Sherman vs the Panzer IV

[Tim the Tank Nut]

Man, I's love to drive that S35 but I am guessing it's had a standard .mil restoration which means the guts are destroyed

[Guest aevans]

Man, I's love to drive that S35 but I am guessing it's had a standard .mil restoration which means the guts are destroyed

 

No guessing involved, like all of the APG static displays, whatever is on the inside has been allowed to just sit for decades. Only the external appearance gets prettied up every twenty years or so.

[Mikel2]

No guessing involved, like all of the APG static displays, whatever is on the inside has been allowed to just sit for decades. Only the external appearance gets prettied up every twenty years or so.

 

 

I think APG's "Restorations" involve removing any oils and grease from the vehicle... For environmental reasons

[Guest aevans]

The Christie features were directly transmitted to the sov fast and early universal tanks though, so that's a very clear lineage. Talking about French inspiration of American designs is not clear cut, nor are any design feature similarities between the HVSS and Christie suspension.

 

There are only so many ways to design machine elements or produce hulls, but it's pretty clear cut when you buy something and more or less directly slap it on.

 

Considering the amount of technological exchange going on in the automotive industry in the Twenties and Thirties, singling out the Soviet adoption of Christie suspension as "a very clear lineage" would be the same thing as saying everyone was significantly influenced by everyone else. Now, there's a sense in which that is absolutely true, but it is in effect a meaningless tautology.

[Colin Williams]

The US Army was smart enough to realize that it had developed a perfectly viable suspension and powerplant system with the M2/M3 light tanks and the M2 medium tank. What they needed was a different, more heavily armored hull mounting something more lethal than a 37mm gun. It's perfectly reasonable to think they may have looked at the S35 and Char B1bis for inspiration and come away with plans for cast turrets and hulls as well clues for how to build a tank with both a hull mounted 75mm and a turret.

[irregularmedic]

Considering the amount of technological exchange going on in the automotive industry in the Twenties and Thirties, singling out the Soviet adoption of Christie suspension as "a very clear lineage" would be the same thing as saying everyone was significantly influenced by everyone else. Now, there's a sense in which that is absolutely true, but it is in effect a meaningless tautology.

 

Except in this case thee Soviets bought the rights to produce his tank and built exact copies at first.

[Ken Estes]

There is little logic supporting the M3 an interim design that led to the M4. Rather, it was an interim medium tank production run serving until the production of the M4 was ready. Although the army sought to use as much of the M3 as possible, this was not the case, and the shared components were few. As King Sargent was fond of pointing out, and the Army Green Book volume on Ordnance Dept showed, the US Army Ordnance Dept developed components, not tanks during the 1930s, and it was these that served the M2, M3 and M5 light tanks and M2, M3 and M4 mediums. There is little to compare between the M3, gussied up to satisfy the Brit tank mission, and the M4, Curiously, both the French and British tank missions hoped to obtain US production of their own vehicles, but only the M2/M3 lights and M3 medium were available in the end.

 

I know of no armor authority citing the M4 as an outgrowth of the M3, just sequenced in that order. With the M4, rivets became scarce, and few components remained from the M3, although it was hoped to use more in order to speed production tool-up. One can only cite the lower hull and drive train as borrowed from the M2/M3 series, the rest being common components of the Ordnance Dept effort. 1Feb41 the M3 design is initially complete, the first pilot delivered Mar41; 18Apr41 the new details of the M4 determined and 2Sept41 the pilot M4 is ready, already beginning to shed many M3 components. It remains an example of parallel design effort, not sequential.

[Ken Estes]

I think APG's "Restorations" involve removing any oils and grease from the vehicle... For environmental reasons

Much more than that. The museum staff cleverly used the environmental standards to justify and fund a new process: detailed disassembly of the vehicles, blasting the lead paint, removing the radium gauges, and reassembling them with fresh paint jobs; no rust. "Restoring" would require matching up missing components and there were no funds for that. They are hardly just externally repainted and rusted out inside; that was the previous regime and anybody thinking that is still going on is just guessing.

[Mikel2]

Much more than that. The museum staff cleverly used the environmental standards to justify and fund a new process: detailed disassembly of the vehicles, blasting the lead paint, removing the radium gauges, and reassembling them with fresh paint jobs; no rust. "Restoring" would require matching up missing components and there were no funds for that. They are hardly just externally repainted and rusted out inside; that was the previous regime and anybody thinking that is still going on is just guessing.

 

 

Yes, I saw what they did to the Elefant... Which will be going outdoors again. I would rather see the entire collection crammed in some warehouse somewhere out of the public's eye than see them rot. The Army must have a roofed surface somewhere...

[shep854]

Can anyone point me to a schematic of the Christie suspension? Wiki only gives a text description, and my Google-Fu does not seem to be up to the challenge.

[Coldsteel]

Can anyone point me to a schematic of the Christie suspension? Wiki only gives a text description, and my Google-Fu does not seem to be up to the challenge.

 

For a Cromwell, I don't recall where it came from.

[Guest aevans]

There is little logic supporting the M3 an interim design that led to the M4. Rather, it was an interim medium tank production run serving until the production of the M4 was ready.

 

...

 

1Feb41 the M3 design is initially complete, the first pilot delivered Mar41; 18Apr41 the new details of the M4 determined and 2Sept41 the pilot M4 is ready, already beginning to shed many M3 components. It remains an example of parallel design effort, not sequential.

 

While you are quite correct that the M3 and M4 overlapped, it's not very realistic to suggest that they were on separate tracks, with experience in desigining and producing the M3 not being incorporated in the design and production of the M4. The fact that they shared many lower hull and automotive components alone means that they were in the same stable.

[Ken Estes]

Yes, I saw what they did to the Elefant... Which will be going outdoors again. I would rather see the entire collection crammed in some warehouse somewhere out of the public's eye than see them rot. The Army must have a roofed surface somewhere...

Far worse is the Mk VIII International, placed in that field since c.1919! There has been some doubt it could even be lifted safely. Elephant is not going to rot away yet. The problem is that, unlike the Armor Museum at Ft Knox, the APG facility simply supports the Ord Corps and School, and no high army leadership, such as chiefs of staff, are from Ordnance, so institutional and command attention was next to nothing over the decades. The new process will suffice for now, and the availability of roofed storage varies considerably over the ages, and now they are moving to the Virginia Tidewater!

[Ken Estes]

While you are quite correct that the M3 and M4 overlapped, it's not very realistic to suggest that they were on separate tracks, with experience in desigining and producing the M3 not being incorporated in the design and production of the M4. The fact that they shared many lower hull and automotive components alone means that they were in the same stable.

Not from your snipped version, but what did I write that stated they were separate tracks? They were virtually simultaneous developments, resolving the same set of problems, but with different approaches, all within the Ord Dept set of materiel developments, chiefly on-the-shelf components. It is simply not true that M4 stemmed from M3, that's all. "in the same stable" remains meaningless, the stable being the United States.

[Colin Williams]

It remains an example of parallel design effort, not sequential.

 

I think it may be more accurate to call it parallel design and sequential development. Hunnicutt writes that preparation of the detailed blueprints for the M4 had to wait until the blueprints for the M3 were completed, which simply means that there weren't enough draftsmen available to produce both sets of blueprints at the same time. This is completely consistent with the standard narrative that the M3 received priority in development and production, but I certainly don't see any indication that important components of the M4 were inherited from the M3 design process rather than from the M2 or the general post-M2 medium tank work.

[Guest aevans]

Not from your snipped version, but what did I write that stated they were separate tracks? They were virtually simultaneous developments, resolving the same set of problems, but with different approaches, all within the Ord Dept set of materiel developments, chiefly on-the-shelf components. It is simply not true that M4 stemmed from M3, that's all. "in the same stable" remains meaningless, the stable being the United States.

 

I think it may be more accurate to call it parallel design and sequential development. Hunnicutt writes that preparation of the detailed blueprints for the M4 had to wait until the blueprints for the M3 were completed, which simply means that there weren't enough draftsmen available to produce both sets of blueprints at the same time. This is completely consistent with the standard narrative that the M3 received priority in development and production, but I certainly don't see any indication that important components of the M4 were inherited from the M3 design process rather than from the M2 or the general post-M2 medium tank work.

 

From the point of view of a system designer, "stable" has a very specific meaning, including, among other things, components and design objectives. In the case of the M3 and M4, the stable is medium tank design objectives plus the components to implement the design, whether they come from the government (as designs or GFE) or industry. The M3 and M4 in fact represent a very common product life cycle that any system developer would recognize. The interim design (e.g. M3) uses everything that will be ready to go in time to make the targeted introduction date. This buys time for the intended design (e.g. the M4) to be perfected and introduced at a later date. The intention is usually to use as many interim design components as possible on the intended design, but whatever falls by the wayside does not change the fact that the intended design is an evolution of the interim design.

Edited August 5, 2010 by aevans

[Panzermann]

Yes, I saw what they did to the Elefant... Which will be going outdoors again. I would rather see the entire collection crammed in some warehouse somewhere out of the public's eye than see them rot. The Army must have a roofed surface somewhere...

Or just move them to a desert. Works with airplanes. Why not with AFV, too?

[Przezdzieblo]

shep854,

part of interesting article, text in Russian, but a lots of drawings --> click

and here you would find Christie`s patens --> click

Edited August 5, 2010 by Przezdzieblo

[rmgill]

 

and finally a different industrail base. The US enjoyed the advantage that they had many industries that could be switched to military production rather quickly. In that regard Germany had no chance to compete. Especialyl if it comes to how quickly new factories could be built. The US was without equal in the regard.

 

And don't forget that some of the designs were easier to produce in 'minimally' equipped foundries. A locomotive foundry that had a large bridge crane, a blast furnace, a heat treating oven, a sand casting facility and basic small machine shops and forging equipment could turn out Sherman tanks. Rolling plate armor took considerably larger and more heavily equipped facilities to handle the plate steel being rolled as armor.

[Guest aevans]

Rolling plate armor took considerably larger and more heavily equipped facilities to handle the plate steel being rolled as armor.

 

One would think that in a pinch the plate armor could be acquired from a nearby steel mill, then cut and welded at the assembly plant.

[Ken Estes]

I think it may be more accurate to call it parallel design and sequential development. Hunnicutt writes that preparation of the detailed blueprints for the M4 had to wait until the blueprints for the M3 were completed, which simply means that there weren't enough draftsmen available to produce both sets of blueprints at the same time. This is completely consistent with the standard narrative that the M3 received priority in development and production, but I certainly don't see any indication that important components of the M4 were inherited from the M3 design process rather than from the M2 or the general post-M2 medium tank work.

No doubt you are correct on the design blueprints sequence, especially because we are just then a half-year into the National Emergency, not at war. And, I think the test of your last point is to ask, 'would the M4 had turned out when and as it did had the M3 never existed,' and I think the answer is yes.

 

But when Mr. 'speaking as a systems designer' invokes his presentism for a period where the systems design discipline did not exist, at least in the same form, we are just seeing obfuscation when his English usage failed to measure up below, so one whips up some weaselwords and claim to use specialtyspeak, but all along?

 

 

Bingo. It was very much an interim, expedient design, but it contributed significant design and automotive features to the M4.

 

The 'it contributed' is not really factual, just contrived: 'significant design and automotive features' would have to be not derived from the M2 and the Ordnance Dept process to make it right ... so it is not.

[shep854]

shep854,

part of interesting article, text in Russian, but a lots of drawings --> click

and here you would find Christie`s patens --> click

 

Thanks to you and Coldsteel both. I couldn't visualize what Wiki described.

[Guest aevans]

No doubt you are correct on the design blueprints sequence, especially because we are just then a half-year into the National Emergency, not at war. And, I think the test of your last point is to ask, 'would the M4 had turned out when and as it did had the M3 never existed,' and I think the answer is yes.

 

It would have shared significant pieces of technology and have several design affinities with the M2. But it would have been the M3 -- just one with a turret-mounted 75mm gun. Except that didn't happen, because the M3 did exists as an intermediate step in the process.

 

But when Mr. 'speaking as a systems designer' invokes his presentism for a period where the systems design discipline did not exist, at least in the same form, we are just seeing obfuscation when his English usage failed to measure up below, so one whips up some weaselwords and claim to use specialtyspeak, but all along?

 

What presentisms? I didn't invoke post-war systems engineering* as a paradigm. I simply pointed out that when designing a system -- a tank is a system, and they knew that in 1941 just as much as we know that today -- one may be constrained to produce an interim solution while the intended target system is still being developed.

 

I also pointed out that the intended target model often incorporates as much of the interim model as can be brought forward. This is certainly the case with the M4, which had the lower hull, running gear, and power plant of the M3.

 

*Though it is arguable that the US approach to the M4 tank was essentially systems engineering without the name, given the variability and modularity of a lot of the components that were fit within essentially the same overall systems package.

 

The 'it contributed' is not really factual, just contrived: 'significant design and automotive features' would have to be not derived from the M2 and the Ordnance Dept process to make it right ... so it is not.

 

Questions, Ken: did the M3 design not exist before the M4 design? Are there not significant M3 design features in the M4 design?

[rmgill]

One would think that in a pinch the plate armor could be acquired from a nearby steel mill, then cut and welded at the assembly plant.

 

Well, that's armor plate that's ALSO needed for other things. But, there were welded hulled Shermans. But in the short term, having the ability to run up production while plate armor rolling mills were brought online probably helped tremendously. The cast turrets continued even with the welded hulls as did the cast final drive housings. Also bear in mind that welding plate armor was NOT an easy thing to do. Even today, it takes special rods, pre-heating and very careful post heating cool down.

 

http://www.tpub.com/content/armyordnance/od16518/od165180068.htm

 

3.Welding Armor Plate

 

a. Properties of Armor Plate.Armor plate is hardened bynormalizing or heating it to its upper critical point and lettingit cool in still air.The base metal quenching effect producednext to a weld in heavy armor plate under normal weldingconditions is about halfway between the effects of air coolingand oil quenching it.During the welding of armor plate thetemperature of the weld metal ranges upwards of 3000Ä F from theoriginal temperature of the base metal. Therefore, a narrow zoneon each side of the deposited weld metal is heated above itscritical temperature.This narrow zone is then quenched by therelatively cold base metal and becomes a hard brittle zone knownas martensite. It is in this zone that cracks are most likely tooccur upon the application of a load. For this reason, specialprecautions must be taken in all welding operations to minimizethe formation of hard zones. In addition, care must be taken toprevent rapid cooling of the armor plate after welding in orderto avoid the formation of cracks in hard zones.

 

b.

Types of Armor Plate.

(1) General.There are two types of armor that are used oncombat vehicles: homogeneous, which can be cast or rolled, andface hardened, which is rolled.It is essential that the armorplate be specifically identified before any welding or cuttingoperations are performed. This is important because the weldingprocedures for each type of armor are distinctly different andare not interchangeable.

 

(2) Homogeneous Armor Plate. Homogeneous armor is heat treatedthrough its entire thickness to develop good shock or impactresisting properties. This type of armor is uniform in hardness,composition, and structure throughout and can be welded on eitherside. Aluminum armor plate is in the homogeneous class. Weldingprocedures for aluminum armor plate are the same as for gasmetal-arc welding, which are discussed in the inert gas weldingoperation subcourse.

 

(3) Face Hardened Armor Plate.Face hardened armor plate has an extremely hard surface layer which is obtained by carburizing.(Carburizing is the process of combining carbon with another alloy or impregnating a metal with carbon to strengthen it). This hardsurface extends to a depth of 1/5 to 1/4 of the outward facingthickness of the armor on the tank or armored vehicle.Theprimary purpose of face hardened armor is to provide goodresistance against penetration from enemy projectiles. The innerside is comparatively soft and has properties similar to those ofhomogeneous armor.As a matter of fact, the inside and outsideof face hardened armor plate has two different kinds of steel.Face hardened steel up to 1/2 inch in thickness should be weldedfrom the soft side only.

 

c. Identification of Armor Plate.

 

A very important part ofwelding lies in the welder having the ability to identify metalproducts to be welded.The following paragraphs describe twosimple but accurate tests that may be made in a field shop foridentifying armor plate.

 

(1) File Test. This type test is performed with the use of anordinary file found in the mechanics and welders tool sets.

 

(a) Homogeneous Armor. A file will bite into homogeneous armoron both the outside and inside of the plate.As the file isdrawn across either surface of the armor plate, the teeth on thefile will bite into the metal, making it necessary to apply forceto draw the file across the metal. This type test is performedby applying the file only once or twice across the surface. Thearmor protection qualities of the armor plate can be impaired byrepeated applications of the file; therefore, the number ofapplications should be limited.

 

( Face Hardened Armor. In this type armor the file will biteonly into the soft side of face hardened armor plate.Whenapplied across the face side (outside) of the armor plate, thefile will slip instead of biting into the metal.But when thefile is applied to the reverse side (inside), the file will biteas in homogeneous metal.

 

(2) Fracture Test.Some metals can be quickly identified bylooking at the surface of the broken part or by studying thechips produced with a hammer and chisel.

 

(a) Homogeneous Armor. The metal edges of holes or cracks madeby an anti-tank projectile in homogeneous armor plate are raggedand bent, with the metal drifted in the direction of penetration.Cracks in homogeneous armor are usually caused by stresses in themetal. These cracks are present at severe bulges or bends in thedamaged armor plate.

 

( Face Hardened Armor.The metal edges of holes and cracksin face hardened armor are relatively clean cut and sharp.Theplates do not bulge to any great extent before cracking.Byexamining the edges of freshly broken face hardened armor, it canbe noted that the metal at the face side is brighter and of afiner structure than the metal at the soft side.The brightermetal extends to a depth of approximately 1/5 to 1/4 inch inthickness from the outside surface.

 

[Guest aevans]

Well, that's armor plate that's ALSO needed for other things. But, there were welded hulled Shermans. But in the short term, having the ability to run up production while plate armor rolling mills were brought online probably helped tremendously. The cast turrets continued even with the welded hulls as did the cast final drive housings.

 

Just looking at it from theindustrial organization and materials management points of view -- there's no fundamental reason why plate has to be rolled and treated at the assembly plant, or castings made there, for that matter. It all depends on whether or not a set of appropriate subcontractors can be assembled.