M4A3 (90) HVSS Sherman, Operation Coronet, 1946

[Guest]

In the spring of 1944, there were some calls in the United States Army, both in the USA and in Britain, to arm the Sherman with a 90 mm gun in order to take on the heavily armoured German tanks that were expected following the Normandy landings. The basic idea was to put the turret from the T25 or T26 designs, which were being developed for use in 1945, onto the M4A3 hull (plus to re-arrange internal stowage in the hull for the 90 mm ammunition, of course). Nothing came of this for a variety of reasons, other than an experiment using an M4, rather than M4A3, hull later that year:

[ATTACH]412151[/ATTACH]

Had it actually been put into production, the tank would have used an M4A3 hull, and be equipped with horizontal volute spring suspension (HVSS) rather than the vertical (VVSS) in the photo above, because both of those were the favoured variant in the US Army by late 1944. It would likely have been available by early 1945, so could have seen action in Germany instead of, or even alongside, the T26E3 (later M26) Pershing in the last few months of the war in Europe.

For a full history of this subject, including why it was not proceeded with, the Chieftain has a good video:

Now, I recently bought the following kit second-hand:

[ATTACH]412139[/ATTACH]

This is an M4A3 (76) HVSS in post-war configuration, as it was used by the Japanese Ground Self-Defence Forces. I never intended to build it as such, but rather, to convert it into what an M4A3 (90) tank may have looked like in operational use. And what better period for that kind of model than Operation Coronet, the second planned invasion of Japan in 1946? (The Allies intended to invade Kyushu in November 1945 in Operation Olympic, followed by Operation Coronet in central Honshu in early 1946 in order to capture Tokyo and hopefully end the war. Wikipedia has more on these invasions.)

Let’s start with what you get in the kit:

[ATTACH]412140[/ATTACH][ATTACH]412141[/ATTACH][ATTACH]412142[/ATTACH][ATTACH]412143[/ATTACH][ATTACH]412144[/ATTACH]

Plus, of course, instructions, decals and poly caps. Again, the modularity of Asuka Sherman kits is apparent, and also that there is some duplication of parts because they started with an M4A3 HVSS and then added sprues for the post-war/Japanese parts. The tracks are interesting: there are four lengths in soft plastic, to which hard plastic track pads and guide horns have to be glued. I will probably replace them by these from AFV Club:

[ATTACH]412146[/ATTACH]

… assuming I won’t get too frustrated by their overly loose fit, anyway

The majority of the turret parts of the kit are superfluous to requirements, as I will of course replace them by most of the following bits:

[ATTACH]412145[/ATTACH]

This is the complete (minus cupola) turret and a few other assorted parts of a Tamiya T26E3 kit (I just noticed there is an M60 stowage bin lid in there too by mistake, probably because it was moulded in the same colour plastic), which I have left over because I converted one of those a loooong time ago into the T26E4 that was actually deployed to Europe in 1945:

[ATTACH]412150[/ATTACH]

[Jim R]

Hi Jakko
Another interesting "Jakko Sherman" build which I'll follow with interest.
Jim

[Guest]

Glad to have you along

[Guest]

Nothing really interesting to report, as I put the main pieces of the hull together, which goes just like any other Asuka Sherman.

[ATTACH]412229[/ATTACH]

One bit I already changed was to replace the hull machine gun by a bit of plastic tube to represent an M3-4 flamethrower, which was designed to be fitted in the same ball mount. These were used in both Europe and the Pacific, and given the widespread use of flamethrowers in the latter, I would expect them to also be fairly prominent in any invasion of Japan.

For the hull rear, I decided to go for the very late configuration:

[ATTACH]412230[/ATTACH]

Compare to the M4A3E2 I built recently (though this photo of course is of the engine deck with all its details fitted):



M4A3s built from about the second half of 1945 had torsion bars along the engine deck hatches, to balance them and so make them easier to lift. They also had an armoured exhaust deflector that hung from the underside of the upper rear plate, for which you can see the mounting points in the photo (the deflector itself isn’t fitted yet). The kit I’m using has parts for both, so you can use it to build either version.

I realised when I was putting this engine deck on, that I’m essentially building a Korean War-type of M4A3 hull, though with a flamethrower that (I think) wasn’t used there.

[Guest]

The suspension bogies are complex and not as well thought-out as they could be. The main aim seems to have been accuracy, which is of course a good thing, but that was achieved at the expense of ease of assembly. Not unexpected, but these have no locating pins at all, when it should have been possible to at least add some. The recommended assembly sequence is also awkward.

[ATTACH]412274[/ATTACH]

What you see here is thirteen parts, and it still needs four wheels and two axles added, so that makes 19 pieces per bogie. Each arm is two pieces, the bracket they sit in is made from four in all, the springs in the middle are two parts that can slide relative to each other, and the shock absorber has two small pieces at the back so it can hinge on the tops of the arms.

The instructions would have you add the shock absorber to the two suspension arms, keeping things moveable. They then want you to add the spring assembly between the arms and slide all of this onto the bracket, before putting on a piece at the front that holds everything on the bracket. This means that you first of all have to make sure the shock absorber isn’t glued to the arms, else they won’t move anymore, and then you have to be careful the springs don’t fall out from between the arms.

Far easier is to put the arms onto the bracket and glue the lock piece onto the front, so the arms can’t fall out, then add the springs and finally, the shock absorber.

For comparison: the bogies on the Tamiya HVSS Shermans are four parts (plus four for the wheels) and the brackets are moulded to the hull sides; and those from the one Dragon HVSS Sherman I built, are nine parts (including bracket) plus four wheels. However, neither of these is moveable, and neither looks as detailed as here, so I guess it’s a matter of what you want from your kits

That still leaves one problem: how to get everything level? Because the arms can pivot (though with difficulty, there is a lot of friction in the system), you can’t just put them onto the brackets and have the tank be level. I can see two ways: one is to keep everything moveable when making the six bogies, then glue them to the tank and place it on a piece of glass so you can adjust all the arms so they touch the ground. The other is to eyeball it when putting the parts together, by comparing the top of the bogie to the shock absorber — possibly aided by a jig. I decided to make one of those:

[ATTACH]412275[/ATTACH]

This is just some 1.5 mm copper wire (from an electrical cable) bent so it fits through the axle holes and goes over the back lip of the bracket that mounts to the hull. I made it to fit the first bogie I put together, after levelling that by eye.

By the way, the mould part line on the arm is not accidentally still there. The real arms were castings (mostly — some were built from steel plate) and had a seam running around them just like the kit parts do. Not cleaning them up gives you a more accurate model

[Guest]

Despite making that jig to get the bogies lined up correctly, I decided to leave them loose until I glued them onto the tank, so I could level the suspension on a pane of glass.

Here is a shot of the bogies plus sprocket and idler wheels:

[ATTACH]412354[/ATTACH]

I didn’t attach the wheels yet, as I’m not sure yet whether to add them before or after painting. When it came to attaching them to the hull, the lack of locating pins was obvious once more:

[ATTACH]412355[/ATTACH]

All you get is a moulded depression (for the front bogie) or raised area (for the others) with which to locate them. The first ones will fit fairly well because of the depression, which is because the floor at the front is thicker, but the others require you to locate them by eye. Why this couldn’t have been done better, I have no idea

The jig had helped to line up the arms nicely, though:

[ATTACH]412356[/ATTACH]

Afterward, I put the model onto a pane of glass and had to make only minor adjustments to get all twelve arms level. Because of the friction I already mentioned, they easily held those positions so I could just pick up the model and flow liquid glue into the arm pivot points and around the ends of the shock absorbers. Once those have dried, I’ll have to push the spring assemblies outward as far as they’ll go and glue them too.

I also began building the turret. The first step was to increase the diameter of the turret ring so it fits the Asuka hull:

[ATTACH]412358[/ATTACH]

This is just two strips of 0.5 mm thickness, because the ring was about 2 mm smaller than that in the hull.

I then put the halves together, removed the seam and began adding details, though I’m not done with those yet:

[ATTACH]412357[/ATTACH]

This is mostly Tamiya parts, except the gun barrel is from an Academy M36 tank destroyer. I still have the Tamiya barrel, but had used the muzzle brake on the T26E4 I showed above, and because the M36 kit has two barrels, and I don’t intend to use this one, I could easily use it here. My initial thought was to just stick the muzzle brake onto the Tamiya barrel, but that wouldn’t have fit well, so I took the Academy barrel instead. That meant I had to cut and file a taper into the end that goes into the mantlet, though — in the end, either option would probably have been about as much work, in retrospect.

The plate on the side is a spare from a Dragon M46 Patton kit, and is a stowage rack for spare track links. I used it because the Tamiya turret had parts for a rack intended for a different type of track links than will be fitted to this model. The white bits are filler where parts fit that I don’t need/want/no longer have. The cupola ring is from the Asuka kit, as I had also used the Tamiya part on the T26E4 (this because Accurate Armour got its orientation wrong on their conversion set).

I also removed the gunner’s sight, which Tamiya moulded closed. I figure that, because the Sherman got an armoured hood over this, a Sherman with Pershing turret might also have gotten that (even if Pershings didn’t in the real world). I still have to cut one off an old Italeri 76 mm turret, though

[adt70hk]

Great work as always Jakko. And interesting what if project.

ATB.

Andrew

[Guest]

Thanks. I’m struggling a bit coming up with ideas for how to actually show it’s a “what if/invasion of Japan 1946” model, though … the only real one I can think of is to put a Japanese soldier on the model, looking into the loader’s hatch, for example. This would necessitate some kind of damage to show a reason for the tank to have been knocked out or abandoned, though.

[Guest]

Aside from antenna bases and machine gun, the turret is now done, I think:

[ATTACH]412419[/ATTACH][ATTACH]412420[/ATTACH]

I replaced the bits of angle iron on the rear by more leftover Dragon bits, because those have the clips for the machine gun barrel moulded on that Tamiya inexplicably missed. I also found a catch for the loader’s hatch on the Dragon sprue, so I put that on as well, after removing Tamiya’s version that doesn’t have the actual catch. The machine gun stowage bracket got a plastic card ring added, because Tamiya’s lacks the upper ring that should be on it. This is just a punched disc with the top drilled through after it was glued in place.

In front of the commander’s hatch, I added the armoured gunner’s periscope housing I mentioned. It’s pretty much the same colour of plastic as the turret so it’s not immediately obvious, but I sawed it off an old Italeri 76 mm turret and put the top of a spare periscope underneath it. Everything else is simply Tamiya T26E3 parts.

[Guest]

When I was lying awake halfway through last night, my thoughts turned to this model and I realised I had made an important mistake with the turret. It has a rack for spare track links on the left side and a bin for foul-weather drivers’ hoods on the right. Sure, fine, except these aren’t needed on a Sherman: the Pershing had them because there was no room for these things in or on the hull, while the HVSS Sherman had spare track blocks on the hull side and the foul-weather hoods were stored above the transmission inside the hull. This is an easy mistake to make, really, because the only photos of the real thing show a standard T26 turret put onto a Sherman hull, while drawings of this tank tend to also show a simple composite of a Pershing turret and a Sherman hull, with no thought given to how either might be changed if this had really been put into production.

That meant a fun bit of work trying to remove them without damaging the other details I had put on the turret already, then scraping down the scars and obliterating them with putty and thinner:

[ATTACH]412508[/ATTACH][ATTACH]412509[/ATTACH]

[Graeme C.]

An interesting 'what if' Sherman Jakko, if you're going for 1946 Japan, how about a log bunker as were used by the Japanese on the Pacific islands?

[adt70hk]

An interesting 'what if' Sherman Jakko, if you're going for 1946 Japan, how about a log bunker as were used by the Japanese on the Pacific islands?

That's a good idea!

[Guest]

That is a good idea, if it weren’t for the fact that the model won’t end up in a diorama Also there’s the historical problem that these log bunkers tended to be constructed from palm trees, which don’t really occur in the central Honshu area, except apparently in parks and gardens

[Jim R]

Hi Jakko
Great progress. Those bogies are certainly a test. You seem to have got them spot on.

This would necessitate some kind of damage to show a reason for the tank to have been knocked out or abandoned, though.

Damage is hard to model convincingly I think.
Jim

[Guest]

It is, and you really have to add it as an integral part of the build, not try to add it afterward. I guess the “Japan 1946” theme will be expressed mainly by dressing the model in the style of US Army tanks in the Pacific, rather than anything that makes it obviously in Japan. That is, markings as used in the Pacific and little stowage, as it looks like most US Army tanks there went into action only lightly loaded — unlike in Germany in 1945.

In the mean time, I’ve been continuing regular construction:

[ATTACH]412578[/ATTACH][ATTACH]412579[/ATTACH]

The brush guards on the driver’s hatches are from a Dragon Sherman kit. This kit has photoetched guards, but I don’t like those because they’re flat when the real things were made from round steel wire.

The three white bits of plastic rod on the left side of the engine deck represent the gun cleaning rods, whose dimensions I got from the technical manual for the M3-series tank gun that would have been mounted on this tank. On 76 mm Shermans, the cleaning rod was in four pieces and stored on the underside the stowage shelf on the back of the hull, but the rods for the 90 mm gun were longer so they didn’t fit there. Because Shermans armed with a 105 mm howitzer had their cleaning rods on the left side of the engine deck, this seems a good location for this 90 mm version as well.

It still needs a number of details added, most obviously the brush guards over the lights and the horn, but also straps to hold the tools down and a gun travel lock. Unfortunately, the latter will have to be scratchbuilt, because the normal Sherman ones are far too short (the gun appears to be mounted about 3 mm higher here than in the 76 mm Sherman) and I also don’t have any Pershing ones left that I could modify.