Alternative History Armoured Fighting Vehicles Part 4

[9 Fanged Hummingbird]

Now I've got a bit of a thought experiment for a scenario I've been pondering over, and I was hoping I'd get input from this thread since there's definitely a lot people who know tank mechanics better than I do. So let's say there's an ATL with a slightly more stable and significantly more interventionist and militarized Mexico in the 1930's. With WW2 looming on the horizon (as IOTL, Mexico was a major supporter of the Spanish Republic) and potential conflict brewing in Central or South America, Mexico looks to develop their heretofore neglected armored force. As IOTL, they buy from Marmon-Herrington, first the CTLS (Combat Tank Light Series) tankette in 1936 and later the CTMS (Medium Series) light tank. They might also exceed IOTL and buy the MTLS.

Here's where the thought experiment comes into play. If any of you have heard of these tanks, you've probably also heard they weren't very good. ITTL Mexico buys them anyway because they're still better than no tanks (or leftover Salinas tanks from 1917), and because I'm assuming they've got a great deal with Marmon-Herrington where they can not only buy cheap tanks but a license to produce them at home as well as getting the (probably much more effective) Marmon-Herrington armored cars. IOTL Mexico (and other Latin American countries) did use them into the 1950's, but that probably had a lot to do with seeing no real action.

What I want to know here is how you guys would go about improving these tanks or, better yet, creating a new tank based on the experience from building these. Specifically I'm looking at a medium tank that you could extrapolate from this platform. It doesn't necessarily need to be something that would be mass-produced, just something that would be built by Mexico to, if nothing else, give their industry and engineers more experience a la the Canadian and Australian Ram and Sentinel tanks, although being produced in decent numbers would be a great plus.

 

[cortz#9]

Now I've got a bit of a thought experiment for a scenario I've been pondering over, and I was hoping I'd get input from this thread since there's definitely a lot people who know tank mechanics better than I do. So let's say there's an ATL with a slightly more stable and significantly more interventionist and militarized Mexico in the 1930's. With WW2 looming on the horizon (as IOTL, Mexico was a major supporter of the Spanish Republic) and potential conflict brewing in Central or South America, Mexico looks to develop their heretofore neglected armored force. As IOTL, they buy from Marmon-Herrington, first the CTLS (Combat Tank Light Series) tankette in 1936 and later the CTMS (Medium Series) light tank. They might also exceed IOTL and buy the MTLS.

Here's where the thought experiment comes into play. If any of you have heard of these tanks, you've probably also heard they weren't very good. ITTL Mexico buys them anyway because they're still better than no tanks (or leftover Salinas tanks from 1917), and because I'm assuming they've got a great deal with Marmon-Herrington where they can not only buy cheap tanks but a license to produce them at home as well as getting the (probably much more effective) Marmon-Herrington armored cars. IOTL Mexico (and other Latin American countries) did use them into the 1950's, but that probably had a lot to do with seeing no real action.

What I want to know here is how you guys would go about improving these tanks or, better yet, creating a new tank based on the experience from building these. Specifically I'm looking at a medium tank that you could extrapolate from this platform. It doesn't necessarily need to be something that would be mass-produced, just something that would be built by Mexico to, if nothing else, give their industry and engineers more experience a la the Canadian and Australian Ram and Sentinel tanks, although being produced in decent numbers would be a great plus.

The first thing that popped into my mind is to remove the turret and mount a larger gun ala Marder, Panzerjager or Sig. 33 for a light TD or SPG.
A quad 50 mount would also make for a neat little SPAAG. Flamethrowers or multiple motors could be mounted as well.

Just take a look at some of the variants of the Pz.I and II for ideas.
If you can find some line drawings of model of tank you want, I'd be happy to draw something up for you or maybe we could use a pic of an M1 Combat Car slightly modified to look like a CTMS, they look similar.

 

[JWilly48519]

How much magical-ability-to-anticipate-future-ordnance-technology do you want to assume?

Mexico, I think, didn't have much ability to build state of the art high performance rifled cannon in say 1935. But if they'd understood the future, they might have built quite good performing low peak pressure but long-barreled smoothbore 75-to-85mm guns with moderate muzzle velocity to fire fin stabilized rounds using slow-burning propellant, with a single round-type comprising a HEAT charge with notched wire overwind for enhanced fragmentation.

With that moderate-cost gun mounted both on a tracked assault-gun chassis and in a front-and-sides-protected, simple rotating gun-mount on a wheeled chassis, quite a bit of combat power would be obtained at low total cost.

 

[9 Fanged Hummingbird]

The first thing that popped into my mind is to remove the turret and mount a larger gun ala Marder, Panzerjager or Sig. 33 for a light TD or SPG.
A quad 50 mount would also make for a neat little SPAAG. Flamethrowers or multiple motors could be mounted as well.

Just take a look at some of the variants of the Pz.I and II for ideas.
If you can find some line drawings of model of tank you want, I'd be happy to draw something up for you or maybe we could use a pic of an M1 Combat Car slightly modified to look like a CTMS, they look similar.

To be honest I wasn't necessarily looking for a drawing to be made, though regardless actual line drawings seems scarce outside of one website which appears to require registration or payment or something, it is alas a rather obscure tank and those Tank Encyclopedia articles I linked earlier seem to be far and away the most detailed online sources I could find of it outside of whatever archives The Chieftain is able to go digging around in (he did a couple videos on them IIRC).

In any case, now that I think about it yanking off the turret might be the best way to go for keeping the original MH-designed vehicles usable, they seem pretty small even by light tank standards and far as I can find I think the suspension and/or transmission struggled when the MTLS put on more weight.

How much magical-ability-to-anticipate-future-ordnance-technology do you want to assume?

Mexico, I think, didn't have much ability to build state of the art high performance rifled cannon in say 1935. But if they'd understood the future, they might have built quite good performing low peak pressure but long-barreled smoothbore 75-to-85mm guns with moderate muzzle velocity to fire fin stabilized rounds using slow-burning propellant, with a single round-type comprising a HEAT charge with notched wire overwind for enhanced fragmentation.

With that moderate-cost gun mounted both on a tracked assault-gun chassis and in a front-and-sides-protected, simple rotating gun-mount on a wheeled chassis, quite a bit of combat power would be obtained at low total cost.

Little to none. I'm assuming outside of small arms most of Mexico's weapons are going to either be imported or licensed production of existing designs. Doesn't quite need to be cutting edge, but let's assume the army wants something that could be passable by early 1940's standards while also being able to be produced in-country on the off-chance they can't rely on American surplus for whatever reason.

EDIT: I mentioned before the Ram and Sentinel as comparable vehicles for what this ATL Mexico wants, a viable medium tank though where Canada and Australia used IIRC the M3 Medium as a base for those Mexico is using the Marmon-Herrington series as a starting point. Though any new tank based off them would definitely have to be quite a bit larger, the MTLS (Marmon's attempt at a medium tank) required literally the entire crew of four to enter through the turret hatch, which doesn't seem ideal. Plus the aforementioned issue with the suspension struggling to carry its modest armor.

 

[Driftless]

Wasn't the biggest knock on M-H tanks being engine reliability? Cut back on weight could help some there. How about an APC? Have Rafeal Mendoza work up a belt fed upgrade based on his well regarded LMG, to serve as onboard firepower. The physical environments of Mexico and Central America range from desert, to jungle, to grassy plains, to coastal scrub, to snow-capped mountain ranges. A go-anywhere vehicle would be useful

 

[La Rouge Beret]

As someone that is writing a TL focused on Mexico in WW 2 (albeit very, very slowly); I am very interested in how this alt M-H tank evolution will unfold. Could it also be used as an APC or even as a mortar carrier or as an artillery tractor?

 

[Driftless]

As someone that is writing a TL focused on Mexico in WW 2 (albeit very, very slowly); I am very interested in how this alt M-H tank evolution will unfold. Could it also be used as an APC or even as a mortar carrier or as an artillery tractor?

A few years ago, I did some reading on the Mexican Revolution and the subsequent indirectly related Panco Villa Expedition by the US, led by Gen John Pershing.

Villa's force had been absolutely decimated in a series of engagements in the spring of 1915, most notably Celayo, facing the skilled General Alvero Obregon. Obregon employed modern(for the time) European tactics: local trenches, extensive barbed wire laid in patterns to funnel Villa's cavalry into narrow killing zones, machine guns, and carefully placed artillery to fire in a coordinated fashion.

A more outwardly military active Mexico might build on those lessons learned. Motorization, armor, and mobile artillery could be routes that they might choose

 

[cortz#9]

As someone that is writing a TL focused on Mexico in WW 2 (albeit very, very slowly); I am very interested in how this alt M-H tank evolution will unfold. Could it also be used as an APC or even as a mortar carrier or as an artillery tractor?

An APC and mortar carrier sure, an APC also doable but it wouldn't be able to carry more than four loaded out soldiers IMO.

 

[JWilly48519]

Who will Mexico fight? Assuming it's not USA, what armaments will they have? Who will be on offense?

The offensive side needs reliable mobility, and armor sufficient to withstand whatever AT capability the other side has. Anything from M-H might be able to provide one or the other, but not likely both.

The defensive side of course might benefit from those characteristics too, if the defender has widely separated points of value and the attacker has route-options.

A defender that knows the attacker is limited to a single route can defend quite effectively against an attacker equipped with MG-armed APCs, using nothing more than otherwise-quite-obsolete FT17s armed with 37mm guns with updated AP, or the casemate model with the short 75mm. Road mobility for those tank assets can be provided by cheap 4x6 trucks with loading ramps.

 

[9 Fanged Hummingbird]

A more outwardly military active Mexico might build on those lessons learned. Motorization, armor, and mobile artillery could be routes that they might choose

Incidentally this started to happen IOTL to some extent, Mexico was the first non-European country to design and build their own tank in 1917, beating even the USA to the punch. However, only one or two vehicles were built as by then there wasn't much use for them. It was armed with a 37mm Hotchkiss Revolving Cannon by the way, Mexico had tons of those lying around and used them plenty during the Revolution.

Who will Mexico fight? Assuming it's not USA, what armaments will they have? Who will be on offense?

By the time WW2 starts Mexico takes a very pro-Allied neutrality and is readying their armed forces for the possibility of expeditionary warfare in support of the Allied Powers. There is also consideration of a possibility of having to intervene in Central or South America (such as an expanded Ecuador-Peru War), but this is more of a remote secondary concern by Mexican military planners in this scenario.

Looking forward through a crystal ball, the main theater of combat for Mexican forces would probably be supporting the US liberation of the Philippines, though they could also send a force to Italy as well in the same vein as the Brazilian Expeditionary Forces. However assume the army's engineers don't have this future knowledge. There's also an ATL thought of butterflies causing Spain to join the war on the Axis side for whatever reason, in which case Mexico would definitely be interested in restoring the Spanish Republican government (which as IOTL they were still hosting them in exile) to power as long as the USA could give them at least some logistical assistance.

As for the vehicles themselves, while they technically came in a variety of sizes, the biggest of the lot (the so-called Medium Tank) was still relatively small compared to contemporary vehicles and one of the main complaints was poor handling as a result of cramped space inside the tank. Mexican tankers likely being generally smaller than their American counterparts could help explain why they kept them in service well into the 1950's whereas the Americans outright called the vehicles unfit for service, but any future developments would probably necessitate building something larger that can support not just a bigger turret but also carry more armor. Another problem seems to be the engine, seems underpowered based on reports. I could see the CTVL being used as a tractor, but it might be necessary to swap out the engine.

EDIT: To reiterate, it's likely they might end up getting surplus tanks from the USA anyways in the above scenario, but the challenge is to come up with an economic but still passably decent fallback option using as a base or source of design inspiration a tank commonly described as "worst of all time".

 

[CaptainCalvert]

As someone that is writing a TL focused on Mexico in WW 2 (albeit very, very slowly); I am very interested in how this alt M-H tank evolution will unfold. Could it also be used as an APC or even as a mortar carrier or as an artillery tractor?

The Vickers 6e was a tank (twin turreted and single turreted), and with minimal adaptation became the Dragon gun tractor,/general carrier and the Birch gun DP SPAA/SPG, and had a 2pounder pompom version used in Siam/Thailand.
That says you can do pretty much anything with your base tank if you can find a reason for doing it. They might not all work, but some will

 

[CaptainCalvert]

Wasn't the biggest knock on M-H tanks being engine reliability? Cut back on weight could help some there. How about an APC? Have Rafeal Mendoza work up a belt fed upgrade based on his well regarded LMG, to serve as onboard firepower. The physical environments of Mexico and Central America range from desert, to jungle, to grassy plains, to coastal scrub, to snow-capped mountain ranges. A go-anywhere vehicle would be useful

I'm guessing a Churchill would be cheating, even though it can go most places.
I was thinking that something like a Panzer 2 would fit the bill - light, fast mobile, wiith the 20mm providing OK anti armour capability and useful short bursts of HE and enough armour to cope with most ordinary rifles and MGs.
The Vickers lights were built for this kind of terrain, but the armour is a bit thin and they really needed a better main gun than the Vickers 0.5" or Besa 15mm.

So maybe a Vickers light suspension, Panzer2 armour, engine and weapons.

 

[Bougnas]

Mexico got Stuarts and Shermans during/shortly after the war so any desperate mods of existing M-H tanks or an extrapolation of it would have to be made in the timeframe 1938-1945 when they got the M-H IIRC. I would add that considering the lack of time, low number of vehicles and limited mexican industry, what they might really need is to force Marmon Herrigton itself to step up their game. M-H would end up designing the flawed but still much more progressive M22 Locust starting from late 1941 OTL, so the company wasn't all bad. The CTMS and MTLS started development in 1941 and were tested through 1943 so evidently the M22 didn't use up their entire capacity.

At a glance, beyond questionable quality of design, construction and materials which made parts too fragile, the CTMS and MTLS appear to have the following limitations/areas of improvement:
- front sprocket and thus likely front transmission with the resulting increase in height and/or clutter in the fighting compartment
- allegedly VVSS or leaf spring 2-weel bogie, only 2 per side, they were clearly not very strong on their own. At least the track is very wide, though not good
- purely bolted/riveted construction with resulting weight inefficiency, reduced armor structural integrity and other issues
- the front hull armor is stepped
- too few access hatches
- straight-6 truck engine with relatively low output per liter. At a glance the claimed 240hp engine in MTLS would be the gasoline HXE

I'd say the avenues of improvement would be to essentially move over to extrapolations of the T9/M22's base concept, eg:

- switch to welding
- reworked front hull with single sloped plate and hatches, preferably on the roof
- transmission moved to the rear, reduction in vehicle height and weight
- reworked suspension
- possibly a switch to the diesel DFXE engine if we stick with Hercules? We keep similar power but still benefit from better torque curve and reduced fuel consumption at similar size to the gasoline engine.
- reworked turret with 37mm M6 and coax MG

The priority would be to reduce weight rather than improve protection as the MTLS was too heavy for the parts and engine.

 

[Claymore]

To be honest I wasn't necessarily looking for a drawing to be made, though regardless actual line drawings seems scarce outside of one website which appears to require registration or payment or something, it is alas a rather obscure tank and those Tank Encyclopedia articles I linked earlier seem to be far and away the most detailed online sources.

Line drawings of Marmon-Herrington light tanks are always available to the worth of the AH AFV thread! I will post something tomorrow…

 

[cortz#9]

Line drawings of Marmon-Herrington light tanks are always available to the worth of the AH AFV thread! I will post something tomorrow…

Huzzah!

 

[JWilly48519]

The sensible tank for Mexico, with hindsight, would be the M3 Stuart.

it'd be the easiest to train on, for operating, commanding, maintaining and supplying, given US Army's extensive tank-related facilities and resources in Texas. Receiving the tanks would be almost trivial, via rail or truck. And, its capabilities would be a good fit with a light infantry force with no history of combined-arms operations.

I'd think any resources and time devoted to an M-H project in the end would have been wasted, once the decision was made to provide M3s. M-H AFVs were losers. Good intentions wouldn't change that.

If Mexico wanted to get started prior to availability of M3s, they'd be best served by obtaining some M2s, and following the same institutional development path as the US Army.

 

[La Rouge Beret]

The sensible tank for Mexico, with hindsight, would be the M3 Stuart.

I was thinking the same way as the Brazillians used the M 3 Stuart IIRC until the 1970s and, given the limited OPFOR the M 3 Stuart or the Vickers 6 ton would seem to be a good fit.

 

[ctayfor]

Mexico had political reasons for being a bit leery of coming to rely on the US for military hardware before WWII in full swing left them essentially the only game in town. Aside from their experience with the US from 1916, and its "Why don't we do things my way?" approach to "helping" client states (and let's face it, the US approach to most countries, apart from the Great Powers, and especially in the Monroe Doctrine zone, in the first half of the 20th century could be classified that way), Mexico was also aware of the giant tar baby that the US military-industrial complex could be. Of course, Eisenhower hadn't coined that term, nor sounded the warning that went with it yet, but the basic awareness was there.

As far as I can tell, Marmon-Herrington was more flexible than most US companies about licensed manufacture of their vehicles (eg. the South African manufactjre of their armoured car which was subsequently exported to third countries) and may look to the Mexicans like one way to develop their own manufacturing base and less of a permanent limiting entanglement.

 

[CaptainCalvert]

Mexico had political reasons for being a bit leery of coming to rely on the US for military hardware before WWII in full swing left them essentially the only game in town. Aside from their experience with the US from 1916, and its "Why don't we do things my way?" approach to "helping" client states (and let's face it, the US approach to most countries, apart from the Great Powers, and especially in the Monroe Doctrine zone, in the first half of the 20th century could be classified that way), Mexico was also aware of the giant tar baby that the US military-industrial complex could be. Of course, Eisenhower hadn't coined that term, nor sounded the warning that went with it yet, but the basic awareness was there.

As far as I can tell, Marmon-Herrington was more flexible than most US companies about licensed manufacture of their vehicles (eg. the South African manufactjre of their armoured car which was subsequently exported to third countries) and may look to the Mexicans like one way to develop their own manufacturing base and less of a permanent limiting entanglement.

There's always the soviet approach of buying something (Vickers 6e) and making a close copy of it (T26).

 

[JWilly48519]

There's always the soviet approach of buying something (Vickers 6e) and making a close copy of it (T26).

But that requires an industrial capability to conduct every industrial manufacturing process utilized in the original design, at a comparable level of outcome-effectiveness and quality.

I don't think 1935 Mexico's industrial capabilities were close to comparable to those of 1935 Vickers and their subcontractors and suppliers. And, if Mexico were to utilize US suppliers and subcontractors for critical parts of the production process...they might as well just buy US M2s or M3s.