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 am sure there are many very interesting stories to share about this topic. Let's start with couple of articles about the weird and sometimes downright crazy history of Czechoslovak assistance which helped Israel to survive its early days. It's true that Czechoslovakia asked a lot of money for bypassing the UN embargo but it doesn't change the fact that it helped in the critical time - before the change of course was ordered from Kremlin in 1949. It's also worth mentioning that the arms-smuggling to Israel brought up to 1/3 of all foreign currency income of Czechoslovakia at that time! It's all in Czech but well understandable with the google translate.
Here in short the story of the secret Czechoslovak operation DI - the military asistance to Israel from the website of the Czech Institute of the military history. The article contains rare historical photos from the covert military training for army specialists (pilots, tankers, mechanics and even an infantry brigade made of volunteers from the former Czechoslovak Army Corps in USSR).
If you really like the topic, you can learn many more details from these six chapters of this superlong article (sure worth studying for anyone interested in the topic).
After that we have the totally crazy story of the Cairo bombing raid actually performed from the communist Czechoslovakia in 1948. Why don't we have yet any movie about three B-17s smuggled from USA, crewed by American-Jewish airmen, armed with former German machineguns and bombs and operating from an airfield located in then communist Czechoslovakia? If that doesn't deserve to be filmed than what does?
Most of you likely know that the first combat aircraft of the Israeli airforce were Czechoslovak Avia S-199 fighters. This stillborn stop-gap modification of the leftover Bf-109G airframe was rather useless in fact (Czechoslovakia had loads of Bf-109 airframes but no spare DB-605 engines whose reliability was absurdly low due to bad late-war steel, so the engines were replaced with Jumo-211 bomber units - completely unsuitable but available) but nevertheless it helped to stop the Egyptian attack on Tel Aviv and brought a very important psychological advantage on the Israeli side. More about these planes here.
To add to the absurdity of that time... the man behind the support for the Israel was Czechoslovak FM Vladimír Clementis who was executed just few years later as a result of an intra-communist power struggle.