Avia S-92

Considering that every jigs, tools and component required to manufacture the Me.262 were left behind in Czechoslovakia by the Germans, were seized by the Soviets and then handed back to Czechoslovak authorities by the Marshal Ivan Konev, it comes no surprise that the Me.262A1-a was manufactured in Czechoslovakia after the World War II.

More precisely, Me.262 fuselages had been produced in Letnany, some other components were built in converted railway tunnels and CKD and Walter Works had manufactured the Junkers Jumo 004 turbojet engine at Cheb, close to the German border.
That way, enough components were recovered and/or manufactured to build 17 single and two-seat Me.262, flying the first single-seater one on 27th August 1946, even if on 5th September it was lost in an accident. A second one, named as Avia S-92 first series, flew on 24th October and was followed by the first CS-92 (the two-seater trainer variant) on 10th December.
It was dubbed Turbina (Turbine) and the 7th aircraft of the CS variant was fitted with a BMW 003 turbojets, with 950kgp of thrust power. However the flight test weren't satisfactory so it fitted back to the standard Jumo engines. The eleventh and twelth aircrafts were completed during 1949 and the summer of 1950 to equip the 5th Fighter Squadron which was exclusively flying the Turbinas, however this unit was disbanded a year later and the S-92 were scrapped.

Sources:
1. Salamander Books - The Complete Book of Fighters
2. http://www.military.cz/czech/air/avia/s92/default.htm (translated)

Avia S-92 - Never were users

This is some atypical post as we cover the intended foreign users of this airplane.

The first country to show interest on this airplane was Yugoslavia, as in 1947 a Yugoslav pilot was trained in Czechoslovakia on the type.
The Yugoslav were very interested on improving their fighter fleet with some jets in order to support their mixed propeller fighters. After reconsidering it, they decided to stick to propeller fighters until the more modern jets like the American F-84 Thunderjet was available. Their other concern was that Avia maybe could cancel the S-92 project as it wasn't economically profitable.

Israel on it's part, showed some interest on the type during 1948 and 1949 in order to fly them or buying the already completed few ones for cash. Apparently, in 1950 there are reports from Egyptian intelligence of an Israeli jet fighter crashing into Ekron airbase, when the whole Israeli Air Force at the time was still piston-powered. According to that report the type that crashed was most likely an Avia S-92. Some time later, an Egyptian transport airplane reported that was harassed by an Israeli jet airplane that looked like a German Me.262.
Actually, the S-92 was never flown by the IAF even if they started negotiations to buy it. It seems that the origin of the urban legend is on the British intentional leaks to Egyptian intelligence in order to cover-up the fact that, in 1950, Israel had already jet fighters, some of the earlier version of the Gloster Meteor and some De Havilland Vampires, even if it wasn't until 1953 that they oficially recognized their existance.
The IAF has stated many times, the last one in 2005 that they have never flown the Avia S-92.

Sources:
1. https://wwiiafterwwii.wordpress.com/2015/08/12/the-s-92-czechoslovakias-me-262/
2. Salamander Books - The Complete Book of FIghters

Avia S-199 - Native users

The Avia S-199 is a propeller fighter aircraft built in Czechoslovakia after the World War II. It was the first fighter to serve with the Israeli Air Force. It was highly unpopular among both Czechoslovak and Israeli pilots who nicknamed it as "Mezek" (Mule in Czech) and "Sakeen" (knife in hebrew) respectively.

As Avia had depleted every Daimler-Benz DB 605 engines that were available, they turned to power the remaining Bf-109G-6 airframes that were left with the Junkers Jumo 211F engines and propellers, initially intended for the Heinkel He.111 bomber. That setting gave the airplane extremely complicated handling capabilities. It lacked the responsiveness of the DB 605 engine and high amounts of torque which, combined with the narrow undercarriage, made the take-off and landings very difficult and risky.

The original DB 605 also allowed a machine gun firing through the propellers, however this wasn't possible with the Junkers Jumo 211F, as they were intended to be used in the Heinkel He.111 which made some Israeli pilots to shot their own propellers when in combat. That's why the S-199 used a modified version of the Luftwaffe's Rüstsatz modification kit which consisted on two MG.151 under the wings. That arrangement further impinged the aircraft's performance.

Approximately 500 of them were built among them the trainers, designated CS-199 which was armed and C-210 which was unarmed. It flew for the first time in 1947 and the last airplane rolled out from the production line in 1949. Last airplanes served with the Czechoslovak National Security Guard until 1957.

Sources:
1. https://en.wikipedia.org/wiki/Avia_S-199
2. Salamander Books - The Complete Book of Fighters

Avia S-199 - Israeli Users, Part two

The Avia S-199, when served with Israel, proved to be unreliable and didn't show good combat performance.
As one of the Israeli pilots remarked "she (the Avia S-199) tried to kill us in every take-off and landing".
Maintenance problems were also present and that caused that no more than five machine were airworthy at any one time.

It however scored some victories, including some against the much better Supermarine Spitfire. They were mostly held from service by late October when only six remained operational. They continued making sporadic flights until late 1948 and on December 15th American pilot Wayne Peake flipped one on it's back.

Sources:
1. https://en.wikipedia.org/wiki/Avia_S-199
2. Salamander Books - The Complete Book of Fighters

Avia S-199 - Israeli Users, Part one

Back in 1948, when Israel was fighting for his independence, their agents negotiated the purchase from the Czechoslovak government in a clear defiance of the arms embargo imposed to Israel at the time.

They negotiated the bought of twenty-five aircraft but only two of them were eventually delivered to the newly created Israeli Air Force. Each of the airplanes costed 190000$ of the time and the first airplanes arrived in Israel on 20th May 1948, just six days after the declaration of independence and five days after hostilites with Egypt began.

It could be safe to say that they were the very first fighters to equip Israel's Air Force and in fact, they formed their first squadron, the 101 Tajeset. After being assembled, they were sent into combat for the first time on 29th May 1948 when they attacked an Egyptian army convoy between Isdud and Ad Halom bridge, located at the south of Tel-Aviv. A few days later, on June 3rd, this type of aircraft scored the IAF first victory when an S-199 piloted by Modi Alon shot down two Egyptian Douglas C-47 Dakota that had just bombed Tel-Aviv.

Sources: 
1. https://en.wikipedia.org/wiki/Avia_S-199
2. Salamander Books - The Complete Book of Fighters

Avia S-99/CS-99

The Avia S-99 was a Czechoslovak copy of the Messerschmitt Bf.109G-6 with an Erla Haube canopy instead of the standard one.

Just after the war, as the German Luftwaffe had used Avia's factories and facilities to produce airplanes, the Bf.109 among them, the Czechoslovak had found that they had a large supply of blueprints, airframes and engines to keep producing their own version of the Bf.109G.

It was officially produced in two Avia's plants, both of them close to Prague as part of the corporative Automobilové zádovy (Automobile works), but they ran out of the German-made Daimler-Benz DB605 engine after many of them were destroyed when a warehouse exploded in Krásné Brezno.

The S-99 was the fighter variant, which was a direct copy of the Bf.109G-6 with some minor alterations like the Erla Haube canopy. The CS-99 on it's part was the training variant of it which was a direct copy of the Bf.109G-12. Twenty-one S-99 were completed plus twenty-three CS-99

Sources:
1. https://en.wikipedia.org/wiki/Avia_S-199
2. Salamander Books - The Complete Book of Fighters

Avia B-135

The Avia B-135 was a Czechoslovak cantilever monoplane fighter. It was based on the third prototype of the Avia B-35 redesigned with a new all-metal wing.

• Czechoslovakia: As the B-135 was developed after Germany occupied Czechoslovakia, the drawing depicted below is speculative of how it would've looked like if it served with the Czechoslovak Air Force.
• Germany: As it was developed mainly during 1939, it was presented officialy in the Brussels Air Saloon of 1939 under German colours. However, as Germany wasn't interested on it, they sold all of them to Bulgaria.
• Japan: Apparently, at least one airplane was sold to the Imperial Japanese Army Air Service to evaluate it. It did even got a nickname from the Americans which nicknamed it as "Alex".

Sources:
1. https://en.wikipedia.org/wiki/Avia_B-135
2. Salamander Books - The Complete Book of Fighters
3. http://www.wardrawings.be/WW2/Files/2-Airplanes/Axis/3-Japan/01-Fighters/B-135/B-135-105.htm

Avia B-135, Bulgarian Users

The Avia B-135 was a Czechoslovak monoplane fighter that was used by Bulgaria.

Back in the late 1930s, the Bulgarian DAR company bought a license to locally build the Avia B-135, which was to be known as the DAR 11 Lyastovitsa (Bulgarian word for "Swallow") but the DAR factories proved to be unsuitable for producing the airplane and only the 12 Czechoslovak made fighters ended serving in the Bulgarian Air Force.

As they were giving engine problems, they were mainly used on training duties. However, four of them were used in combat on 30th March 1944 when they intercepted some USAAC bombers returning from a bombing mission in Ploesti, Romania. Apparently an Avia B-135 piloted by Yordan Ferdinandov managed to shot down a B-24 bomber which crashed into Bulgarian soil that day.

Sources:
1. https://en.wikipedia.org/wiki/Avia_B-135
2. Salamander Books - The Complete Book of Fighters

Avia B-35

The Avia B-35 was a prototype single-seat monoplane fighter designed and built in Czechoslovakia in the years prior to the World War II.
It was a low-wing monoplane with an elliptical wing. Fuselage was made out of steel tube and the wings were made entirely out of wood. It had also a fixed landing gear, hoping that it would improve the speed, but in reality it was just an improvised solution because the mechanism for retracting the undercarriage wasn't yet available.

The first prototype, labelled B-35/1 showed good flying characteristics and was powered by an Hispano-Suiza 12Ydrs piston engine. The engine was changed shortly after to a 12Ycrs in order to refit the nose to instal a cannon there to fire through the propeller hub. The testing of the first prototype ended on 22nd November 1938 when the prototype crashed killing it's test pilot, Arnost Kavalec.
A second prototype, B-35/2 was already almost completed and featured redesigned ailerons and flaps. It flew for the first time on 30th December 1938 and it was tested on February 1939. It's known that a pre-production series order was placed, but the German occupation of Czechoslovakia in March 1939 stopped it.

Sources:
1. https://en.wikipedia.org/wiki/Avia_B.35
2. Salamander Books - The Complete Book of Fighters

Avia Bk-534, Czechoslovak Users

Now it's the time for the last post about the Avia B-534, this time covering the native and some foreign and exotic users of the Bk-534.

The Bk-534 was designed to have a 20mm Oerlikon FFS-20 cannon firing through the nose and just two 7.92mm machine guns firing through the sides of the nose.
Apparently there were some problems to adapt the new gun that weren't solved until the summer of 1938. In order to make more airplanes, Avia decided to replace the cannon with a third machine gun in the nose with an extra amount of ammunition.
As the time was running out due to the German occupation of the Sudetenland, two series of the Bk-534 were produced, with only three of the second batch serving in the Czechoslovak Air Force and the remaining 63 ones serving either with the Luftwaffe or the Slovak Air Force after March 1939 when the rest of the Czechoslovak state was occupied by Germany.

Sources:
1. https://en.wikipedia.org/wiki/Avia_B-534
2. Salamander Books - The Complete Book of FIghters

Avia Bk-534, German users

The German Third Reich used the Avia Bk-534 mainly for training purposes but also for some testing about the hub mounted cannon.

Apparently some Bk-534 were also used to test arrester hooks for the aircraft carrier Graf-Zeppelin in 1940 and 1941. The tests showed that the airframe wasn't ready for rough carrier landings.

Sources:
1. https://en.wikipedia.org/wiki/Avia_B-534
2. http://surfcity.kund.dalnet.se/avia_germany.htm
3. Salamander Books - The Complete Book of Fighters

Avia B-534-IV, Czechoslovak users, part two.

The Avia B-534-IV demonstrated an excellent performance at a flying exhibition in Switzerland in 1937. The German Bf.109 won the categories of best climbing and diving and the German competitor pilot, handling a Henschel Hs.123 pushed his biplane to claim the second post, so the Avia B-534-IV got the next three places. It did even manage to outflight other fighters taking part, including the Bf.109 even if it was 11 Km/h slower than this one.

As Czechoslovakia was occupied in March 1939, this airplane couldn't be used in combat by it's native nation. By that date, high performance monoplane fighters such like the German Bf.109, the British Hawker Hurricane or Supermarine Spitfire or the American Curtiss P-36 were raising the bar for fighter/interceptor standards and biplanes were started to be obsolete.

Sources:
1. https://en.wikipedia.org/wiki/Avia_B-534
2. Salamander Books - The Complete Book of Fighters

Avia B-534-IV, Czechoslovak users, part one.

The last Avias B-534 to be done carried the serials 534.174 to 534.193 and they all belonged to the IV series.

This variant was characterized by their enclosed canopy and, even if it's not that visible, they had a metal light alloy propeller manufactured by Letov. Those and various other refinements made the IV series to reach top speeds of over 200mph, placing it on par with the best biplane fighters of those years.
Another small changement was the replacement of the tail skid with a tail wheel and, after having made some field testing, the main wheel spats were often removed after discovering that they clogged very easily with mud.

Sources:
1. https://en.wikipedia.org/wiki/Avia_B-534
2. Salamander Books - The Complete Book Fighters

Avia B-534-IV - Czechoslovak Policial units

The Avia B-534-IV was also used by the Czechoslovak gendarmerie's aerial branch in order to perform aerial patrols in their territory.

We apologize for this post being this short but we only could find graphical info about the Czechoslovak Gendarmerie usage of the Avia B-534.

Avia B-534-IV - Slovak Users

Today it's the turn for the Slovak users of the Avia B-534-IV, excluding the early and the insurgent ones.

The Slovak Air Force (SVZ) was much more involved in the attack on the operation Barbarossa than in the invasion of Poland. Right on 7th July 1941 two SVZ squadrons, the 12th and 13th Letka were assigned to Ternopol, in Ukraine. They had the mission of escorting the German Ju.87 and Hs.126 of 3(H.)/Aufkl. Gr.32 and 4(H.)/Aufkl. Gr.32 of the Luftflotte 4.
Since then, they were employed several times, from ground attack duties, to escort ones.
On 28th July 1941 the Slovaks made their first claim when machines from 12th Letka damaged a Soviet Polikarpov I-153 forcing them to land in the Yuzefpol area. It's noteworthy that the Soviets had initally advantage thanks to their new MiG-3 airplanes that took part that day on the combat.
On 15th August the 13. Letka returned to Piest'any and redesigned later to Kiev sector, far from Odessa.
They remained in the frontlines on the Eastern Front until 1st June 1942 when the 11. Letka was assigned to anti-partisan duties in the hinterland. It lasted two months and two machines were lost due to anti-aircraft fire.
Their frontline career was heavily conditioned by the supply problems of the BiBoLi fuel type which was a mixture of alcohol-benzol-petrol that was used by the Czechoslovak pre-war air force. But the main problem overall was the obsolescence and the wear and tear caused by the war operations.
In February 1942 the first Slovak pilots arrived on Denmark in order to be trained in the usage of the Bf.109G that would become the standard airplane of the Slovak air force from then on.

Sources: 
1. http://surfcity.kund.dalnet.se/avia_slovakia.htm
2. https://en.wikipedia.org/wiki/Avia_B-534
3. Salamander Books - The Complete Book of Fighters

Avia B-534-IV - Slovak insurgent & Early Slovak users

Today it's the turn for the first part of the Slovak users of this airplane.

After the fall of the Czechoslovak Republic, the newly stablished Slovak Air Force seized the B-534 that were based in their territory and , when the war started back in September 1939, they were the only official ally of the Luftwaffe.
The Slovak Air Force committed three squadrons to fight against Poland. Two of them were fighter squadrons. However, the Slovak units limited themselves to occupy only some parts of northern Slovakia that had been under Polish control since 1918. Their participation was limited to the escort role of German Ju.87 during eight missions performed from Vinné air base close to the Slovak city of Michalovce.
It was during this campaign that the catár (Sergeant) Viliam Grun was shot down in Polish territory but wasn't taken prisoner as he scaped back to Slovakia.
Another pilot, the desiatnik (Corporal) Viliam Jaloviar was killed in a landing accident after returning from a sortie in Presov.
The only confirmed victory of the B-534 during the Polish Campaign came on 26th September when a two-airplane patrol attacked, and shot dow, a Polish RWD-8 that was fleeing to Hungary by the catár Grun. The Polish airplane force landed near Presov.

Some years later, during the autumn of 1944, the B-534 formed the backbone of the combined squadron of the Slovak Insurgent Air Force. Even if the Slovak National Uprising failed, the last operational air mission of the B-534-IV happened during that event when the Master Sergeant Frantisek Cyprich shot down a Hungarian Junkers Ju.52 which was on it's way to a base in Poland. That was the first aerial victory for the rebel air force and the penultimate biplane air-to-air victory. As the rebellion was being crushed, the B-534-IV were burned at Tri Duby when the base was burned on 25th October 1944 to prevent it's usage by the axis users.

Sources:
1. http://surfcity.kund.dalnet.se/avia_slovakia.htm
2. https://en.wikipedia.org/wiki/Avia_B-534
3. Salamander Books - The Complete Book of Fighters

Avia B-534-IV - German Users

The German Luftwaffe used most of the B-534 taken from the Czechoslovaks. They served during the early years of the World War II as trainers, gliders tows, night fighters or even as regular fighters.

Maybe the most famous usages of a B-534 by the Luftwaffe was when they used them to perform arresting hook trials for the cancelled German aircraft carrier Graf Zeppelin and when they used them, disguished as Polish Fighters for a propaganda film.

Many units employed them as trainers, for instance, the I/JG.51 from July 1939 to October 1939, based at Bad Aibling. They were also employed as night fighters by the 3/JG.70 and the 3/JG.71 between July 1939 and the beginning of 1940 before replacing them with the Bf.109.

As glider tows they were used DFS 230 Staffel/1-10 in the occupied France before being reallocated to the Eastern Front where they served, in the same role, at the battle of Demyansk Pocket by towing the gliders that would supply the German troops.
Another glider-tow group, the Erganszungsgruppe (S) 1 from Langendiebach at Hanau during 1942-1943 which was a traning group for assault glider pilots. This unit was particularly special because they used a wide variety of airplanes to train their pilots. Among the airplanes there were some Letov S-328 and at least 10 captured Gloster Gladiators.

Sources:
1. https://en.wikipedia.org/wiki/Avia_B-534
2. http://surfcity.kund.dalnet.se/avia_germany.htm
3. Salamander Books - The Complete Book of Fighters.

Avia B-534-IV - Various Foreign users

Today we cover the next users for the Avia B-534-IV

• Independent State of Croatia: Apparently the Air Force of the Independent State of Croatia received some surplus machines from Germany. Further details are unknown so the drawing should be considered speculative.
• Kingdom of Hungary: One B-534-IV was captured from Slovakia during the Slovak-Hungarian war in March 1939. It was pushed into service as a fighter trainer. Later, in 1941, it was used as a glider tow bearing civilian registrations until it was destroyed during the battle of Budapest in 1945.
• Kingdom of Romania: The Royal Romanian Air Force received some Avia B-534-IV together with the DFS 230 gliders. The Avias were used as glider tows. As the graphical sources for these are inexistant, or at least we couldn't find them, the drawing should be considered as speculative.
• USSR: Apparently the NKVD used some captured machines to form a secret squadron. As there isn't graphical evidence on this, it should be considered as speculative.

Sources:

1. https://en.wikipedia.org/wiki/Avia_B-534

2. Salamander Books - The Complete Book of Fighters

Avia B-534-IV Bulgarian users

In the summer of 1939 the Bulgarian Air Force bought 78 B-534 from Germany. These were initially assigned to the 2. Istrebitelen Orlyak (2nd Fighter Air Regiment) and to the training squadron.

The last batch of this airplanes to arrive to Bulgaria was in March 1942 when 6. Istrebitelen Orlyak received some B-534-IV.
On 1st August 1943 they took part on the biggest operation this airplane would take part on when seven of them made two passes at American Consolidated B-24 Liberator bombers which were coming back from bombing Ploesti, in Romania. Even if they hit some B-24, not a single one of them were shot down due to the small calibre of their machine guns.
Some of the B-534-IV were damaged and crecked up on landing.
After Bulgaria switched sides on 9th September 1944, the B-534-IV were oftenly used in the ground attack role against German units and it's known that some B-534-IV were involved in a brief melee with six German Bf-109 at low altittude. One B-534-IV was lost and the Germans quickly broke off from combat aware of the high maneouvrability of the B-534-IV at low altittudes.

Sources:
1. https://en.wikipedia.org/wiki/Avia_B-534
2. http://surfcity.kund.dalnet.se/avia_bulgaria.htm
3. Salamander Books - The Complete Book of Fighters

Avia B-534-III

Following the sales success from the II series, the Czechoslovak Air Force ordered another batch of B-534 to be made.

In 1936 a second order was placed to Avia to manufacture more B-534. The first 25 of them belonged to the B-534-III denomination and were started in the second half of 1936. The III series featured some minor changes like aerodynamic refinements which saw the frontal carburator's air intake streamlined. Mudguard spats were also added, however as they tended to clog, they were usually removed.

This was the least produced variant before switching to the famous B-534-IV version, which was a success in sales. However, it was used by many countries like Bulgaria, which used it in very limited numbers, Germany or Slovakia.

Sources:
1. https://en.wikipedia.org/wiki/Avia_B-534
2. Salamander Books - The Complete Book of Fighters

Avia B-534-II - Native Users

The Avia B-534-II was a Czechoslovak biplane single-seat fighter airplane from the 1930s.
The II series were a modification of the first series ordered by the Czechoslovak air force and comprised 45 airplanes.
Like the I series, they were armed with four guns, however, as the wing mounted gun in the original version was troublesome, these guns, upgraded to the vz.30, were placed in the fuselage together with the other two, firing through the propeller.

Some small number of them were tested with a bubble cannopy, certainly a very modern innovation for the era, but it was an experimental feature rather than an standard fit.
It was also powered by the Hispano-Suiza 12Ydrs V12 engine.

Sources:
1. https://en.wikipedia.org/wiki/Avia_B-534
2. Salamander Books - The Complete Book of Fighters

Avia B-534-II Never-were Spanish users

This is a bonus post in order to show some intended users for the Avia B-534-II, that never-were. The Spanish ones.

• Republic of Spain: Twenty Avia B-534-II were ordered by the Republicans from Czechoslovakia, but the train that was delivering them was stopped on it's way through Poland to Danzig by the Polish authorities obeying orders from the non-intervention committee.
• Nationalist Spain: As it would've happened, most likely those machines would've fallen into nationalist hands.

Sources:

1. http://bioold.science.ku.dk/drnash/model/spain/didnt.html

Avia B-534-II Foreign Users

Today it's the turn for the non-native users of this Czechoslovak fighter.

The users covered in this post are:

• Germany: Just like other variants of this one, Germany used some airplanes with the bubble type canopy, most probably for evaluation and/or training purposes.
• Greece: a wealthy Greek bussinessman, G. Koutarellis, bought two B-534-II from Avia and donated them to the Greek Air Force in August 1936. They served with the 24. Mira (24th Squadron) and were destroyed in the Greco-Italian war of 1940-1941.
• Slovak Republic: The main user of this airplane. The B-534-II variant was employed by the Slovak Air Force during the invasion of Poland on September 1939 and later they were used as a second-line/home defence fighters as the most advanced ones were used at the front lines.

Sources:

1. https://en.wikipedia.org/wiki/Avia_B-534

2. Salamander Books - The Complete Book of Fighters

3. http://greek-war-equipment.blogspot.com.es/2011/12/1937-1941-avia-b534.html

Avia B-534-I - Native users

The Avia B-534-I was a direct variant of the Avia B-34/2 which flew for the first time on 25th May 1933 and was designated retroactively as B-534.1 on September of that same year.
After further testing, an order of 34 airplanes followed which was soon increased to 147 on 17th July 1934.

It was a single-engine biplane fighter powered by a license built Hispano-Suiza inline engine and a fixed landing gear. The first airplane of the I type were delivered for the first time in October 1935 and 100 of them were supplied to the Czechoslovak Air Force.
The I series was based on the second prototype and was armed with four 7.92mm vz.28 guns, two of them placed in the sides of the engine, just like the B-34 and two of them mounted on the lower wings, however, those proved to be troublesome and only the first 47 airplanes were armed with them.
It was powered with an Avia built licenced version of the Hispano-Suiza 12Ydrs engine delivering 850hp of power. It had capacity for 347 litres of fuel which were located in two fuselage tanks of 90 and 257 litres.

Sources:
1. https://en.wikipedia.org/wiki/Avia_B-534
2. Salamander Books - The Complete Book of Fighters

Avia B-534-I Foreign Users

We're covering the foreign users of the first variant of the Avia B-534 airplane.

• Germany: After the annexation of the Czechoslovak state the Luftwaffe got some B-534-I. As the first version was obsolete, they were destined to training duties.
• Slovak Republic: When the Slovak Air Force was created, they operated some of them. As they were already obsolete by 1939, they were most probably relegated to second line defence duties.

Sources:

1. https://en.wikipedia.org/wiki/Avia_B-534

2. Salamander Books - The Complete Book of Fighters