The J-2 Polonez aircraft, designed by Jaroslaw Janowski with the help of Andrzej Wisniewski from the Institute of Aviation, is a development of Jaroslaw Janowski’s first design, the J-1 Przasniczka. It was also of wooden construction and had a pusher propeller engine, but used a cantilever mid-wing configuration and a single-wheel monowheel landing gear. The main principle was maximum simplicity of construction, so that the aircraft could be built using the simplest tools. The first example of the Polonez, powered by a modified Trabant car engine, was built by Jozef Leniec from Szczecinek in 1977.
In Poland in the 1980s, several examples of Polonez aircraft were built, powered by Trabant car engines, and one with a Walter Mikron aviation engine. They had conventional two-wheel landing gear. In 2017, an example powered by a Rotax engine was built. In total, around 200 sets of J-2 Polonez documentation were sold worldwide.
The exhibited example was built by Andrzej Fiuk, a glider and aeroplane pilot of the Grudziadz Aero Club, who collaborated with Jaroslaw Janowski in the Amateur Constructors Club (KAK). Andrzej Fiuk, in consultation with the designer, carried out a number of modifications to the original design — he enlarged the cabin to improve comfort and ergonomics, added a steel fuselage truss with a modified frame construction to which he mounted a two-wheel landing gear with a tail wheel, and enlarged the vertical stabiliser. This modified version was named J-2B.
Construction of the aircraft began in 1986 and it was flown for the first time in 1991 with a Trabant engine by test pilot January Roman, after which it was registered with the markings SP-048. It participated several times in the European Amateur Aviation Rallies in Olesnica.
The purchase was co-financed from the funds of the Minister of Culture and National Heritage from the state budget under the National Institute of Museology and Collections Protection’s own programme “Expansion of Museum Collections”.
| Wingspan | 7.24 m |
| Length | 5.06 m |
| Height | 1.50 m |
| Empty weight | 180 kg |
| Takeoff weight | 290 kg |
| Maximum speed | 160 km/h |
| Cruising speed | 140 km/h |
| Stall speed | 82 km/h |
| Maximum rate of climb | 1.4 m/s |
| Powerplant | 2-cylinder two-stroke air-cooled piston engine Hirth F23A in flat configuration of 40 hp |
