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{{Short description|1933 fighter aircraft family by Avia}}
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{{Infobox aircraft
 |name= Avia B-534
 |image= File:Avia B-534 IV. verze.jpg
 |image_border= yes
 |caption= Avia B-534 fighter, late variant
 |type= [[Fighter aircraft]]
 |manufacturer= [[Avia Motors|Avia]]
 |designer= [[František Novotný]]
 |first_flight= 25 May 1933
 |introduction= 1935
 |retired=
 |status= Retired
 |primary_user= [[Czechoslovak Air Force]]
 |more_users=
 |produced= <!--years in production, e.g. 1970-1999, if still in active use but no longer built-->
 |number_built= 568<ref>Aeroarchív – Avia B-534, Jiří Vraný, 1991, p. 3, {{ISBN|80-7030-114-7}}</ref>
 |unit cost=
 |variants=
}}

The '''Avia B-534''' is a [[Czechoslovakia|Czechoslovak]] [[biplane]] fighter developed and manufactured by aviation company [[Avia Motors|Avia]]. It was produced during the period between the [[World War I|First World War]] and the [[World War II|Second World War]]. The B-534 was perhaps one of the most well-known Czechoslovak aircraft of the era.<ref name="Krybus p10"/>

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 [[Aerospace engineering|aeronautical engineer]] [[František Novotný]]. During its development, various alternative engines were considered and trialled before eventually settling upon the [[licensed production|licence-built]] [[Hispano-Suiza 12Y]] engine. Other improvements during the prototype stage included the adoption of an enclosed cockpit along with a revised tail and undercarriage arrangement. On 14 April 1934, the second prototype, while flown by test pilot Václav Kočí, successfully attained a Czechoslovak national speed record of {{convert|365.7|km/h|mph}}. Deliveries of aircraft to the [[Czechoslovak Air Force]] commenced in October 1935.

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). During the late 1930s, Czechoslovakia sought to expand production of the type in response to German claims over the [[Sudetenland]] (the western border area of Czechoslovakia). Large numbers of the type saw combat with multiple nations during the course of the Second World War. 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.

==Development==
===Origins===
During 1932, the Czechoslovak aircraft company [[Avia Motors|Avia]] flew the first prototype of a single-engined fighter [[biplane]], the [[Avia B-34]], designed by [[Aerospace engineering|aeronautical engineer]] [[František Novotný]]. After modification, the Czechoslovak Ministry of Defence placed an order for B-34s.<ref name="AIJul74 p26">''Air International'' July 1974, p. 26.</ref> A second prototype, the Avia B-34/2, was built, which was intended to be powered by a {{convert|600|hp|kW|order=flip}} [[Avia Rr 29]] [[radial engine]] instead of the [[Hispano-Suiza 12N]] [[V12 engine]] of the first prototype and the initial production series. This engine proved prone to overheating and vibration, however, and it was decided to re-engine the B.34/2 before it flew, fitting it with a [[Hispano-Suiza 12Y]]brs V12 engine.<ref name="AIJul74 p26-7">''Air International'' July 1974, pp. 26–27.</ref>
[[File:Avia B-534 - prvý prototyp.jpg|thumb|B-534.1, the first prototype of B-534]]
The Avia B-34/2 made its maiden flight on 25 May 1933.<ref name="Krybus p3"/> The prototype was sent for testing in September and was redesignated as the '''B-534.1'''.<ref name="AIJul74 p27">''Air International'' July 1974, p. 27.</ref> On 10 September, the B-534 was displayed to the public for the first time at an [[Army]] Air Day. It was to compete against the [[Praga E-44]] and [[Letov Š-231]].<ref name="Krybus p3 4">Krybus 1967, pp. 3–4.</ref>

A second prototype, the B-534.2, was completed in September 1933.<ref name="Krybus p3">Krybus 1967, p. 3.</ref> It differed from the first prototype by having an enclosed cockpit and a revised tail and undercarriage. On 14 April 1934, the second prototype, while flown by test pilot Václav Kočí, successfully attained a Czechoslovak national speed record of {{convert|365.7|km/h|mph}}.<ref name="AIJul74 p27"/>

===Initial production===
More testing followed, and an initial order for 34 aircraft for the [[Czech Air Force#History|Czechoslovak Air Force]], soon increasing to 147, was placed on 17 July 1934.<ref name="AIJul74 p27-8">''Air International'' July 1974, pp. 27–28.</ref> At that time, the B-534 was well ahead of its contemporaries. The [[United Kingdom]] was still dependent on [[Hawker Fury|Hawker Furies]], with the first [[Gloster Gladiator]]s being produced at this time. The [[Soviet Union]] was placing its hope on its [[Polikarpov]] aircraft designs. The [[United States]] was still using descendants of the [[Curtiss Hawk]] series, with the [[Seversky P-35]] and [[Curtiss P-36 Hawk|Curtiss P-36]] about to fly as prototypes.{{Citation needed|date=January 2021}}

[[File:Avia B-534 I. verze.jpg|thumb|left|B-534, early variant]]
The B-534 was designed as a single-[[Reciprocating engine|engine]] biplane [[Fighter aircraft|fighter]] with a licence-built [[Hispano-Suiza]] [[inline engine (aviation)|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 [[monoplane]]s, 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 [[aircraft canopy|canopies]], preferring to have the wind in their faces. Aircraft with two fabric-covered wings and fixed landing gear were also less expensive to manufacture.{{Citation needed|date=January 2021}}

First deliveries of the B-534 to the Czechoslovak air force began in October 1935, and 568 had been completed by 1939. The first 100 of these were of the first series. The second prototype was the blueprint for the '''I series''', although it was built with an open cockpit. These early series aircraft were initially armed with four 7.92mm vz.28 guns. Two were located in the nose on either side of the engine in a similar manner to the [[Avia B-34]] and two were fitted in the wings. At an early stage of production, it was however recognised that the wing-mounted guns were troublesome. Aircraft from serial number B-534.47 were completed without the wing guns, which were also removed from the earlier aircraft. The first to fourth series aircraft were fitted with the [[Avia Motors|Avia]] licence-built version of the [[Hispano-Suiza 12Y]]drs engine. This was a liquid-cooled [[V12 engine|V12]]-cylinder engine with a capacity of 36.05 litres. On the ground its normal power rating was 650&nbsp;hp, it could deliver 750&nbsp;hp for two minutes.<ref name=vrany57>{{Harvnb|Vraný|1994|p=57}}</ref> At an operational height of 3,000&nbsp;m (9,842&nbsp;ft), it could deliver 850&nbsp;hp for 30 minutes.<ref name=vrany57/> At an operational height of 4,000&nbsp;m (13,123&nbsp;ft), it could reach 860&nbsp;hp. Total fuel was 347 litres (76 gal) which was held in two [[fuselage]] fuel tanks of 90 and 257 litres.<ref name=vrany54>{{Harvnb|Vraný|1994|p=54}}</ref>

===Further development===
[[File:B-534 III. verze.jpg|thumb|B-534, 3rd variant]]
The '''II series''' completed the remainder of the first order from the Czechoslovak Government, These were 45 aircraft numbered B-534.102 to 147. Like the '''I series''' these carried four guns. However the solution to the problems with the wing-mounted guns was to move these guns, now upgraded to the vz.30 to the fuselage with the others. The four 7.92&nbsp;mm (0.312&nbsp;in) [[machine gun]]s were located on the sides of the [[fuselage]], firing through the [[propeller (aircraft)|propeller]].<ref>Bílý, Miroslav and Jiří Vraný. Avia B-534: Cz. Fighter, 3rd and 4th Version, 2008, pp. 42–44, {{ISBN|978-80-86524-15-3}}</ref> 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.<ref name="Krybus p4"/>

During 1936, a second order for 46 aircraft were issued by the government. The first 25 of these were the '''B-534/III''' version serial numbers B-534: 148–173. Production took place in the second half of 1936. It entered service between March and April 1937. The '''III series''' had aerodynamic refinements which saw the streamlining of the front [[carburetor]] air intake. Mudguard spats were also often added at the factory to the main gear.<ref name="Krybus p4">Krybus 1967, p. 4.</ref>

The remainder of the second order from 534.174 to 534.193 were the '''IV series'''. With later orders the fourth series would occupy the serial numbers .174 and 445 and was therefore the most numerous of the types. The most important change to the earlier series was the enclosed cockpit.<ref name="Smith">{{cite book |last1=Smith |first1=Peter |title=Combat Biplanes of World War II |date=2014 |publisher=Pen & Sword |location=United Kingdom |isbn=978-1783400546 |pages=30}}</ref> The '''IV series''' also enjoyed a metal light alloy [[Letov Kbely|Letov]] ([[Hochfeld, Duisburg|Hochfeld]]) Hd-43 propeller. The various refinements allowed the '''IV series''' to have an increased speed of over 200&nbsp;mph, and this placed it on par with the best of its contemporary biplanes. A common alteration to the '''IV series''' was the replacement of the [[tailskid]] with a [[tailwheel]]. Operational experiences had shown that the spat on the main landing gear could become clogged with mud on grassy airfields and cause takeoff and landing problems. The spats were then often removed.<ref>{{Harvnb|Vraný|1994|p=22}}</ref>

During 1937, the superb performance of the B-534 was demonstrated at a flying exhibition. The aircraft was tested against the best in the world at the IV International Air Meeting at [[Zürich]]'s [[Dübendorf]] airport.<ref name="Krybus p5"/> The B-534 entered three of the competitions. The first of these tested climbing and diving. A [[Germany|German]] [[Messerschmitt Bf 109|Bf 109]] took first place and a [[Henschel Hs 123]] pilot pushed his biplane to claim second. The B-534 took the next three positions. The 534 outflew every other fighter participating, bar the Messerschmitt Bf 109 – and even then, the Avia was only 11&nbsp;km/h slower than the German aircraft.

Allegedly, problems were encountered with the redesign effort to adapt to installation of a newly installed cannon. 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. Judging by the size of the gun magazine, the nose machine gun was matched with an increased supply of ammunition.<ref name = "avia 36 37">{{Harvnb|Vraný|1994|p=36-37}}</ref> 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). Two series Bk-534 were produced, cn's 501 – 554 (63, for Czechoslovak air force), and cn's 555 – 620.<ref name = "avia 36 37"/> Only three of the second batch were completed for the Czechoslovak air force, and the remaining 63 aeroplanes from this production block were finished for the Germans, after the German invasion of the remainder of Czechoslovakia on 15 March 1939.<ref name = "avia 36 37"/>

==Design==
[[File:Bk-534.jpg|thumb|Bk-534]]
The Avia B-534 was a single-seat unequal-span [[biplane]] fighter aircraft.<ref name="Krybus p5">Krybus 1967, p. 5.</ref> The fuselage used a rectangular structure composed of steel tubes, which were attached together using a mixture of [[bolt (fastener)|bolt]]s and [[rivet]]s and braced together using streamline wires.<ref name="Krybus p5"/> The wing, which had a riveted steel structure and fabric covering, was attached to the fuselage using ''N'' [[strut]]s; similar struts were present in the outer section of the wings attaching the wings together. The forward section of the fuselage was covered with detachable metal panels, while the rear section had a [[fabric]] covering.<ref name="Krybus p5"/>

Production aircraft were exclusively powered by the [[Hispano-Suiza 12Y]] 12-cylinder water-cooled engine, rated to produce a maximum of 850&nbsp;hp, which was [[licensed production|built under licence]] by Avia.<ref name="Krybus p5"/> 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.<ref name="Krybus p5"/> Engine ignition was provided via the cockpit, along with automated [[fire extinguisher|fire-fighting]] equipment.<ref name="Krybus p5"/> Other cockpit equipment included a [[radio]] set, [[oxygen]] provision, and an adjustable seat and cockpit cover. Early-built aircraft featured an open cockpit, while later-built examples were furnished with an enclosed cockpit.<ref name="Krybus p4 5">Krybus 1967, pp. 4–5.</ref>

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]].<ref name="Krybus p5"/> Both the rudder and the [[elevator]] were statically and aerodynamically balanced. The [[landing gear|undercarriage]] was of a split-type configuration, being [[oleo strut|oleo]]-sprung and equipped with [[Dunlop Rubber|Dunlop]]-built wheels.<ref name="Krybus p5"/> The wheels, which were housed within streamlined fairings, were fitted with brakes; for conducting operations under winter conditions, [[ski]]s could also be fitted to the undercarriage.<ref name="Krybus p5"/> According to reports from pilots who flew the B-534, it possessed excellent handling characteristics for the era.<ref name="Krybus p5"/>

The Bk-534 was designed to carry one 20&nbsp;mm (0.79&nbsp;in) Oerlikon FFS-20 cannon firing through the nose, along with a pair of 7.92&nbsp;mm (0.312&nbsp;in) machine guns to the sides of the fuselage. 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.<ref name = "avia 36 37"/> 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. Judging by the size of the gun magazine, the nose machine gun was matched with an increased supply of ammunition. Consequently, however, the fuel load was decreased<ref name = "avia 36 37"/>

==Operational history==
===Czechoslovakia===
[[File:Avia B534.jpg|thumb|Avia B-534, 42nd letka (squadron)]]
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 aircraft|interceptor]] role.<ref name="Krybus p5 6">Krybus 1967, pp. 5–6.</ref> Initially, the responsibility for pursuit and aerial combat was shared with several other aircraft, including the [[Avia BH-33|Avia BA-33L]] and the [[Letov Š-31]]; however, by 1938, the B-534 was the sole type of aircraft in Czech service to be tasked with this role. By 10 November 1938, a total of 370 B-534 and Bk-534 aircraft in service; additionally, 53 aircraft had been written off as a result of accidents.<ref name="Krybus p6">Krybus 1967, p. 6.</ref>

On 1 September 1938, less than a month before the [[Munich Agreement]] would cause Czechoslovakia to lose 30 per cent of its territory and 34 per cent of its population,<ref name="Tatra p63">Rajlich and Sehnal 1994, p. 63.</ref> 328 B-534s and Bk-534s equipped 21 fighter squadrons of the Czechoslovak Air Force, while other aircraft were assigned to reserve and training squadrons, and deliveries continuing of the final batch of fighters.<ref name="AIJul74 p33">''Air International'' July 1974, p. 33.</ref>

On 14 March 1939, Germany forced the partition of Czechoslovakia, with Slovakia being declared as the nominally independent [[Slovak Republic (1939–1945)|Slovak Republic]] with Germany annexing the remaining "Czech" part of Czechoslovakia as the [[Protectorate of Bohemia and Moravia]] the next day.<ref name="Krybus p7">Krybus 1967, p. 7.</ref> The abrupt partition of Czechoslovakia during 1939 prevented any actual combat operations of the B-534 to be conducted by the nation that had produced it. 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. The [[Slovak Air Force (1939–1945)|Slovak Air Force]] was organised out of the units of the Czechoslovak Air Force that were based in Slovakia at the time of partition, and inherited about 71 B-534s and Bk-534s.<ref name="Tatra p63"/>

Slovakia had to quickly make use of its newly formed air force, weakened by the departure of many Czech pilots,<ref name="Krybus p6 7">Krybus 1967, pp. 6–7.</ref> to defend itself when neighbouring [[Hungary]] [[Slovak-Hungarian War|launched an invasion]] on 23 March 1939.<ref name="Krybus p8">Krybus 1967, p. 8.</ref> During the ensuing combat, a pair of B-534s were shot down by Hungarian [[anti-aircraft fire]] while a further four were claimed to have been shot down by Hungarian [[Fiat CR.32]] fighters. Another Avia was compelled to perform a forced landing behind Hungarian lines and was captured.<ref name="Tatra p64-5">Rajlich and Sehnal 1994, pp. 64–65.</ref>

During September 1939, Slovakia [[Polish Campaign of Slovak Army|participated]] in the [[German Invasion of Poland]]; the nation held the aim of regaining territories which had been previously lost to Poland at Munich.<ref name="Krybus p9">Krybus 1967, p. 9.</ref> A pair of squadrons of B-534s were assigned to support the invasion. In the theatre, these were typically used to escort ''[[Luftwaffe]]'' aircraft, such as the [[Junkers Ju 87]] dive-bomber, on eight missions.<ref name="Tatra p65">Rajlich and Sehnal 1994, p. 65.</ref> On 6 September the Avias shot down Polish reconnaissance aircraft [[Lublin R-XIII|Lublin R.XIIID]] over [[Prešov]], killing its two-men crew.<ref>{{cite magazine |first =Andrzej|last= Olejko |title =Szachownice nad Słowacją 1939 |magazine = Lotnictwo |date=September 2016|id=9/2016|volume=XIX|issue=185 |issn = 1732-5323 |publisher = Magnum-X |pages=96|language=pl}}</ref> One Avia was shot down by Polish anti-aircraft cannons, the other one crashed on 9 September (a pilot was killed).<ref name=vrany48>{{Harvnb|Vraný|1994|p=48}}</ref> Also the downing of Polish [[RWD-8]] liaison aircraft fleeing to Hungary was reported.<ref name=vrany48/>

The same squadrons fought alongside the elements of the German military in the area of [[Ukraine]] during summer 1941.<ref name="Krybus p9"/> 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. During 1942, one of these squadrons was redeployed to Slovakia to conduct anti-[[Partisan (military)|partisan]] operations.<ref name="Krybus p9"/> 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, [[Benzene|benzol]] and petrol) finally relegated the surviving B-534s to performing the trainer role and other secondary duties during 1943.<ref>Chant 1999, p. 28.</ref><ref name="Krybus p9"/>

The training role would have been the last operational service of the B-534s in Slovak colours if not for the [[Slovak National Uprising]] of September–October 1944.<ref name="Krybus p9"/> 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 [[Sliač Airport|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 [[History of Poland (1939–1945)|occupied Poland]].<ref name="Krybus p9"/> This was at once the first aerial victory for the Uprising and the last recorded biplane fighter air-to-air victory.<ref>{{cite book |last1=Rajlich |first1=Jiri |last2=Boshniakov |first2=Stephen |last3= Mandjukov |first3= Petko |date=2004 |title=Slovakian and Bulgarian aces of World War 2 |chapter=National Uprising| page=58 |location= Oxfordc|publisher= Osprey Publishing |isbn=978-1-84176-652-2}}</ref> 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. The last pair of B-534s at Tri Duby were burned as the base was evacuated on 25 October 1944.<ref name="Krybus p9"/>
[[File:B-534 Kombinovana letka.jpg|thumb|Avia B.534.217 of Combined Squadron, in which Frantisek Cyprich shot down a Hungarian Junkers Ju 52/3m, September 2nd, 1944]]

===Bulgaria===
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.<ref name="Krybus p91 10">Krybus 1967, pp. 9–10.</ref> The last batch of these aircraft were delivered from Czechoslovakia during March 1942. On 1 August 1943, 48 of these aircraft were able to make two passes at American [[Consolidated B-24 Liberator]] bombers returning from the raid on [[Ploieşti]]. Hits were scored but no B-24s were shot down and some of the B-534s that received damage in the combat, cracked up on landing.<ref name=vrany45-46>{{Harvnb|Vraný|1994|p=45-46}}</ref>

The B-534s saw little use as frontline aircraft as Bulgaria had also procured the more capable Bf 109E and the French-built [[Dewoitine D.520]] monoplane fighters.<ref name="Krybus p10"/> After the [[Bulgarian resistance movement during World War II#Takeover of the government|anti-German coup of 9 September 1944]], Bulgaria switched sides overnight. As such its B-534s were quickly pressed into use to conduct ground attacks against German units. On 10 September 1944, a flight of six B-534s were involved in a brief melee with six German Bf 109s at low altitude. One B-534 was lost, but the Germans quickly broke off, wary of both the low altitude and the B-534's manoeuvrability.{{Citation needed|date=January 2021}}

===Other operators===
During 1937, a batch of 14 B-534s was supplied to [[Yugoslavia]]; some of these aircraft were still in service when Germany launched the [[Invasion of Yugoslavia]] in early 1941.<ref name="Krybus p6"/> During 1937, a handful of fighters were delivered from Czechoslovakia to [[Greece]], additional Greek B-534s appear to have been acquired from Yugoslavia as well.<ref name="Krybus p6 10">Krybus 1967, pp. 6, 10.</ref> During 1940–1941, these fighters were later used during the [[Greco-Italian War]] as part of efforts by Greece to resist the invading Axis forces.<ref name="Krybus p10"/>

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''.<ref name="Krybus p7"/> In German service, the type was heavily used as a fighter-trainer at several fighter pilot training schools;<ref name="Smith" /> another major use was as a [[Gliding|glider-tug]] and [[target tug]], which involved those B-534s involved being outfitted with cables and release-gear.<ref name="Krybus p7"/>

Germany was also interested in potentially using the B-534 as a [[carrier-based aircraft]].<ref name="Krybus p7"/> In order to evaluate its suitability for such a role, three aircraft were equipped with [[tailhook]] and underwent structural strengthening before the commencement of a flight test programme; however, none of Germany's [[aircraft carrier]]s, the [[Graf Zeppelin-class aircraft carrier|''Graf Zeppelin''-class]], were ever completed.<ref name="Krybus p7"/> The B-534 also featured in the German [[propaganda]] movie [[List of German films of 1933–45|Kampfgeschwader Luetzow]] in which the type was used as a stand-in for Polish [[PZL P.11]], being painted in [[Polish Air Force]] markings.<ref name="Krybus p7 8">Krybus 1967, pp. 7–8.</ref>

Germany also sold a number of the captured B-534s to its allies, reportedly at 40 per cent of their original cost.<ref name="Krybus p9"/> Following the German occupation of [[Yugoslavia]] in 1941, the Axis-aligned [[Croatian Air Force]] was created and supplied with B-534s by Germany, as well as the integration of remaining examples from Yugoslavia's own B-534s ordered prior to the outbreak of the conflict.<ref name="Krybus p10"/>

==Variants==
* '''B-534/1''': First prototype.
* '''B-534/2''': Second prototype.
* '''B-534-I''': First production version. (cn's 2 – 101)
* '''B-534-II''': (cn's 102 – 147)
* '''B-534-III''': (cn's 148 – 173)
* '''B-534-IV''': Closed [[Aircraft canopy|canopy]] (cn's 174 – 445)
* '''Bk-534''': Cannon version (cn's 501 – 620)

==Surviving aircraft==
[[File:Letecké muzeum Kbely (169).jpg|thumb|A replica B-534 at the Prague Aviation Museum, Kbely]]
[[File:Replica of Avia B-534 at the Museum of Aviation in Košice 02.jpg|thumb|A replica B-534 (pre-war Czechoslovak Air Force) at the Museum of Aviation, Košice, Slovakia]]
There are no real surviving airframes, but a B-534-IV replica is on display in the [[Prague Aviation Museum, Kbely]], [[Czech Republic]]. A second replica (Bk-534), using (like the Kbely example) some original parts, is displayed at the [[Museum of Aviation (Košice)|Museum of Aviation]] at [[Košice International Airport]], [[Slovakia]].{{Citation needed|date=January 2021}}

==Operators==
{{flag|Bulgaria}}: [[Bulgarian Air Force]] – The Bulgarian Air Force operated between 48<ref name="Krybus p10">Krybus 1967, p. 10.</ref> and 100 aircraft (though mostly the number 78<ref name="Vraný 1994">Vraný 1994, p. 45.</ref> is named), which they called "Dogan" (Hunting Hawk).<ref>Vrany 1994, pp. 34, 45–46.</ref>

{{flagcountry|Independent State of Croatia}}: [[Air Force of the Independent State of Croatia]] – An unknown number of Avia B-534 aircraft were supplied by the Germans.<ref name="Krybus p10"/>

{{CZS}}: [[Czechoslovak Air Force]]

{{flag|Germany|Nazi}}: ''[[Luftwaffe]]'' – The German Luftwaffe used most of the airframes confiscated from the Czechs. These aircraft served through the early years of the war as [[Trainer (aircraft)|trainers]], night fighters, and [[glider tug]]s; three were used to test [[Aircraft carrier|carrier]] landing operations for the aborted {{Ship|German aircraft carrier|Graf Zeppelin}}.<ref>Vrany 1994, pp. 39, 44.</ref> The Germans had another use as well: B-534s also starred disguised as Polish fighters in a German propaganda film, "[[Kampfgeschwader Lützow]]".<ref name = "Krybus p8">Krybus 1967, p. 8.</ref>

{{flag|Greece|old}}: [[Hellenic Air Force]] – Greek businessman Giorgos Koutarellis, a millionaire expatriate living in Egypt, bought two B-534s and presented them to the Greek government in August 1936.<ref name="Smith" /> They were lost in the chaos of 1941.<ref name="Krybus p10"/><ref>Vraný 1994, p. 46.</ref>

{{flag|Hungary|1920}}: [[Royal Hungarian Air Force]] – One B-534 was captured by the Hungarians during the border war in 1939 and tested for a period, carrying the code HA-VAB,<ref name="Vraný 1994"/><ref>Vraný 1991, backcover</ref> later serialled G.192.<ref>Kudlička 2006, backcover.</ref> The Hungarians concluded that the B-534 was an inferior aircraft to their existing fighters. In 1943 the B-534 was handed over to the Gliding and Aero Club at [[Győr]], and was destroyed in 1945 when the Soviet Army overran the area.

{{flag|Romania}}:Together with three [[DFS 230]] gliders, Romania received an unknown number of Avia B-534 tugs according to one source.<ref name="Vraný 1994"/>

{{flag|Slovak Republic (1939–1945)|1939|name=Slovak Republic (1939–1945)}}: [[Slovak Air Force (1939–1945)|Slovak Air Force]] – The Slovak Air Force operated several B-534s from Czechoslovakia.<ref>Šumicrast 2003, pp. 2–51.</ref><ref>Vraný 1994, pp. 46–49.</ref>
*[[Slovak Insurgent Air Force]]

{{USSR}}: A number (eight is given in some sources) of B-534s were allegedly used by the Soviets in a secret NKVD squadron to shadow flights of German aircraft.<ref name="Vraný 1994"/>

==Specifications (B-534 IV)==
[[File:Avia B-534 3-view.svg|thumb|Avia B-534 3-view]]
{{Aircraft specs
|ref=''Aircraft of the Third Reich Vol.1'' <ref name="Greenaottr">Green 2010, pp. 93–96.</ref>
|prime units?=met
<!--
        General characteristics
-->
|crew=one
|length m=8.1<ref name="Avia B-534 1994, p. 60"/>
|span m=9.4
|height m=3.15<ref name="Avia B-534 1994, p. 60"/>
|wing area sqm=23.56
|empty weight kg=1,460
|gross weight kg=2,120
|max takeoff weight kg=1,980<ref name="Avia B-534 1994, p. 60"/>
<!--
        Powerplant
-->
|eng1 number=1
|eng1 name=[[Hispano-Suiza 12Ydrs]]
|eng1 type=liquid-cooled [[V12 engine]]
|eng1 kw=633<!-- prop engines --><ref>Avia B-534, Jiří Vraný, 1994, pp. 57–58, {{ISBN|80-901263-6-7}}</ref>
<!--
        Performance
-->
|max speed kmh=405
|max speed note=at {{convert|4,400|m|ft|abbr=on}} (standard 380 km/h)<ref name="Avia B-534 1994, p. 60">Avia B-534, Jiří Vraný, 1994, p. 60, {{ISBN|80-901263-6-7}}</ref>
|cruise speed kmh=345
|range km=600<ref name="Avia B-534 1994, p. 60"/>
|ceiling m=10,600
|climb rate ms=15.15<ref name="Avia B-534 1994, p. 60"/>
|climb rate sigfig=3
|time to altitude={{convert|5,000|m|ft|abbr=on}} in 5 minutes 30 seconds<ref name="Avia B-534 1994, p. 60"/>
|wing loading kg/m2=84<ref name="Avia B-534 1994, p. 60"/>
|power/mass= 0.32 kW/kg (0.2 hp/lb)<ref>Avia B-534, Jiří Vraný, 1994, {{ISBN|80-901263-6-7}}</ref>
<!--
        Armament
-->
|guns=4× 7.92 mm (0.312 in) {{ill| Letecky kulomet vz. 30|cs|Kulomet_vz._30}}  (Česká zbrojovka Strakonice)<ref>{{cite web|title=7,92 mm letecký kulomet vz. 30|url=http://www.brannamoc1938.eu/kulomety/7-92-mm-letecky-kulomet-vz-30/|work=Československá armáda 1938|access-date=25 February 2014|archive-url=https://web.archive.org/web/20150414231944/http://www.brannamoc1938.eu/kulomety/7-92-mm-letecky-kulomet-vz-30/|archive-date=2015-04-14|url-status=dead}}</ref> machine guns with 250–300 rpg
|bombs=6× 10 kg (22 lb) or 4x 20 kg (44 lb) bombs
}}

==See also==
{{Portal|Aviation}}
{{Aircontent
|related=
* [[Avia B-34]]
|similar aircraft=
* [[Blériot-SPAD S.510]]
* [[Fiat CR.32]]
* [[Fiat CR.42]]
* [[Grumman F3F]]
* [[Hawker Fury]]
* [[Heinkel He 51]]
* [[Kawasaki Ki-10]]
* [[Polikarpov I-15]]
|see also=
|lists=
* [[List of fighter aircraft]]
* [[List of interwar military aircraft]]
}}

==References==
{{Reflist}}

===Bibliography===
* Bílý, Miroslav and Jiří Vraný. ''Avia B-534: Czechoslovak Fighter, 3rd and 4th Version (Model File)''. Prague, Czech Republic: MBI, 2008. {{ISBN|80-86524-15-9}}. With 71 pages the most comprehensive detail publication about the B-534 to date.
* Chant, Chris. ''Aircraft of World War II''. New York: Barnes & Noble, 1999. {{ISBN|0-7607-1261-1}}.
* Cieślak, Krzysztof. ''Samolot Mysliwski Avia B.534 (Typy Broni i Uzbrojenia 34)'' (in Polish). Warszawa, Poland: Wydawnictwo Ministerstwa Obrony Narodowej, 1975.
*{{cite journal |last1=Cony |first1=Christophe |title=L'Avia B-534 (1ère partie) |journal=Avions: Toute l'aéronautique et son histoire |date=May 1996 |issue=38|pages=23–29 |language=French |issn=1243-8650}}
*{{cite journal |last1=Cony |first1=Christophe |title=L'Avia B-534 (2ème partie) |journal=Avions: Toute l'aéronautique et son histoire |date=June 1996 |issue=39|pages=39–42 |language=French |issn=1243-8650}}
*{{cite journal |last1=Cony |first1=Christophe |title=L'Avia B-534 (3ème partie) |journal=Avions: Toute l'aéronautique et son histoire |date=July 1996 |issue=40|pages=39–43 |language=French |issn=1243-8650}}
*{{cite journal |last1=Cony |first1=Christophe |title=L'Avia B-534 (4ème partie) |journal=Avions: Toute l'aéronautique et son histoire |date=August 1996 |issue=41|pages=43–22 |language=French |issn=1243-8650}}
*{{cite journal |last1=Cony |first1=Christophe |title=L'Avia B-534 (5ème partie): en operations sur le front de l'Est |journal=Avions: Toute l'aéronautique et son histoire |date=September 1996 |issue=42|pages=2–6|trans-title=The Avia B-534: Operations on the Eastern Front |language=French |issn=1243-8650}}
*{{cite journal |last1=Cony |first1=Christophe |title=L'Avia B-534 (6ème partie): l'insurrection national slovaque |journal=Avions: Toute l'aéronautique et son histoire |date=October 1996 |issue=43|pages=5–6|trans-title=The Avia B-534: The Slovak National Uprising |language=French |issn=1243-8650}}
*{{cite journal |last1=Cony |first1=Christophe |title=L'Avia B-534 (7ème partie): au service de la Luftwaffe |journal=Avions: Toute l'aéronautique et son histoire |date=October 1996 |issue=44 |pages=37–42|trans-title=The Avia B-534: in Luftwaffe Service |language=French |issn=1243-8650}}
*{{cite journal |last1=Cony |first1=Christophe |title=L'Avia B-534 (8ème partie): B-534 bulgares contre B-24 Liberator! |journal=Avions: Toute l'aéronautique et son histoire |date=December 1996 |issue=45 |pages=39–43|trans-title=The Avia B-534: Bulgarian B-534s Versus B-24 Liberator! |language=French |issn=1243-8650}}
*{{cite journal |last1=Cony |first1=Christophe |title=L'Avia B-534 (9ème et dernière partie): "en service restreint": URSS, Grèce, Roumanie et Hongrie |journal=Avions: Toute l'aéronautique et son histoire |date=October 1996 |issue=44 |pages=18–19|trans-title=The Avia B-534: in Limited Service |language=French |issn=1243-8650}}
* Green, William. ''Aircraft of the Third Reich'' Vol.1 (1st ed.). London: Aerospace Publishing, 2010. {{ISBN|978-1-900732-06-2}}.
* Green, William. ''War Planes of the Second World War, Fighters, Volume One''. London: Macdonald & Co.(Publishers) Ltd., 1960. {{ISBN|0-356-01445-2}}.
* Krybus, Josef. ''The Avia B.534 (Aircraft in Profile number 152)''. Leatherhead, Surrey, UK: Profile Publications Ltd., 1967. ISBN B000-7K11J-M.
* Kudlička, Bohumil. ''Avia B.534 Czechoslovakian Fighter 1933–45''. Prague, Czech Republic: CMK, 2006. {{ISBN|80-903778-0-7}}.
* "The Last Belligerent Biplane – The Avia B 534". ''[[Air International]]'', Vol. 7, No. 1, July 1974, pp.&nbsp;25–35.
* Rajlich, Jirí and Jirí Sehnal. "'Tatra Eagles' The Slovak Air Force in Combat 1942–1945. ''[[Air International]]'', No. 56, Winter 1994. pp. 63–68.
* Šumicrast, Peter. "Avia B.34, B.534 a Bk.534, Slovenských Pilotov 1939–1944." ''HT model špeciál 905''. Poprad, Slovakia: HT Model, 2003, ISSN 1335-3667.
* Titz, Zdeněk. ''Czechoslovakian Air Force, 1918–1970''. Reading, Berkshire, UK: Osprey Publications Ltd., 1971. {{ISBN|0-85045-021-7}}.
* Vraný, Jiří. ''Avia B.534'' (in Czech). Prague, Czechoslovakia: AeroArchiv, 1991. {{ISBN|80-7030-114-7}}.
* {{Cite book |title=Avia B-534|first=Jiři |last=Vraný|date=1994|publisher=MBI|place=Prague|language = en|pages=48|isbn=80-901263-6-7 }} 

==External links==
{{commons category|Avia B-534}}
* [http://surfcity.kund.dalnet.se/avia.htm Avia B.534 and Avia Bk.534 by Håkan Gustavsson]
* [https://web.archive.org/web/20070928184148/http://www.tgplanes.com/planfile.asp?idplane=13 "Avia B.534"]. Paul Tagliaferri ''The Great Planes'', 3 June 2002. Retrieved: 5 July 2006.
* [http://greek-war-equipment.blogspot.com/2011/12/1937-1941-avia-b534.html Avia B.534 Series II in Greek service]

{{AVIA aircraft}}
{{RLM aircraft designations}}

{{Authority control}}

[[Category:Biplanes]]
[[Category:Single-engined tractor aircraft]]
[[Category:1930s Czechoslovak fighter aircraft]]
[[Category:Avia aircraft|B-534]]
[[Category:Aircraft first flown in 1933]]
[[Category:Aircraft with fixed conventional landing gear]]