent support for Cromwells and easier to fight than a Firefly not to mention having similar maintenance systems to the Cromwells, being a stretched Cromwell.

I admit that the Charioteer suggests that they could have simply used normal Cromwells adapted to a new turret as the Charioteer took the 20 Pounder and was tested successfully with the same 105mm L7 gun as is going into the new USA support tank today. Before anyone says so, yes, I am aware that the Charioteer was classed as a self propelled anti tank vehicle not a tank given the thin turret armour.

 

[Elan Vital]

The Soviets developed the T-50 - the best light tank in 1941 (and maybe during the entire war) which was in production and should be produced in much greater numbers than the T-34. It was far better than any Soviet wartime improvisations, such as the T-70 and any Allied light tank. In this discussion, the existence of the T-50 is persistently ignored, even though it was the tank that was to become the Soviets' main tank.

What about the American M24 in 1945? It mounts a 75mm gun in a 3-man turret, although it is arguably less efficient automotively and less well armored.

T-50 absolutely is the best light "Infantry support" tank however.

 

[bf109xxl]

What about the American M24 in 1945? It mounts a 75mm gun in a 3-man turret, although it is arguably less efficient automotively and less well armored.

The T-50 had plenty of reserves for modernization - perhaps other than installing a more powerful gun (thus, the T-34 was indeed more optimal solution despite of all its shortcomings!). It is hard to say what it would have been by 1945. The M24 had weaker armor, otherwise it may have been undoubtedly better than the T-50. Still, the difference of 4 years of war had a big impact.

It seems that the most important thing was to correctly determine the size, weight and layout of the [medium] tank. The rest could already be adjusted to them. In case of unsuccessful choice of size/weight/layout, no technical measures led to the optimum. In my humble opinion, the Soviets did it best. But, I repeat, the concept alone did not make the tank perfect or the best - low technological level could spoil even the best concept.

 

[Shortround6]

The Challenger was not a poor tank. Not wonderful but an excellent support for Cromwells and easier to fight than a Firefly not to mention having similar maintenance systems to the Cromwells, being a stretched Cromwell.

It certainly was not a good tank. It was an OK tank. Yes it may have been better than the bodged together Firefly. They still hadn't come up with cupola for the commander. There was no stowage for ammo in the turret (?), there was in the turret basket. A number of rounds were stowed sort of behind where the bow gunner would have sat, had there been a bow gunner. How much this stowage intruded into that area I don't know. This may have been the idea for the 2nd loader (?), getting the ammo from stowage up to where the primary loaded stood? Armor was thinner than the Cromwell. Just 40mm on the turret side and that was plumb vertical. Rate of fire was???

I admit that the Charioteer suggests that they could have simply used normal Cromwells adapted to a new turret as the Charioteer took the 20 Pounder and was tested successfully with the same 105mm L7 gun as is going into the new USA support tank today. Before anyone says so, yes, I am aware that the Charioteer was classed as a self propelled anti tank vehicle not a tank given the thin turret armour.

Charioteer had a few other issues aside from thin armor. One was the 25 rounds of main gun ammo. Another was that it didn't often operate as a "tank". Originally designed for a 3 man crew, commander/gunner, loader/radio operator, driver. A 4th man was added who rode in the bow gunners seat. In action the commander dismounted to observer the fall of shot and correct aim and the 4th man got from his seat on the left front of the hull to the gunner position in right side of the turret.
I don't know if the commander dismounted because of the muzzle blast kicking up too much dust, dirt, debris and smoke or if the tank moved under recoil enough to keep the gunner looking through his sight to observe the fall of the shot. It seems that the much heavier Centurion did not have that problem

edit: A Centurian had + 20, -10 degrees of elevation. The Charioteer had +10,-5 degrees according to one source. Other sources may differ?

Yes the 17pdr kicks a lot less and probably would not have that problem. On a standard Cromwell hull you are going to have an ammo storage problem though.

 

[Frog]

It certainly was not a good tank. It was an OK tank. Yes it may have been better than the bodged together Firefly. They still hadn't come up with cupola for the commander. There was no stowage for ammo in the turret (?), there was in the turret basket. A number of rounds were stowed sort of behind where the bow gunner would have sat, had there been a bow gunner. How much this stowage intruded into that area I don't know. This may have been the idea for the 2nd loader (?), getting the ammo from stowage up to where the primary loaded stood? Armor was thinner than the Cromwell. Just 40mm on the turret side and that was plumb vertical. Rate of fire was???

Charioteer had a few other issues aside from thin armor. One was the 25 rounds of main gun ammo. Another was that it didn't often operate as a "tank". Originally designed for a 3 man crew, commander/gunner, loader/radio operator, driver a 4th man was added who rode in the bow gunners seat. In action the commander dismounted to observer the fall of shot and correct aim and the 4th man got from his seat on the left front of the hull to the gunner position in right side of the turret.
I don't know if the commander dismounted because of the muzzle blast kicking up too much dust, dirt, debris and smoke or if the tank moved under recoil enough to keep the gunner looking through his sight to observe the fall of the shot. It seems that the much heavier Centurion did not have that problem

Yes the 17pdr kicks a lot less and probably would not have that problem. On a standard Cromwell hull you are going to have an ammo storage problem though.

By some historical irony, the first tank that a Centurion destroyed in Korea was its forerunner, a Cromwell captured by the Chinese.

 

[Elan Vital]

The job of the French tank gun (as it was the case with other people's tank guns) of 47mm was to outperform the armor protection of the enemy tanks. In that, it was more than suitable for the job.
It was also better than the 37-40mm guns of the day wrt. the HE performance.

True but the French 47mm had very little stretch. Most other tanks didn't have much stretch either. Higher velocity guns are easier to hit with at 600-1000 meters range. Remember that the projectile will drop 16ft (4.88 m) in it's first second of flight. yes you set up the gun so it hits a little high in the first 200-400meters so you can still hit in the last parts of the 1st second or even the first 1/10 or 2nd tenth of the 2nd second of flight. The projectile will fall 48ft (14.63m) in the 2nd second of flight.
French were also loading 37mm guns of differing abilities in a lot more tanks per month than they were loading 47mm guns into. They were certainly using more of the HV (700ms) 37mm guns in the last few months though.

I think the tank "powerful 37mm" (the SA38, powerful being one of the designations for it) and tank 47 are best assessed within their very particular use-cases, e.g employment in quite small 1-man turrets with emphasis on short ammunition and thus low overall power to be remotely easy to handle. With the 37 being constrained to boot by the requirement to fit the existing APX-R turret with minimal modifications (mask change pretty much). When that restriction could be lifted, you could fit bigger in a modified (Romanian 45mm conversion) or new (second generation French light tank turrets with the 47mm tank gun), even within the same turret ring (or rather same standard hull roof opening which the 2nd gen light tank turrets could fit).

Once you allow 2 or 3-man turrets, it becomes much easier to accomodate a more powerful gun from day one.

Admittedly, the merits of the tank 47mm were still well exploited: the Czech LT vz.35 and 38 also started with 1-man turrets in Czech service, with apparently somewhat larger turret rings, but only had 37mm guns below 800 m/s. While the analogous Italian 47mm L32 used much more dated uncapped APHE and was mounted on larger 2-man turrets which could otherwise probably have used something more powerful, as indicated by the use of the 47 L40 in the M15.

I do believe however that all these sub 700 m/s 47 and sub-800 m/s 37 with sometimes uncapped/APHE ammo were only acceptable precisely because a lot of tank building nations used excessively light armour even when more was possible or could have been designed for while keeping acceptable mobility, weight and reliability. Eg, the French tank 47 and 37 would have become really limited had France held and fought uparmored German tanks of late 1940/41. But when one accounts for what Britain or the Germans could reasonably have designed in the late 30s*, it is a stroke of luck that these guns found a favourable environment.

*And it is also why the sometimes touted merits of "heavy armor and powerful guns" of French tanks were highly circumstancial. In another world, the compromises they made would have been even less warranted.

 

[tomo pauk]

I do believe however that all these sub 700 m/s 47 and sub-800 m/s 37 with sometimes uncapped/APHE ammo were only acceptable precisely because a lot of tank building nations used excessively light armour even when more was possible or could have been designed for while keeping acceptable mobility, weight and reliability. Eg, the French tank 47 and 37 would have become really limited had France held and fought uparmored German tanks of late 1940/41. But when one accounts for what Britain or the Germans could reasonably have designed in the late 30s*, it is a stroke of luck that these guns found a favourable environment.

I'd say that it might be reasonable to expect that French, had they survived in a good shape by spring/summer of 1941, would've been introducing the better ammo for their guns, as well as the better guns. It is not a long shot that the spin-off of the 47mm ATG would've found it's place on the tanks and/or other AFVs. There are still the towed 47mm ATGs for the Germans to take into account, as well as the 75mm guns turned into AT guns.
France surviving into 1941 also means the 6pdr is available for the British.

There is also a question of how many Pz-IIIs and -IVs would've Germans had for Spring/Summer of 1941 if the high-intensity combat went through the 2nd half of 1940 and into 1941.

 

[Elan Vital]

I'd say that it might be reasonable to expect that French, had they survived in a good shape by spring/summer of 1941, would've been introducing the better ammo for their guns, as well as the better guns. It is not a long shot that the spin-off of the 47mm ATG would've found it's place on the tanks and/or other AFVs. There are still the towed 47mm ATGs for the Germans to take into account, as well as the 75mm guns turned into AT guns.
France surviving into 1941 also means the 6pdr is available for the British.

There is also a question of how many Pz-IIIs and -IVs would've Germans had for Spring/Summer of 1941 if the high-intensity combat went through the 2nd half of 1940 and into 1941.

It is true, though in the case of the tank-mounted long 47, I remain unsure how long it would have taken the French to notice the urgency (sufficient number of uparmored tanks encountered) and to implement it. While it can be reasonably rushed in 1941 on the Somua (see IRL FCM concept in 1942) and Char B family (apply B40 setup on B1 Ter to minimize deployment time and risk*), even the future light tanks are a fundamental difficulty. If it only followed the intended schedule, you would only see it in early 1942 on the battle tank.

Back in 1938, the tank 47 was expected to benefit from research on 37mm ammo. Maybe the documents I am going to see in January(pertaining to ammunition and ballistic research) will tell more. Strictly speaking, French guns usually ran on 240 MPa pressure so there is room for a hot loading while retaining acceptable barrel lives. But projectile side, I'm not sure how much they can improve on an APC with already modern shape and materials (BC will not help as the potential penetration distance is very short) if they were looking at full caliber solutions (APCR and APDS were not the go-to solutions at the time in the French army).

*Or 75mm turret as per late B40

 

[tomo pauk]

It is true, though in the case of the tank-mounted long 47, I remain unsure how long it would have taken the French to notice the urgency (sufficient number of uparmored tanks encountered) and to implement it. While it can be reasonably rushed in 1941 on the Somua (see IRL FCM concept in 1942) and Char B family (apply B40 setup on B1 Ter to minimize deployment time and risk), even the future light tanks are a fundamental difficulty.

French can play it safe: seen that both them and the British are fielding the very well armored tanks, it is only to be expected that Germans will up the armor protection of their stuff. Germans might've done that already in 1940, seeing that their tanks are vulnerable basically to anything with "AT" suffix in the Entente arsenal.

Back in 1938, the tank 47 was expected to benefit from research on 37mm ammo. Maybe the documents I am going to see in January(pertaining to ammunition and ballistic research) will tell more. Strictly speaking, French guns usually ran on 240 MPa pressure so there is room for a hot loading while retaining acceptable barrel lives. But projectile side, I'm not sure how much they can improve on an APC with already modern shape and materials (BC will not help as the potential penetration distance is very short) if they were looking at full caliber solutions (APCR and APDS were not the go-to solutions at the time in the French army).

The APCR-ish ammo was developed for the short 37mm already by 1935 (at least the ammo was called Mlle 1935), and was, for example, exported to Poland.
Brandt company was working with the APDS ammo before France fell, ditto with the squeeze-bore stuff.

Experimenting with the hotter loading for all the guns involved should've been a really low-hanging fruit.

 

[EwenS]

It certainly was not a good tank. It was an OK tank. Yes it may have been better than the bodged together Firefly. They still hadn't come up with cupola for the commander. There was no stowage for ammo in the turret (?), there was in the turret basket. A number of rounds were stowed sort of behind where the bow gunner would have sat, had there been a bow gunner. How much this stowage intruded into that area I don't know. This may have been the idea for the 2nd loader (?), getting the ammo from stowage up to where the primary loaded stood? Armor was thinner than the Cromwell. Just 40mm on the turret side and that was plumb vertical. Rate of fire was???

Why is having no ammunition in the turret a bad idea for Challenger? It was considered an improvement in the Sherman.

Look at the Sherman. Initial ammunition stowage. Initial "dry storage" layout.

https://www.theshermantank.com/wp-content/uploads/M4A4-small-hatch-storage-1.png

They quickly found that stowage above track level was vulnerable to AT guns and had to weld additional armour to the hull exterior to protect it. The above track ammo storage was the main cause of early Sherman losses, not petrol fires. Kits were manufactured to retrofit to earlier production vehicles.

Then we have Sherman Gen 2 produced from the early 1944.
"The real big change in Sherman storage came when the hull changed from the small hatch to large hatch configuration, though all the late model M4A2 tanks with large hatch hulls and 75mm turrets still got the dry ammo storage setup with add-on sponson armor [all bar about 200 of these for the USMC went as Lend Lease to the USSR] The other exceptions are the M4 and M4A3 105 tanks, they had their on dry storage setup. [meant to be support tanks] The M4 Composite hull tanks with large hatch hulls also kept the dry storage layout [production of these only ran Aug 1943 to Jan 1944 with 1,976 produced]. So, the M4A1 (76)W, M4A2 (76)W, the M4A3(75)W, The M4A3 (76)W tanks all had the improved wet ammo racks. This change included moving all main gun ammo into the floor of the hull under the turret. These ammo racks were also surrounded by water filled jackets. Early production wet tanks retained the turret basket, and had hatches that could be opened to access the hull ammo racks, later they only installed a half basket, and eventually removed the basket floor entirely."

Ammo Storage | The Sherman Tank Site

www.theshermantank.com

A30 Challenger had stowage for 48 rounds. Only 2 rounds were stowed horizontally above track level (just behind driver's position). 4x3 rounds around turret basket stowed vertically. 3 rounds left side rear of fighting compartment stowed vertically. 18 rounds stowed horizontally next to driver. 6 rounds stowed vertically between driver & 18 round bin. 5 rounds stowed vertically on lhs of fighting compartment behind bin and a final 2 under the gun breech.

Extracting some of the rounds was difficult, just as it was in the later Shermans. Trials of an early vehicle showed about 6rpm was possible.

Unlike most tanks where the turret sat on a ring on the upper hull, Challengers turret was supported from beneath by a heavy basket that sat on a ball bearing arrangement on the vehicle floor. There was then a series of guides around upper part of the basket to keep it in place. So there was no room under the turret in Challenger to stow ammunition.

As for its turret armour in early vehicles the turret front was 63mm with the rest being 40mm. BUT from vehicle 41 (of the 200 produced) the front turret plate was increased to 102mm (July 1944 production onwards). Then from Nov 1944 (around vehicle 110) Challenger was produced with an applique armour kit fitted. This increased the thickness of the turret front side plates, driver's visor plate and turret box front plate to approx 89mm and the nose plate to 82.5mm (sloped at 20 degrees). An additional 10mm was welded to the turret box bottom plate increasing it to 18mm.

 

[SaparotRob]

I never even heard of the T-50 before. I guess it wasn't involved in any fleet actions.