Rubicon 1/56th Vietnam Gun Truck

A couple of months ago someone posted on Facebook a picture of an American Vietnam era gun truck made from a M54As truck with a redundant M113A1 hull on the rear load bed. It was called “The Big Kahuna”……I thought wow! What a fantastic subject for a model this would make.

All these vehicles were built in-theatre by their crews, to use as convoy protection vehicles. Initially they tried armouring jeeps with some success, but then took to mounting an armoured, open-topped box on the truck’s load bed. Armour plate was not easy to find, so when someone noticed that there were a number of written-off M113 APC available, and they would fit on the rear of the truck if their former running gear was removed, an instant solution was achieved!

Initially I thought no more of it until I noticed that Rubicon had a kit of the M54A2 and, of course, they made the M113 as well…..

I bought the truck from eBay for £15, and a friend sold me their unmade M113 from their stash and I was up and running.

There are many varied vehicles that can be built; however, they all have these features in common.

1.  A crew of four
2.  Armament of 3-4mgs – a mixture of M60’s and 0.5” HMGs
3.  Added armour to the driver’s cab
4.  Re-painted overall in Black to cut-down on reflection at night
5.  Outrageous artwork on the former APC’s hull sides

I decided to go for an imaginary vehicle that incorporated some of the best features I’d seen in the many photographs available on-line. Interestingly, the Rubicon instructions for the truck actually suggest doing this conversion.

The M54A2 Truck

I first was to build the truck chassis. Whilst things like the drive shaft are simplified, there is still adequate detail there given the scale and it is designed to be a strong finished model.

The chassis incorporates a winch and all the toolboxes and fuel tanks. There are a couple of driver figures – Army and Marines. At first, I thought I’d have someone riding shotgun with the driver, but research seems to point to the driver riding up front alone.

The cab goes together simply and, again, has more than adequate detail for the scale. The only thing missing is the distinctive wing mirrors (as seen on the box art).

I added scratch built armoured doors from plasticard, intending to add glazing (from figure blister packaging) at the end of the build. I textured these with Mr Surfacer 500.

Then, at total departure for me, I had a go at scratch building the wing mirror frames from soldered brass wire! This went reasonably well – the actual mirrors were made from plasticard and strip together with some sliced sections of sprue.

The wheels were all made from two parts and the load bed just required the framework to be removed before assembly. I added some stays for the dropped-down tailgate and some brass wire securing loops on the front edges – ready to secure the M113 hull with chain.

I left the finely moulded radiator grill and the fabric cab roof (a solid one is provided too, as well as a 0.50” + ring mount as options) to aid painting and that was the truck completed.

The M113a1 APC

The actual hulls used were stripped of all that wasn’t needed. So, engine, transmission, suspension arms, torsion bars, fuel tank, trim vane etc. were all scrapped.

Some had the light clusters removed, whilst others left them in place – I opted to leave them on.

For the kit build it was easier to leave the engine as it helped to position the internal dividing walls. There is at least one example I’ve seen, where a route from the truck cab to the interior of the APC via the engine hatch was created. That would make an interesting model.

I did remove the fuel tank from the lefthand inner wall, replacing it with plasticard. But I retained the internal seating, radios etc.

The suspension arms were removed with my Dremel circular saw. The final drive casings should be retained as per the real vehicles. When mounted on the truck bed, the APC hull should have a pronounced upward slop towards the front where they rested on these final drive casings.

I stuck with the vehicles provided ACAV armament of two M60’s + one 0.50” HMG as the 2 crew figures were designed to go with these.

Once all the parts were assembled into sub-assemblies, I clipped it all together to see what the finished article might look like.

Painting.

I wanted a very worn, battered look to the finished model, so planned to firstly paint everything in US Olive Drab.

Before doing that, I sprayed the interior with a light duck egg green and painted all the internal details. I added the warning notice decals and weathered the whole interior before gluing the hull together. After masking all the open hatches, I sprayed all the outer surfaces with a coat of US OD.

I then sprayed a coat of Vallejo Chipping Solution. Once this was dry, I sprayed a coat of Vallejo Black, followed by some minor modulation with a slightly lightened black in the centres of any large open areas.

As soon as the black paint had dried, I attacked it with water, a stiff paint brush and a cocktail stick to scratch the black paint off wherever I thought wear would occur. This revealed the undercoat of OD, just what I was after.

I wanted to do my own artwork for the sides and decided to have a go at making my own water slide decals!

I purchased some white decal paper from eBay (works out about £1 for an A4 sheet, you can get clear sheets too) and set to designing some artwork in PowerPoint.

I took graphics from Google and used one of the hand-written fonts available in Microsoft to try a variety of designs. I finally decided to go with the Wile-E-Coyote designs as he’s my favourite Warner brothers’ character of all time.

With hindsight I should have done this in Publisher, as there was a slight difference in the formatting when I printed them out, to how they looked on screen. Nevertheless, I was left with enough useable prints that I could get on with the task.

The next stage you’re advised to take is to apply 2-3 coats of spray lacquer. I used matt spray varnish which seemed to work OK.

I then cut the decals out leaving no overlap at the edges as this would have been white. Then applied them just as you would a commercial decal using softener.

The 3 coats of varnish had created a slightly raised profile which is exaggerated in the photographs. This was not what I needed, so I decided to sand down the edges with a fine grit sanding stick to feather the edges and better blend them in. I then re-painted as much of the exposed hull side, including the decal, as I could with the same Vallejo black. This didn’t look too bad.

Other colours I painted were the yellow strip on the bonnet front, the grey rubber dust guards on the sides of the APC and the “Stars & Stripes” decoration for the ACAV turret.

Crew figures.

Between the two kits there are five figures you could use – two seated and three standing. All are sculpted wearing flak jackets over fatigues and have US issue jungle boots. There are a variety of heads – wearing M1 helmets, berets or vehicle crew helmets.

I went with one seated figure with M1 helmet as the driver and three standing figures for the M113 hull crew.

One was the man operating the 0.5” HMG wearing a helmet, another the M60 gunner, again in M1 helmet.

I then created a third figure to place in the former driver’s position, armed with an M3 “Grease Gun”. I’d read online that these weapons (still being issued to AFV crews in the 1990’s) were popular close-in defence weapons, together with shotguns and M79 “Blooper” grenade launchers. The arms with the Grease Gun came from the Warlord Games US Para’s sprue, and whilst a little large for the slim Rubicon figure, worked with a bit of careful re-sculpting. He’s wearing a vehicle crew helmet as he would be the radio operator, and crews favoured the built in helmet headsets.

The figures were all primed in white and finished using a variety of Speed paints from Citadel and AK.

Weathering.

Previous Vietnam vehicles I’ve modelled have been dirtied using a MiG Red earth pigment as lots of contemporary photographs show the ground colour to be this reddish brown. Reading about the convoys and the roads they used I now believe the earth in the southern areas of Vietnam were a much lighter dusty brown, so this time I used MiG Desert dust mixed with Earth Brown pigments instead.

I mixed these two pigments with Vallejo Desert Dust wash to make a watery paste and then applied this around any raised detail. As it dries it settles to leave a deposit of dust/dirt around the raised detail which I think looks quite authentic.

The wheels (having been painted in black with black rubber for the tyres) were given the same treatment to ensure the dust mix settled into the tyre tread grooves.

Areas around the cab where the crew would stand and the scratch-built ladder on the rear, were given a rub of graphite from a soft pencil to simulate the wear.

To help further with breaking up the overall coat of black paint, and to blend the decals in, I added “water” streaks running down the vertical panels using neat Vallejo Desert Dust wash.

Final Assembly.

Now it was time to bring all the sub-assemblies together.

With the Rubicon models being made from ABS I find it important to scrape the areas back to the grey plastic, where I’m going to apply Tamiya Extra Thin Cement. This is the best way to ensure a good, long-lasting bond, but requires a bit of dry-fitting and forward planning to avoid wrecking the paintjob.

First job was to attach the securing chains to the M113 hull. I bought a short length of scale chain (2mm link) from eBay and cut that to length. I then formed a hook at each end with some thin brass wire. These hooks were secured in the kits lifting eyelets with some super glue.

The M113 hull was attached to the load bed and the chains were crossed over the truck’s spare wheel and attached to the brass loops I’d made on the front edge of the load bed. These were secured with super glue as well.

The ACAV turret and the two M60’s were added, together with the two gunner figures from the M113 kit. The third crew figure was glued standing on the M113 driver’s seat.

The M113 hull was then glued to the truck’s load bed, a small amount of sprue was used to pack under the final drives to ensure I had that slightly sloped look to the hull.

The truck cab was glued to the chassis and then the combined load bed & M113 hull was then attached behind the cab.

Finally, the wheels were added. The almost completed model was then given a coat of Ultra Matt varnish to seal all the weathering.

The last job was to add the glazing I’d cut from an old Warlord blister pack with a little PVA glue. The canvas cab roof could then be added, and the build was finished.

Basing.

I designed a simple base to display the model and 3D printed this on my Creality Ender 5 Pro.

The road surface was simply recreated using Vallejo grey pumice which was then sprayed brown and finally dry-brushed. A few strategic grass tufts finished the job.

The truck was secured to the base by short pins cut from a paperclip. These were super glued into small holes drilled into the tyres and fed through corresponding holes drilled in the base. They were then bent over to stop the vehicle from falling off.

The sides of the base were decorated with a number of thumbnail pictures of actual vehicles taken from the internet. These were formed into strips in Publisher, printed, laminated and attached with double sided tape.

And there you are, all finished. On to the next one now…..something a bit simpler, I think!