LWD Żak

The LWD Żak was a Polish touring and trainer aircraft of the late 1940s, designed in the LWD and built in a short series.

LWD Żak
Role Touring and trainer aircraft
Manufacturer LWD
Designer Tadeusz Sołtyk
First flight 23 March 1947
Introduction 1947
Retired 1955
Primary user Polish civilian aviation
Produced 1947-1948
Number built 13

Design and development

The Żak (old-fashioned "student") was designed in the Lotnicze Warsztaty Doświadczalne (LWD, Aviation Experimental Workshops) in Łódź, directed by Tadeusz Sołtyk in 1946, as one of the first Polish post-war aircraft. It was a light low-wing cantilever monoplane of a mixed construction, with a crew of two, sitting side by side, and fixed conventional landing gear. The first prototype Żak-1 was first flown on March 23, 1947. It was powered by the Czechoslovak 65 hp straight engine Walter Mikron III and carried markings SP-AAC. The second prototype Żak-2 was powered by the 65 hp flat engine Continental A-65 and had an open cockpit. It was flown on November 27, 1947 and carried markings SP-AAE.

The design appeared successful and the Ministry of Communication ordered a series of 10 aircraft. They were to be powered by licence-built A-65 engines, but since plans of engine production were abandoned, it was decided to fit them with Walter Mikron engines. They were also fitted with a closed canopy, sliding rearwards, and named Żak-3. Ten planes were built by the LWD in the end of 1948, the first of them was flown on November 8, 1948. They had markings: SP-AAS to SP-AAZ, and SP-BAA to SP-BAC. At least one (SP-AAX) had engine replaced later with 85 hp (63 kW) Cirrus F.III. They were used in the Polish regional aero clubs until 1955.

On October 20, 1948 there was flown a prototype of the last variant, Żak-4, meant for a glider towing. It had stronger 105 hp Walter engine and an open canopy. Since it showed unsuitable for glider towing, and old Polikarpov Po-2 appeared the better plane for this purpose, Żak-4 was not built in series, and the prototype was re-fitted with a closed canopy and used as a touring plane in aero club (markings SP-BAE).

Variants
Żak-1 (SP-AAC)
The first prototype powered by Walter Mikron III engine.
Żak-2 (SP-AAE)
The second prototype without canopy and powered by Continental A-65 engine.
Żak-3
Main production version with closed canopy and powered by Walter Mikron III engine, 10 built.
Żak-4 (SP-BAE)
Prototype of the glider towing version with open canopy (later refitted with a closed one) and powered by Walter engine.

Operators
 Poland
  • Aeroklub Polski

Survivors

Żak-3 SP-AAX is preserved in the Polish Aviation Museum in Kraków (disassembled as for 2007)

Specifications (Żak-3)

Data from Jane's All The World's Aircraft 1953-54 [1]

General characteristics

  • Crew: 2
  • Length: 7.60 m (24 ft 11 in)
  • Wingspan: 11.80 m (38 ft 9 in)
  • Height: 1.95 m (6 ft 5 in)
  • Wing area: 17.0 m2 (183 sq ft)
  • Empty weight: 400 kg (882 lb)
  • Gross weight: 620 kg (1,367 lb)
  • Powerplant: 1 × Walter Mikron III air-cooled 4-cylinder straight engine, 48 kW (65 hp)

Performance

  • Maximum speed: 160 km/h (99 mph, 86 kn)
  • Cruise speed: 130 km/h (81 mph, 70 kn)
  • Stall speed: 62 km/h (39 mph, 33 kn)
  • Range: 400 km (250 mi, 220 nmi)
  • Service ceiling: 3,500 m (11,500 ft)
  • Rate of climb: 2.7 m/s (530 ft/min)
gollark: Umwerican, even.
gollark: Perhaps umwn is also 12 and simply reading a thesaurus quite fast.
gollark: The sesquipedalian loquaciousness of umwn is impressive.
gollark: Watch for any papers on stuff like this.
gollark: They're studying how 12 year olds interact with a world of strange broken physics in a somewhat weird economy.

See also

Aircraft of comparable role, configuration and era

References
  1. Bridgman 1953, p.173.
  • Babiejczuk, Janusz and Grzegorzewski, Jerzy: Polski przemysł lotniczy 1945-1973 (Polish aviation industry...), Wydawnictwo MON, Warsaw 1974 (in Polish)
  • Bridgman, Leonard. Jane's All The World's Aircraft 1953-54. London:Jane's,1953.
  • Krzyżan, Marian: Samoloty w muzeach polskich, Warsaw 1983, ISBN 978-83-206-0432-0 (in Polish)
  • Photo and description at Poser page (in Polish)
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