1/35 HEMTT Explorer

[Frank3k]

Inspired by Weaver's post of an AI generated HEMTT Expedition over at WhatIf 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!

[Kerick]

Sounds like a remake of operation paperclip.
This is going to be fun to watch.

[Jeffry Fontaine]

The new tires/wheels look fantastic Frank.  The slight/subtle increase in dimensions really makes the things look more "rugged" than the original kit parts. 

Where are you going to place your auxiliary generator to charge your batteries?  Also where are you putting your battery banks?  Inquiring minds wish to know more. 

[Story]

Just to be the Devil's Advocate, there IS a Command Post Connex that could be bolted onto a HEMMET flatbed.



Bet you a nicely worded email to them would result in a set of drawings
https://intelligence.airbus.com/industries/defence/military-mobile-solutions/fortion-mobile-command-post/

[Kerick]

Where’s the giant map board and all the grease pencils!!

[robunos]

Reminds me of this . . .


https://all-andorra.com/15v148-topol/


cheers,
Robin.

[Frank3k]

Just to be the Devil's Advocate, there IS a Command Post Connex that could be bolted onto a HEMMET flatbed.

That is 3x bigger than what I imagined would fit.

Why do they need that much space for Powerpoint presentations?

[Frank3k]

Reminds me of this . . .


https://all-andorra.com/15v148-topol/


cheers,
Robin.

That's sort of the inspiration; I like the exterior details. I'm using an ICM KUNG shelter to get ideas/dimensions, even though it's smaller than the space available on the HEMTT

[Frank3k]

Where are you going to place your auxiliary generator to charge your batteries?  Also where are you putting your battery banks?  Inquiring minds wish to know more. 

I was thinking of putting the aux generator either at the rear of the vehicle (reducing the "office space" by a bit) or where the current engine is, only sideways to allow for a passage from the cabin to the shelter.

the batteries will be in the space under the shelter - it looks like there's room for 2x the number of batteries in the typical EV semi. I won't put that many in, since that would put the batteries at around 15,000 lbs. So about 1/2 - 3/4 the space will be for batteries. For the projected range, the diesel generator can charge the batteries and make up for the difference, so maybe this is more of a hybrid EV truck.

[Jeffry Fontaine]

Just to be the Devil's Advocate, there IS a Command Post Connex that could be bolted onto a HEMMET flatbed.

That is 3x bigger than what I imagined would fit.

Why do they need that much space for Powerpoint presentations?

It is not about the PowerPoint presentation, it is about the number of people that you can torment with the presentation in one room.  The more that suffer through the presentation together the better. 

[Jeffry Fontaine]

Reminds me of this . . .
https://all-andorra.com/15v148-topol/

cheers,
Robin.

That's sort of the inspiration; I like the exterior details. I'm using an ICM KUNG shelter to get ideas/dimensions, even though it's smaller than the space available on the HEMTT

-- The shelter component looks like a great idea so far.  Just like to add to that, Italeri did offer a nice (yet generic) S-280 type electronics shelter a few years back (2001) that would also be an excellent candidate for your HEMTT.  Especially if you could combine two of the things together end to end.   

Link: ScaleMates.Com > Italeri (6388) 1/35th scale - Shelter

Where are you going to place your auxiliary generator to charge your batteries?  Also where are you putting your battery banks?  Inquiring minds wish to know more. 

I was thinking of putting the aux generator either at the rear of the vehicle (reducing the "office space" by a bit) or where the current engine is, only sideways to allow for a passage from the cabin to the shelter.

the batteries will be in the space under the shelter - it looks like there's room for 2x the number of batteries in the typical EV semi. I won't put that many in, since that would put the batteries at around 15,000 lbs. So about 1/2 - 3/4 the space will be for batteries. For the projected range, the diesel generator can charge the batteries and make up for the difference, so maybe this is more of a hybrid EV truck.

-- With the switch to electric motors would there not be space available behind the truck cab for the generator?  You indicated that there would be two motors (one for each set of 4 X front and 4 X rear wheels).  With the removal of the engine from the location behind the cab there would be enough space available for the generator unit to occupy that area?  Putting the generator unit at the rear would also be an excellent choice as it would/could replace the hydraulic lifting apparatus that is mounted at the rear of the vehicle.

[Frank3k]

This is what I designed today, based roughly on the EPS 40kWh diesel generator. In 1/35 it's 62mm x 22mm:



It fits over either side of the engine platform or in the middle, where the old engine would have been. The electric motors would be in the bay under the generator. It would also fit on the crane platform as well,
 although at about a ton, it should probably go on the engine deck

[Story]

Just to be the Devil's Advocate, there IS a Command Post Connex that could be bolted onto a HEMMET flatbed.

That is 3x bigger than what I imagined would fit.

Why do they need that much space for Powerpoint presentations?

It's an expando van (like what they mounted on the old 5 ton trucks), it compresses to 1/3 the width when on the move.

https://www.oshkoshequipment.com/products/detail/1/4287/M820-Expansible-Van-Military-5-Ton-Truck-C-200-48

[Story]

It is not about the PowerPoint presentation, it is about the number of people that you can torment with the presentation in one room.  The more that suffer through the presentation together the better.

How positively Lovecraftian a notion. 

[ChalkLine]

I really want to see one of these with little outrigger wheels so I can imagine it scooting down the road while inside the guys' coffee goes everywhere 

[Frank3k]

I really want to see one of these with little outrigger wheels so I can imagine it scooting down the road while inside the guys' coffee goes everywhere 

Vodka, in this case. Probably wouldn't need to be in motion for it to slosh around. Вова, а грузовик движется или водка?

[Frank3k]

I really should pause to 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)

[Frank3k]

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

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:

[LemonJello]

Awesome work.  I'm really digging the 3D printed parts - I need to get my setup back in operation.  This is inspirational.

[Frank3k]

Thanks - at times it's 100% a PITA, especially the cleanup.

I'm thinking of replacing the former engine platform with a 3D printed slab (because it's easier to print a square 1mm think slab of plastic than it is to cut it neatly) that extends (or at least matches) the cargo area height.

[robunos]

Probably a bit late now, but I had a thought. how about using an ISO container as the basis for the body ?


cheers,
Robin.

[Frank3k]

Robin - I have a 20 foot container in my stash that I've been eyeing. I'll see if it fits.

[Jeffry Fontaine]

@Frank. 

I was going to suggest the same option as Robin but opted to keep my pie-hole shut.  But as Robin said, adding the 20.0' ISO Container would be a quick alternative to the build a box from scratch. 

My own experience with the Italeri 20.0' ISO container had mixed results.  The roof and floor are created from two near-identical parts on two separate runners and getting the things to align properly when glue was applied caused some small hiccups for me.  The resulting floor that was created had a large obvious seam right across the middle of the floor.  Same problem for the roof but not much can be done about the top.  I added some ICM PAG-14 airfield plates to cover the seams on the floor and have something that resembled an actual floor.  The 1/1 scale 20.0' ISO container in front of my residence has a very crude floor so it was not too far off from what I added to the 1/35th scale Italeri ISO container.  I also have some of the Trumpeter ISO containers in the stash but have yet to actually do a close inspection of the contents. 

Also, love the GENSET and tires that you have printed.  How long would it take for you to print up some GENSETS and wheels? 

[ChalkLine]

There's free containers over at Cults

[Frank3k]

@Frank. 

I was going to suggest the same option as Robin but opted to keep my pie-hole shut.  But as Robin said, adding the 20.0' ISO Container would be a quick alternative to the build a box from scratch. 

I'll try it - at least the walls. I was planning on covering up the roof with equipment, anyways.

Also, love the GENSET and tires that you have printed.  How long would it take for you to print up some GENSETS and wheels? 

At 30u resolution, about 5 hours, each.

At 50u, about half that. I can send you one (or two) of the spare generators and a bag of wheels that failed. The resin I was using was old, so I risked using the parts as their own "calibration" so some of the axle connections are defective. Easy solution is to either drill out a new one or glue a plate with epoxy and add a new axle hub.

I should get some of my favorite resin today, since I still need to print more parts.