The IS-1 Sep glider, which will be on display at the new permanent exhibition “With the Wind and Against the Wind. Civil Aviation”, underwent comprehensive conservation in 2023-2024 at the “Jezow” Glider Works, including cleaning of all components, reconstruction of missing parts, re-covering and varnishing of the structure.
The IS-1 Sep was the first Polish competition glider designed and built after World War II. Developed in 1947 by engineers Wladyslaw Nowakowski and Jozef Niespal from the Institute of Gliding in Bielsko-Biala, it represented an important step in the rebuilding of Polish sporting aviation.
The prototype glider, with registration marks SP-443, was first flown on 2 June 1947 by engineer Piotr Mynarski at the Bielsko-Biala airfield. After successful tests, a series of five units designated IS-1 Sep bis was produced in 1948 and operated by the Aero Club in Bielsko-Biala until 1962.
The Sep was characterised by wooden construction, a wingspan of 17.5 metres and a maximum glide ratio of 27 at a speed of 72 km/h. Its performance and modern design contributed to the development of Polish gliding in the post-war period.
The project was realised thanks to funding from the Programme of the Minister of Culture and National Heritage “Supporting Museum Activities” as part of the task “Restoration of unique gliders of the Polish Aviation Museum — Stage II: IS-1 Sep, IS-C Zuraw and SZD-10 Czapla”.
| Wingspan | 17.50 m |
| Length | 7.50 m |
| Height | 1.25 m |
| Wing area | 17.00 m² |
| Empty weight | 276 kg |
| Takeoff weight | 353 kg |
| Minimum speed | 40 km/h |
| Maximum permitted speed | 225 km/h |
| Minimum sink rate | 0.74 m/s at 67 km/h |
| Glide ratio | 27 (at V=72 km/h) |
| Wing loading | 20.7 kg/m² |
