Israel Defence Forces M247 DIVADS

Jakko

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In the early 1970s, the US Army recognized that it needed a modern anti-aircraft gun system to protect its armoured units. All it had at the time was the M163 Vulcan Air Defense System (VADS) that was essentially an M113 APC with a small turret on top carrying an M61A1 six-barreled 20 mm cannon and a simple range-finding radar. As this had been intended as a stopgap, it was time to develop its replacement.

The basic requirement was for a fully armoured vehicle with one or more guns in the 30 to 40 mm calibre range, controlled by radar, and mounted on the chassis of the M48A5 main battle tank. The choice for the chassis was simply because the US Army had plenty of those to spare now that the new M1 Abrams MBT was about to go into production, allowing the M48A5 tanks still in use to be replaced by M60-series tanks that would themselves be phased out of frontline service in favour of the M1. The programme was initially known as the Advanced Radar-directed Gun Air Defense System (ARGADS), but then renamed to Division Air Defense (DIVAD).

By 1977, five companies had submitted proposals for such a vehicle.
  • Raytheon’s design used the turret of the Dutch PRTL (Pantser, Rups, Tegen Luchtdoelen, lit. “Armour, Track, Against Aerial Targets”), which is basically the German Gepard turret but with Dutch search and tracking radars, and which was coming into service in the Netherlands at the time. This turret had two 35 mm Oerlikon KDA guns, one on each side of the narrow turret, with the search radar on the rear of the turret and the tracking radar on the front.
  • General Electric had a well-sloped turret carrying their GAU-8A cannon, as used in the A-10 close-support aircraft. This had both radars on the rear roof of the turret, the search radar on the right and the tracking radar on the left.
  • Sperry had designed a six-barrel 37 mm gun for the T249 Vigilante anti-aircraft system of the 1950s, and adapted it to NATO 35 mm ammunition (the same as fired by the PRTL) for their entry, installing it in a bulbous, asymmetrical turret with the radars on the rear roof like GE, but the other way around: search radar on the left and the tracking radar on the right.
  • General Dynamics also used the Oerlikon KDA, but in a large turret with the two guns mounted centre-forward. It had the tracking radar to the right of the guns, on the turret’s front, and the search radar centrally on the rear.
  • Ford’s turret carried two 40 mm Bofors L/70 guns, in the middle like GE’s, but put the search radar in the middle on the rear roof and the tracking radar on the left side of the turret.

On 13 January 1978, contracts were awarded to GE and Ford to build two prototypes each, for testing. The former would be known as the XM246, the latter as the XM247. This video shows both in action during the test programme:


in 1981, the M247 was chosen and the following year, officially named “Sgt. York” after Alvin C. York of First World War fame. Further testing showed all kinds of issues, but production was started, and the first examples came off the production line in 1984. Though efforts were made to solve the various problems, the whole project was cancelled on 27 August 1985 after around fifty vehicles had been produced. The M163 was to remain in service for another decade or more, and various other anti-aircraft vehicles would be put into American service, none of them as capable as the DIVAD was supposed to have been.

M247_2.jpg
(source)

(The irony here is, IMHO, that had the US been prepared to “buy foreign”, they could have had a system that served well in NATO and has been very satisfactory to the Ukrainians as well over the last two years …)



So far for the real world :smiling3: Some reading on the subject over the last year or so has convinced me that the reasons the M247 had the plug pulled on it were at least as much political as they were to do with its unreliability. When it worked, it seems to have worked quite well — and that means it should have been fixable, if the will was there. But it looks to me like the US Army had used up all its credit by mid-1985, and that was what actually lead to it being cancelled rather than fixed.

Now, of course, that brings us to the question of what if it hadn’t been. The US Army would have had the M247 in service, but that’s been done to death in model form — Takom’s kit from last year even gives a number of marking options for it. So who else would perhaps want (or get) one?

Some thinking about that makes me think there wouldn’t be that many countries with M247s. They would probably already have to have M48A3, -A5s or M60s in service, because else it would introduce a whole new chassis with all of its spare parts issues. And they would need to be politically trustworthy enough that the USA would want to supply them with a very advanced system. IMHO, that quickly limits it to a handful of countries: Israel, Italy, Norway, South Korea, Taiwan, and that’s probably about it. I can’t really see Italy or Norway wanting M247s — if they had a need for modern armoured AA gun systems, I would think they would buy Gepards instead. South Korea could be interesting for a model, upgrading the vehicle much like the M48A5K MBT, and Taiwan could have similar (but different) additions. However, Israel makes the best option for the modeller, IMHO, because of their propensity to tinker with their vehicles …
 
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Jakko

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Last year, right after it came out, I bought the Takom M247 kit:

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That, incidentally, comes in a big box. Here’s a comparison to the more usual size of the Tamiya Panzer IV I’m close to finishing (which is why I’m starting this thread now :smiling3: )

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It’s over twice as deep, 13 cm in all says my ruler. And it’s pretty much packed with sprues — they’re not giving you a box that big just because they can. Here’s most of them:

IMG_0563.jpegIMG_0564.jpegIMG_0565.jpegIMG_0566.jpegIMG_0567.jpegIMG_0568.jpegIMG_0569.jpeg

Instructions for this kit are on Scalemates, BTW, so I didn’t photograph them. (Well, not to post here, anyway — Scalemates has them because I put them there :smiling3: )

Missing are the track sprues (B and D), because as soon as I opened the box I decided I wasn’t going to use them. Construction of them is very similar to Rye Field Model’s Sherman HVSS tracks that I reviewed here on the forum (similar enough that I suspect the same person designed both), and TBH, one set like that was kind of enough for me. So I immediately sold them to another sucker a fellow modeller. I originally intended to use a set of AFV Club T142 tracks, as those are easy to assemble and I had a set in my stash already anyway.

Though that was before I decided on making it an Israeli vehicle. I figure they would have eventually upgraded the vehicle with Merkava track, like they put on their M60 tanks by the late 80s/early 90s, so I bought a set from Legend in resin with those, and the appropriate drive sprockets. However, once I got it, I soon started reconsidering. The casting quality is fine, but all of the lengths are warped sideways, and anyway, I don’t like link-and-length track in plastic, never mind in resin …

But where to get a better set? You can buy them from some manufacturers, but only Legend seems to include the drive sprocket that you need for an M60 (or M48) to use the tracks. So in the end, I took a drastic step and bought this kit:

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Meng’s Magach 6B Gal, which has the track and sprockets I wanted. Luckily, there are photos of this particular variant of the Magach with T142 tracks, so I just put the AFV Club set I had, into this kit’s box.

That gave me these tracks:

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Five of those sprues, that is. On the right are the assembly jig (the clear parts) and the drive sprockets from the Meng kit, plus the final drive housings from that kit as well. If you look closely at the Takom sprues earlier, you will notice the corresponding parts from the M247 are missing there, because I cut them off and put them in the Meng box before thinking to take sprue pictures …

(If you’re wondering if this will fit: it should, given that the M60 is basically an improved M48, and the Magach 6-series is Israel’s improved M60.)

But we can do better than just swap tracks … I also have these:—

IMG_0573.jpegIMG_0576.jpeg

Actually, in the first picture there, I have two each of the two sprues on the left. They’re from an AFV Club Israeli M113 kit but as I bought that to build it as an American one (but could only find the Israeli version), I have all of them spare. The tan sprue in the second photo is from the Academy M113 Fitter, which I also didn’t build as Israeli (25+ years ago …) so again, spare to use bits from here. The tow cable I did buy specifically for this model, because Israeli M60 tow cables are rather complex affairs so I thought I’d take the easy way out.

And then, let’s go all the way … Israel upgraded its M163s by fitting a four-round Stinger missile launcher, and IMHO it’s quite reasonably to assume the M247 would have gotten Stingers at some point anyway. Fitting the same launcher as on the Israeli M163 makes sense, but where to get that? There is a conversion set from Legend (again), but looking for that, I found it cost more than this complete kit from Italeri:

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… which made the decision quite easy :smiling3: So from that I’ll be taking these bits:

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If I’m smart I’ll only use one launcher, leaving the other to be fitted to the LAV, as it has one removable launch pod … Not sure yet if I will be, though :smiling3:
 

Jim R

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A very interesting introduction Jakko. A well considered build. It will be interesting to see how easy or difficult it is to work the various kits together.
 

JR

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I'm in please, always thought you prefered WW2 as your builds in the past.
 

Jakko

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It will be interesting to see how easy or difficult it is to work the various kits together.
I don’t expect any issues, as it will really be just a matter of building the Takom kit and grafting on the Meng drive sprockets, then adding Israeli details to the basic vehicle. No major conversion work planned :smiling3: (I did consider sticking the turret onto an M60 hull, but that would require a lot more conversion work because the M247 has an entirely different rear hull that would also need to be transplanted, and I don’t want to go to that level with this one.)

Sounds like a cool project.
Sounds interesting.
That’s the intention :smiling3:

always thought you prefered WW2 as your builds in the past.
In recent years I’ve been building a lot of Second World War stuff, yes. But I’ve also gone through phases of making mostly Vietnam models, or a whole series of Humvees, or half a dozen M48/M60 variants, etc. :smiling3:
 

Jakko

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The Panzer IV is approaching being finished, so I decided to start on the M247. With step 1, even:

IMG_0586.jpeg

If this was the Tamiya kit, that would have been about a single part. But this is the Takom kit, and it’s more like 45 …

It’s one of those kits with working suspension, a feature I don’t see the point of, but it has to go in else you can’t fit the suspension arms:

IMG_0587.jpeg

I only glued them on the inner end, leaving the outboard side free to rotate so I can later line out the suspension arms before glueing them in place.

If you build one of these Takom M48 kits, follow the instructions for the suspension parts positioning very carefully! The torsion bars can go in in one of three directions, but only one is correct, and it’s not the same on both sides. I found the best way to do it was to insert the bar, rotate it so the lug on it was pointed as per the instructions and the triangular inner end sits correctly in its recess. By pressing down on that with your fingernail, you can easily feel if it’s in the right orientation, or if it needs to rotate slightly more (or back).
 
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Jakko

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Cool, hope you like it :smiling3:

In typical Takom fashion, the instructions want you to stick all kinds of detail to the upper hull before gluing it to the lower hull. But because there will be seams between the two halves, I didn’t want all kinds of fragile bits in the way of filling and removing those, so I instead stuck the upper hull and the engine compartment sides to the lower hull already:

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And we’re at the first bit of actual conversion work already. Because I want to fit the Merkava-style tracks, I also need to install the drive sprocket from the Meng Magach kit, and that means its final drive units as well, else the sprocket won’t be at the correct distance from the hull to fit the track.

Here is the Takom final drive in grey on the left, the Meng version in sand colour in the middle, and a Meng inner part with a Takom outer on the right:

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As you can see, it’s possible in theory to use the inner from one kit and the outer from the other, but they don’t fit well. You would have to remove the locating ridges on the outer part, but that’s not a big deal. More important is that the parts from the two kits are different enough in shape and size that you can tell they don’t really go together. So I discarded that option.

But just putting the Meng final drives onto the Takom hull is also not as simple as it seems, because their mounting holes are completely different:

IMG_0591.jpeg

Takom’s parts have two holes to fit over the large bosses you can see on the rear hull sides in the first photo in this post, above. Meng’s have two small holes top and bottom for locating pins instead. A poor design choice by Takom here is that you can swap the left and right parts, but if you do, they will end up too high on the hull side — whereas Meng’s parts have a thicker pin at the top than at the bottom on both sides, so you can’t put them on the wrong side. (As I had already removed the Takom parts from the sprues and put them in a bag in the Meng box, I had a great time trying to work out which was which using the sprue diagrams in the instructions. This is why I carved the part number and L and R into them.) Even stranger here is that you can’t put the outer parts on the wrong inner part in the Takom kit, while Meng gives the exact same outer part for both sides.

Anyway, to locate the final drives correctly, I needed to make holes in the Meng parts. I put the parts from the two brands together (left Takom on top of right Meng and vice versa) so I could mark the holes with a pencil and then drill them out using increasingly larger sizes of drill. The smaller, front hole is 2.5 mm, the larger, rear/upper hole is 4.5 mm.

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However …

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… I had only actually marked out the rear hole, not the front one, because the Meng parts have a little bump on the inside with some bolt heads around it, which looks like it’s in the same place as the front hole in the Takom part, so I drilled the 2.5 mm hole in its centre. Except it isn’t — it’s slightly further back. I’ll have to enlarge it forward a bit so the final drive housing will actually fit.
 

JR

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Nice start, will follow.
 

Jim R

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Looks as if a lot of thought has gone into sorting the final drive. The result looks very neat.
 

Jakko

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It looks neater than it really is, trust me :smiling3: But because all of this will be hidden once the parts are in place, that’s not a big deal.

Main thing to remember to do before I glue any of this, is to also use the Meng parts as templates to drill locating holes in the Takom parts, else I’ll have more trouble when building the Magach kit …
 

Jakko

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After scraping down the seams between the hull parts, filling gaps between them with putty, and attempting to recreate the texture that got lost, I added the engine deck and hull rear:

IMG_0594.jpeg

I also glued the inside pieces of the final drives on, and guess what I forgot to do? :sad:
 

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Love your conception of mating two or three kits into one.
The trouble with the loss of the M247 was that the world went missile mad, like the 120mm anti-tank gun I used, replaced it with a missile of some description, all well and good when fired on a range, but in the hands of a squaddie, shivvering with the cold, soaking wet, having slept in a trench/dugout all night, then to manhandle the launcher - the miss rate was a 1 in 3 hit rate. Whereas with the 120mm if the sighting round hit the main armament followed, if you were cold or not. And I watched some of these fly by wire launches that would have made NASA proud. Gravity tended to reclaim what was meant to fly horizontal.
I noticed the height of the final drives were the same, but the centre hubs were different heights, will you be packing them up to match the Takom offerings.
And to further add to your IDF idea will you be adding the ball and chain anti RPG around the base of the turret as that turret looks very vulnerable. I am sure I have spares from my Merkave kits you can have.
But an interesting project and thought provoking one and of course I will follow with great interest.
 

Jakko

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Love your conception of mating two or three kits into one.
You’ll love the ideas I’ve got for another one, then: this kit’s hull plus a Takom Gepard turret plus a Perfect Scale PRTL conversion set to make the DIVAD vehicle the US Army could have had :smiling3:

The trouble with the loss of the M247 was that the world went missile mad
The American solution to almost any problem is more technology. There’s plenty of applications where that is indeed the best solution, but they also do it when, say, better training would be just as effective.

And I watched some of these fly by wire launches that would have made NASA proud. Gravity tended to reclaim what was meant to fly horizontal.
M47 Dragon ATGMs are always a good one in that respect. Supported by a bipod at the front but the firer’s shoulder at the rear, and the guidance system is attached to the tube. So … on firing, the missile’s weight is suddenly taken off that shoulder, so it goes up — and if the firer breathes in and out, his shoulder moves up and down. The missile’s trajectory follows nicely along in the opposite direction :smiling3: Quite a number apparently plowed into the terrain because of that, even if the firer supposedly just had to keep the crosshairs on the target until the missile hit.

I noticed the height of the final drives were the same, but the centre hubs were different heights, will you be packing them up to match the Takom offerings.
That smaller hub is exactly why I need to use the Meng final drives: so the sprocket will be at the right distance from the hull to fit the Merkava track from the Meng Magach kit. If I had used the Takom final drives, the sprockets would be spaced out too far from it.

And to further add to your IDF idea will you be adding the ball and chain anti RPG around the base of the turret as that turret looks very vulnerable. I am sure I have spares from my Merkave kits you can have.
Good idea, one I hadn’t thought of, and thanks for the offer :smiling3: However, having thought about it now that you’ve mentioned it, I don’t think I want to add them. Merkavas need it because of the huge rear overhang of the turret, while the M247 overhangs only a bit, nowhere near as far as on the M60 or even the M48, and the Israelis didn’t add chain armour on those either.

an interesting project and thought provoking one and of course I will follow with great interest.
Nice, I hope you’ll like whatever it turns out to be (which I’m not yet sure of myself at this time :smiling3: ).

For now it’s basically a standard M247 still, and I’ve gotten to the suspension:

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All of it is fully working. Here the idler mount and front two roadwheel arms:

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The arms are just stuck on the torsion bars without glue here, they’re tight enough that they don’t fall off. The shock absorbers work due to being in two pieces, and the idler arm also moves back and forth via the linkage to the front roadwheel arm. If you glue the arms carefully to the torsion bars, you can keep it all working, too.

But I want it to be fixed, and they don’t quite line up properly on their own accord. I first stuck the hull to a pane of glass with some Blu-Tack, then carefully levelled it. I could then press the roadwheel arms down against the pane of glass and flow liquid cement into the joins. However, to prevent them coming back up, I still had to employ a ruler:

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The tweezers just serve to weigh the ruler down so the arms stay lined up.

Notice also that I didn’t glue the front roadwheel arm and the idler mount yet. The front arm is longer than the other five, so just pushing it against the glass would result in it sitting too high. Once the glue has dried on the rear five arms, I’ll use the ruler to line up the front arms too and glue them down.
 
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minitnkr

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Love the Gephard turret idea. Would have been my recommendation back then.
 

JR

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Ooh, :smiling3: Neat work there with the different parts being used.
 

Jakko

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Love the Gephard turret idea. Would have been my recommendation back then.
It was one of the proposals submitted for the DIVAD, but not taken up by the US Army. In retrospect, it seems like probably the worst decision in the whole programme, given how successful Gepard and PRTL turned out to be. But expensive, of course — off the top of my head, one Gepard cost about the same as two or three Leopard 1s. But even though they’re 40+ years old now (plus 1990s upgrades), they have proved effective:

 
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