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Why did we have both designs? It seems like a new tank a year or so later would be a huge waste of resources. Was the M-47 design even that much of an improvement over the M-26/46 to begin with?

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The M46 was essentially a M26 with improved engine and transmission. The M47 was an interim step to put a new turret and fire control on what was pretty much a M26/M46 chassis awaiting the development of the M48 (which was having "teething problems"). As the M48 problems continued, the M47 production continued. When full production of the M48 began, there was a significant inventory (8,576) of M47. The decision was made to use the M47 to build up the tank fleets of allied countries and use the M48 production for US Army requirements.

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Well, I was this far along when Richard posted:

 

It was inefficient, but then...

Korea happened, with the attendant realization that the peace that had broken out in 1945 was not to last and that Korea might not be the worst thing that could happen. There was a definite shortage of M46s and the M26's from which they could be converted. The M47 was the fastest-to-produce design that could be hastily implemented using such design components as could be carried over from the M46 while permitting inclusion of various advances (like fire control) to better meet the under-appreciated advances in Soviet designs. It was completely understood that it would be an interim vehicle until a design with better ballistic protection could be designed from the ground up. Effectively a wartime emergency (not just in view of the war that had broken out in Korea, but that other disturbing developments elsewhere could overwhelm existing systems if conflict widened). Viewed in that light, it was not so much a waste of resources but the fastest route to an acceptable solution to what was obviously going to be a long term problem requiring more design work and the adaptatons to the means of production that would spring from it (hull and turret castings).

 

It is significant that Hunnicutt's history on the Patton describes the environment surrounding M47 development with the chapter title "The Emergency".

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Essentially, the emergency was that we would have to support the army fighting in Korea while simultaneously going from a constabulary in Germany to a full scale armored/mechanized army both to be equipped with modernized equipment as opposed to WWII leftovers.

 

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The M46 was not a new-build tank but rebuilt M26 tanks. The total number of M26 tanks built was not high to begin with, and initally after the war the US army intended to keep several thousands of Shermans in service. The M47 as others said used the existing hull design of the M46. Wikipedia says that the turret also belonged to an existing tank project, the T42.

The M47 was basically the mass production line of the M26 restarted in a haste, with what was available at the moment.

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Many things I've read describe the M48 (and thus the later M60) as descendants of the M46 Patton, but it had a new hull, new turret, and new gun. Where is this relationship?

 

Did any of the European countries that got M47s investigate the possibility of upgunning them to the 105mm L7?

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Many things I've read describe the M48 (and thus the later M60) as descendants of the M46 Patton, but it had a new hull, new turret, and new gun. Where is this relationship?

 

Did any of the European countries that got M47s investigate the possibility of upgunning them to the 105mm L7?

 

The M-47 inbetween with the new fire control system was the biggest link along with the gun and ammo.

 

But the gun was basically the same as was the running gear , suspension which can be directly linked to the Abrams. The ammo was able to be fired from the M-26 through the M-48A3.

 

In 1964 we were firing 90MM mfg'd during the WWII years.

Edited by Old Tanker
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Did any of the European countries that got M47s investigate the possibility of upgunning them to the 105mm L7?

 

Spain did an upgrade to a 105mm on some of theirs.

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Did any of the European countries that got M47s investigate the possibility of upgunning them to the 105mm L7?

Wikipedia says that the Spanish upgraded some of their with a 105mm gun. I'm also pretty sure that both Israel* and germany offered upgrade packages for M47s.

 

*I remember reading the phrase, almost certainly in the Greek "Panzer" magazine several years ago, that even though the IDF never operated the M47 the Israelis had the necessary know-how on the Patton family to offer upgrades for foreign customers.

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Many things I've read describe the M48 (and thus the later M60) as descendants of the M46 Patton, but it had a new hull, new turret, and new gun. Where is this relationship?

 

 

Engine and suspension, general configuration. All the vehicles in the M46/47/48/60 series used iteratons of the Continental AV 1790 engine. Some gasoline, some diesel, etc., but the drivetrains were essentially all evolved from the first one. Compare to WWII designs...Shermans were variously powered with (at least) three completely different engine configurations that had nothing whatsoever in common, not even the number of cylinders.

 

The turret, which you mention, was one of the major hurdles to be overcome to even produce the M48 (relative to the M47 interim vehicle). At the time, it was the largest single cast piece ever installed on an American AFV.

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Many things I've read describe the M48 (and thus the later M60) as descendants of the M46 Patton, but it had a new hull, new turret, and new gun. Where is this relationship?

 

Did any of the European countries that got M47s investigate the possibility of upgunning them to the 105mm L7?

The M60 is to the M26 as you are to your great-great-grandfather. Much DNA moves through the generations but there is the DNA from the mother which has to be accounted.

First we have the M26, the roadwheels, track, and suspension smoothly tracks all the way to the M60A3 with minimal evolutionary changes. Roadwheels, support rollers, wheel hubs, and bearings remain essentially unchanged for forty years.

 

The M46 is essentially the M26 with a modified hull and introduces the AVDS-1790 engine, CD850 transmission, and final drives which (except for converting the 1790 from gasoline to diesel) also track smoothly from the M46 through the M60A3.

 

The M47 introduces a new better ballistically shaped turret and a fire control system incorporating a stereoscopic rangefinder.

 

The M48 brings the power package, suspension, gun, and essentially the same FCS from the M47. The biggest changes are dropping the 5th crewmember and changing the shape of the hull and turret.

 

M60 is esessentially the M48A3 with a 105mm gun....then the twenty year evolution of the M60 to become the M60A3.

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One thig I never understood was why move from balisticly superior shape of M47 turret front to more rounded M48 turret with large, relatively weak mantle? Why not M60A1 style turret from the beginning?

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One thig I never understood was why move from balisticly superior shape of M47 turret front to more rounded M48 turret with large, relatively weak mantle? Why not M60A1 style turret from the beginning?

That's a very good question...no answer. I suppose one could speculate about the desire to increase the base length of the RF meant a larger diameter turret, but because the turret would be such a large casting a more conservative shape was used.

 

Edit to add. The general turret shape of the M60A1 owes more to the M41 than to the M47.

Edited by DKTanker
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One thig I never understood was why move from balisticly superior shape of M47 turret front to more rounded M48 turret with large, relatively weak mantle? Why not M60A1 style turret from the beginning?

 

Your assertion that the M47 turret is ballistically superior is both purely subjective and based on erroneous information (or a lack of considering available information). For starters, the M47 turret ring is 73" (inside) and it's turret front and side armor thickness is 4" and 2.5" respectively. The M48 turret has an internal ring diameter of 85" and front/side armor of 7" and 3" respectively. The M48 turret was designed at the outset to accomodate a larger gun of a type not determined at the time. The M48 makes a very clean arc from the turret top to the top of the hull. The shape was optimized maximum armor protection for a given volume with a minimum of weight and it met those objectives. Shot traps are fewer on the M48 than on the M47. The turret design was considered to be excellent and optimal for the design objectives. Just because some other turret looks "slicker" or "narrower" does not make it ballistically superior. The M47 has a number of near vertical surfaces on it's turret side (as did the M60A2 which was also a narrow-configured turret). Apart from the development of the elliptical hull, the turret was regarded as one of the principal design improvements over the M47 and it's longer design timeline was partially due to making sure they could build the thing. Now you want to leap immediately to the M60A1 turret shape with an attendant longer timeline? The M48 turret was considered adequate for the first gen M60 in addition to the M48 so perhaps you should re-examine your assessment of this turret design.

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Doug, no need to be rude or consider me idiot, I know perfectly well what was an armor and turret ring diameter on M47/48.

Look again what I asked, - front turret ballistic shape. Not vertical sides, not armor thickness. So please read question again what I asked and tell me did you answer that question or just went to "it was done that way hence was right" mode. Fact that it was "adequate"* does not erase a fact that turret front was redesigned to new shape that had much more to do with M47 or M41 then previous hemispherical M48 turret.

 

*Through I would like to see results of real world fire test vs M48 turret, considering that thicker T-54 turret of the same basic shape could be penetrated by 90/100mm guns firing AP.

Edited by bojan
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Doug, no need to be rude or consider me idiot, I know perfectly well what was an armor and turret ring diameter on M47/48.

Look again what I asked, - front turret ballistic shape. Not vertical sides, not armor thickness. So please read question again what I asked and tell me did you answer that question or just went to "it was done that way hence was right" mode. Fact that it was "adequate"* does not erase a fact that turret front was redesigned to new shape that had much more to do with M47 or M41 then previous hemispherical M48 turret.

 

*Through I would like to see results of real world fire test vs M48 turret, considering that thicker T-54 turret of the same basic shape could be penetrated by 90/100mm guns firing AP.

 

No where did I refer to you as an idiot. I am saying (and based upon your reply) confirming that you seem to be overly influence by shapes that seem to you to be "cleaner"...or more probably, narrower. The M60A2 had the ultimate in narrow turrets and look what became of that.

 

The shape of the M48 turret was very specifically designed to the following specifications: Maximum armor +maximum internal volume + minimum of weight. Right there you have been dictated the shape by imposing those very requirements...and exactly that was achieved. I don't understand your facination with a prettyier shape that does not meet the stated design objectives. To make it narrower would be to ignore a very specific requirement...max internal volume. You simply cannot have both (look inside an M60A2 sometime). There were very good reasons for imposing these design objectives...as already stated, to accommodate a larger yet unspecified gun, and enhanced fire control (wider rangefinder) and to increase interior volume (which also enhances your combat loadout). You can't have those things without a wider turret. That's just the way it is.

 

By the way, there is no complete agreement that the M60A1 or A3 turrets offer any additional ballistic protection vs. the "turtle" turret. The subjective view is that they do...over a narrow angle of incidence. Other than a frontal shot, they likely are not as good as the turtle. Everything comes at a compromise.

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By the way, there is no complete agreement that the M60A1 or A3 turrets offer any additional ballistic protection vs. the "turtle" turret. The subjective view is that they do...over a narrow angle of incidence. Other than a frontal shot, they likely are not as good as the turtle. Everything comes at a compromise.

It is all about the frontal arc because it is, as you say, about compromises.

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Take the M48 turret, move the ventilator to the other side, change the cupola, call it an M60 turret. Two years later say, aw fuck, that needle nose shape we used on the M41 and M47 just might have had something to it.

 

And the M60A1/A3 turrets have significantly thicker armor at the front and on the sides. This shape is a compromise on both the internal volume requirement and the minimal weight requirement.

 

You can have a more ideal shape, or a more capacious turret, or less armor. But can't have all three if you have a weight requirement to meet.

 

I use (and have been in the position that it wasn't hypothetical) this system: if I have to go to war tomorrow with the following selection of tanks, what would I choose? I'd choose first the M60A3/A1 (at the time, the A3 hadn't been thunk of yet), then and M60, then and M48, then an M47, because from top to bottom, that's where this guy thinks his best chances of survival lay.

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And the M60A1/A3 turrets have significantly thicker armor at the front and on the sides. This shape is a compromise on both the internal volume requirement and the minimal weight requirement.

 

You can have a more ideal shape, or a more capacious turret, or less armor. But can't have all three if you have a weight requirement to meet.

His original question was why not the M60A1 style turret from the beginning? It is historically self-evident that the designers of the day did believe the longer turret with the smaller frontal aspect did provide the best compromise. We see that first with the M41 (ignore the M26 which predated the M41, and ignore the M46 because it was an emergency lash up), then with the M47. Then inexplicably the turret shape changed for the M48 (the M60 was another emergency design to quickly get a 105mm fielded), and then the M60A1.

 

Bojan's question was, and remains, a quite valid one. I agree with you that it offered more volume for a given weight of armor. I disagree that the shape was believed the best possible ballistic design for fighting other tanks, rather (scratching what I thought about casting ability) it was believed the best design shape and compromise to survive on the nuclear battlefied.

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And the M60A1/A3 turrets have significantly thicker armor at the front and on the sides. This shape is a compromise on both the internal volume requirement and the minimal weight requirement.

 

You can have a more ideal shape, or a more capacious turret, or less armor. But can't have all three if you have a weight requirement to meet.

His original question was why not the M60A1 style turret from the beginning? It is historically self-evident that the designers of the day did believe the longer turret with the smaller frontal aspect did provide the best compromise. We see that first with the M41 (ignore the M26 which predated the M41, and ignore the M46 because it was an emergency lash up), then with the M47. Then inexplicably the turret shape changed for the M48 (the M60 was another emergency design to quickly get a 105mm fielded), and then the M60A1.

 

Bojan's question was, and remains, a quite valid one. I agree with you that it offered more volume for a given weight of armor. I disagree that the shape was believed the best possible ballistic design for fighting other tanks, rather (scratching what I thought about casting ability) it was believed the best design shape and compromise to survive on the nuclear battlefied.

Nor did I say that the shape was the best possible ballistic design. What I'm pointing out is that the "users' had three requirements, and that the hemisphere shape best met those requirements. In fact, given the specifications, no other shape would have been geometrically possible, it would have drawn itself with the requirements input. Geometry dictates that the most efficient shape (least surface area) into which a given volume will fit is a sphere. Since half (or more) of the contents of the turrent are in the hull, we are speaking of a hemisphere, or a fraction thereof. Have a look at the turrets of virtually all the Russian designs after the T34/85....(not KV and such, but the T54/55/62/72). All of them are sections sliced off of a sphere. Oh, there are subtle distortions to the shape, but the effect is a sectioned sphere....that's just math and geometry at work dictating the most efficient shape for a given volume. Happily, it also gives you an acceptable, if not ideal, ballistic shape. Anything else cannot help but intrude into the fighting space of the turret. The M48 design was the best that could achieve the priorities stated in the requirements. Additionally, I suspect that trying to cast compound shapes into a single casting is either much more difficult or cannot be done. I love the lines of the M41, too, but notice how many welds it has. The objective was a large, well armored turret cast in one piece (Bojan does not seem to consider welds as participants in structural integrity/ballistic goodness. Well, they are. The M48 turret was intened to be of one piece with no structural welds, which makes it stronger. (hatches, mantlets, infantry rails, etc. are hardly part of the main structure). Every joint is a weak spot and the M48 has fewer of them than other designs of the era since it is of one piece.

 

I'd like to see figures for the internal volume of an M60 turret vs an M60A1 turret. My suspicion is that the volume will be less (unless the turret was stretched to compensate, which I think it was) in the A1 because it was later determined that the width provided for on the m48 turned out no longer to be as critical as expected when it was designed....but that's hindsight and has nothing to do with why one should have preceded the other.

 

I'm having severe sinus problems right now and looking at the screen does not help. I may draw a picture tomorrow and post so it is more easily scene what the introduction of a narrowed, planar surface does to a sectioned spherical shape.

Edited by Doug Kibbey
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Did any of the European countries that got M47s investigate the possibility of upgunning them to the 105mm L7?

 

Spain did an upgrade to a 105mm on some of theirs.

 

And it was not very successful, it being too cramped.

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I vaguely recall seeing a picture of a German-designed upgrade for the M47, including the mounting of a 105mm gun (possibly L7/M68, not sure) and the relocation of the driver to the centre of the hull, removal of 5th crewman & glacis MG position. Never heard anything about it being produced so I assume it was only a prototype?

 

With 8500+ of them produced, that's not bad for an interim vehicle really. Is there a total figure for all M48's built?

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