Kołobrzeg 2024-11-15
PZL CSS-13, S-13, Polikarpow Po-2.
Polish Arms Museum in Kołobrzeg.
One of the CSS-13 aircraft is exhibited in the Polish Arms Museum in Kołobrzeg, in the hall with heavy weapons. The aircraft is disguised as a Po-2 and is painted green, with blue on the bottom. The aircraft has red stars with yellow borders and white and red checkerboards. There are no other markings. A machine gun was placed in the second cabin. Six 50 kg bombs were suspended under the wings.
Development of the design.
In 1918, the Great World War ended, and the Polish Nation regained its statehood. The two main aggressors in Europe, Bolshevik Russia and Germania, were punished by the international community after the Great World War. Numerous restrictions were imposed on them. Bolshevik Russia was additionally isolated. Economic contacts with the free world collapsed. However, the signed Treaty of Rapallo (1922) once again connected the two countries with another bond of love.
Backward Moscow made efforts to rebuild the army. Attempts were made to build its own aviation industry and develop its own aircraft designs. There was a particular shortage of training aircraft. The team of Nikalai Nikalaevich Polikarpov got to work.
Nikalai Nikalaevich Polikarpov (1892 – 1944). In 1916, he graduated from the Polytechnic University in Saint Petersburg. He collaborated with Igor Sikorsky. Also in the design of the Ilya Muromets bomber. In 1917, the designer sided with the communists. In 1918, he was appointed head of the No. 1 Aviation Plant. He organized the licensed production of French SPAD VII fighters. From 1924, he designed his own, primitive fighters; I-1/3/5/6, DI-1/2, R-5 (reconnaissance). The I-5 was the basic Soviet fighter until 1940. In 1926, he began developing the U-2 training aircraft (later Po-2). During Stalin’s purges in October 1929, the designer was arrested and sentenced to death. But then he was transferred to work in a special design bureau of the OGPU, and the sentence was commuted. In 1931, the designer was granted amnesty and Stalin ordered him to create his own design bureau. There, the designer built more fighters; I-15, I-16. Polikarpov’s OKB was developing well. However, in 1944, the designer suddenly died.
U-2 (Po-2).
In 1926, the team of Nikalai Nikalaevich Polikarpov began work on a training aircraft. The aircraft received the designation U-2. The task was difficult. The engineers lacked experience and, above all, were ordered to use non-strategic materials, i.e. wood, plywood and canvas. A power unit was also assigned by order. A simple, weak, 5-cylinder, radial engine, from Shvetsov’s office, designated M-11. Despite this, work on such a simple aircraft went very slowly. The prototype was ready after about 12 months. On June 27, 1927, M. M. Gromov made its first flight. The aircraft turned out to be unsuccessful and was thoroughly rebuilt. The improved prototype was ready for flight only in 1928 and the first flight was made that year. The first flight was probably made on January 7, 1928, and the pilot was again M. M. Gromov.
The aircraft was put into mass production, with the designation U-2. This designation remained until 1944. Production continued at Plant No. 23 in Leningrad (now Saint Petersburg). In the period 1928-1940, a total of 1,235 U-2s were produced. It was unofficially named Kukuruznik by the trained young pilots. The aircraft was designated Mule in the Allied code, which well reflects its temperament in the air. During World War II, opponents referred to the aircraft as a sewing machine, due to the sound it made in flight. In Poland, after the CSS-13 production was launched, the aircraft was called Pociak or Papaj. The machines were used in World War II and the Korean War. In 1944, the aircraft’s name was changed to Po-2, after the designer.
Improved Po-2. 1944.
After the death of Nikalai Nikalaevich Polikarpov, his position was taken by G. I. Bakshayev. His team made a small modification to the aircraft design. The machine received improved ailerons. They now became slotted and received an increased surface area and a changed outline. Of course, their suspension system changed. The elevator received a trimmer (trim tab) controlled from the cockpit. The fairings of the primitive landing gear shock absorbers received new aerodynamic fairings. The engine start system was changed. Now compressed air from a cylinder was pumped into the cylinders. The cylinder was airport equipment and was connected by a hose to a nozzle located on the left side of the fuselage, just behind the engine. The flight instruments on the instrument panel were improved. An engine pressure and temperature indicator was integrated. An electric tachometer was installed instead of a mechanical one. The pressure sensor (pitot tube) was moved to the strut, closer to the lower wing and on a longer boom. Several inspection windows were installed in the wings and fuselage. They simplified the inspection of the aircraft’s technical condition.
However, the modernization carried out was not revolutionary, and the aircraft was still primitive. The aircraft’s greatest advantage was preserved: the ability to take off from random landing sites. It is not true, as some periodicals report, that the aircraft could fly in all weather conditions. It was sensitive to strong gusts of wind, and taking off or landing in the rain was quite a feat. Due to its catastrophically low altitude, it made more turns (to avoid clouds) than it traveled kilometers. The range between stall speed and maximum speed was only 80 km/h. Maximum speed was 150 km/h and that was with the wind. Since 1970, helicopters have been flying twice as fast. It is also not true that the aircraft was easy to repair. The breakage of one of the four structural beams of the fuselage caused the machine to be written off as a loss. Repair was unprofitable. It was cheaper to build a new machine.
The aircraft in a dive could not exceed a speed of 250 km/h, and a speed of 300 km/h caused the destruction of the aircraft. The U-2 in a dive, losing 8 m/s, reached a speed of 195 km/h. The aircraft in test flights, when the pilot had an oxygen system, reached an altitude of 6,900 m. Since such an installation was not installed on serial aircraft, the aircraft did not exceed an altitude of 3,000 m. The maximum speed was 150 km/h at an altitude of 100 m, but the higher the altitude, the more the speed dropped. At 6,900 m, the aircraft had a speed of only 103 km/h. The maximum climb speed in tests was 3.23 m/s, and the aircraft with cargo climbed only 0.5 m/s. This was very little. The aircraft climbed to the maximum altitude (6,900 m) for over 35 minutes. It was no better in horizontal maneuvers. At a speed of 122 km/h, at an altitude of 1,000 m, the horizontal turn lasted 16 seconds. The maximum range was about 400 km, and it was reached after about 3 hours 30 minutes of flight.
The aircraft were primarily used by the army and special units. The U-2 / Po-2 accompanied the operations on the Eastern Front all the time, during World War II. However, the T-T features required the use of special tactics. First of all, combat flights were only at night. Mass attacks were also used, due to the small load capacity of the weapons. However, the low speed favored accuracy.
Due to propaganda, the most famous unit using Po-2 aircraft was the 588th Night Bomber Regiment, which (both ground and flying personnel) consisted of only women. The task of the regiment was the night-time harassing bombing of military installations located behind enemy lines. The two most decorated female pilots, Katya Ryabova and Nadya Popova, flew a record 18 bombing missions in one night. The effects of the women’s unit’s actions were not only material losses, but also a drop in the morale of the Germanic soldiers, who called the pilots night witches. The psychological effect of night operations was also intensified by the tactics of air raids. The planes gained altitude in wide circles, above their own airfield (climb speed with bombs was only 0.5-0.6 m/s), and near enemy lines they attacked with 50 kg bombs from a gliding flight (with engines working at minimum power), when the only sound was the noise of wings, metal cables stiffening the structure and the whistle and explosions of bombs. After dropping the bombs (maximum 6 bombs of 50 kg), the planes moved away from the place of attack at full power. The engine could not be turned off in the air, because it could not be started in the air. It could only operate at a minimum speed of 400-500 rpm, instead of about 1,750 rpm.
The Po-2, contrary to appearances, was a very difficult machine for Luftwaffe aircraft to shoot down because its maximum speed was lower than the stall speed of German fighters Messerschmitt Bf 109 and Focke-Wulf Fw 190, which made aiming much more difficult. Ground fire was much more dangerous, which is why these machines did not fly during the day. Theoretically, the crews had parachutes to save themselves in a critical situation. Theoretically. Because in practice, the crews did not have parachutes. The idea was for the crew to bring the plane to their own airport at all costs. The defensive armament consisted of one mobile ShKAS or DP (Degtyaryova) machine gun, both caliber 7.62 mm with a supply of 250 rounds. The field of fire was very limited, especially vertically.
The Po-2 aircraft also took part in the Korean War. Due to their small size and non-metallic construction, they gave a weak radar echo. So they were harder to detect and shoot down. However, they were not able to inflict significant losses on the enemy.
The U-2/Po-2 was produced for 35 years. According to available information, 33,000 units were built, and together with licensed units, over 40,000 units. However, these data are not very reliable. The number of 1,235 U-2 machines built in the period 1928-1940 is credible. If the number of 33,000 units were true, then in the period from 1941 (the beginning of the fratricidal German-Soviet war) to 1949 (the end of Po-2 production), 31,765 units should have been built. Annually 3,529 copies, monthly 294 copies, daily 10 copies. That’s why we have doubts.
Aircraft versions:
U-2 UT – basic training version, two-seater, two-control. Used as; training, training, reconnaissance. M-11 drive with 75 kW (100 hp). From 1944, designated Po-2 UT.
U-2 SP/PS – three-seater version, pilot and two passengers. The prototype was built in 1938, and in 1944, the designation was changed to Po-2 SP.
U-2 A/AP – agricultural version for spraying loose chemicals. The prototype was built in 1930.
U-2 S – sanitary version, pilot and patient on a stretcher.
U-2 S – sanitary version, planned. “Soviet miracle of technology”. Two patients on stretchers were to be placed on the wings or between them.
U-2 P/M – seaplane on floats. One main float and two auxiliary outer floats. Several copies were built.
U-2 L / Po-2 L – machines for Aeroflot with a built-in cabin.
Po-2 experimental – Aircraft modifications could carry up to 6 people (!). “Soviet miracle of technology”. Then passengers should weigh no more than 55 kg and sit on each other’s laps. Because with classic cabins the last cabin would fall out at the tail.
E-23 – experimental aircraft built in 1934, for tests in inverted flights, upside down.
U-2 LSz – experimental attack. One mobile 7.62 mm ShKAS machine gun, RS-82 rockets or 2 x 120 kg bombs. Launching RS-82 rockets proved to be very dangerous, due to the low speed and low weight of the aircraft.
U-2 LNB/NLB/NB – light night bomber produced since 1941.
U-2 WS – basically the U-2 LNB. In 1945, there should have been 9,000 copies of both versions.
Po-2 LNB/NLB – in 1944, the U-2 LNB/NLB/WS aircraft were redesignated.
Po-2 GN – 1944, the aircraft was equipped with a megaphone and was intended for propaganda tasks.
Po-2 NAK – 1944, an aircraft for correcting artillery fire at night. This aircraft was used in the Polish Military Aviation since February 1945.
Po-2 in the Polish Army.
The first aircraft that Polish Military Pilots had to deal with, in the far depths of the CCCP, were training aircraft; UT-2 and Po-2 UT. In the 2nd Night Bomber Regiment Kraków, training began on Po-2 UT training aircraft. A student pilot performed about 100 flights in a total time of about 25 hours. Among these flights were also flights in the so-called covered cockpit, i.e. flight according to instruments. This was very important, because due to the extremely outdated design, the aircraft could only achieve any success in night attacks. Then the pilot changed to the bomber (combat) version of the Po-2 NB.
The entire combat route of the 2nd PNB Kraków, combat tasks were performed only on Po-2 NB aircraft. The rearmament of the Regiment took place only after the end of the war. On August 17, 1944, Po-2 NB aircraft from the 2nd PNB Kraków landed at the Dys Airport near Lublin. This was the first landing on Polish soil in the new reality, when the Soviets occupied, as a spoil of war, the Polish Eastern Borderlands.
UT-2 and Po-2 aircraft were also used to train subsequent pilots on Polish territory after the Soviet front passed. In November 1944, the United Aviation School was organized in Zamość. This school was to educate both pilots (gunners, navigators) and ground (technical) personnel. The school had 34 UT-2 and Po-2 aircraft at its disposal. In March 1945, training flights of Po-2 and UT-2 aircraft were to begin at Mokre Airport (Zamość). However, due to the thaw and the too marshy terrain, it was decided to transfer the training personnel to Dęblin, which had already been liberated. This also had political implications. (The return of Polish pilot training to its cradle). But another reason was the undisguised hostility of the Zamość region’s population towards the new occupier. (There were sabotage actions and desertions of Poles from the Polish Army subordinate to the Soviets).
As a result, UT-2 and Po-2 aircraft were relocated to Dęblin Airport. The Military Pilot School was organized there. In May 1946, the school was renamed the Polish Army Officer Aviation School. This name survived until 1968, when the school became the Higher Officer Aviation School, educating officer engineers-pilots.
In May 1945, the school in Dęblin had: 26 UT-2s, 6 Po-2s, 22 Yak-9 Ms, 2 Yak-1 Ms, 10 Il-2s, 12 Pe-2s, 2 Szcze-2s. As can be seen from this list, the equipment was outdated, and what is worse, significantly worn out. The need for a modern (for those times) training aircraft was urgent. Unfortunately, Polish actions in this direction were effectively blocked by the Soviets.
An attempt to build a Polish training aircraft was made in Zamość at the turn of 1944/1945. A group of designers and engineers, lecturers at the Zamość school, was formed spontaneously; Lieutenant Michalski, Second Lieutenant Dylewicz and Senior Sergeant Maszyński. However, they failed to implement this bold project.
However, the desire to have a good training aircraft was not completely stopped by the Soviets. Attempts were still made. Several designs were created that did not make it beyond the prototype stage; Żak-1, CSS-10, CSS-11. Some designs managed to reach serial production, but were produced in small quantities; Żak-3, Zuch-2, a variant of the Junak aircraft. Finally, the Junak-2, Junak-3, and a few years later the TS-8 Bies aircraft were successful.
It was not until 1947 that an order was given to prepare a Polish variant of the Po-2 aircraft, which was designated CSS-13, as described below.
Po-2 aircraft played an extremely important role in the Kremlin imposing communist rule on Poland. The Soviets created a transport air squadron for the needs of the Polish Committee of National Liberation. In reality, it was an already functioning Soviet unit, namely the Special Air Squadron “OsNaz”, or “osoboje naznaczyje”.
The “OsNaz” units (not only aviation) were subordinate to the KGB. The “SpecNaz” units were subordinate to the GRU. The Polish Committee of National Liberation, in turn, was the Polish Committee of National Liberation. A self-proclaimed, puppet, temporary body of executive power in the Republic of Poland, operating from July 21, 1944 to December 31, 1944. This body operated on the territory of Poland between the Soviet-Germanic front and the so-called Curzon Line (cutting off the Polish Borderlands). The PKWN was established in the Kremlin and was created by dictator Józef Salin.
The first aircraft placed at the disposal of General Zygmunt Berling (a Polish officer in the service of Moscow) was a three-seater Po-2 SP. The machine had one pilot and two passenger seats.
We will mention that on February 25, 1945, when there were no longer any Germans in Warsaw, the 6th Independent Transport Squadron began its operations. The unit was established by order of the Supreme Command of the Polish Army, based on the Special Air Squadron “OsNaz”, subordinate to the PKWN. It was stationed at Okęcie Airport. The squadron was organizationally subordinate to the 17th Independent Transport Aviation Regiment. Then the Squadron was reorganized into the 36th Special Transport Aviation Regiment, which was disbanded in August 2011.
Returning to the Po-2 aircraft, these aircraft were the basic equipment in the transport squadron. They were used to transport; press, mail, secret documents and VIPs. Interestingly, in addition to the typical two-seater version, a three-seater version was used.
CSS-13.
Due to the urgent need for a large number of cheaply operated training and liaison aircraft and the Soviet blocking of the development of Polish post-war designs, it was ordered that Poland launch licensed production of the already widely known Po-2 aircraft designed by Nikalai Nikalaevich Polikarpov.
In 1947, the Central Aircraft Study (CSS) was ordered to develop license documentation for the Po-2 aircraft. The Central Aircraft Study (CSS) was a partially independent institution serving as an aircraft design office. It was organized by engineer Franciszek Misztal in 1946 in Warsaw’s Okęcie. It operated within the framework of the Aviation Industry Association. In 1950, it was transformed into the Communication Equipment Factory No. 4 Warsaw – Okęcie.
Work on the documentation of the Po-2 aircraft was undertaken by a group of engineers and technicians led by engineer Stanisław Lasota, who translated the documentation into Polish and adapted the aircraft to domestic production capabilities. Especially in the field of flight instruments already produced by the Polish aviation industry. Soviet documentation included a slightly improved version of the Po-2 produced in a Soviet factory in the period 1944-1949. This version of the aircraft was developed by a team led by G. I. Bakshayev, who became the successor of N. N. Polikarpov after his death.
Production of the aircraft under the designation CSS-13 was launched at PZL Mielec in 1948. In December 1948, the factory released a prototype of the aircraft with the factory number 48-013 and registration marks SP-AKZ. The first flight was performed on 18 December 1948, and the pilots were Ludwik Lech and Kazimierz Tyrlik.
The following months were devoted to flight tests and preparations for serial production. On 2 September 1949, the first serial aircraft CSS-13 was flown. The aircraft had the serial number 49-015 and registration marks SP-AWO. The pilots were Ludwik Lech and Roman Lewandowski.
The production of the M-11 D engines was undertaken by two factories; PZL Rzeszów and PZL Wrocław Engine Factory No. 3 “Fasil”. The propellers were produced by WSK No. 4 in Okęcie. Instruments and accessories were produced by WSK Warszawa II.
In 1949, the Institute of Aviation carried out the aircraft homologation, required for mass production.
The CSS-13, like the Po-2, was characterized by poor performance. It took off quickly from the ground, but the power of the power unit was definitely lacking. It was incapable of performing higher piloting maneuvers. It was dangerous in deep rolls. It forgave many mistakes of novice pilots (due to its low forward speed), but provided that the pilot did not approach critical values. Nevertheless, it was suitable for learning basic piloting. Due to its spartan design, it was simple and easy to operate. Operation did not require extensive technical support or highly qualified mechanics.
In June 1949, the CSS-13 aircraft was exhibited at the XXII Poznań International Fair. The aircraft was exhibited at the aviation industry stand and was an export proposal.
On September 11, 1949, the CSS-13 aircraft was presented to the public for the first time in flight. It was during the central celebrations of the Aviation Day at Okęcie Airport. The flight was demonstrated by three machines with unfurled national flags. Then parachute jumps were performed from machines of this type. At the end, there was a team flight of planes piloted by young pilots.
Already in 1949, new planes were sent to military units (as liaison) and aviation league aeroclubs. In 1950, aviation clubs received a large number of these planes. These planes were also sent to: the Officers’ Aviation School in Dęblin, the civilian Aviation League Training Center in Ligotka Dolna, the Parachute Training Center in Nowy Targ.
In 1950, after about 180 machines had been built, production of the CSS-13 in Mielec was discontinued. This was dictated by preparations for the production of turbojet fighters. The CSS-13 aircraft were to continue to be manufactured at the newly established WSK Świdnik plant. However, these plans were also changed, as WSK Świdnik was also to start producing fighters. Ultimately, CSS-13 production was moved to WSK No. 4 in Warsaw at Okęcie. Engine production was moved to WSK Kalisz. Necessary machinery, equipment and materials were transferred from WSK Rzeszów and WSK Wrocław. Propellers were still manufactured at the WSK No. 4 Warsaw propeller factory, and on-board instruments and electrical equipment were still manufactured at WSK Warsaw II. For some time, some components, such as wings and empennage, were made at WSK No. 5 in Łódź. However, over time, these elements were also built at Okęcie. Thus, after almost two years, CSS-13 production returned to Warsaw.
The CSS-13 aircraft began the export of Polish flying equipment in 1953. Around 20 of these aircraft were sold to Romania and Hungary at that time. A little later, the Aeroklub PRL sold 1 aircraft to Korea, and a dozen or so more to the GDR.
Thus, in the first half of the 50 years, the CSS-13 aircraft were the basic liaison equipment in the air forces.
The basic version of the CSS-13 used in the Polish Military Aviation was the two-controller version, which could be flown from both the first and second cabin. A bomber version was also produced for the army (to match the Great World War). The aircraft had a sight glass in the lower right wing for aiming the gunsight. DER-7 bomb locks were installed under the wing, mechanically controlled from the second cabin using Bowden cables. In the second cabin, or rather behind it, a holder for mounting a movable ShKAS machine gun was mounted on the back. Aircraft in this version were used by the army to break ice on the Vistula and Oder.
In addition to the air forces, CSS-13 aircraft were used by the Navy and the Border Protection Forces. The WOP air unit with CSS-13 machines was established in the spring of 1957. They patrolled the sea and land borders with these machines. CSS-13 aircraft were replaced by SM-1 helicopters at the beginning of the 1960s.
In the period 1953-1955, PLL LOT received 20 CSS-13 machines. Almost all (19 machines) were rebuilt into agricultural versions. The conversion was carried out at the Sports Aviation Equipment Plant No. 3 in Poznań, installing equipment according to Soviet documentation. In place of the second cabin, a tank for 250 kg of bulk chemical preparations was placed. A fan was also installed, which powered the mixer in the tank via a gear, and a powder sprayer was placed under the fuselage. Among the rebuilt machines was the prototype CSS-13 registration SP-AKZ. In 1956, agricultural aircraft were transferred to selected regional aeroclubs, in connection with the APRL taking over the operation of dusting crops and forests.
Aircraft production ended in 1955, after about 320 aircraft were released from WSK Okęcie. Adding to this 180 aircraft built in Mielec, this gives a number of about 500 units. Of this number, about 300 aircraft went to the Polish Army, 180 units to aero clubs and 20 units for export. Also in 1957, the construction of M-11 engines in D and FR versions was completed in Kalisz. In total, over 1,500 engines were built.
From 1955, the army began systematically transferring aircraft to aero clubs. Over 7 years, until 1962, 209 CSS-13 aircraft were transferred. (In subsequent years, it looked like this: 1955 – 73 units, 1956 – 8 units, 1957 – 52 units, 1958 – 16 units, 1959 – 0 units, 1960 – 41 units, 1961 – 19 units). The last CSS-13 No. 42071 from Dęblin to Inowrocław (Kujawy Aeroclub) was transferred on September 27, 1961. The machine received the registration SP-AIN.
In aeroclubs, the planes were used for: basic pilot training and piloting without the ground in sight, parachute jumper take-off, glider towing, and on-demand flights.
In October 1962, the Institute of Aviation received an order from the APRL in Warsaw and the Glider Center in Leszno to examine the CSS-13 aircraft, registration SP-BFM. The aircraft received a reinforced M-11 FR engine with a WD-451 propeller. As a result of the tests, it turned out that the aircraft gained slightly in speed and reached a higher altitude by 300 m. However, the conclusion was that the engine upgrade was economically unjustified. Only later did the engine go to the CSS-13 and S-13 aircraft.
Most of the CSS-13s were crossed out of service at the turn of the 60s/70s. Nevertheless, individual copies were used for several years longer, even until 1976. This was the case in the Grudziądz Aeroclub (SP-BFN, built in 1952, flew 2,000 hours, flew 300,000 km), in the ROW Aeroclub in Rybnik, in the Kujawski Aeroclub in Włocławek, in the Szczecin Aeroclub (SP-AOL was demonstrated in the air as late as 1978).
The CSS-13 aircraft permanently entered the history of Polish Aviation. Pilots took their first steps in it in the 1950s and 1960s. The CSS-13 was the first aircraft in the Polish People’s Republic built on a mass scale by the Polish industry.
S-13.
The aircraft designated as S-13, although derived from the CSS-13 design, became a completely new aircraft that could be safely called a Polish design.
At the beginning of the 50s, there was practically no medical aviation in Poland. There were several outdated and different types of aircraft used to transport the sick and wounded. The army itself also needed to organize medical aviation structures. In 1953, the need to build such an aircraft was already very strong. Therefore, the Institute of Aviation was commissioned to develop a medical aircraft based on the CSS-13. The aircraft was to carry; a pilot, a doctor and one patient. The prototype was developed in the Airframe Design Office of the Institute of Aviation, then headed by Master of Science in Engineering Tadeusz Sołtyk.
As a result of analyses, it was decided to transport the patient placed on a stretcher in a gondola located on the fuselage truss. The gondola was basically a cover with hinges that was tilted to the side for loading and unloading the patient. The cover protected not only the patient, but also the doctor. Its front part was glazed and additionally moved backwards along guides. The doctor sat facing the direction of flight or with his back to the pilot, facing the patient. The plane was equipped with a first aid kit and an oxygen set.
The plane’s engine was covered with a Townend ring, improving the aerodynamic flow of the plane.
The prototype was built and flown in 1953. During the tests, it turned out that the center of gravity had been shifted too much to the rear. This phenomenon increased as the fuel from the tank was used up. The machine was unstable and difficult to pilot. Engineer Stanisław Lasota’s team joined the work. Certain design changes were made. The horizontal tail surfaces were enlarged.
The plane passed state tests and an order was issued to start serial production. 9 machines were built by modifying CSS-13 (6 CSS-13 and 3 Po-2) in the training and liaison version and 50 pieces from scratch. 40 S-13 machines were delivered to the army. 19 S-13 aircraft were purchased by civil aviation in 1954 and distributed in the medical aviation as follows; Bydgoszcz, Poznań, Łódź, Katowice, Kraków, Lublin, Białystok, Wrocław, Warsaw.
Thanks to the medical machines, the production of CSS-13 / S-13 exceeded 550 pieces in all versions.
One three-seater version was also built to transport a patient in a seated position. It was strongly emphasized at the time that the aircraft was created as a social undertaking. In principle, it was a passenger aircraft combining the CSS-13 and S-13. It was designated CSS-13 P and received the registration SP-KPE. The aircraft received a completely covered cabin. This aircraft served in the period 1954-1971 as the company’s service aircraft, and was usually used by party and state dignitaries.
In military aviation, the S-13s served for an extremely short time, until the end of 1959, when they were replaced by the medical version of the Soviet Yak-12 aircraft. In the period 1956-1958, the army transferred 37 S-13 aircraft to civilian use (1956 – 12 units, 1957 – 20 units, 1958 – 5 units). In 1958, there were 56 S-13 aircraft in civil medical aviation. They transported patients until 1965, and then were used to transport medicines and food, especially during natural disasters. In the 1970s, single examples were already flying, and these were with different owners. They were used as business aircraft and for light transport. One of the machines, registered SP-KXF, went to the Scout Parachute Troop at the Wrocław Aeroclub. Another, SP-AXN, went to the Opole Aeroclub, and SP-AXS to the Workers’ Aeroclub in Świdnik.
Written by Karol Placha Hetman