M41 Cargo Tractor (1/35)

[Frank3k]

I have a spare Tamiya M-41 lower hull and tracks that Jeff sent me a while ago. I want to make a cargo tractor or tracked exploration using the hull. The first thing was to reverse the tracks and "direction" placing the engine in front.
The inspiration is the "Kharkovchanka", a Soviet Antarctic vehicle. It just won't be as big:



The first variation of the cab was as wide as the tracks, and slopes up to the rear, where it would connect to a shelter (ignore the stringing - it may be due to the humidity):



Top view:


It seems too big for the hull, so I made a shorter and narrower version that would allow for some fenders on the sides of the cab. The cargo or shelter would still be as wide as the tracks:



But the roof slant bothered me, so I made a version with a flat roof:







I may try a flat roof version that's as wide as the tracks, but I can't decide if I should make it as tall as the shelter (which would be about 2m/ 6.6' high) or as tall as the last picture, only wide. I'll add the rest of the cab details once I pick the size. Any suggestions?

[Kerick]

I would go with the full width flat roof cab that’s a little taller. But that’s just my $0.02.
This will be fun to watch. It just made me think that I have a Heller Leopard kit in the stash that sucks but might work for this sort of vehicle. Anybody want a Leopard turret and upper hull? The upper parts aren’t too bad.

[The Big Gimper]

Very Nice.

2nd Ken's idea on a cab you that stand up in. I like the astrodome.

[Jeffry Fontaine]

Chiming in to add a third voice to Kericks' recommendation.  More space inside plus reduction of debris being tossed up by the tracks while travelling overland. 

Have to also say that your ability to create a 'rough draft' by 3D printing is a major leap forward in creativity.  My own interpretations on this concept involved trashing the Renwal/Revell Mace Missile TeraCruzer vehicle to obtain the cab for a similar vehicle but based on the M8 High-Speed Tractor which shares most of the M41 components along with a longer hull. 

[Frank3k]

Jeff - the M8 high speed tractor is part of the inspiration. These cabs take about 1-2 hours to print, especially if I print at high speed, "draft" quality.

I decided to make a wide but shallow cab, since it's almost identical in height to the cab of the M977.  I'm not sure I like the results. The driver would obviously have to scoot to the right a bit to keep the control levers above the hull body:



There's some ringing in the print (wavy vertical lines) - which means I have to calibrate the printer better or slow it down - but it's a draft print, so good enough for now:





With the same height but narrower cab, I would add fenders over the tracks, but the cargo or shelter would go directly over the tracks. Something like this:

[Kerick]

I foresee railings for the fenders. Cool!

[Jeffry Fontaine]

@Frank - As far as the position of the vehicle driver goes, why not place the driver in the center of the cab with passengers on either side in a similar arrangement as found in the Alvis Stalwart.  That simplifies things easily enough as to the driver control issues and perhaps allows you to place an entrance to the van body directly behind the driver for connectivity and ease of access. 

[Buzzbomb]

Nice, never heard a lot of people complaining about too much space or room in a supply vehicle.

[Old Wombat]

Full width cab with the driver seated in the middle, with lackeys either side.

[Frank3k]

I thought of the driver in the middle, but right now there's a motor and radiator cover in the way. I could move them.

[Mig Eater]

Random idea, but what about making the sides of the cab angled?

[Kerick]

That’s an interesting looking truck. What type is that?

[Mig Eater]

Its an Oshkosh M1083, its the same truck used for the M142 HIMARS.

[Frank3k]

Thanks for the suggestion, Mig Eater. I drew up a wide cab version inspired by the M1083. The light bar has LEDs (round lenses) and orange formation/warning lights:



Here's are some quick print of the cab minus extras to see how it looks:







The floor plate is from an earlier print - it won't extend from the bottom of the cab. I also drew up (but didn't print) a narrow cab version. I'll finish adding details to the cab and I'll do a test print in resin while I work on the interior. I think the driver can still sit in the left (or right) seat - the control linkages can be angled; no reason they can't be hydraulic or electric vs direct mechanical linkages.

[Kerick]

I approve of this latest version!
Also, Steve says his sport coat is a little thin. It’s getting chilly.

[Mig Eater]

Thanks for the suggestion

Looks good, having the two small windows on the sides was exactly what I had in mind too

[Ramba]

The latest test print looks like the best fit so far.

[Buzzbomb]

Building up to the point where it will all come together.

One of the really good things with 3D prototyping is getting options out relatively quickly. I might take 3 hours to print, can almost guarantee it would take almost 3 hours or more to scratchbuild from sheet as well to the same level

[Dr. YoKai]

That is a wiiiiide cabin. Looks pretty neat in that format-really gives the vehicle a sense of mass.

[Frank3k]

I'm still working on the CAD for the cabin - currently trying to figure out the interior - in the meantime, I printed out some seats, radios and bits.

The seats and the two random equipment boxes came from this 1/35 Pantsir-S1 combat compartment interior . One of the other seats was this seat: 1/10 scale car seat, scaled down to 1/35. I also printed yet more of the radio set I designed a couple of years ago and have since used in several builds. At some point, I'll CAD and print another style.

Prints are in Siraya Fast Navy Grey ABS-Like resin. I love the color, finish and speed of this resin.  I didn't angle the prints, since the parts don't have details on their undersides. They also printed faster.   The seats have some stepping - which should go away under a coat of paint.

After washing:


After removing the supports (although some parts still need cleanup):


Closeup of my radio, still on the supports:


the handles on all the radios printed beautifully. They're very thin (about 0.25mm thick) and would usually break off in the cleaning machine. This time I cleaned the parts with a spray of denatured alcohol (methylated spirits) from a spray bottle and it worked great.
Here are the parts off the supports - some cleanup still needed:



These are the two random boxes from the Pantsir files:





The cutting mat squares are 1cm on a side, so they're pretty small.

I tacked the seats into the FDM printed cabin and I was able to fit four, with plenty of space left. If I redo the engine cover, I could probably fit 5-6.

[Buzzbomb]

Just terrific work on those bits and pieces

[Kerick]

This interior will deserve big windows to see all this goodness! Or maybe a lift off cabin roof?

[ChalkLine]

Do you use a washing station Frank?
Those are amazing prints

[Old Wombat]

 

[Frank3k]

Do you use a washing station Frank?
Those are amazing prints

I have a wash and cure station, but the washing action causes parts to slam into each other, so they can be damaged. Also, the washing isn't the best. I've found that dunking the parts up and down in alcohol for a few seconds in the wash tank gets the worst of the uncured resin off. Spraying the parts with alcohol, followed by a brush where there's stubborn spots left works the best, by far. I then cure it in the station and that works well.

The Siraya resin is top notch. Darker resins are better if you want to maximize detail.