M41A2D (105) in Belgian service, somewhere on the Rhine 2000ad

[ChalkLine]

So the saw came out and I've started on the M41 Bulldog.

The premise is:
After NATO went over the East/West German border the counter-thrust from the WTO pushed NATO back to the Rhine, splitting the NATO forces. The French armed forces warned any WTO forces approaching within 10km of the French border would initiate a nuclear strike. By a heroic effort that virtually annihilated their forces the Spanish, Belgian and French armies stop the WTO thrust just short of the Alpha Line and allowed the other NATO nations, reinforced by REORGER at great cost, to strike from the flanks. It goes on but that's enough to describe the background of this vehicle.

This vehicle is one of the repurposed obsolete stocks taken from inventory and rebuilt as best as can be. As the 76mm gun tubes are all shot out it has been re-armed with an M139 105mm howitzer from storage after Belgium converted its M108s into M109s. The vehicle has no indirect fire capability and is built for infantry close support. Modern optics and electric turret drive replace the obsolete Korean War era versions, a Detroit Diesel 8V-71T engine and the vehicle is up-armoured with applique armour. The vehicle has an M26 cupola M2TTHB .50 cal mount similar to that of the YPR and Lynx vehicles.

[ChalkLine]

Let's get cutting.

So this image of butchery, equal parts of lack of skill, arthritis and the knowledge that it'll be largely covered in applique armour, shows the start.

1) Ugly, ragged hole of cupola chopped out to be filled with sheet stock containing new M26 cupola with .50cal M2TTHB HMG

2) Equally ragged hole of loader's hatch cut out from underneath with a scriber in an effort to keep the splash guard. I'm really not looking forward to thinning the plastic here to create a lip for the new hatch. Good news is the hatch survived largely intact so I can measure off it.

3) Goodbye to that rear storage bin! This will be replaced with a rack for jerry cans (T2K is a fuel-poor setting and these things run on some magical alcohol that doesn't make sense but hey, the setting is cool). The storage rack should protrude far enough to the sides that the new side-racks will butt up against it neatly.

4) Old pintle mount cut off and sanded back. A 0.5mm square sheet of plastic stock with tine holes drilled in each corner will be 'welded' here to make it look like the pintle was unbolted.

5) The old mechanical-optical drive has been removed and a new plate is to be 'welded' over the hole. I'm tossing up fabbing a Leopard 1 panoramic sight and mounting it here but I'm not sure if it'd either work/fit or be needed with the blunderbuss.

I'm not sure what to do about the mantlet. I might fab up a new one.

I DL'd the M139 105mm .stl yesterday, next up is (mis)adventures in 3D printing.

[Claymore]

 Go to it!     

[Kerick]

This is really interesting. Keep doing what you’re doing!

[ChalkLine]

Looks like the M26 cupola is out.
Scaling off a plan into 1/35 gives it a (huge) diameter of 32.0mm at the base of the offset turntable. However that's all saved for a future project. I really liked the M26 because it didn't have much penetration into the turret.
The redoubtable Mr Fontane offered me an M1 cupola off an M48A1 but on checking they weigh in at around 650kg, too much for a light tank I feel. I must look further afield it seems.

[Frank3k]

The turret surgery looks better than I imagined. The cupola hole looks workable/fixable.

[ChalkLine]

The turret surgery looks better than I imagined. The cupola hole looks workable/fixable.

You will not I slipped with the razor saw and put a cut in the side of the turret

[Jeffry Fontaine]

@Chalkline - That turret looks very familiar to what I attempted and abandoned a few years back.  Save for the loader's hatch which I left intact.  Thankfully the Tamiya M41 is readily available and priced low (in most locations) that if mistakes are made the replacement costs are not astronomical. 

Your mention of Leopard I parts is also not unfamiliar as I looked to the Leopard 1A4 turret as a possible replacement for that asymmetrical M41 turret.  While my own project is stalled and on the extreme back burner of motivation I hope you proceed without interference to a more successful outcome. 

[Buzzbomb]

Sounds to be an interesting model coming up.

Some first class hackage as well.. I like it 

[Kerick]

How’s this project going? Looking forward to more of this one.

[ChalkLine]

How’s this project going? Looking forward to more of this one.

Hardly any work done I'm afraid as I'm packing the house up to move and getting it clean (as well as taking former flatmate to court which rolls my guts).

I have to get the 3D print worked out next to fit the turret as I want to scratch-build the French cupola and that means having the cupola ring filled once it's in place. I've also run into problems with the putty, I should have listened to that voice in my head that says "buy cheap, buy twice" before getting cheap putty as a back up to the Milliput.
To go inside are some free 3D-print M19 periscopes I want to learn how to size so they fit in things.

So, so far:

- cut out the rear fenders. To have a large muffler one side and small the other for the APU. I also want to make up some mesh in CAD but have to learn how to do solids (I was a surveyor so we didn't do solids, everything was planes). Replaced with stock and they're getting their lip put on them now.
- front applique points on, misaligned due to magnifying visor parallax and this is where the Milliput disaster struck. Not sure how to fix this. May have to get covered in stowage to just hint at what's underneath. I'm very disappointed here. I also cut the front and rear fender-flaps at an angle to show it was a Belgian M41.
- filled the top of the turret's cupola-plate. The very thin rain-lip(?) went which was sad, it looked good. Most of it was in the actual cupola moulding though. I also cut off all the periscopes as I'll replace them with Leopard 1 versions. The pintle mount went too as it was both not needed and woefully inaccurate, I ran into a lot of problems getting new drill holes lined up squarely on the tiny plate that has to replace it. It was recommended that I glue it to something with PVA to keep it steady while drilling, I might try that or simply drill it before cutting it out.
- chopped out the turret ring. All the hatches are open so this was needed. I might just add a bit of greeble on the interior turret right under the hatches and some seats to make it look right and to practice with.
- drilled out the mount for the gun-lock as the 105mm uses a little stubby one up front.

Next;
- I have to the print gun barrel and see how it fits on the 'trunnion' in the kit. I then have to make up a exterior mantlet applique kit.
- Then I have to heat the sheet plastic in hot water and make applique sheets for the turret. I'll be experimenting with new weld beads first.
- Then scratch-build the cupola. This will be complex, it's the one off the old AMX-13. I might consider doing this in CAD if I don't think I can get it to look regular. Of special concern are the armoured bumps between the periscope apertures, getting eight of those exactly the same might be difficult.
- I have to buy some decal sheet and laser print some Belgian markings, this should just be fun research

[ChalkLine]

This is where the applique armour goes next

[Old Wombat]

Busy! Busy! Busy!

Unfortunately, none of it kit related.

Hopefully the move goes smoothly & everything else resolves itself quickly & positively (for you).

[ChalkLine]

Busy! Busy! Busy!

Unfortunately, none of it kit related.

Hopefully the move goes smoothly & everything else resolves itself quickly & positively (for you).

Thanks, it's a real pain. I liked it here and there was a big yard for the dog.

I might do this kit again once I've got more experience with the aspects of the build. I'm not even close to the stowage racks yet and they'll be the hard part :)

[Kerick]

Sorry to hear about the move and all that mess. It would really put a dent in model mojo.

[ChalkLine]

Sorry to hear about the move and all that mess. It would really put a dent in model mojo.

Yeah, I think that may have added to the mistakes I made. I was kinda looking to mellow out but wasn't really concentrating

[Kerick]

When the move is done and you get settled in then get back to it. It’s frustrating no matter what.

[ChalkLine]

Had a bit of time to think.
I'll cut that disastrous glacis plate off and replace it then put on a 1mm stock sheet spaced up as the SABRA composite armour along with the turret armour.

[ChalkLine]

Just a quick whinge

So after the debacle with the upper glacis I trimmed back the applique plates and chiselled off the milliput with a scriber (I love those things). I then cut a new monolithic plate to cover the three skewed applique plates and use them as a spacer. It turned out shorter again! I measured that thing more than twice and I was a surveyor before I studied history, I'm good at measuring.

I decided to use this piece as a test piece to work out where the applique-fixing bolts would go. I got out my aftermarket resin sheet of bolt heads out, gently applied a new, sharp blade to it and it promptly snapped into three pieces, right across the bolt heads and not the spaces in between naturally.

At that point I decided to walk the dog and cool down.

[Old Wombat]

Just a quick whinge

So after the debacle with the upper glacis I trimmed back the applique plates and chiselled off the milliput with a scriber (I love those things). I then cut a new monolithic plate to cover the three skewed applique plates and use them as a spacer. It turned out shorter again! I measured that thing more than twice and I was a surveyor before I studied history, I'm good at measuring.

I decided to use this piece as a test piece to work out where the applique-fixing bolts would go. I got out my aftermarket resin sheet of bolt heads out, gently applied a new, sharp blade to it and it promptly snapped into three pieces, right across the bolt heads and not the spaces in between naturally.

At that point I decided to walk the dog and cool down.

Remember: We do this for fun!

[Mig Eater]

When I made my Taiwanese Type 64 I made the turret's applique armour by taking a sheet of paper clamping it to the side of the turret and then trimming it down until it was the correct shape. I could then take it off an use it as a template to cut the thicker plastic card. The same technique might be useful for your turret armour too.   

[ChalkLine]

That's a brilliant technique and I'll definitely adopt it.

All my kits and stuff are going into a container for an unknown amount of time though so this will happen when I get a place again.

[ChalkLine]

Still haven't got the modelling bench set up but it shouldn't be too far away.

My engine swap for the M41 has been finalised. It's the Detroit Diesel 8V-92TA as used on the Oshkosh M1070 TTTU. Statistics comparison is as follows:

Detroit Diesel Model 8V-92TA DDEC II, 500hp @ 2100 rpm Proposed new engine

L: 110–120 cm
W: 97–99 cm
H: 120–130 cm (Raised 32cm: 9mm @ 1/35)
KG: 1,064–1,095 (+235.9kg)

Continental AOS-895-3, 500hp @ 2,800rpm Original M41 Engine

L: 120.5 cm
W: 131.0 cm
H: 88.42 cm
KG: 859.1 kg

So at 1/35 this engine needs a 9mm rise in the centre of the engine deck to cover the height of the turbocharger. This is also where the exhaust will exit so there'll have to be a hole on the side of it. My idea is to rise the forward two thirds of the engine deck and have two holes in the side spacers inserts, one for the engine exhaust and one for the APU exhaust. Both exhausts will run onto a single fender and I'll make a new exhaust system and use the bare fender as stowage.
Really, the turbo could just be reposition to one side of the engine, the new engine is much thinner and it would be the same height. The idea remains the same though.
I might have to move the engine deck grilles around.

Images, the new engine to give an idea of the shape and the exhaust from the nifty Japanese Type 74 SPG as to what sort of muffler I'd like to try.

[ChalkLine]

And then after a little more research the idea falls apart.

I wondered why the diesel conversions always have this big fan installation at the back. Looking at images of the Continental AOS-895-3 engine it becomes apparent; the petrol engine is a flat-opposed engine with the fans of top.
I'm really not a 'fan'* of that fan deck. I don't think an M60-style vertical rear fan setup would work as the transmission sits right next to the rear of the hull. I'm wondering if the fans could somehow go vertically beside the engine but that would probably mean vulnerable side intakes under the fenders. Time for more thought.

Images: Continental AOS-895-3 engine and Uruguayan diesel conversion

(*Yes, I know. Lame)

[Kerick]

This is very helpful as I’ve taken a saw to the old Tamiya Bulldog kits in my stash last night. I think Brazil did the same thing with some of their M41s IIRC. I said kits as I lengthed the hull by one road wheel making six on each side which leaves me with a four wheeler I don’t know what to do with right now.
I’ve been thinking about how to change the engine deck to something like the M48, M60 series. I have a 1/48th M60 kit I could possibly cast a copy of the deck. Otherwise I might cobble together some assorted spare parts. Didn’t the M48, M60 series draw air in from the top of the deck and exhaust it out the back grills along with the engine exhaust? I remember tank crews and infantry guys telling me about standing behind the tanks in the winter trying to stay warm.