The Versailles Treaty put German industry in a very cramped working environment. In order to avoid military developments, observers of the victorious countries in the First World War kept German factories and design bureaus under control. Engineers had to, bypassing the commissions, secretly take the assembly and testing of "sanctioned" vehicles to other countries. This also happened with the development of the heavy three-engined aircraft Junkers G 24, which was flight tested in Zurich, Switzerland. In the early autumn of 1924, work was in full swing and promised the aircraft a good future, but on November 4, Entente controllers still noticed the aircraft, as well as its overly powerful 230 hp Jumo L2 engines. with. each. Everything indicated that a heavy bomber was being developed in Germany under the guise of a passenger aircraft. In those days, all bombers that had more than one engine were automatically classified as heavy.
I must say that the Germans approached the design of the new machine very carefully, and the plane did not at all resemble a combat vehicle in its outlines. The main part of the fuselage was occupied by a voluminous passenger compartment for nine people, and equipping the aircraft with three motors at once spoke of increased safety requirements in civil aviation. It was assumed that even if two engines stopped, the Junkers G24 would be able to safely reach the nearest airfield. There was an option for landings on the water surface, however, in most cases it had to be smooth as glass (the plane did not like waves very much). On the water, the plane held two floats of 6900 liters each. Based on this, the control commission from the Entente made a claim only to the power of the motors. The Germans successfully solved the problem by submitting to the winners a harmless Junkers G23 aircraft with less powerful engines. They demonstrated four variants of the car with different engines at once: the German Jumo L2, Mercedes D. III a and D. I, as well as the English Lion. As a result, the commission was satisfied with everything, and the plane went into series. However, the Germans were not going to leave such low-speed engines on the finished equipment and quietly assembled Junkers G24 in Dessau without equipping them with engines. The secret was that further such flightless semi-finished products were sent to the Hugo Junkers plant in Switzerland, where they mounted three Jumo L2 motors of 230 hp each. with. The admission commission allowed only the twin-engine version of the G23La to be put into production. When the plane was returning to Germany on its own, the observers could not do anything formally - the cars were already in the category of imported ones and the restrictions did not apply to them. The aircraft was produced according to the same scheme at the Swedish Junkers plant in Limhamn. Of course, there is connivance here on the part of the control commissions of the winning countries - with the proper level of adherence to such a "gray" production scheme could be stopped in time.
What does the Soviet Union have to do with it? The point is in the military version of the Junkers G24, which from the very beginning was designed under the K.30 index and was supposed to be produced in the Moscow Region Fili. The secret concession enterprise of Junkers was located there, based in the buildings of the former Russo-Baltic plant. The history of this enterprise began with the receipt by the Germans of the concession agreement No. 1 dated January 29, 1923, according to which Junkers received production facilities for the assembly of military equipment on lease, and Russia got access to advanced aviation technologies. The plans were to organize the assembly of at least 300 aircraft per year, of which half was purchased by the Air Force of the Soviet country, and the rest of the Germans sold at their own discretion. In addition, the office of Hugo Junkers was supposed to train Soviet specialists in the precision assembly of aviation equipment, as well as transfer technologies for the production of aviation aluminum.
Realizing that the Germans actually had no alternatives, the government of the Soviet Union demanded that the plant in Fili be equipped with the most modern production equipment for the early 1920s. In response, Junkers' firm asked for permission to aerial photographs of the territory of Russia and the organization of flights between Sweden and Iran. It was at this concession enterprise that it was planned to organize the secret assembly of the three-engine Junkers K30. The bomber differed from the civilian vehicle by a reinforced fuselage, three machine-gun points and external mountings for aerial bombs. The Jumo L2 motors were replaced with more powerful L5s, which in total produced 930 hp. I must say that the true civilian nature of the aircraft had a negative impact on the bomb load - only 400-500 kg, which for the 20s was already a rather mediocre indicator. At the same time, in the USSR there was nothing to choose from - the best bomber of N. N. Polikarpov P-1 could take on board 200 kg of bombs. Everything was corrected with the appearance in 1929 of the Tupolev TB-1 with a bomb load of more than a ton.
Junkers K30 becomes YUG-1
The first contract for the purchase of three-engine Junkers K30 bombers by the Soviet Union dates from July 1, 1925 and provides for the supply of three vehicles with spare engines. The aircraft were named YUG-1 (Junkers cargo - 1) and arrived disassembled in Fili by September. Despite the fact that the Yug-1 turned out to be more than 100 kilograms heavier than expected, the car made a good impression on the aviators. It is worth remembering that by the mid-1920s the TB-1 had not yet been commissioned, therefore the level of claims of the Red Army was appropriate. In the fall of 1925, the government already ordered twelve aircraft. And with the beginning of 1926, long and difficult negotiations began with the management of the Junkers company about the feasibility of producing the car in Fili. Economists from Germany assured that it was unprofitable to assemble Junkers K30 in the USSR from vehicle kits and it was much easier to manufacture aircraft in German Dessau, and then secretly retrofit them to a military version in Sweden. They also referred to the low qualifications of workers at the plant in Fili, and in the end they also bribed the officials responsible for the purchase of the Junkers K30. As a result, the price of each German car was overstated by at least 75 thousand rubles. In this story, the Russians and the Germans by the end of 1926 quarreled, closed the concession plant and … signed a new contract for 14 aircraft.
What was YUG-1 in technical terms? It was a duralumin monoplane with a square fuselage in cross section. The crew consisted of five people - the aircraft commander, co-pilot, navigator, radio operator and flight mechanic. The cockpit was open, which seriously complicated piloting in bad weather. To repel the attacks of fighters on the South-1, three machine-gun points with 7, 69-mm Lewis were provided at once. The aircraft could only take bombs with a caliber of up to 82 kg on an external sling, and was optionally equipped with removable mine throwers. A feature of the bomber's power supply system was the widespread use of dynamos with windmills. They powered the fuel pump, the electrical system with batteries, the Marconi radio station and the Kodak camera.
The first YUG-1 after testing was put on floats and sent to serve in the 60th Black Sea Squadron in the Nakhimov Bay in Sevastopol. By 1927, this unit was replenished with three more bombers. The first impressions of the flight crew were positive - the aircraft was easy to fly, stable and relatively effective in exercises. At the same time, many minor flaws were recorded, namely, drips of fuel, water and oil, unreliable operation of windmills and an extremely primitive intercom system through hoses with horns and headphones. But the armament has come under more serious criticism. The celluloid in the machine-gun turrets quickly became cloudy and made it difficult for the shooter to see, the standard German bomb sight had an unfortunate location, and to use it, one of the machine-gun turrets had to be raised. Due to the unreliable bomb release, they developed and installed domestic analogues Der-6bis and SBR-8. On the late deliveries of YUG-1, the weak design of winter skis was noted, the batch of which was generally refused to be accepted from the German side.
The 60th squadron (later replaced by seaplanes), the 62nd mine and torpedo squadron in the Baltic and the 55th bomber squadron were equipped with YUG-1 aircraft. The machines did not have time to fight and in the early 30s all were written off to the civil aviation of the Soviet Union. Such a quick retirement could be explained simply - the Air Force began to receive domestic TB-1s, which were utterly superior to the German ersatz bomber. And the most famous operation involving YUG-1 was not connected at all with military operations, but with the heroic rescue of the crew of the Italia airship that crashed in the Arctic in the summer of 1928. Then an airplane with the call sign "Red Bear" from the 62nd squadron under the command of Boris Grigorievich Chukhnovsky was allocated for the search. The car on the icebreaker "Krasin" was transferred to the site of the alleged crash, but after several search flights, Yug-1 itself made an emergency landing in the ice and did not participate in the further operation. It is noteworthy that Chukhnovsky suggested that Krasin not be distracted by the search for its own emergency aircraft, and the crew ended up spending five days in the Arctic frost. For such a selfless act, all crew members were awarded the Order of the Red Banner.
Despite all the shortcomings, YUG-1 turned out to be very useful in the military aviation of Soviet Russia. With this machine, it was possible to wait out the time when the air fleet did not have its own massive heavy bomber. And with the arrival of the TB-1, German aircraft were converted into civil aircraft, and they successfully operated on Soviet airlines until the end of the 30s.
