1/35 HEMTT Explorer

[frank2056]

Inspired by Weaver's post of an AI generated HEMTT Expedition I decided to try and make a "realistic" HEMTT exploration vehicle. The back story in my head takes place after the inevitable and chaotic collapse of the Russian Federation and an attempt by NATO and others to get into the former Russian vassal states and ascertain what weapons systems were still a threat, disable them on site or mark them for future destruction. That may change, though.

I have an Italeri M977 HEMTT



It's an average to good kit, withe the advantage that it's in my stash and not terribly expensive.

This is my preliminary design; I was tempted to try making the AI generated version, but I don't want this project to drag on for months on end:



The gray areas roughly define the living/working areas. I'm going to make this an electric truck with dual motors feeding the original transmission, and a diesel generator to charge the batteries and provide electricity. I'm guessing the range would be around 600-800KM, about 1.5x the standard HEMTT range.

One issue with the kit is the downright anemic tires. I've been lucky to have figured out the magic of making tires in CAD, so I took the design of the generic HEMTT Michelin tires and cranked it up to 11 (or 10.5).
I printed the tires on my new (to me) Saturn 8K resin printer, which hasn't been fully dialed in yet, but the results seems to be OK.

New printer, new resin I haven't tried before (Siraya Tech Fast Navy Grey) and I managed to drop the tires before they were cured, so they have surface scrapes and a couple of dings. Still, not bad:



One of the dinged front tires:



Compared to the kit tires:



Test fit - the tires (especially the front ones) aren't pushed in all the way, so they're a little wonky:



I modified the cabin to remove the engine cover. The front of the cab will still have one of the radiators, though.


Suggestions welcome and appreciated.

[kerick]

Those new tires look great! Quite the improvement. I'll be following this build closely.

[Weaver]

As will I. 

What occured to me for an electric HEMTT (HEMTT-E? - Cue "running on HEMTT-E jokes...") was to have two smaller diesel generator sets in place of the original engine, one forward on the right witha a corridor to the cab next to it, and one aft on the left with a corridor to a rear door next to it. However this is assuming a full electric conversion with wheel-hub drive motors, so the gearboxes and shafts are gone, making room for battery boxes under the chassis.

[Wardukw]

Frank ive had that kit many times before and yep the stock wheels are terrible so very nice work on the new ones .
I've got the Trumpeter M983A2 HEMTT Tractor with the trailer and damn what a kit but your choice is a better option..quite a few parts less than the Trumpeter kit.

I'm going to watch this build..im gonna enjoy this 

[buzzbomb]

Oh yes... this has a lot of promise

[Old Wombat]

[frank2056]

As will I. 

What occured to me for an electric HEMTT (HEMTT-E? - Cue "running on HEMTT-E jokes...") was to have two smaller diesel generator sets in place of the original engine, one forward on the right witha a corridor to the cab next to it, and one aft on the left with a corridor to a rear door next to it. However this is assuming a full electric conversion with wheel-hub drive motors, so the gearboxes and shafts are gone, making room for battery boxes under the chassis.

I was thinking along those lines, but I looked up some EV truck batteries, and there's enough room between the cargo area and the bottom of the frame for more than one EV Semi battery pack. I wouldn't add two, or the HEMTT would sink through concrete...

I'll probably keep the gearboxes and either add on large electric engine or split it into two power units (front and rear feeding the forward and rear gearboxes.

I drew (CADed?) up a 40kWh generator, based on the EPS 40kWh diesel generator. In 1/35 it's 62mm x 22mm:



So it can fit over either side of the engine platform or in the middle, where the old engine would have been, although at about a ton, it should probably go in the middle of the engine deck.

I now have to deconstruct the generator, because I don't want to run a 9hr print (in the best orientation). I think I can break it down into some quicker to print sections and not sacrifice on detail.

[Wardukw]

Enjoying this Frank mate 👍 

[frank2056]

Phill - the thing is I'm sitting here with the skeleton of the HEMTT with little building going on (at least physical building) while things get printed. I think the motors will be next and maybe a plastic box for the batteries - since they'll be mostly invisible, except for everyone watching this build...

[Wardukw]

Phill - the thing is I'm sitting here with the skeleton of the HEMTT with little building going on (at least physical building) while things get printed. I think the motors will be next and maybe a plastic box for the batteries - since they'll be mostly invisible, except for everyone watching this build...

Well Franky mate it's always the case ..have a grand idea ..attack said idea with speed and them sit there trying to figure the bloody thing out 
As for those batteries..an armoured box is definitely the way to go cause they'll never be seen .
Just stuff some danger decals on it and bingo ..a battery box 📦 

[scooter]

Phill - the thing is I'm sitting here with the skeleton of the HEMTT with little building going on (at least physical building) while things get printed. I think the motors will be next and maybe a plastic box for the batteries - since they'll be mostly invisible, except for everyone watching this build...

Just a thought, if you're doing them, I'd put your fresh, grey, and black water tanks under your battery boxes.  And clustered around the CG of the vehicle.

[frank2056]

I really should calibrate the printer, especially now that I've used up this old (but excellent) resin. This is the generator - it has some printing flaws, but good enough for now:



Closeup. I sanded off some of the supports, hence the dusty appearance:



I have to rethink the location and layout of both the generator and office space.

Also, with all the tires on, this is a very heavy model. I have to rethink my approach next time I make tires this big (I could hollow them out, or make the tires and wheels/hubs separate)

[frank2056]

I printed a couple of generators, large electric motors and some motor supports. The generators came out OK; I started some pre-processing before painting them.

The generator in the middle was printed with 30 micron layers; the other two (and the motors) in 50 microns; much faster and the loss in resolution is minor. The motor in the middle lacks motor supports (on purpose):



Here's a closeup of the control panel for one of the 50 micron generators. The keyhole is just under 0.6mm in length:



The engines are completely made up; I used images of large electric semi engines that I found online for inspiration:



The two smaller boxes are for cooling (oil, I assume).

Engine end. You can see some printer artifacts, but they'll disappear with some light sanding and primer (maybe only primer):



Underside with the engines tacked in roughly the correct position:



 The white "battery pack" is from the Space: 1999 Nuclear Waste Disposal Area 2 Diorama Set it's a good source of parts.

Top side with the battery pack in place. Fits perfectly:

[Rick Lowe]

 

[NARSES2]

The quality of those prints amazes me. The speed the technology is advancing at even more so. Terrific work