[2] During 1932, work had commenced on the development of a new single-engined biplane fighter aircraft, the Avia B-34, which had been designed by aeronautical engineer František Novotný.

On 14 April 1934, the second prototype, while flown by test pilot Václav Kočí, successfully attained a Czechoslovak national speed record of 365.7 kilometres per hour (227.2 mph).

Partially as a result of its impressive maneuvrability, as well as some operators continuing to maintain a preference for the established biplane configuration over the incoming generation of monoplane fighters that would soon prove to outperform them, the B-534 stayed in production for considerable time (1933-1939).

While relatively ineffective in combat during the later stages of war due to its obsolescence, the type formed a sizeable proportion of several countries' military aviation components.

On 14 April 1934, the second prototype, while flown by test pilot Václav Kočí, successfully attained a Czechoslovak national speed record of 365.7 kilometres per hour (227.2 mph).

[citation needed] The B-534 was designed as a single-engine biplane fighter with a licence-built Hispano-Suiza inline powerplant, and fixed landing gear.

The air forces of the 1930s were reluctant to abandon the manoeuvrability and climb rates of biplanes for the speed of monoplanes, even in the face of new and better technology.

The success of Soviet pilots with biplanes may have contributed to this reluctance; they were known to strip their aircraft of sliding canopies, preferring to have the wind in their faces.

[11] One very modern innovation was a bubble canopy; this had been tested on a small number of the early series aircraft, although it certainly was not a standard fit.

These were not resolved in the summer of 1938; by this point, Czechoslovakia, sensing rising political tension amongst German claims to Czech-held territory, was eager to get more aircraft in the air, Avia decided to use a third machine gun in the nose.

[16] For the nation, time was running out and drew to Munich Diktat, at which point Germany commenced its occupation of the Sudetenland (the western border area of Czechoslovakia).

[15] The fuselage used a rectangular structure composed of steel tubes, which were attached together using a mixture of bolts and rivets and braced together using streamline wires.

[15] Production aircraft were exclusively powered by the Hispano-Suiza 12Y 12-cylinder water-cooled engine, rated to produce a maximum of 850 hp, which was built under licence by Avia.

[15] The total fuel capacity was 70 gallons (320 litres); a combined cooler and oil tank was installed beneath the fuselage, while a water-based radiator was also set below the engine.

[17] The B-534 was furnished with a monoplane tailplane, composed of steel and covered by fabric; similar construction methods were used for the fin and rudder.

By the summer of 1938, Czechoslovakia, sensing rising political tension caused by German claims to Czechoslovak border territory, was eager to get more aircraft in the service, thus Avia decided to use a third machine gun in the nose.

[16] However, there have been claims that the company had encountered substantial difficulties in adapting the aircraft to accommodate the additional weapon and these were not quickly resolved.

Consequently, however, the fuel load was decreased[16] Upon its introduction to squadron service with the Czechoslovak Air Force during the latter half of 1935, the B-534 was put to use in the interceptor role.

By then, high performance monoplanes such as the Bf 109 and Britain's leading models – the Hawker Hurricane and Supermarine Spitfire – were raising the bar of fighter/interceptor standards.

[20] Slovakia had to quickly make use of its newly formed air force, weakened by the departure of many Czech pilots,[23] to defend itself when neighbouring Hungary launched an invasion on 23 March 1939.

[27] On 6 September the Avias shot down Polish reconnaissance aircraft Lublin R.XIIID over Prešov, killing its two-men crew.

[26] According to aviation author Josef Krybus, on this front, moral amongst the Slovak pilots was low and no significant victories were achieved during their deployment.

[26] Over time, a combination of obsolescence, the lack of spare components and the old Czechoslovak air force's proprietary fuel mixture (BiBoLi, or some other mix of ethanol, benzol and petrol) finally relegated the surviving B-534s to performing the trainer role and other secondary duties during 1943.

[26] 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 leftover aircraft, including several B-534s stationed at Tri Duby airfield.

On 2 September 1944, Master Sergeant František Cyprich, just after testing a repaired B-534, downed a Junkers Ju 52 transport under Hungarian colours on its way to a base in occupied Poland.

[31] As the Slovak National Uprising was desperate for available aircraft, Sergeant Cyprich was derided by his colonel for not trying to force the Junkers Ju 52 to land and be captured instead.

[26] During 1939, Bulgaria opted to procure a batch of 78 B-534s, well after the enactment of the Czech partition, from Germany, who had captured a large number of the type.

[2] Following Germany's forced annexation of the remaining "Czech" part of Czechoslovakia as the Protectorate of Bohemia and Moravia on 15 March 1939, large numbers of captured B-534s were pressed into the Luftwaffe.

A second replica (Bk-534), using (like the Kbely example) some original parts, is displayed at the Museum of Aviation at Košice International Airport, Slovakia.