I would like to highlight one of the undeservedly bypassed topics: the air forces of the Balkan states. I'll start with Bulgaria, especially since few people know that the Bulgarians were the second in the world after the Italians to use aircraft in the war and produced their own rather interesting designs.
The history of Bulgarian aviation began in August 1892, when the first international industrial exhibition in Bulgaria was held in Plovdiv. The participant of the show was one of the pioneers of aeronautics, the Frenchman Eugene Godard, who made several flights on August 19 in his "La France" balloon. To help him, the "host" sent 12 sappers from the Sofia garrison under the command of Second Lieutenant Basil Zlatarov. In gratitude for the assistance, the aeronaut took the young officer with him on one of the flights. Together with them, another Bulgarian military man, Lieutenant Kostadin Kenchev, took a place in the La France basket.
The impressions of the flight and the realization of the undoubted suitability of aeronautics for military purposes forced Zlatarov to "knock the thresholds" of headquarters in order to use balloons in military affairs, which he eventually succeeded in. By the highest decree No. 28 of April 20, 1906, an aeronautical squad [aeronautical squad] under the command of Captain Vasil Zlatarov was created as part of the railway squad (battalion) [iron squad] of the Bulgarian army. By this time, the squad had already existed for at least a month and was fully staffed with two officers, three sergeants and 32 privates. Initially, the unit had one 360 m3 spherical balloon, which allowed observation from an altitude of 400-500 m. At the beginning of 1912, the first Bulgarian-built aircraft, named "Sofia-1", was made from materials purchased in Russia. This was a copy of "Godard", which allowed to rise to a height of 600 m.
The development of heavier-than-air flying machines has not gone unnoticed in Bulgaria either. In 1912, a group of Bulgarian military personnel was sent to France to train pilots and aircraft technicians.
The first use of Bulgarian aviation for reconnaissance of enemy forces took place during the First Balkan War. At 9:30 am on October 29, 1912, Lieutenant Radul Milkov took off in the Albatross and conducted a 50-minute reconnaissance flight in the Adrianople area. The observer was Lieutenant Prodan Tarakchiev. During the first ever combat aircraft sortie on European territory, the crew conducted reconnaissance of enemy positions, discovered the location of reserves, and also dropped two improvised bombs at the station of the Karaagach railway station.
Special aviation ammunition did not yet exist, so the bombing was aimed exclusively at the moral impact on the enemy.
By the end of January 1913, Bulgaria already had 29 airplanes and 13 certified pilots (8 of them are foreigners).
Bulgarian aircraft of the First Balkan War
In 1914, a flight school [aeroplane school] was opened in Sofia, which was transferred in October of the following year to the Bozhurishche airfield (10 km west of the capital). Of the ten cadets in the first set, seven were admitted to training flights.
During the first year of the First World War, the Bulgarian kingdom stayed away from the big war, but then decided to join the seemingly indestructible alliance of Germany, Austria-Hungary and Turkey.
Before the outbreak of hostilities, the Bulgarian army had only one detachment of airplanes, headed by Captain Radul Milkov. He was subordinate to six pilots, eight observers and 109 ground personnel with five airplanes: 2 Albatrosses and 3 Bleriot (single and two double).
In total, during the war, three dozen Bulgarian pilots flew 1272 sorties, conducted 67 air battles, in which they won three victories. Own combat losses amounted to 11 aircraft, including 6 in aerial battles (four were shot down, two were damaged so much that they could not be repaired).
Bulgarian aircraft of the First World War
On September 24, 1918, the Bulgarian government appealed to the Entente countries with a request to end hostilities, and on September 29, 1918, a peace treaty was signed in the city of Thessaloniki. In accordance with the agreement, the size of the Bulgarian army was significantly reduced, and the air force was disbanded. Until 1929, Bulgaria was allowed to have only civilian aircraft.
Nevertheless, the Bulgarians continued to develop their aviation industry. So, 1925-1926. in Bozhurishte, the first aircraft plant was built - DAR (Darzhavna aeroplanna laborer), where the production of aircraft began. The first serial Bulgarian aircraft was the training DAR U-1, developed by the German engineer Herman Winter on the basis of the German DFW C. V reconnaissance aircraft, during the First World War. The aircraft had a German Benz IV engine, which allowed speeds up to 170 km / h. and was released in a small series.
Bulgarian training aircraft DAR U-1
Following the DAR U-1, a series of DAR-2 aircraft appeared. This is a copy of the German aircraft "Albatros C. III". DAR-2 had a wooden structure and was no worse than the German original.
DAR-2 training aircraft series
While the DAR U-1 and DAR-2 were being produced, the design bureau prepared an original design - DAR-1.
This is how the plane appeared, which was destined to become a "training desk" for hundreds of Bulgarian aviators. The DAR-1 and its improved version of the DAR-1A with the German Walter-Vega engine flew until 1942, although much more modern training vehicles appeared at that time. The quality of the machine is well illustrated by this fact. In 1932, the pilot Petanichev performed 127 dead loops on it for 18 minutes.
[center] DAR-1
DAR-1A
The success of this design was the impetus for the creation of the next DAR-3 aircraft, already conceived as a reconnaissance and light bomber. In 1929, the prototype was ready. DAR-3, called "Garvan" ("Raven"), was a two-seat biplane with trapezoidal wings of a thick profile. The aircraft was produced with three types of engines and had three modifications: "Garvan I" had an American Wright-Cyclone engine; "Garvan II" German Siemens-Jupiter; the most widespread version of Garvan III is the Italian Alfa-Romeo R126RP34 with 750 hp, which allowed a maximum speed of 265 km / h. The aircraft served until World War II and some of them took part in it as communications aircraft.
DAR-3 Garvan III
When the first series of aircraft began to be produced in Bozhurishte in 1926, in the vicinity of Kazanlak, the Czechoslovak company AERO-Prague began construction of an aircraft factory. But while the factory was being built, it turned out that the machines offered by AERO did not meet the Bulgarian requirements. An auction was announced, in which the Italian firm Caproni di Milano won. She has undertaken for ten years to produce aircraft, approved by the competent Bulgarian services, making maximum use of local materials and labor. After this period, the enterprise became the property of the Bulgarian state. The chief designer of Kaproni-Bulgarian was engineer Calligaris, and his deputy was engineer Abbati.
The first aircraft built at the factory was the Peperuda (Butterfly) trainer KB-1 produced in a small series, which was reproduced almost unchanged by the Italian aircraft Caproni Ca.100, popular all over the world.
KB-1
KB-1 defeated the DAR-6 training biplane - the first independent development of the prominent Bulgarian aircraft builder Professor Lazarov: a light and highly technological aircraft.
DAR-6 with Walter Mars engine
In the 1930s, the rapprochement of the government circles of Bulgaria, Germany and Italy began, including in the field of military cooperation, which intensified after the military coup on May 19, 1934.
The second KB-2UT aircraft, produced in a small series in the spring of 1934, was an analogue of the Italian Caproni-Ka.113 fighter with a 10% increase in size and a double cockpit. The series of aircraft did not appeal to the Bulgarian pilots due to the poor visibility from the pilot's cockpit, the tendency towards nosing and the inconvenient navigator's cockpit.
KB-2UT
The unsuccessful debut of KB-1 and KB-2UT prompted the dispatch of a group of Bulgarian aviation engineers from the DAR plant, headed by the aforementioned Tsvetan Lazarov, to the Kaproni-Bulgarian plant. In 1936, from KB-2UT, they created a practically new aircraft, KB-2A, called the Chuchuliga (Lark) with a star-shaped German air-cooled Walter-Castor engine, which allowed a maximum speed of 212 km / h.
KB-2A "Chuchuliga"
However, in addition to its own development and production of training aircraft, Bulgaria began to receive combat aircraft from abroad. So, in 1936, Germany donated 12 Heinkel He 51 and 12 Arado Ar 65 fighters to the Bulgarian Air Force, as well as 12 Dornier Do 11 bombers. Of course, both fighters and bombers were outdated and were replaced in the Luftwaffe by more modern machines, but as you know, “don’t look a gift fighter in the mouth…” German fighters and bombers were the first combat aircraft of the recreated Bulgarian Air Force.
Fighter Heinkel He-51B Bulgarian Air Force
Fighter Arado Ar 65 Bulgarian Air Force
Repair of the engine on the Do 11D of the Bulgarian Air Force
Eleven Heinkel He-51s survived until 1942 and continued to operate as training aircraft for some time. The Arado Ar 65, which entered service in 1937 under the name of the 7027 "Eagle" aircraft, was transferred to the flight school in 1939, and was used as training vehicles until the end of 1943; the last aircraft was decommissioned in 1944. Dornier Do 11 under the designation 7028 Prilep, used until the end of 1943, decommissioned by order of December 24, 1943.
In 1936, Germany also donated 12 Heinkel He 45 light reconnaissance bombers with a maximum speed of 270 km / h, armed with 2 machine guns of 7 caliber, 92-mm synchronous MG-17 and
MG-15 on a mobile installation in the rear of the cockpit, capable of carrying up to 300 kg of bombs.
Light reconnaissance bomber He.45c of the Bulgarian Air Force
The Bulgarians then ordered 18 more Heinkel He 46 light reconnaissance bombers, featuring a more powerful 14-cylinder air-cooled Panther V engine, as well as some structural reinforcement and equipment relocation to compensate for the weight of the heavier engine built by Gothaer Wagon Factories under designation He.46eBu (Bulgarian) in 1936.
Light reconnaissance bomber He.46
Along with combat aircraft, training aircraft 6 Heinkel He.72 KADETT, Fw. 44 Steiglitz and Fw. 58 Weihe arrived in Bulgaria from Germany.
Also in 1938, two transport Junkers Ju 52 / 3mg4e were received from Germany for the Bulgarian Air Force. In Bulgaria, Ju 52 / 3m were operated until the mid-1950s.
Junkers Ju 52 / 3mg4e transport aircraft
However, the supply of outdated German combat aircraft did not satisfy the Bulgarians and they began to look for another supplier. Great Britain and France fell away immediately, since they supported the so-called. the countries of the "Little Entente": Yugoslavia, Greece and Romania, with which the Bulgarians had territorial disputes, so their choice fell on Poland. Few people know, but in the 30s of the last century, Poland not only fully satisfied the needs of its Air Force, but also actively supplied aircraft for export. Therefore, in 1937, 14 PZL P-24V fighters were purchased from the Poles, which was a successful version of a "budget" fighter for poor countries and was already in service with Bulgaria's neighbors: Greece, Romania and Turkey, and the latter two were produced under license. Thanks to a more powerful engine, it surpassed the speed of the P.11 aircraft built for the Polish Air Force. The fighter was equipped with a French engine Gnome-Rhône 14N.07 with a capacity of 970 hp, which allowed it to reach speeds of up to 414 km / h, armed with 4 7, 92-mm Colt Browning machine guns in the wing. The Bulgarian R.24B entered service with the 2nd fighter bracken (regiment), in 1940 they were transferred to training units, and in 1942 they were returned to the 2nd bracken. Most of them were destroyed in 1944 by American bombing.
Fighter PZL P-24
Fighter PZL P-24 Greek Air Force
At the same time, PZL P-43 light bombers were ordered in Poland, which was a version of the Polish Air Force PZL P-23 KARAS light bomber with a more powerful engine. By the end of 1937, the Bulgarian Air Force received the first 12 PZL P-43A aircraft equipped with the French Gnome-Rhone engine (930 hp), which received the name Chaika in the Bulgarian Air Force. Unlike the P-23, this aircraft had two machine guns in front and a simpler bonnet.
Light bomber PZL P-43A of the Bulgarian Air Force
Operations confirmed their high flight characteristics, and the Bulgarians ordered another 36 P-43s, but with the "Gnome-Rhone" 14N-01 engine with a capacity of 980 hp. This modification was designated P-43B. The bomber had a crew of 3 people, developed a maximum speed at the ground of 298 km / h, at an altitude of 365 km / h and carried the following weapons: one 7.9 mm front machine gun and two 7.7 mm Vickers machine guns in the rear dorsal and ventral positions; 700 kg bomb load on external bomb racks
Light bomber PZL P-43В Bulgarian Air Force
Subsequently, the order was increased to 42 units with a delivery date for the summer of 1939. But in March 1939, after the occupation of Czechoslovakia by Nazi troops, the ready-to-send P-43s were temporarily requisitioned for the Polish Air Force. The Bulgarians were unhappy and demanded that the Poles immediately return the aircraft to them. As a result, after much persuasion, 33 planes were sent to the Bulgarians, and the remaining 9 were ready for dispatch and loaded into wagons on September 1. The Germans, who captured Poland, did not give the planes to the Bulgarians either, and at the end of 1939 they repaired all the captured planes and made them training bombers.
Light bomber PZL P-43B at the training center Rechlin, Germany
Bulgarian bombers did not participate in the war, but played a positive role, for some time making up the backbone of the assault aviation. At the end of 1939, these bombers became part of the 1st Army Group of a three-squadron, which also contained 11 training aircraft. For some time they were in reserve, and from 1942 the Polish P.43s were transferred to aviation schools, replacing them with German Ju.87D-5 dive bombers.
In addition to combat aircraft, Poland also supplied 5 PWS-16bis training aircraft.
Bulgarian PWS-16bis
All these purchases allowed in 1937 the Bulgarian Tsar Boris III to officially restore the Bulgarian military aviation as an independent type of troops, giving it the name "His Majesty's Air Forces". In July 1938, 7 Bulgarian pilots went to Germany to the Verneichen fighter aviation school, located 25 km north-east of Berlin, for training. There they had to go through three courses at once - fighters, instructors and commanders of fighter units. At the same time, their training was carried out according to the same rules as the training of fighter pilots and instructors for the Luftwaffe. In March 1939, 5 more Bulgarian pilots arrived in Germany. Despite the fact that during the training two Bulgarian pilots were killed, the pilots mastered the newest German fighter Messerschmitt Bf.109, and left Germany in July 1939. A total of 15 Bulgarian pilots were trained in Germany. Soon they were all assigned to a fighter aviation school at the Marnopol airfield, 118 km east of Sofia. There they trained young pilots who later formed the backbone of the Bulgarian fighter aviation.
Bulgarian pilots training in Germany
At the same time, the construction of its own Bulgarian aircraft continued. In 1936, engineer Kiril Petkov created the DAR-8 "Glory" ("Nightingale") two-seater trainer aircraft - the most beautiful Bulgarian biplane.
DAR-8 "Glory"
On the basis of the DAR-6, which did not enter the series, he developed the DAR-6A, which, after an additional improvement, turned into the DAR-9 "Siniger" ("Tit"). It successfully combined the positive aspects of the German training aircraft "Heinkel 72", "Focke-Wulf 44" and "Avia-122", and in such a way as not to cause patent claims from Germany. For Bulgaria this saved 2 million gold leva. Such a sum would be required for the purchase of a license for Focke-Wulf in the event of organizing the production of PV 44 in DAR-Bozhurishte. In addition, an additional payment of 15 thousand gold leva was required for each aircraft produced. On the other hand, one FV-44 "Stieglitz" aircraft purchased in Germany cost as much as two DAR-9 aircraft manufactured in Bulgaria. "Tits" served until the mid-50s as training aircraft in military aviation and flying clubs. After World War II, 10 aircraft of this type were transferred to the reconstituted Yugoslav Air Force. And today, in the Zagreb Technical Museum, you can see the DAR-9 with the signs of the Yugoslav Air Force.
DAR-9 "Siniger" with Siemens Sh-14A engine
The development of aircraft continued at the Kaproni-Bulgarian plant. On the basis of KB-2A "Chuchuliga" ("Lark"), modifications of "Chuchuliga" -I, II and III were created, of which 20, 28 and 45 vehicles were produced, respectively.
Training aircraft KB-3 "Chuchuliga I"
Light reconnaissance aircraft and training aircraft KB-4 "Chuchuliga II"
Light reconnaissance aircraft and training aircraft KB-4 "Chuchuliga II" at the field airfield
Moreover, KB-5 "Chuchuliga-III" was created already as a reconnaissance aircraft and light attack aircraft. It was armed with two 7, 71mm Vickers K machine guns and could carry 8 bombs weighing 25 kg each. As a training vehicle, KB-5 flew in the Air Force units until the early 50s.
In 1939, the Kaproni Bulgarian company began developing a light multipurpose aircraft KB-6, which later received the designation KB-309 Papagal (Parrot). It was created on the basis of the Italian Caproni - Ca 309 Ghibli and was used as a transport aircraft, with the ability to carry 10 passengers or 6 wounded on a stretcher; a training bomber, for which two pneumatic bomb throwers were installed on it, each for 16 light (12 kg) bombs; as well as for the training of radio operators, for which radio equipment was mounted on them and four workplaces were created for training. A total of 10 machines were produced, which flew in parts of the Bulgarian Air Force until 1946. Bulgarian cars differed from their progenitor by more powerful engines, tail shape, chassis design and glazing scheme. The flight performance of the Parrot was higher than in Italy, as it was powered by two 8-cylinder in-line V-type air-cooled Argus As 10C engines. The maximum power of this engine is 176.4 kW / 240 hp. against 143 kW / 195 hp Italian aircraft with an Alfa-Romeo 115 engine.
KB-6 "Papagal"
KB-11 "Fazan" is the last aircraft developed and mass-produced in Kazanlak. It appeared as a result of the 1939 competition for a light attack aircraft for frontline aviation, which was supposed to replace the Polish PZL P-43. "Pheasants" were originally equipped with an Italian engine Alfa-Romeo 126RC34 with a capacity of 770 hp. (a total of 6 cars were produced). Just before the start of World War II, a contract was signed between Bulgaria and Poland for the construction of PZL-37 LOS bombers and Bristol-Pegasus XXI engines with a capacity of 930 hp were delivered. for them. However, in connection with the outbreak of World War II, the contract was terminated and it was decided to install the supplied engines on KB-11. The aircraft equipped with the new engine were named KB-11A, developed a maximum speed of 394 km / h and had two synchronous machine guns and one twin machine gun to protect the rear hemisphere. They carried 400 kg of bombs. A total of 40 KB-11 units were produced. The aircraft was in service with the Bulgarian Air Force from the end of 1941. It was used in the fight against the Bulgarian and Yugoslav partisans. The aircraft took part in the first phase of the Patriotic War of 1944-1945 (this is how the military operations of the Bulgarian troops against Germany at the end of the Second World War are called in Bulgaria). But because of the resemblance to the enemy Henschel-126s that attacked the Bulgarian positions, ground troops fired at them, and the Air Force command took these vehicles out of active combat activity. After the war, 30 "Fazans" were transferred to the Yugoslav Air Force.
Light bulgarian bomber and reconnaissance aircraft KB-11A
Bulgarian and Soviet officers in front of the KB-11 "Fazan" aircraft, autumn 1944
KB-11 "Fazan" was adopted by the Bulgarian Air Force under pressure from the wife of Tsar Boris, Tsarina Yoanna - the former princess Giovanna of Savoy, daughter of the King of Italy, instead of the much better DAR-10 aircraft of engineer Tsvetan Lazarov, which was created precisely as an attack aircraft. DAR-10 was a single-engine, cantilever monoplane with a low wing and fixed landing gear, completely covered with aerodynamic fairings (bast shoes). It was equipped with an Italian engine Alfa Romeo 126 RC34, with a capacity of 780 hp, allowing a maximum speed of 410 km / h. Armed with a 20mm synchronous cannon, two 7.92mm machine guns in the wings and one 7.92mm machine gun to protect the tail section. It was possible to bombard both from horizontal flight and when diving with bombs of 100 kg caliber (4 pcs.) And 250 kg (1 bomb under the fuselage).
Bulgarian attack aircraft DAR-10A
In 1941, the contract of the Caproni di Milano firm with the Bulgarian state expired. The plant in the vicinity of Kazanlak was renamed into the state aircraft factory, which existed until 1954.
As I wrote above, the Bulgarians planned to establish licensed production of Polish medium bombers PZL-37 LOS ("Los"), in addition, 15 bombers were ordered.
Bomber PZL-37В LOS Polish Air Force
The plant also planned to launch licensed production of Polish PZL P-24 fighters. Before September 1, 1939, a group of Polish engineers arrived in Bulgaria with plans for the ordered factory. Polish specialists were greeted fraternally, they were awarded with Bulgarian military orders and transported through the Bulgarian intelligence channels to Cairo, since it was dangerous for them to remain in Bulgaria, where Gestapo agents were beginning to appear more and more often. According to the documentation delivered by the Poles, a plant was built, where the equipment of the first Bulgarian aircraft plant - DAR (Darzhavna aeroplanna laborer) from Bozhurishte was subsequently transferred, in connection with the outbreak of World War II and the threat of enemy bombing. But more on that …
