C.Jerzy Polish Aircraft 1893-1939 (Putnam)
Wladyslaw Zalewski began his design career while still a young student at the Wawelberg Technical College in Warsaw. In 1908, at the age of 16, he designed and built two rubber-cord driven model monoplanes based on natural forms. One of these was of a heavily loaded type, while the other was a 'light' model. Both models were tried in the air with good results, but the lighter machine performed best, on occasions covering distances in excess of 60 m (197 ft). Studying the behaviour of his models in the air, Zalewski gained knowledge and experience which enabled him to undertake work on full-size aircraft.
In 1909 Zalewski conceived a full-size light pusher biplane, which in general features resembled a scaled-down Henri Farman machine. Construction of this elaborate aircraft began in December 1909, and was continued in a disused village theatre near the designer's home in Milanowek near Warsaw. Due to lack of sufficient time and funds, this work progressed at a very slow pace and was frequently interrupted, various modifications and improvements meanwhile being introduced to the structure. Zalewski originally intended to power his biplane with a 25 hp two-cylinder rotary engine of his own design, but as he was unable to find a contractor willing to cast the necessary parts of the engine, this idea had to be abandoned, and eventually a 28 hp Delfose three-cylinder rotary engine was to be used. The engine was to be mounted in the cut-out at the rear of the lower wing and drive a pusher airscrew.
By 1913 the airframe reached the final stages of assembly, but by that time all aeronautical activities in Russian-occupied Polish territory were banned, and the aircraft, which was later retrospectively designated W.Z.I, in Zalewski's personal designation sequence, was never completely finished. Various parts and materials for the biplane, stored at Milanowek, were used 12 years later in the construction of the W.Z.XI Kogutek I.
Construction: The W.Z.I was a single-seat unequal-span two-bay biplane of Henri Farman configuration and wooden construction. The wings, with a total area of 22.5 sq m (242.2 sq ft), were built up of curved lattice ribs on two laminated spars, the front spar forming the leading edge, and were covered with rubber-proofed fabric on both surfaces. The top wing had dihedral extensions outboard of the outermost struts. Lateral stability was controlled by ailerons. Two elevators were used, the front one being hinged to outriggers attached to the main fuselage frame. The rear elevator formed part of the top surface of the biplane tail bay and was moved jointly with the front elevator. The fore-and-aft movement of the control lever operated the elevators, whilst lateral motion controlled the ailerons. Two rudders were fitted and were operated by a rudder bar. The landing gear consisted of two skids forming part of the framework to which was attached a cross-axle with pneumatic-tyred wheels. Overall dimensions included a span of 8 m (26 ft 3 1/4 in), a length of 8.6 m (28 ft 2 3/4 in) and a height of 2.5 m (8 ft 2 3/4 in). Estimated loaded weight was 240 kg (529 lb).