PZL Bielsko SZD-39
| PZL Bielsko SZD-39 Cobra 17 | |
|---|---|
 SZD-39 Cobra 17 |
|
| Type: | High performance glider |
| Design country: | |
| Manufacturer: | |
| First flight: |
March 17, 1970 |
| Commissioning: |
1970 |
| Production time: |
1970 |
| Number of pieces: |
2 |
The PZL Bielsko SZD-39 Cobra 17 is a Polish high-performance glider for the open class and in this capacity the last wooden model built for a competition . SZD stands for Szybowcowy Zakład Doświadczalny (Glider Development Plant). Two copies were made.
development
The Cobra 17 is a parallel draft Cobra 15 and was like this from Władysław Okarmus for participation in the 1970 in Marfa held XII. Developed world championships in gliding. In contrast to the standard class model with a 15 m wingspan , the aircraft was intended for competition in the open class and was therefore given wings with a wingspan increased by two meters (hence the name Cobra 17 ). Another difference was the installation of two water ballast tanks made of rubber with a total of 60 l in the wing nose, which had two drain cocks in the luggage compartment and in the fuselage floor behind the main wheel and ensured drainage in 55 seconds. Both copies were built in the SZD plant in Wrocław . The first flights took place on March 17 (registration number SP-2539 ) and on April 30, 1970 ( SP-2540 ) and were carried out by Jerzy Śmielkiewicz. The tests showed good stall behavior , good steering maneuverability and effectiveness of the airbrakes. The curve change time was about four seconds at 2 × 45 °. Participation in the glider world championship ended for the Cobra 17 when Edward Makula achieved 5th place in the open class. In contrast to its sister construction Cobra 15, of which over 280 pieces were produced, the SZD-39 remained with two prototypes .
construction
The SZD-39 Cobra 17 is basically identical to the SZD-36 Cobra 15 apart from the enlarged wingspan and the wing ballast tanks . It is a wooden structure in cantilever monoplane construction method with Sperrholzbeplankung and GRP -Anteilen. The trapezoidal wing has a continuous spar and is coated with plastic. The cantilevered T-tail unit has an arrow-shaped fin and a pendulum elevator . The chassis consists of a retractable main wheel, the brake of which is coupled to the airbrakes , and a spring-loaded tail spur.
Technical specifications
| Parameter | Data |
|---|---|
| crew | 1 |
| length | 6.98 m |
| span | 17.00 m |
| height | 1.59 m |
| Wing area | 12.27 m² |
| Wing extension | 23.56 |
| Wing swept | 1.5 ° |
| V position | 2 ° |
| Wing profile | Wortmann FX 61-168 (root) to FX 60-1261 (end) |
| Glide ratio | 41 at 96 km / h |
| Slightest sinking | 0.62 m / s at 71 km / h |
| Preparation mass | 298 kg |
| Takeoff mass | maximum 430 kg (without ballast) maximum 490 kg (with ballast) |
| Wing loading | maximum 29/35 kg / m² |
| Minimum speed | 65 km / h |
| Top speed | 250 km / h |
| Load multiple | + 6 / -3 g |
Others
The abbreviation SZD-39 was also given to a prototype and predecessor of the Jantar series , a high-performance sailplane for competitions that was tested by Jerzy Popiel in 1971. Its exact designation is SZD-39-19 Jantar 19 .
literature
- Kazimierz Wojciech Chudzinski: Polish gliders . Volume 1: 1945-1970. Verlag für Technik und Handwerk, Baden-Baden 2014, ISBN 978-3-88180-454-7 , p. 270/271 and 286 .
- Heinz A. F. Schmidt: SZD-39 "Cobra 17" . In: Flieger-Jahrbuch 1972 . Transpress, Berlin 1971, p. 98 .
- Heinz A. F. Schmidt: Airplanes from all over the world . 2nd, revised edition. tape IV . Transpress, Berlin 1973, p. 111 .
Web links
Individual evidence
- ^ Ulrich Langer: The aviation industry of the People's Republic of Poland . In: Flieger-Jahrbuch 1980 . Transpress, Berlin 1979, p. 96 .