LWD Żak

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

General characteristics

Crew: two

Capacity: one

Length: 7.6 m (23 ft 11 in)

Wingspan: 11.8 m (38 ft 8½ in)

Height: 1.95 m (6 ft 5 in)

Wing area: 17 m² (183 sq ft)

Empty weight: 400 kg (880 lb)

Loaded weight: 620 kg (1,365 lb)

Powerplant: 1 × Walter Mikron III air-cooled 4-cylinder straight engine, 65 hp (48 kW)

Performance

Maximum speed: 160 km/h (86 knots, 99 mph)

Range: 400 km (216 nmi, 248 mi)

Service ceiling: 3,500 m (11,500 ft)

Rate of climb: 2.7 m/s (520 ft/min)