The B-534 was first used in combat by the Slovak Air Arm. Germany took control of the “Czech†part of Czechoslovakia as Protectorate of Bohemia and Moravia, leaving the “Slovak†part, Slovakia, as a minor ally. Slovakia acquired some 80 B-534s and Bk-534s from the Czech air force and quickly had to use them against Hungary during the border war of 1939. Later, two squadrons of B-534s assisted the Luftwaffe during the Invasion of Poland in September 1939. The same squadrons served with the Germans in the Ukraine during the summer of 1941, with one squadron returning in 1942 for anti-partisan duty. Obsolescence, lack of spare parts and the old Czech air force’s curious fuel mixture (BiBoLi, or some other mix of alcohol, benzol and petrol) finally regulated the surviving B-534s to training duties.
This would have been the last of the B-534s in Slovak colors if not for the Slovak National Uprising of September-October 1944. The rest of the Slovak air assets did not turn-coat as expected and the leaders of the Uprising were faced with using a rag-tag collection of left over planes, including several B-534s at Tri Duby airfield. On 2 September 1944, Master Sergeant Frantisek Cyprich, just after testing a repaired B-534, downed a Junkers Ju 52 transport under Hungarian colors on its way to a base in occupied Poland. This was at once the first aerial victory for the Uprising and the last recorded biplane victory of the 20th century. As the Slovak National Uprising was desperate for anything with wings, Sergeant Cyprich was cussed out by his colonel for not trying to force the Junkers Ju 52 to land and be captured instead. The last two B-534s at Tri Duby were burned as the base was evacuated on 25 October 1944.
Bulgaria bought 78 B-534s in 1939, well after the Partition. The last batch of these aircraft arrived in March 1942. On 1 August 1943, seven of these aircraft were able to make two passes at American B-24 bombers returning from the raid on Ploieşti. Hits were scored but no B-24s were shot down, and some of the damaged B-534s cracked up on landing. After the anti-German coup of 9 September 1944, Bulgaria switched sides overnight and its B-534s were often used in ground attacks against German units. On 10 September 1944, 6 B-534s blundered into a brief melee with 6 German Bf-109s at low altitude. One B-534 was lost, but the Germans quickly broke off, wary of the B-534's maneuverability and the low altitude.
Source - Internet - Wikipedia
