PZL S-4 Kania
|PZL S-4 Kania|
|S-4 Kania-3 at the Polish Aviation Museum|
|Role||Trainer and glider towing aircraft|
|First flight||17 May 1951 (S-3)|
|Primary user||Aeroklub Polski|
|Number built||3 + 1|
Design and development
The aircraft was designed by Eugeniusz Stankiewicz in 1950, its primary purpose was towing gliders. The first prototype was named S-3 Kania (kite (bird), S for Stankiewicz, it probably had no PZL prefix). It was built in the Szybowcowy Zakład Doświadczalny (SZD, Glider Experimental Works) in Bielsko-Biała and first flew on 17 May 1951. It appeared quite successful, and was cheaper in production and service, than the CSS-13 (licensed Polikarpov Po-2), but was not produced, because the Aviation Institute (Instytut Lotnictwa, IL) found some lacks in calculations and too weak landing gear. The work ceased, while the prototype was abandoned to ruin.
In 1956, the design was taken over by WSK-Mielec factory (partly due to an interest of the press, combined with shortages of aircraft in aero clubs). It was developed and improved by Stankiewicz's team and on 2 September 1957, a new prototype, the PZL S-4 Kania-2, was flown. On 19 September 1958, another further improved prototype, the PZL S-4 Kania-3, flew, with enlarged tailfin. This underwent state trials in 1960 with good results. It offered good handling and was useful to training, glider towing, and basic aerobatics. It could tow 2 or 3 gliders at a time. The S-4 did not enter production, though, because due to a long development, the design had become dated. At that time, it was preferred to use metal aircraft in aeroclubs, and the PZL-104 Wilga was in development. The other thing was, production of the obsolete M-11 engine had ceased in Poland.
Work on the third S-4 prototype was suspended. It was completed only in 1964 by the Aircraft Repair Works in Krosno.
The first S-4 Kania-2 prototype (registration SP-PAA) was shown on World Glider Championships in Leszno in 1958, among others it hauled several gliders. Along with the second S-4 prototype (registration SP-PBB), it was used by the aero club in Mielec. The third S-4 prototype was used in Krosno (registration SP-PBE). The second prototype was written off in the end of 1970, the rest around the same.
- Aeroklub Polski operated two S-4 prototypes in Mielec and the third S-4 prototype in Krosno.
- Polish Air Force one aircraft only.
Wooden construction high-wing monoplane (parasol wing), conventional in layout. Semi-monocoque fuselage. Crew of two, sitting in tandem, in open cockpits with windshields. Fixed conventional landing gear. Two-blade propeller. Fuel tanks 165 l.
- Crew: 1, instructor
- Capacity: 1, student
- Length: 8.72 m (28 ft 7¼ in)
- Wingspan: 12.16 m (39 ft 10⅝ in)
- Height: 2.35 m (7ft 8½ in)
- Wing area: 19.7 m² (212 sq ft)
- Empty weight: 660 kg (1,452 lb)
- Loaded weight: 945 kg (2,079 lb)
- Powerplant: 1 × Shvetsov M-11D air-cooled 5-cylinder radial engine, 125 hp (92 kW)
- Maximum speed: 171 km/h (92 kn, 106 mph)
- Stall speed: 63 km/h (34 kn, 39 mph)
- Range: 580 km (313 nmi, 360 mi)
- Service ceiling: 5,100 m (16,700 ft)
- Rate of climb: 4.5 m/s (890 ft/min)
- PZL S-4 Kania at Poser site
- Janusz Babiejczuk, Jerzy Grzegorzewski: Polski przemysł lotniczy 1945–1973, Warsaw 1973 (Polish language)
|Wikimedia Commons has media related to PZL S-4 Kania.|
- Photos at Ugolok Neba site