Light auxiliary aircraft First flight: 1937 Siebel

The company Siebel ("Siebel flugtsoygwerke") was founded in 1935 under the name "Flugtsoygwerke Halle" (it was located in the city of Halle, 40 km from Leipzig). Under the name Siebel Flugzeugwerke AG, it was entered into the register in 1937. However, it was not about creating a new enterprise, but only about renaming a company that already had its own history. At its origins was the famous sports pilot and designer Hans Klemm. The design bureau of the company, headed by engineer Friedrich Feher, began its activities with the finalization of the design of the Kl-104 twin-engine light passenger aircraft. In 1936, the company was taken over by F. Siebel, also a well-known pilot, and became known as Siebel Flugtsoygwerke Halle.

In early 1933, the leadership of the Commissariat of Air Communications (Luftfahrtkommissariat; predecessor of the RLM) decided, for strategic reasons, to transfer the company Klemm Leichtflugzeugbau GmbH, known for its all-wood training and sports aircraft, from Böblingen (Böblingen), located near Stuttgart, to the center of Germany . There, in a new location in newly built production facilities, it was to become one of the main suppliers of aircraft of all categories. Already in the following year, the new company Klemm Flugzeugbau Halle a. was founded. d. Saale GmbH, which was given the letter designation Fh by the authorities (the name of Hans Klemm, who used the letters Kl, was dropped from the designation to avoid confusion with his previous aircraft). The independence of the new company Klemm lasted only three years: in 1937, financial control over it was taken by Fritz W. Siebel (Fritz W. Siebel). He took over as CEO and changed the company name to Siebel Flugzeugwerke AG. This is only a brief history of the company, since the actual course of events was much more complicated...

The Halle-based Klemm Leichtflugzeugbau GmbH started production in early 1935 with licensed Focke-Wulf Fw 44 Stieglitz training biplanes. At the end of the same year, the company launched the production of Heinkel He 46 reconnaissance aircraft. At that time, Franz Walter was still the director of the company, and Dipl. Ing. Friedrich Echer, a graduate engineer, was the chief designer.

The remaining Hans Klemm plant in Böblingen remained in operation, being an independent company from the company in Halle. Aircraft built there retained the original letter designation Kl; soon G. Klemm himself returned there, again taking up sports aircraft. However, he managed to develop in Halle, together with Echer and other designers, a project for a light twin-engine aircraft, initially designated Kl 104. Since the company was already working with metal, a mixed design was chosen for the aircraft.

The two-spar wing with a transverse V angle of 6 ° and simple flaps had a wooden power set and plywood sheathing, and the ailerons equipped with trimmers were made of duralumin and covered with canvas.

The fuselage had a semi-monocoque all-duralumin construction with a smooth skin. According to the German practice of those years, the door leading to the glazed saloon and the cockpit was located on the left side of the fuselage. The pilot's seat was installed along the axis of the aircraft, and behind it, two passenger seats were placed on either side of the central aisle.

The tail unit is all-metal; the elevators and rudders were equipped with trim tabs and had fabric covering.

The power plant consisted of two inverted eight-cylinder air-cooled Hirth HM 508 engines with a take-off power of 240 hp. (176 kW) with two-blade variable-pitch wooden propellers with a diameter of 2.35 meters. The fuel tanks placed in the wing had a total capacity of 320 liters, the oil tanks were located in the engine nacelles and each of them had a capacity of 12.5 liters.

The landing gear of the aircraft consisted of the main and tail supports; each of the racks was equipped with one wheel. The main landing gear was of simple single strut design and retracted into the engine nacelles by turning back. The tail support was fixed. If necessary, the wheels could be replaced with skis.

Since the production capacity of the Halle plant was at full capacity at the time, the development work and the production of the prototype were delayed. The construction of the first copy, which received the civil registration number D-IQPG, was completed at the end of 1936 under the new designation Fh 104, and the first flight took place in Halle on February 25, 1937. The second prototype, which was already a serial version of the machine, was equipped with two 280-horsepower (206 kW) HM 508D engines.

Both prototypes soon became famous thanks to their participation in the 1938 aviation competitions. The second prototype was the winner of the closed air race held in Italy - III Raduno Aereo del Littorio. For 21 hours, factory pilot Ziese flew 6,200 kilometers over twelve European cities. The cars also successfully participated in other competitions. A year later, a crew from Anhäuser, Balthasar and Kaldrack flew across Africa to Cape Town, flying a total of over 40,000 kilometers.

The Fh 104 was put into mass production in 1939. Two series of machines were produced: the first - from 11 aircraft, the second - from 35. Production was completed in 1942. After the outbreak of war, most Fh 104 Hallores were requisitioned by the Luftwaffe as courier aircraft, and some of them were private aircraft of high-ranking officials. Among the famous personalities who constantly flew the Fh 104 were Field Marshal Albert Kesselring, General Adolf Galland and others.

As part of the German Air Force, the number of passengers was reduced from four to three: the fourth place (to the left behind the pilot) was occupied by a navigator-radio operator. In 1940, a modification of the Fh 104C was developed in Halle, equipped with the more popular Argus As 10C engines, but it remained only in the project.

Photo	Description
	Drawing Siebel Fh 104

Trainer aircraft First flight: 1938 Siebel

The Si.202 aircraft was developed under the guidance of designer Friedrich Feher, who worked for Siebel Flugzeugwerke KG in Halle. Work on a light single-engine aircraft intended for pilot training and courier functions began in 1937. Probably the impetus for its creation was the British light aircraft built by Percival and Miles. A whole series of successful light monoplanes of the M.9 \ M.19 "Master" and "Proctor" types since 1937 formed the basis of British training aviation and were often involved in other tasks. All of the above aircraft were characterized by a two-three-seat cabin, a low wing arrangement and a low-power engine. Thanks to the use of non-deficient materials and ease of manufacture, these aircraft were built by the thousands and served for a long time after the end of the war. Approximately the same tasks were set by F. Feher.

During the design of the aircraft, which received the designation Si.202, it was decided that its structure would be solid wood with predominantly plywood skin. The pilot and cadet (or passenger) were located in a closed spacious cockpit shoulder to shoulder, which significantly improved their interaction in flight. Some issues arose only when choosing a power plant, but they were planned to be resolved already during the construction of prototypes.

The first prototype Si.202V-1 (D-ESFH) entered testing in May 1938 and was powered by a Salmson AD9b (59 hp) radial engine. The experience was successful, but the French engine was soon abandoned, although the fourth prototype Si.202V-4 (D-EHCB) was built with it at the end of the year. It was assumed that they would become samples for the Si.202A series. What happened to the second prototype is unknown, but the Si.202V-3 that followed received a Walter "Micron" II four-cylinder inline engine (62 hp). In the end, German engineers settled on a domestic Zundapp motor.

The first pre-production batch of Si.202Bs with Zundapp 9-092 engines (55 hp) was produced in small numbers in 1939 and was soon replaced by Si.202C modification aircraft with Hirth HM 515 engines (60 hp). With.). From the previous series, except for the engine, they differed in the new shape of the wing and horizontal tail, which received a more rounded outline. The construction of Si.202C aircraft lasted about two years - in 1939 the first 25 aircraft were received, and from 1940 to March 1941. built another 41 aircraft. They were used mainly for courier purposes.

The Si.202 aircraft were not included in the large series for a completely prosaic reason - in 1940, the Fieseler Fi.156 unconditionally took the leader's place among the liaison aircraft and the need for a similar aircraft was no longer felt.

Photo	Description
	Drawing Si 202 A-0

Light auxiliary aircraft First flight: 1941 Siebel

At the end of 1939, Feher began working on a project for a new Si-204 aircraft ordered by Deutsche Lufthansa. She needed a twin-engine aircraft for eight passengers and two crew members. Feher designed an all-metal, twin-keel, low-wing cantilever monoplane.

His power plant consisted of two in-line air-cooled Argus As410А engines with 465 hp each. The main landing gear retracted back into the engine nacelles, in the raised position the wheels partially protruded from the nacelle doors, protecting them during an emergency landing. The tail wheel did not retract. Thus, for the late 1930s, the Si-204 was a completely modern machine.

The design was completed fairly quickly. In May 1941, the first prototype Si-204V1 made its first flight. The machine demonstrated good flight performance, stability and ease of piloting. After the construction of another prototype aircraft in Halle, the Si-204A-0 installation series was made, and then a small number of improved serial Si-204A-1. Since the Second World War was already in full swing, most of the built aircraft did not end up in civil aviation, but in the Luftwaffe, where they were operated as communications and training.

A special version of the Si-204D was ordered for the training of bomber and reconnaissance aircraft crews. It was supposed to train pilots in piloting twin-engine aircraft and "blind" flight, to train navigators and radio operators. It was believed that the Si-204D would replace the outdated Focke-Wulf FW-58. The designers were required to bring the layout and equipment of the cabins closer to combat vehicles. As a result, a new heavily glazed forward fuselage was designed, somewhat reminiscent of the He-111N bomber.

The Si-204V3 became the prototype of modification "D". He successfully passed the tests, confirming compliance with the requirements of the military. But the plant in Halle did not build serial Si-204Ds. Enterprises in the "Reich" focused on the production of the main types of combat aircraft. In Halle, the Ju-88 bomber was put on stream. The release of less priority training and transport vehicles began to be transferred to the factories of the occupied countries. For the Si-204D, they found suitable capacities in Czechoslovakia and France.

In France, the German authorities loaded the plant of the SNCAC concern in Bourges with the production of Siebels and began to develop them at the beginning of 1942. The invaders gave the company an order for 450 aircraft of modifications "A" and "D". It was in Bourges that they released the Si-204D-0 installation series and began to assemble the Si-204D-1, which differed in equipment configuration and placement. All production vehicles of the "D" modification were equipped with Argus As411TA-1 engines with a takeoff power of 580 hp each. But production in France unfolded sluggishly. This was affected by the lack of components and qualified personnel, and the work of the French underground, who repeatedly committed acts of sabotage. In total, by August 1944, when the plant stopped completely, only 150 aircraft were produced.

In the "protectorate of Bohemia and Moravia" the Germans were more fortunate. There they attracted three enterprises at once to this program - "Aero" and "ČKD-Prague" in Prague and "Walter" in Janonica. Production began in June 1942. During the years of occupation, the Czechs produced 1007 Zibels. These machines were widely distributed in many flying schools "Reich". They were also used at the front as light transport and staff. For long-range flights, additional gas tanks were installed in the fuselage, supplied by the plant as kits for conversion in the field. "Siebels" have earned an excellent reputation as a durable, reliable and unpretentious machine.

Some of these aircraft have undergone various alterations. They were equipped with devices for towing gliders, various equipment for use as flying laboratories. When radar stations appeared on German night fighters, it became necessary to train radio operators. For this, they adapted Si-204D, in the bow of which antennas were mounted. The Siebels were fitted with FuG218V2R and FuG217R radars.

One of the main drawbacks of the Si-204D is the lack of weapons, which did not allow performing many exercises of the combat training program. The old FW-58 had both small arms and bomb weapons. Therefore, the designers in Halle developed projects for the installation of bomb racks, machine gun turrets and other necessary equipment. But such training machines were not mass-produced, although some flight schools carried out such re-equipment of the Siebels on their own.

On the other hand, a modification of the Si-204E appeared - the combat Siebel. Two fixed 13 mm MG131 machine guns were mounted under the forward fuselage. Of these, the pilot fired, in whose cockpit a Revi16A sight was placed. The third machine gun of the same type was mounted in a shielded HDL 131 turret on top behind the cockpit. The transparent dome of the turret was clearly visible and is the most visible external sign of the "E" modification.

In the former passenger cabin, ETC cluster bomb racks were installed for 50-kg or 70-kg bombs. Maximum placed in the fuselage up to 12 bombs of 70 kg. The bomb bay, which was closed by doors, was cut in the lower part of the fuselage. There was also an external suspension. Bombs of caliber from 50 to 500 kg were hung on holders under the fuselage (in front of the bomb bay). Isn't it true that two "five hundred" is not a weak combat load for a former training vehicle? If the Siebel carried bombs only inside, then even up to 160 kg of lighting bombs were placed under the wing. Bombing was carried out using the Letfe 7K sight.

The Si-204E crew consisted of four people. Armored backs with headrests were hung on the pilot's seats. The takeoff weight of the Si-204E at maximum bomb load reached 6000 kg, while the Si-204D even with additional gas tanks did not exceed 5600 kg.

Two Si-204Ds converted into experimental V22 and V23. They were followed by a small series of machines of the E-0 type. Three Si-204E-0s were sent to military trials in Belarus. They were considered as special anti-guerrilla aircraft. The scope of the actions of the Belarusian partisans forced the Germans to throw against them not only regular troops, but also armored vehicles and aircraft.

From the air, the Einsatzkommando Liedtke (named after the commander) from three squadrons supported the punishers. They equipped it with all sorts of junk - from early series Bf-109s to the unforgettable Junkers F-13s of the 1920 model, somehow converted into attack aircraft. Three Si-204Es were transferred there. But, despite a much more modern level, "Ziebeli" did not win big laurels. Some sources speak of German attempts to use the Si-204E as night bombers at the front, regarded as extremely unsuccessful. In addition to the installation series "E-0", these machines were no longer produced.

By the end of the war in Germany began to affect the lack of raw materials. Including aluminum. In Halle, they developed a technology for manufacturing detachable parts of the wing and plumage from wood. But they did not manage to introduce such a mixed design into mass production.

Quite a lot of "Siebels" were used in the USSR. Many of them were captured at the end of the war. At first, captured Si-204s were operated mainly by the military. The headquarters of many regiments and divisions stationed in Germany used the Siebel for service flights. These aircraft were considered supernumerary and often their presence was not reflected in the documents. Later they were officially registered and partially transferred to the territory of the USSR.

They were also interested in civil aviation, which did not have machines of this class. There, a gap formed between two mass categories - large Li-2 and S-47 and small Po-2. The long-awaited Antonov biplane never showed up. So we decided to try "Siebel".

The first of the civilian departments to receive these aircraft was the GUSMP Polar Aviation Administration. Its park was greatly thinned during the war years. The administration began to replenish with captured equipment in the summer of 1945. In June-August, the crews of the Moscow GUSMP air group overtook from Germany, among other aircraft, nine Siebels (we called them C-204s). Two Si-204s remained in Moscow for transportation in the middle lane, and all the rest were sent to Krasnoyarsk, to the plant No.477 named after Pobezhimov to be finalized for operating conditions in the north. For the Si-204, 10 sets of skis were made, since it was planned to receive only 10 of these aircraft.

Already in 1945, Si-204 flights began in the north. The Chukotka air group received the H-370 aircraft. He was transferred from Moscow at the end of July. This machine was not equipped for cold weather and was hardly used. In September 1946, she was returned to Moscow for revision. But back in May-June, three more Siebels arrived. Or rather, two flew. H-379 crashed during distillation. Pilot K.F. Kukanov drove the C-204 from Zyryanka to the Kolyma Crosses. The left motor failed, then the right one overheated. An emergency landing followed on the spit of the Fedotikha River, after which the car was written off. Three more Siebels entered the Igarsk air group. During the 1946th Si-204 GUSMP flew 596 hours.

By April 1947, there were nine Si-204s in the Polar Aviation. During that year, the GUSMP lost three Siebels. One H-414 crashed in May in the Tula region. Failure of one and failures of the second engine led to an emergency landing. The second H-408 fell victim to the self-confidence of the pilot Vyaltsev. He certainly wanted to land on the Chokurdakh airfield on one engine. But the pilot failed, the car went across the runway and hit the bank of the Indigirka.

The cause of the death of the third Siebel, H-409, remained unclear. After taking off at Dudinka, he lost speed and fell. Pilot V.P. Brekhov died. After this series of accidents and disasters, it was concluded that German aircraft were still poorly adapted to work in the north, and the improvements made were insufficient. Si-204 did not pass special tests at low temperatures. As a result, in 1948, the Polar Aviation removed the Siebels, the number of which by that time had reached 12, from operation. The planes were mostly transferred to other departments.

On the lines of "Aeroflot" these machines appeared a little later than the polar explorers. They were interested in the Civil Air Fleet primarily for the possibility of exploitation in the Pamirs. There, long-obsolete P-5s (disarmed P-5s) continued to fly to Khorog. The planes were already about ten years old, the production of the M-17F engines standing on them was also stopped long ago. Other vehicles that the Civil Air Fleet had either could not land on the sites there, or did not have a sufficient ceiling for flights in the mountains. Initially, they wanted to replace the P-5 with German captured Junkers W34 aircraft. As an alternative to this single-engine "Junkers" for flights in the mountains, the Si-204 was considered.

For trial operation, one Si-204 was borrowed from the GUSMP. By the end of August 1945, he was transferred to Stalinabad, but flights to Khorog were delayed due to the failure of one engine. The motor was urgently delivered by plane and the flights began. After a month of successful operation in the highlands, this Siebel was returned to the Polar Aviation, and the head of the Main Directorate of the Civil Air Fleet, Astakhov, asked the Air Force to provide 20 captured C-204s. In total, according to management estimates, at least 50 such machines were required for lines in mountainous areas.

By the end of 1945, the Civil Air Fleet received its first "own" C-204. He was sent to Tajikistan, but on the way the plane made an emergency landing in Aktobe. A month later, there were already two Zibels in Tajikistan and another one was driving a crew from the 10th Guards Transport Division there. A little later, the deployment of the C-204 was changed: one went to Uzbekistan, one to Armenia, and one remained in Tajikistan. Another aircraft, again borrowed from the GUSMP, also worked in the latter. In the second half of 1946, "Siebel" appeared in Azerbaijan. In May of the same year, the Air Force offered to hand over seven aircraft that were in Czechoslovakia and required repairs. The repair was carried out by a factory in Prague, which they built under the Germans. He paid for the work from his GVF currency fund. These machines arrived in the USSR the very next year.

The Si-204 enjoyed a good reputation among the flight and technical staff. He had good maneuverability, was easy to manage, and had excellent visibility from the cockpit - the entire nose was completely glazed. The problems were mainly associated with the Argus engines, which often stalled in flight.

So, in March 1947, while checking a plane with a suspiciously running engine in the air, Simonyants, an instructor pilot of the Armenian squadron, had an accident. On the landing circle, the engine slowed down, then again came back to normal. Simonyants hesitated with the landing, as he stubbornly did not want to leave the right landing gear. As a result, the engine stopped at a height of about 100 m. Not reaching the runway, the Siebel crashed into a large shed. The crew was injured.

During 1946, the Civil Air Fleet received four Si-204s. Further, the role of German aircraft in domestic civil aviation was steadily declining. Released from the disbanded transport divisions and regiments, Li-2 and S-47 returned to intra-union lines. There was no longer a great need for German cars. The depreciation process has begun, but is still rather slow. Some aircraft were transferred to departmental aviation. In June 1947, an order was issued by the head of the Main Directorate of the Civil Air Fleet on the write-off and further use of captured equipment. By December, there were seven C-204s in total.

In 1948, the Civil Air Fleet received the last captured aircraft, the only C-204. On the other hand, intensive write-offs were carried out: four C-204s disappeared from the lists in a year. In November, the new head of the Civil Air Fleet Baidukov planned, after the arrival of the first An-2s in the 1st quarter of 1949, to completely decommission the Ziebeli. The receipt of the An-2 was somewhat delayed, but in 1949 the German machines were indeed completely abandoned. According to the results of the Civil Air Fleet census conducted in May of that year, two Si-204s remained in stock (both were subject to depreciation).

By June, only one "Siebel" remained in the lists of aircraft of the Civil Air Fleet. By the end of the year, he was gone. The people's commissariat (then the ministry) of the aviation industry had no less fleet than the GUSMP. And there were also enough captured German aircraft. After the transfer of part of the equipment from the Civil Air Fleet, by October 1947 there were five Si-204s. Since 1948, the process of gradual decommissioning of captured equipment began here as well. That year, three C-204s were scrapped (one of them after an accident). By the end of 1949, the Ministry of the Aircraft Industry had three C-204s. All of them were written off in the 1st quarter.

The third major owner of captured equipment was the Ministry of the Interior. In the post-war period, the border guard and, accordingly, its aviation were already removed from its jurisdiction. But there was a whole empire of camps serving factories, mines, logging, construction. The needs of these enterprises were served by the so-called "economic" aviation of the Ministry of Internal Affairs.

The Main Directorate of Railway Construction Camps had three C-204s, which were used to transport people and goods, as well as for aerial photography. By April 1949, only one Si-204 remained from this farm, which was operated until the beginning of 1950.

In 1948, the Main Directorate of the Hydrometeorological Service received nine C-204s from the GUSMP. These machines were given new numbers - from M-351 to M-360. They were scattered one by one among different detachments and links - in Moscow, Leningrad, Alma-Ata ... By April 1950, only five Zibels remained. By the end of spring, four of them were decommissioned. When the last one was scrapped is unknown. And, finally, the Selkhozaerosemka trust of the Ministry of Agriculture received the only C-204 in 1947 from Polar Aviation. The new number F-274 was applied to the car. She was based in Orsha. As a result, by the beginning of 1951, there were no more Siebels left in our country.

Photo	Description
	Drawing Si 204D-0
	Si 204D in the USSR

Bibliography

• Twin-engine "Siebel" / Wings of the Motherland. Vladimir Kotelnikov./
• Captured German aircraft in Soviet civil aviation /Aviation. Vladimir Kotelnikov./
• Siebel Si 204D /Aviation News 2004-03./