I haven't found an appropriate thread where to put some interesting rare stuff related to WW2 development, be it industrial one or makeshift field modifications.
Let's start with two things. The first one is a relatively recently found rarity from Swedish archives - a drawing of ČKD/BMM V8H-Sv tank. The drawing and a letter was found by WoT enthusiasts in Swedish archives in 2014 (the original announcement and the drawing source is here). The drawing is from a message dated 8th September 1941. One of the reasons why this drawing was not known before may be that the Czech archives were partially destroyed by floods in 2002. Anyway it is an export modification of the V-8-H tank accepted into Czechoslovak service as ST vz.39 but never produced due to the cancelation of all orders after Münich 1938 (for the same reason negotiations about licence production in Britain failed). Also later attempt to sell the tank to Romania failed due to BMM being fully busy with Wehrmacht priority orders. The negotiations with Sweden about licence production of V8H-Sv lasted till 1942, at least in May 1942 Swedish commission was present in Prague for negotiations. The tank differed compared to the base ST vz.39 in thicker armor with different front hull shape (armor 60 mm @ 30° on the hull front and also 60 mm on the turret; all sides were 40 mm thick). The tank was heavier (20 tons) and had the LT vz.38 style suspension with probably even larger wheels. The engine was still the same Praga NR V8 (240-250 Hp per source). The armament was unchanged with 47 mm Škoda A11 gun and two vz.37 HMG. The commander's cupola was of the simple small rotating type similar to those used on AH-IV-Sv tankettes. It is known that the Swedes officially asked to arm the tank with 75 mm gun, replace the engine with Volvo V12 and adding third HMG to the back of the turret. In the end the Swedes decided to prefer their own Strv/m42.
Source of the drawing
The second is makeshift field modification found on Balkans. It appears Ustasha forces (and possibly some SS anti-partizan units) used several Italian M15/42 medium tanks with turrets from Pz.38(t). There are several photos of such hybrids but little more is known. On one photo it is possible to see Ustasha registration number U.O. 139.
Few more photos of such hybrid.
It appears that the source of all those photos to be found on the internet is this book, Armoured units of the Axis forces in southeastern Europe in WW2 by Dinko Predoevic.
11-12th May 1945 near Příbram, Czechoslovakia.
I guess it's little known event but in fact it was a real battle in terms of scale. While the German capitulation was signed already on 8th May the war continued in Czechoslovakia for coupple more days. Fighting in Prague ceased finally on 9th May but the German units didn't want to surrender to the Red Army and intended to fight their way to the Americans. Quite a strong group of them found themseves south-east of Příbram. Roughly 6-7 thousand soldiers from various SS and Wehrmacht units, mainly remains of SS Kampfgruppe Wallenstein, commanded by the SS chief commander in Protektorat Böhmen und Mähren Carl von Pückler-Burghauss tried to negotiate with the US Army but without success. Meanwhile his men started to fortify themselves hoping to find an agreement with the Americans. The German units were frustrated and murdered several civilians around the area. Due to that several partisan and so called Revolution guard units engaged in the figting with them but those were too weak (not more than few hundred men). In one occassion SS used waving a white flag to lure the partisan out of a cover and kill them. On May 11 Red Army engaged in the fighting and so did some elements of the US army serving as the imaginary wall behind the back. On 12th May early morning von Pückler-Burghauss finally handed his capitulation to the hands of Soviet general Seryogin from 104th Guard Rifle Division and American colonel Allison from 4th Tank Division. Some six thousands of German troops were takken prisoners by the Soviets while hundreds of soldiers and around two dozens of partisans died on the battlefield (the last one - armed local was killed two hours after the capitulation was signed). SS-Gruppenführer Pückler-Burghauss shot himself in the head shortly after he signed the capitulation.
There is a monument built on the place as You can see here.
Usually they hold a small memorial event on the battlefield but this year it was canceled due to the COVID-19 pandemy. Nevertheless here is some footage from 2018.
I think that possibly some of you might be interested in our interwar Czechoslovak stuff. For starter I've decided to share with you a wonderful online document about our fortification system. At the very beginning I'd like to say that I have nothing common with its creators. It's just an incredible gem that deserves to be shared with you. If you know it, sorry for that, nevertheless I think most of you don't. Since I am new here I will not waste your time debating what if scenarios. Don't worry.
Well, enough of talking. What I want to share with you is a massive interactive map of our fortification system containing nearly 11 thousand objects with information about every single one of them. You can switch on even such crazy details like cable networks or construction facilities used for building of the fortifications. The map is directly linked with an online database of the fortification buildings where more than 2000 objects are listed with detailed description (plans, 3D models, photos, weapons, crew, important dates, recent state etc.). Unfortunately this database is only in Czech language but it can be a great source of information for you anyway (especially when linked with the map). The good thing is that the map alone supports other languages and you can easily switch them.
This is the base view where I have already switched on all objects. You can change background map type, information etc. on the left side and visualise everything what You want to see on the right side.
Let's zoom in a little bit. Here You can see one of the strongest fortified places - a valey at Králíky in north-east Czechia. As you can see the object marks have different shapes, colours etc. The shape is matching the menu on the right side. Triangles are concrete pillboxes vz. (mark) 36. Small circles are pillboxes vz. 37. The letter inside means type of the object (with one firing post, two on each side, angled one etc.). The color can be decoded from the information table in the bottom right corner. Basically it shows whether the object was actually built, if it was later destroyed or the works were only started or even not so. The heavy objects are the large circles. The numbers have also a meaning. It's a resistance class (1 -> 2 -> I -> IV from the lowest to the most resistant).
You can switch on also the ground plans of the artilery groups (fortresses with underground network between the casemates). You can see it here (fortress Hůrka).
You can also switch on the firing lines. Here You can see heavy artilery coverage of the most fortified section of the line (the sad thing is that no heavy artilery pieces were installed by the time of Münich crisis - but lets leave such details aside for now).
You can switch on the firing lines even for the pillboxes as you can see here on the example from the souther border. Nearly all Czechoslovak objects were built for side fire having superheavy resistance frontal walls with stone and earth covers.
If You zoom even more and switch for satelite map you get something like this. In this case the red color shows anti tank 47 mm guns and the blue color is 7,92 mm (sometimes double) heavy machine guns of a heavy separated casemate (possible use of light machine guns in observation cupolas is not marked). The grey color shows vz.26 light machine guns of the neighbouring pillbox.
You can click on every single object and you get available details. The first icon shows detailed lines of fire including realistic range. Bellow the L: L1 M ZN 3-4 means: Left side: L1 = 47 mm anti tank gun with 7,92 mm coaxial heavy MG; M = twin 7,92 heavy MG; ZN is I think type of the cupola but I'm not actually sure about it. The codes for the weapons are shown at the table in the lower right corner (you need to keep the cursor on the question mark).
The Second icon leads to a database of objects which is unfortunately only in our weird language. Anyway you can dig a lot of information from it as well (drawings, recent state, photos, exact location etc.).
The best thing is that most of the objects still exist till today (all of those heavy ones). The Germans managed to destroy roughly 2000 light objects (and gain some 11000 tons of steels from them). They managed to damage also many heavy ones when they were testing weapons and tactics for the future use duirng the WW2. They even moved some cupolas (and of course the famous hedgehogs) to other fortifications along the Atlantic wall or elsewhere. Many of them are made into better or worse museums today (large quantity is private now). Huge number of them is just left alone and freely accessible for anyone. If you are more interested I can give you tips which ones to visit. On the Czech map portal You can use a mode panorama which is basically the same thing as Google street view but it's much more up to date and it's nearly everywhere where they got at least with a motorbike. Since the fortifications are also visible there, you check where they are for easier access.
If you are interested I can continue the fortification topic with some other information (I'm no historian but I have visited quite many of the objects myself and read some books about them).
OK, so this was my first post on the forum. I hope you find it interesting and maybe for some of you it can be a reason for a trip, who knows :-)