I am positive that the turret top shown on Ultravanillasmurfs build is PERFECT for a 1939 T-26. The turret top has a round hatch with hinges to the front of the tank.
Ripley posted two blueprints for the T-26, both with Russian writing. The first says 1938, and the second says 1940. The one that says 1940 is one of several blueprints I have found for the 1939 model. Clearly shows a round hatch with hinges to the front.
Regarding crew positions, the driver sits on the right hull (when looking forward). The loader sits in the left of the turret. The gunner sits in the turret right, behind the driver. Usually, the loader was also the commander.
Which brings us to the periscopes. The T-26 "should" have two, one for the loader, and one for the gunner. But two were not always present. Plenty of photo evidence to show that sometimes only one was present. When only one is present, it is often the loader - remember this is ALSO usually the commander - who gets a periscope. The gunner has a sight so doesn't "need" a periscope. Those are for looking around the battlefield. The sight is used to aim the gun.
Regarding the turret top that ultravanillasmurf "fixed" by adding a rod to the cylinder. That is of course fine, and now that tank has two periscopes. But there is a lovely photo in Light Tanks (Mikhail Baryatinskiy) on p35 that shows a T-26 Model 1939 in the Kubinka Armor History Museum that shows a turret with only one periscope, on the left, for the loader/commander. If you google the museum name and T-26 you will find it.
So will that turret top work for a 1938 build? Yes. In T-26 Variants Part One (Miroslav Baric, Mike Collins) the photos are arranged by model type. And there are lots of photos that show forward hinged hatches open on the 1938 and 1939 models. There are also plenty of photos showing only the loader/commander having a periscope in the later models of the T-26.
I will say it again ... the parts combos allowed by the Rubicon kit allow one to build with reasonable accuracy any version of the T-26 except for what I refer to as the Model 1936. They missed having the proper turret top piece for that model year. But you have the parts to build all the others.
Like I said in another thread, while T-26s were being built, they would start to make a change in production, and then later, that was considered the new way to make them. So (for example) the 1938's were built with AA MGs on the turret top. By the time the 1939 model was "official" those were no longer being added. But can you find some 1939's with the AA MG? Yes you can.
The Model 1938 was almost entirely build WITHOUT the ball MG at the back of the turret. But not always. Can you find a Model 1938 with an MG at the back of the turret? Yes.
You also have the modernization of many T-26s. Those built int he early 30's were sometimes pulled in for engine overhauls and transmission replacements, and given whatever "new model" equipment and changes they could get. So you will find photos of what look like oddball T-26s. An earlier hull (evidenced by the placement of the headlight or horn or tools placement on the hull) but with a newer turret.
About the only bit of kit that is firmly fixed in time is the "rumble seat" cover for the rear engine deck. That change was a result of having T-26s fighting during the Spanish Civil War. The cover was made standard to the Model 1939 production. So if you are building any model of the T-26 with the intent of fielding it in a game that takes place before 1939, and you include that cover piece ... you are historically incorrect. But once that was added to the Model 1939, it started being retrofit to earlier models of T-26 as well. So a Model 1936 or 1938 (fighting the Germans in 1941) could certainly have the rumble seat air intake cover.
Happy building!
