I came across a plan view of a Vickers online, and a length, so I just worked out all the dimensions from that. The Vickers is basically a box with a cylinder attached, and all the details were all boxes and cylinders, so it was just a matter of puying the right styrene stock, cutting it up, and sticking it all together. The body and turret are .5mm styrene, which is almost the perfect scale thickness for the armour at 1/16. I tried to follow the construction of the original wherever possible, since everything was going to be pretty visible at that scale. I have a 3D modelling program to work out a pattern for the turret armour plates. I glued them together in a ring, and I cut an internal ring of thicker styrene to hold it in a circular shape. For the body, I took measurements off a plan I found in a WWI armour modelling website, scaled them to 1/16 in Photoshop, and measured and cut from those. Those plans were for a 1920s vintage AC. and since then, I've found some better references of WWI vintage ACs, including photos of what is possibly the only surviving WWI vintage Rolls AC, so I want to redo the body.