During the years 1941 thru 1943, Great Britain sent a little over one thousand Matilda tanks to the Soviet Union as part of the Allied Lend Lease Program. The Soviets appreciated the armor protection of the Matilda but were underwhelmed by the 2 Pounder cannon as it became less and less effective against the improving German armor. To improve the penetrating power of the Matilda, plans were made to install the M1941 ZiS-5 76mm tank gun found in KV-1 tanks.

The turret interior was modified and a new mantle and gun mount based on the on the KV-1 was installed. One prototype was built and tested but was deemed unsatisfactory. The turret was already cramped with the 2 Pounder so installing the 76mm gun only made things worse for the loader. By the time the prototype was ready for testing, the project was cancelled as the guns set aside for the conversion were needed for Soviet production lines. 

I became aware this prototype on an online model forum and was instantly drawn to it. That particular build used a resin conversion kit to modify a Tamiya Matilda into the Soviet prototype. It took a little while to locate the obscure Russian resin kit online and as I studied the available photos of the contents I determined the conversion kit has some accuracy issues. Discouraged, I looked through my spare parts bin from various Trumpeter KV-1 projects and found enough pieces to get started with a scratch built conversion. After further studying the few available reference photos of the prototype, I decided I wanted to try a different approach to build the unique parts. It was time to break out the digital calipers and 3D CAD software and design my own parts for 3D printing.

Images of the final build.


In progress images and descriptions

My day job is designing complex parts and assemblies in 3D CAD so I was able to transfer that skill set to designing parts for my own use. For this build I used the Tamiya 35355 Matilda Mk.III/IV "Red Army" as the base of my conversion. The reference photos show the prototype has the large side hatches for running gear access of an earlier production Matilda but I was OK with this difference since I wasn't trying to replicate the prototype but build a Matilda as if the 76mm conversion program continued.

The model was detailed with the Eduard 36094 PE set for the Tamiya Matilda 35300. I didn't use everything in the set as reference photos showed a bare bones turret missing most of the external fittings. The one extra detail added to the turret was replacing the kit mount for the exterior grenade launcher. It's unpopulated on the Soviet prototype and I thought this was a nice detail to add. The kit part was a little thick so I made a new one out of styrene sheet and few Aber photoetch screw heads.

The rest of the steps were pretty straightforward. Before gluing the armored side panels in place, I sprayed the hull undersides and running gear black- green since it was going to be difficult to get paint up there once the panels were in place. I assembled the panels and applied a smooth grey primer layer over the whole model to check for defects. These were cleaned up and then I applied a black- green pre-shade to any areas that might be in shadow. The model was first painted with a custom mix for the base color. I let this dry for a few days then applied a couple of light coats of hairspray. Over this hairspray layer,  flat white was airbrushed in a cloudy pattern. When dry to the touch, I scrubbed the white paint with a damp brush to chip and distress the finish.
Several different oil paint washes were applied to highlight details. A dark green was used for the upper surfaces while a dark brown-green was used on the side panels, running gear and engine deck. Additional dark brown and rusty-brown washes were used to add some interest. 

The tools and small details were painted with acrylic. The wooden handles were treated with oil paints. The metal parts were burnished with powdered graphite.

The tracks were airbrushed a black-brown base color. When fully cured, enamel and oil washes were applied to add tonal variations. I dusted the tracks with dry pigments and set with thinner first then followed up with a pigment fixer. The track contact faces were polished with powdered graphite. The tracks were installed - with some difficulty now that the side panels are installed. I realized later that I had installed the tracks backwards so had to remove and reinstall them on the finished model.

After the tracks were installed, I applied dry pigments to the running gear and  armored sides. This was first set with thinner and when dry manipulated with a brush. Once satisfied with the result, the pigments were set with pigment fixer.
The figure is the Tamiya kit figure with an Alpine resin head replacement. It was painted with acrylics and fortunately the raised hatches hide most of my ham-fisted attempt at figure painting.