Holt 150 Ton Field Monitor

[CharlieC]

As well as the pale khaki colour there are a lot of options for camouflage colours. The US Army in WW1 had 3 camouflage schemes before everything went Olive Drab at the end of WW1.

3-colour - White, Mid Green and Ochre
4-colour - White, Mid-Green, Dark Green and Ochre
5- colour - White, Mid-Green, Dark-Green, Mauve and Ochre. (used on large pieces)

The colours were separated by black lines - these are actually the layout lines for the camouflage (but that's another story). The attached image was borrowed from Ralph Lovett's artillery website and is a page from a contemporary book published by American Car Foundry.

Charlie

[rockpaperscissor]

Thanks for the information on early US Army camouflage schemes, Charlie. The Holt field monitor definitely falls into the "large piece" category so mauve would have been one of the applied colors. I wonder what the rationale for that color choice was?

So, the second turret is in place which completes this part of the build. The wheels are next and, as with most armor models, will likely be the most tedious, parts intensive, and time consuming portion of the build.

As designed, each wheel is made up of 44 parts excluding the treads. I haven't really decided on what form the treads will take yet. There are twelve T-shaped spokes on the inside of the wheel radiating from a central hub. Riveted to the spokes are 12 sectors that complete the circular wheel. Each side of the wheel has 6 arcs that are also riveted together. Each arc is made up of two pieces. Finally, a wide two-piece rim wraps around the whole assembly. Finally finally, some kind of steel treads will be applied to the rim: square to the rim, angled to the rim, staggered, cleated? I just don't know yet.

I slapped together a B&W wheel to verify the parts fit. It's a whopper - 3 1/4" in circumference. The rim pieces turned out to be about 1/16" too long, but everything else was fine. From the alpha build of the wheel I learned how important it is to precisely glue the hub in place - if it's not perfectly perpendicular to the wheel, the fit of the spokes will be affected, as well as the spacing of the wheel against the hull side. Some kind of jig is called for.

On to the pics.

[CharlieC]

I don't know what the rationale was for Mauve as a US camouflage colour. Ralph Lovett has noted that he's never seen any evidence that the 5 colour scheme was ever implemented although the 3 and 4 colour certainly were. In general there seem to have been two objectives in WW1 camouflage. Use colours which could help equipment blend into the background and break up the apparent visual outline of equipment so it was less obvious. Often artists were employed by armies to devise colour schemes and patterns to achieve these goals. The most famous one was by the painter Solomon who devised the camouflage scheme for the British Mark I tank. Unfortunately the tanks very quickly were covered in mud in action so it was a bit pointless and was why British armour was painted Brown until the 1920s. The Germans were known to use unusual colours in their camouflage schemes - Red and Purple in small amounts were observed so Mauve isn't too much of a stretch.

The Vector 1:25 model of the Lebedenko tank uses a card jig to build the wheels - and it certainly needs it - so it might be the best solution for the Holt 150-ton model.

How about the angled treads Holt used on the Steam Wheel tank which came from the Holt agricultural machinery? The form of these treads can be seen on the Steam Wheel Tank model on Landships II. Holt used to recycle their designs as much as possible so if they had built the 150-ton monitor reusing their tread design would have been likely. Image is a very early Holt tractor before they went to tracked vehicles.

Charlie

[xanthar]

There's a contemporary Holt project which has a different type of wheel that matches your source material and would look very cool on your model.
Here's a link to a 3D printed model of that :

1/35 WW1 Holt 3-wheel Steam Tank
– vargas_lg

[CharlieC]

Originally Posted by xanthar

There's a contemporary Holt project which has a different type of wheel that matches your source material and would look very cool on your model.
Here's a link to a 3D printed model of that :

1/35 WW1 Holt 3-wheel Steam Tank
– vargas_lg

A model of the Wheeled Steam Tank with the correct Holt wheels is on Landships II - the resin ones are approximate but not accurate. No one ever photographed the front of the tank - all of the existing images show the rear of the tank with the double trailing wheels. The tank almost certainly wasn't armed with a howitzer - the original specification asked for a pair of machine guns only. A copy of the text of the original documents about the Steam Tank are at:
Steam Wheeled Tank - Landships WW1 Forum (scroll down to the post by user "Neal").

Charlie

[xanthar]

Yeah. That wheel design just scaled up. I took a stab at modelling it. Would you like me to print some for you, Don?

[rockpaperscissor]

I'm back after a bit of an absence. Thank you for your very kind offer, xanthar. Your 3D model of the Holt steam tank wheel looks great. I see from the link that you provided that the 3 wheeled steam tank weighed in at 10 tons. The monster I'm modeling was projected to weigh 15 times that. Assuming that each wheel would have weighed at least 5 tons, we're still talking about them having to support a 130 ton hull. I just can't imagine lattice work wheels holding up to the stresses of traversing the uneven rocky terrain of the American southwest and northern Mexico bearing that kind of burden.

So...in the end I went with something more substantial and simpler to build. Even my simpler wheel is made up of 94 individual parts. It took quite a while to assemble the first one, and I had to make a few slight modifications to dial in the fit of the parts. Building the remaining three wheels should go quicker. In fact, the assembly line has already started.

Since I took the photo of the parts page (pic 1), I've added numbers to the wider arc shaped pieces so any future modeler would place them around the wheel in the correct sequence. I took the time to highlight the top of each rivet, so proper placement is important (to me, anyway) to preserve that little detail.

The rest of the photo shows the wheel from various angles. The last photo shows it slid in place over the axle.

[Don Boose]

Excellent work, Don!

It has been fun following this project.

Don, too

[Vermin_King]

It's a lot of fun trying to figure things out on the unique models. I hope this continues to be a pleasant challenge for you

[CharlieC]

The wheels came out very nicely. It seems to me you've hit the sweet spot of just enough of a challenge to build without falling into obsessive detail.

(I'm building the Model-Kom Comintern tractor at the moment - I looked at the free MBA Comintern - talk to me about obsessive detail).

Charlie