Zybin Z-25
| Zybin Z-25 | |
|---|---|
| Type: | Glider |
| Design country: | |
| Manufacturer: | |
| First flight: |
1948 |
| Number of pieces: |
251 |
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The Zybin Z-25 ( Russian Цыбин Ц-25 , NATO code name Type 25 ) was a Soviet cargo glider . Together with the Jak-14 she was in service with the Soviet and Czechoslovak Air Forces (there as NK-25 for Nákladní kluzák, glider). The two types were the last cargo gliders in service and were retired in the mid-1950s, while their tasks were taken over by more flexible transport aircraft and helicopters.
Development and use
The construction work was carried out by Pawel Zybin from 1944/45 as an "assault transporter for airborne troops" and was based on the Kolesnikow-Zybin KZ-20 , the heaviest cargo glider used by the Red Army of the Second World War , which could carry 20 equipped soldiers. A larger parallel design was the Jak-14 and the Il-32 , which was not put into series production.
The Z-25 was developed in a mixed wood-metal construction. The fuselage had a square cross-section with a cabin attached. The bow could be opened and was used as an entry. The wings were made entirely of wood, braced and attached to the fuselage in a shoulder- wing configuration. The wing trailing edges had a negative sweep . The tail unit was self-supporting and designed normally. The nose wheel landing gear was rigid and some had additional landing skids.
In 1948 flight tests were completed and the model was released for series production. The numbers given in the literature vary widely and range from 45 to 500 Z-25s. Twin -engine Li-2 and Il-12 were used as tow planes . As a test, a specimen designated as the Z-25M received two M-11FR-1 radial engines .
A spectacular Arctic flight of two Z-25s was carried out in 1950 to supply the drifting polar station SP-2. The three-man crews under the command of Vadim Schmeljow and Alexei Frolow were towed by two Il-12s under Alexander Charitoschkin and Wassili Rodin from Tula over the stages Kazan , Sverdlovsk , Krasnoyarsk , Stony Tunguska and Khatanga to Tiksi , where initially about ten Training flights were completed for days under arctic conditions. The last stopover was on the island of Kotelny , where the tow trains were loaded. On April 5, 1950, the teams started and reached the station after a six-hour flight, where they landed safely. Two days later, both Il-12 and Z-25 flew over the North Pole and then started their way back. On May 11th, Tula was reached as the starting point of the trip. The company primarily served to identify economical alternatives for supplying the polar stations. However, since it was particularly for the glider crews under extreme conditions (the Z-25 had no on-board heating and the flight on the 100-meter tow rope was very problematic due to sometimes stormy weather), this was the only venture of this type and thus the only pole crossing one Towing team.
Technical specifications
| Parameter | Data |
|---|---|
| constructor | Pavel Zybin |
| crew | 2 |
| Passengers | 25 armed soldiers |
| length | 16.15 m |
| span | 24.38 m |
| height | 5.00 m |
| Wing area | 75.00 m² |
| Wing extension | 7.9 |
| Empty mass | 2320 kg |
| payload | 2200 kg |
| Takeoff mass | 4520 kg |
| Towing speed | maximum 232 km / h |
| Landing speed | 90 km / h |
literature
- Wilfried Copenhagen , Jochen K. Beeck: The large aircraft type book . Motorbuch, Stuttgart 2005, ISBN 3-613-02522-1 , p. 549 .
- Manfred Jurleit: The silent weapon . In: Fliegerrevue . No. 7/1975 (269) , pp. 286-293 .
Individual evidence
- ↑ Manfred Jurleit: Airplane types of the Soviet Union: Zybin Z-25 (1948) . In: Fliegerrevue . No. 6/1973 (244) , pp. 257 (data sheet).
- ↑ Wilfried Copenhagen: Encyclopedia Soviet aviation . Elbe-Dnjepr, Klitzschen 2007, ISBN 978-3-933395-90-0 , p. 141 (keyword cargo glider).
- ↑ Vladimir Borisovich Kazakov: The flight to the pole . In: Fliegerrevue . No. 1/1985 (383) , p. 18-22 .