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