1/35 M70A2 Krueger MBT, Desert Storm, 1991

[Jakko]

Recently, over on the TWENOT forums, a new group build was launched, with the theme of Prototype and 'What if' tanks and AFVs — basically, tanks etc. that never went beyond prototype or design stage, but built as if in service. I immediately began thinking of something like the T95 medium tank or the MBT-70, but then discovered that it’s limited to Second World War subjects

Not to be deterred from a cool idea, I ordered the Dragon kit of the MBT-70/KPz. 70 and I’m going to be building it as if it may have appeared in upgraded form, had it actually been adopted for service rather than cancelled like it was in the real world. (The designation in the title of this thread is because the US Army would, to the best of my knowledge, have assigned the MBT-70 the number M70; I still need to figure out a good general’s name to tack behind it, though. Addendum: I named it Krueger, as explained in a later post in this thread.)

Let’s start with the basics:



This is Dragon Models kit No. 3550, from 2014. It represents the German version of the tank, known as the Kampfpanzer 70 (“Battle Tank 70”), and which differs in many details from the American one. I find it interesting, and somewhat strange, that Dragon didn’t supply the parts for both, because it wouldn’t have meant much extra stuff — the largest would have been a second engine deck. But alright, no worries, I can convert it myself.

What you get in the pretty large box is this:



Lower and upper hulls.



Sprues A and B, with details and the main turret parts.



Sprues C and D, details and wheels.



This is also sprue D, but with an extra bit on it with suspension arms, drive and idler wheels, etc. You get two of this whole sprue, but only one of all the others. Also one of the lengths of track, of which there are four in the kit.



The clear parts, mainly for the commander’s viewers. Oddly, the box claims clear parts for the driver’s periscopes, but there are none. Also the decals, obviously rather generic, and naturally limited to German markings.



One instruction sheet, which folds open into a three-panel affair.



And a full-colour booklet with some detail photos of the KPz. 70 in the Panzermuseum Munster. Plenty of photos of this tank can also be found online, though.

As I said, I’ll be building this as a “what if” model: What if the MBT-70 had gone into service, upgraded along the lines of the M1 Abrams, and used in the 1991 Gulf War? For this, I’ve scrounged up a number of parts from my spares boxes, the main ones being:



A track-width mine plough and 120 mm gun barrel from a Tamiya M1A1 Abrams (more on that particular model in a future thread, I suspect). Not quite sure yet I’ll add the plough, but the gun barrel is a certainty. This will not be the limit of the upgrades, though — I have more planned that will become obvious when I actually start building this model, so stay tuned

 

[Jakko]

When you begin something like this, you never realise how much work it’s going to be …



I knew the American tanks had a different engine deck, because they used a different engine from the German ones, but only when I started to really look where to cut air inlet grille openings, that I noticed the rear of the deck was also wider, with vertical sides rather than sloped like on the German version.

So, I cut off the whole rear, at the line where the engine deck bends from sloping to horizontal, and then removed the centre section as well down to where the slope begins. The American deck has grilles on either side for the whole length of the slope, with a solid centre section, while the horizontal deck is plain apart from some filler openings. I still need to remove the round thing on the right side and the raised part and grille on the left, as those also weren’t on the American tanks.

With those removed as well, again mostly by sawing, I needed to out a piece of plastic card in to keep the left front engine bit of the engine deck in place:



The model will also need an entirely new rear plate, because the fittings there were also completely different. I had intended to just modify the kit part, but now that it also needs its upper sides squared off, I figure I might as well make it completely from scratch. That, though, pretty much necessitates a quick fix:



This because the rear end of the lower hull is warped a little, causing the sides to bend inward. The normal rear plate would have fixed this easily enough, because it has some locating ridges that will push the sides out to the correct position, but my rebuild won’t. All it takes is a brace from sprue, of course.

 

[minitnkr]

Cool project. How about Rose? PaulE

 

[Jakko]

Not heard of him, but looking him up, he does seem like the kind of general who may have a tank nMed after him — except that I don’t think his actual name works well for a tank. “I’m a gunner on a Rose.” “You’re what?” I kind of want to go for Washington, partly because I think it’s kind of odd no tank has been named after him.

Some more progress:



I attached the upper hull to the lower and added a piece of plastic card under (not in) the opening in the sloped engine deck, and filled the other holes with plastic card and filler. Only once the filler is fully cured can I continue on that bit, as it obviously needs to be sanded flat, and I don’t want to risk damage to other details.

However, I did add the lower rear hull plate, the glue on which needs to cure as well before I can go on, and a I-beam to support the front of the flat engine deck:



I was going to cut a plate of the necessary size to put there, but noticed that Evergreen 7.9 mm I-beam was just the right height, and would be stronger for attaching the engine deck and side plates to, so I used that instead.

 

[Mr Bowcat]

M70 Schwarzkopf.

 

[Jakko]

I was thinking of naming it after an America general with a German name, but Schwarzkopf won’t work if this is to represent a tank in 1991

20 minutes later: Found the perfect general — Krueger. Born in Germany, emigrated to the USA as a child, rose from private to general, and died a few years before the “M70” would have been adopted.

(My second choice was MacArthur, on the basis that the MBT-70 shall return )

 

[Jakko]

Making engine deck gratings, part one.

The American MBT-70 had two sets of prominent mesh gratings on the engine deck, one either side in the sloping part of the deck. Since gratings like these are normally recessed, they can be a bit tricky to build, though. That’s why I had put the plate underneath the opening I had cut, so I could build the gratings on top of it yet keep the below the level of the rest of the engine deck.

Dragon’s upper hull is 1 mm thick, and I had some mesh that my callipers told me was about 0.25mm, so the best way to do it is to laminate the deck: first an 0.25 mm sheet of plastic card, then the mesh, and then the actual engine deck made from 0.5 mm sheet. That makes for these pieces:



The mesh is from an old kit (an Academy Warrior MICV if I’m not mistaken), which supplied it to add to the stowage basket on the turret, and cut so the pattern runs diagonally. The bottom plate is in two pieces because I had cut it a little bit too narrow, but that’s not a problem because cut in half the seam will be covered anyway — these bits mainly need to fit well along the sides, front, and rear. This is them installed in the hull:



The next layer is the two pieces of mesh and the plastic card for the centre section:



I superglued the mesh down as well as I could, but this isn’t easy to do because this kind of mesh tends to warp. I could have used a single piece of mesh for the whole engine deck, but I decided to do it in two pieces so that the top plate had something to firmly attach to. Speaking of which:



I got the measurements for the deck by measuring up a drawing in Hunnicutt’s Abrams: A History of the American Main Battle Tank, Vol. 2, but I won’t claim them to be truly accurate because different drawings in that book don’t agree with each other all that well However, as this will be completely covered by the turret when that’s in the forward position, this isn’t a great concern.

I’ll turn my sketches into a computer drawing and attach it to a future post here, in case anyone else ever wants to build an American MBT-70 too

Still to do is to build the framework around the gratings, as well as add a couple more, one in front of the engine deck and two in the horizontal part. This I’ll cover when I get there.

 

[Jim R]

Hi Jakko
The title caught my attention - just had to read on to find out what it was about. Then had to Google TWENOT Great idea. I reckon you're right when you said ....

When you begin something like this, you never realise how much work it’s going to be

However you have the skills to make this work and already you're well on the way.
Jim

 

[scottie3158]

Jakko,
I will tag along, nice modifications so far.

 

[minitnkr]

Rose no worse than Matilda, but Kreuger makes absolutely better sense for this project. PaulE

 

[Jakko]

The title caught my attention - just had to read on to find out what it was about. Then had to Google TWENOT

Maybe I should make the name a link to the site, instead of only the group build title to the thread for that …

Great idea. I reckon you're right when you said ....

Thing is, I have more planned that’s about as much work as this engine deck, but at least I saw that part coming because I’d thought of it before I’d even ordered the kit

However you have the skills to make this work and already you're well on the way.

It’s not actually that difficult, given that it’s all flat plates. It’s compound curves and other intricate shapes I don’t like, though I can do them if I really want to.

Rose no worse than Matilda

True, that. On the other hand, given the differences between American and British culture, I think Americans would be much more likely to be given a hard time over something like this.

Kreuger makes absolutely better sense for this project.

Good to see someone agree with the choice

 

[Jakko]

Two steps forward, one step back …



Yes, that’s the engine deck I built, cut from the model to leave a gaping hole.

Looking at my bookshelves yesterday night, to see if I might have more on the MBT-70 than I had already found, my eye fell upon Waffensysteme Leopard 1 und Leopard 2 by Walter Spielberger (Stuttgart: Motorbuch Verlag, 1995). Figuring it might cover the Leopard 2’s predecessors, I began leafing through it and yes, indeed, it had not only an apparently official drawing of the MBT-70, but the American version to boot:



Though it’s not that easy to see even in the actual book, let alone a poor photo, it contains pretty much all engine deck details needed to build a model, and probably more accurately than the drawings in Hunnicutt’s book. It confirmed what I had suspected from that, though, namely that the front engine deck of the American tank was wider than that of the German one. That in turn means the dimensions I had worked out for the engine deck features, mainly the gratings, were too small as well … Just as I had finished the drawings, of course. So I spent much of today correcting them, and because I decided to also change the way I’d put many of the measurements in, this was about as big a job as drawing them in the first place. Oh, well. I’ve attached a PDF file with the drawings I made to this message — see the bottom.

You may also notice in the photo of the model above that the rear engine deck is on, partly anyway. I had started building that to my original drawings, and attached the lower layers already, after installing the vertical side plates first:






All of these plates are intentionally too big. I find that when I try to cut these sorts of things exactly to size, they usually end up too small and I have to start again. By making them slightly oversize where they overlap other plates, I can glue them down first and then trim them down to fit once the glue is dry.

The silver lining is that I made the recesses for the mesh big enough that it will also accommodate the correct size — all I have to correct is the top plate, which wasn’t on yet because I intend to scribe the hatches and filler caps into it first. Another bonus is that the drawing in Spielberger’s book seems to indicate the mesh runs fore-and-aft, not diagonally, which is much easier to cut correctly for a model, not to mention less likely to unravel, like some of mine had at the corners.

 

[Jim R]

Hi Jakko
A slight rethink and extra work but sounds as if you're having fun and the model will be unique when complete.
Jim

 

[Jakko]

I’ve seen a few other MBT-70 models built along similar lines on other sites (these turn up automatically when you search for photos of the real thing), but all of them have built on the German baseline vehicle — this very nice one on Armorama, for example. Looks like I’m the only one crazy enough to attempt to actually convert it to an American tank

 

[Jakko]

I’m back where I was last night:



Built the same way as before, but now to more correct dimensions. The top plate of the rear deck is still loose, but the rest is all glued down.

The mesh is no longer from an old kit, but brand new:



Rummaging through my stocks of plastic card and similar materials, I found the above unopened package with metal mesh that I recall buying earlier this year but hadn’t remembered when I was looking for mesh the other day. I think it’s steel, but it cut well enough with common household scissors. I did have to take care to get it to lie flat, though, which required some judicious bending between my fingers.

 

[Jakko]

Here’s the engine deck with all the hatches and things marked out on it:



And with the hatches scribed:



This was somewhat tricky, as I don’t have much experience with scribing things like this — I’ve never rescribed panel lines on an aircraft kit, for example. However, I did have a selection of extremely sophisticated tools at my disposal for this job:



A Trumpeter panel line scriber (bought at some point because I figured it might be useful eventually. Oh, and it was dirt-cheap), a Tamiya plastic cutter (which I wouldn’t want to do without), a steel ruler, and a piece of etched fret from a Tamiya Dragon Wagon kit That last one I used for the rounded corners on the inside of one of the openings in the fret, so I could put round corners on the hatches. I used the Trumpeter scriber for those, but the Tamiya one for the removable centre of the engine deck, as I figured this would have wider, deeper lines around it than the crew-openable hatches.

I then glued the engine deck into place and added the basic filler caps:



Originally, I intended to scribe those, but couldn’t find a good way to do that neatly, so I made them from very thin plastic card instead with another sophisticated tool:



Finally for now, I trimmed the engine deck to size once the glue had dried and added the frames around the gratings from thin plastic strip:



I began with the edgings around the outsides of the openings, the added the transverse strips, and finished with the fore-and-aft bits, which are actually in four pieces. To get them all to stay on the model, I first applied plastic cement where they touch each other, and then flowed superglue underneath each to stick them to the mesh as well.

 

[scottie3158]

Jakko,

Nice work so far.

 

[Jakko]

Thanks, though I noticed another problem: though I got the hatches correctly spaced from the centreline, something else has gone wrong so that the engine deck on the right is wider than on the left You can tell in the photo because the long hatch on the left side (on the right in the picture) is closer to the edge of the deck than the other one. I’m debating whether to fill the hatches on the right and rescribe them, or to cover them with something so I can save myself the effort.

 

[Jakko]

Now that the engine deck only needs detail work, it’s time to start on the major conversion of the turret. The MBT-70 was designed with spaced armour and a thick layer of polyethylene to block nuclear radiation (apparently, it reduced the radiation inside the tank by a factor 20 compared to outside). This was also the reason for putting the driver into the turret, by the way: so all the crew could be shielded from radiation effectively in a single compartment. The armour was apparently designed to defeat 105 mm APDS at 800 metres. (See the photo of the Spielberger book above )

The M1 Abrams was designed a bit later, and could take advantage of developments in armour technology, initially chobham armour and then depleted uranium. So what would stop the US Army from redesigning the turret to allow it to be fitted with that kind of armour too? Not all that much, I think, so my plan all along has been to replace the curved turret front by flat plates — chobham armour can’t be made into curved sections effectively, as far as I know. So far I’ve produced a card mockup:



It was a bit of a fiddly job, first attaching a piece of card to the bottom of the turret to indicate the lower edge of the armour, and then tinkering with cut bits of card to get the angles right so I can later duplicate this in plastic card.I’m not sure yet if I’ll cut away the kit’s turret front or build the new armour on top of it. Probably the latter.

The armour extends as far forward as is possible without fouling the engine deck. The cut-away front corner is there for the same reason; ballistically it would probably be better to extend it forward, but then it would be blocked by the engine deck. I also put the armour far enough forward to enclose the gun trunnions, which seemed rather exposed on the MBT-70. I have indicated the size needed for the cutout for the sight, but may not put it there after all — looking at the model, moving the sight up a bit would be an option that improves both armour protection and the vehicle’s turret-down silhouette, after all.

On the left side, there is a square projection for the missile tracker sight, and that will get removed on the model since with a 120 mm gun, the tank wouldn’t fire MGM-51 missiles. I will keep the remote gun mount, though.

There is also a bit of plastic tube on the kit trunnion, so I can slot a Tamiya 120mm gun barrel into it:



Based on the balance point of the real gun, the tube should actually be a centimetre longer, but as I’ll also build a new mantlet instead of using the cast original piece, I figure it would add enough mass at the front that the gun would be mounted more to the rear.

 

[Jakko]

Braving the heat (about 30 degrees here, both outside and in my hobby room), I continued working on the turret armour. Using the card templates, I cut plastic card to shape, then trimmed it down to actually fit the turret:





As you can see, I decided to make a cut-out for the gunner’s sight after all, so this will go in its original position. Now I need to close the gaps with more plastic card and filler. On the left side of the turret, I removed the missile tracker and glued a piece of plastic card in its place to form the turret side armour. I’m going to build angular plates around the curved armour, again on the principle that chobham armour is flat, but will still need to accommodate the remotely controlled turret. This is why there’s still a bit gap at the bottom of the curved area: it will simply be covered over, so there’s no need to fill it.

For the hull, I began building the suspension, and noticed the six stations on each side arrn’t exactly the same. The instructions don’t tell you how they differ, but the third and fifth wheel stations have a different suspension arm from the other four. I looked at the sprue and couldn’t see why this was so, until I noticed a very hard to spot difference. A photo with a simple aid illustrates it quite well:



Nos. 32 (for the left side) and 33 (for the right) are ever so slightly shorter than 30 (left) and 31 (right). Even then I’m hard-pressed to tell the difference between the parts for the two sides … Dragon should have take a cue from Tamiya here: differently sized or -shaped locating lugs would prevent any mixup at all.