Kraków 2025-03-01
J-1 Prząśniczka amateur aircraft.
The amateur aircraft J-1 Prząśniczka was designed and built by Mr. Jarosław Janowski, who was assisted by Mr. Witold Kalita and Stefan Pulawski. The engine was also designed by Mr. Jarosław Janowski and Mr. Stefan Pulawski. The Saturn 500 engine used elements from two MZ-250 motorcycle engines. Flat two-cylinder engine. The first flight was made on July 30, 1970, and the pilot was Mr. Jerzy Orłowski.
The designer’s intention was to build a simple and easy-to-fly aircraft, using readily available materials. Thanks to this, the aircraft was cheap to build and operate. The designer and his teammates were members of the Łódź Aeroclub. The aircraft design was created in July 1967. The prototype was built in an apartment in a block of flats, on an area of 18 m2, on the 2nd floor. At the beginning of 1969, the wings and fuselage were ready. On April 15, 1969, the Saturn 500 engine was started for the first time.
The designer applied for permission to fly the aircraft, providing documentation and a technical description of the aircraft to the Inspectorate of Civil Aircraft Control. However, the office did not make a decision. On July 30, 1970, pilot Jerzy Orłowski flew the aircraft without the necessary documents. The first flight confirmed the correct construction of the aircraft. The flight was carried out in secret from the authorities of the Polish People’s Republic. There was a general reluctance of the communists to build amateur aircraft by citizens. They claimed that the aircraft lacked detailed plans and strength calculations.
Despite this, the aircraft quickly began to enjoy great interest. The aircraft and its designers were invited to Polish television. There were articles in the press, and the designer emphasized the problems of registering the aircraft in Poland. The Institute of Aviation accepted the aircraft for testing in 1972, but the tests and research were not started. In 1973, Professor Zbigniew Brzoska of the Warsaw University of Technology performed an expert opinion on the aircraft’s design and performed structural calculations. Professor Zbigniew Brzoska’s positive opinion resulted in the aircraft and the engine undergoing tests, research, and flight tests, after which it obtained a certificate from the Institute of Aviation after 4 years, under the influence of the media and public opinion. On June 8, 1976, the J-1 aircraft was registered as a motor glider and was entered into the Register of Civil Aircraft with the registration mark SP-002.
A version of the J-1A Don Quichote was also developed, which was adapted to American regulations. Several dozen copies were built, which were created based on plans distributed by Mr. Jarosław Janowski. Four copies were built in Poland, which differed in the engine used and dimensions.
The J-1 Prząśniczka aircraft presented at the Polish Aviation Museum belonged to the designer Jarosław Janowski. The aircraft had 400 hours of flight time. On July 11, 1981, the aircraft was involved in an accident at Lublinek Airport in Łódź. The designer transferred the aircraft to the Polish Aviation Museum, where the aircraft was renovated.
The J-1 Prząśniczka design. The classic high-wing aircraft is a single-person structure. Built of wood. The aircraft received a fixed landing gear. The engine was placed with the pilot’s cabin and moves a pusher propeller. The propeller is two-blade, with a fixed profile.
T-T data of the amateur J-1 Prząśniczka aircraft: Saturn 500 B engine, 2-cylinder, 2-stroke, with a power of 23 HP. Span 7.6 m. Length 4.8 m. Height 1.75 m. Wing profile Clark-Y. Empty weight 130 kg. Takeoff weight 250-270 kg. Maximum speed 150-165 km/h. Cruise speed 110 km/h. Landing speed 65 km/h. Ceiling 2,500 m. Range 250 km. Fuel capacity 20 litres. Take-off run 100 m. Landing run 50 m.
Written by Karol Placha Hetman