The model of the central object of my diorama was built out of the Dragon kit number 6421 "Quad Gun Trailer M55":
This is a very interesting kit, this type of armament is available as injection model for the first time. Although modelers attempted to build similar subjects taking the mount from kits of the M16 vehicle, the M20 trailer was only available in resin kits, now the complete M55 comes as complete plastic kit. I think the Dragon's product is very good, the parts' fit is almost perfect, and the detail level and accuracy are also very good.
I started the build from the power charger, which charged the battery powering the whole mount. The power charger is like the heart of the whole system, without it running the power from the battery wouldn't last for long. Using the TM photos (see here) I corrected a minor flaw in the power charger's shape - the distance between the motor and the blower.
I fabricated such details as ignition cable and carrying handle from copper wire. I also replaced the exhaust pipe with copper. Because of their complicated shapes, all parts were painted black before assembly, to avoid problems with unpainted spots later. I used black Gunze paint, which is solvent-soluble after it dries, so it doesn't have to be scraped off the joints glued with acetone, as I do it.
Next I took care of the battery, slightly reworking its retainers:
After painting, the battery and the power charger looked like on the photo below. The battery should be matt black. When researching I encountered opinions that this type of generator is incorrect for the Vietnam War period. The correct one was manufactured by Lycoming and the quads using such generator can be distinguished by a large control box located behind the gunner's head, in the rear of the mount, above the generator. The photos I have partially prove this, unfortunately it's very hard to get more details on this, so in my model I left the corrected kit power charger.
Then I started building the mount itself, I wanted to prepare the place for the gunner to occupy, while the gunner's figure is built in parallel.
There were some problems with the photoetched part from the kit, shown on the picture below. It required narrowing, which was a relatively hard, precise operation.
Then I went on to build the transport trailer. For many modelers exactly this part of the kit is the reason to buy it. wherever the M45 mount showed up in Vietnam, it was always in connection to th M20 trailer, and the trailer was only available in resin before. The kit parts fit very closely and they depict the trailer with good accuracy. The bottom of the trailer might need filling, although it won't be visible unless somebody wants badly to look at the model from the underside.
While mounting the trailer light it's important to pay attention and not mount it "upside down" like the instructions want, but to orient it properly, like shown on the picture below:
I built the jacks, that lift the trailer for transport and lower the trailer for firing. I replaced the pins in the jack rods with copper wire, I also drilled out the sockets for the jack handles:
I built the cannoneer's platform according to kit's instructions, but after checking the references it turned out that such platforms were only installed on mounts in the M16 and M17 vehicles and were absent on M55 trailers and because of that I didn't install the platform.
Next I painted the subassemblies that I have built. The right color would be the American Olive Drab, my take on this shade is a coat of Humbrol 66 overcoated with acrylic floor polish with a slight addition of acrylic black paint:
The kit's wheel attachments are meant to be installed in the transport mode. If they are to be displayed detached, as in firing mode, they need to be modified, which I did using TM photos as a reference. In the picture below the attachments can be seen with their hollow structure and the opening that receives the wedge securing the wheels for transport.
Next I went to build the trunnions carrying the M2HB machine guns:
The trunnions are relatively complicated-looking subassemblies that require precise assembly so that the machine guns are parallel to each other. The machine guns' mounts also hold the ammunition containers. The kit contains the "Tombstone" ammo chests, so called because of their shape. Such chests were out of use at the time of Vietnam War and I had to come up with something different. First thing I did was to scratchbuild the ammo container attachments out of sheet copper:
The kit-supplied M2HB machine guns are done nicely, have good detail and also have separate receiver covers, enabling the modeler to depict them in open position, for example as if when reloading the gun. It must be noted, however, that the cocking handles ale molded together with the receiver covers and must be cut off and glued onto the cocking levers (molded together with the gun body), if one would go for open receiver covers. When putting the covers on in closed position, everything looks fine without modification. The cocking handles should have the color of dark wood.
Additionally I decided to fabricate the flash suppressors, often seen on the M2's in Vietnam. The cones were made by turning a polystyrene rod using a little hand-held drilling/milling motor. The mounting brackets were made of copper wire and stretched sprue. I also slightly drilled out the cooling jacket's holes:
After painting the guns Gun Metal colour (Humbrol 53) they looked like the following foto shows:
There still remained the question, from what kind of ammo container will the guns be fed. After withdrawing the "Tombstones" standard 12,7 mm ammo boxes holding 100 rounds on trays were used. But I also encountered references showing a modification that used part of the ammo box tray welded to a cut-down jerry can, like on the photo below:
Such modification allowed to load the machine gun with 200 - 300 rounds, instead of the standard 100.
I decided to try this on my model. I cut down scale jerry cans from the Academy's kit number 1326 "M151-A2 Mutt & Trailer" and I glued the tray details (made out of styrene sheet) to them, like in the next picture:
The ammo belt comes from the AFV Club kit number 35035 "Cal.30/Cal.50/40mm Modern U.S. Ammunition Box & Ammunition Belt". The ammo cans were painted rusty and gun metal colors:
I put hair spray thick on top of the Gun Metal (Humbrol 53) paint layer, and after it dried I painted the ammo cans olive drab, like the other parts of the model.
This allowed me to depict chipping paint by scrubbing the surface with various materials, brushes and so on. This exposed the colors below the olive drab layer:
Then I started assembling the trunnions - I painted the machine gun supports and after they dried I glued the machine guns to the trunnions:
Next were the ammo cans and the hardest part - appropriately bent ammo belts and their feed ramps:
I also fitted the gunner's figure and seat:
To permanently fix the gunner in place, I still had to fit the handles controlling the mount's traverse and elevation:
The gunner fixed in place, also traces of sand colored wash can be seen. I wanted this wash to simulate the effect of dust laying in the crevices of the mount:
After fitting the trunnions the mount looked like on the following photo:
In the next picture the gunner's armored shield can be seen with it's top flaps, that I cut off and posed in folded position. In Vietnam these armored flaps often remained folded, which greatly enhanced the gunner's field of view. I also couldn't find a picture from Vietnam, where the optical sight would be fitted to the quad, so I left it out in my model.
The quad with it's trailer rests on two pieces of wood - in my opinion this would help keeping the base level on uneven surface and also would prevent getting water into the trailer insides, so I decided to show it this way on my model:
The mount is painted standard olive drab color, with no unit or service markings, like, for example, recommended tire pressure, as such markings were often painted over while repainting the equipment. Sometimes the crew would paint colorful ornaments and slogans on the armored shield, but my example didn't have it.