J.Zynk Polish Aircraft 1893-1939 (Putnam)
There can be little doubt that Dipl Ing Edmund Libanski was one of the most outstanding figures among the leading pioneers of aviation in Poland. He was the source of inspiration for the Lwow aeronautical activities in the pioneering era of the first years of the 20th century and his inexhaustible energy and drive turned that city into the most dynamic and enterprising aviation centre in Poland, overshadowing even Warsaw. With the publishing of his popular work, the Conquest of Atmosphere, (in 1905), and several articles and the delivery of numerous lectures, Libanski succeeded in bringing aviation to the notice of the public and stimulated Lwow Technical University with enthusiasm for flying. The increased general interest in aeronautics provided Libariski with the right climate for the creation of the first important aviation organization in Lwow, the Galicyjski Zwiazek Techniczno-Lotniczy 'Awiata' (Galician Aviation-Technique Association, the 'Awiata'), which was formed in the autumn of 1909 and had over 100 members. The 'Awiata', which became the Polish branch of the Austrian Aviation-Technique Association, was to operate over the entire region of the Galicia (the southeastern part of Poland then under Austrian occupation), and its broad aims included the propagation and support of all aviation undertakings and the preparation of a basis for the development of indigenous aircraft designs and industry. The 'Awiata' soon found an ardent ally in another, even bigger organization, the Zwiazek Awiatyczny Sluchaczow Politechniki we Lwowie (Aviation Association of Technical University Students in Lwow, which became known as ZASPL from the first letters of its full title). This came into being in November 1909, with the aim of promoting scientific research into the problems of aeronautics and aircraft construction and the creation of a faculty of aviation engineering at the University.
Organizing the aviation movement was not enough for Libanski; he undertook the development of his own aircraft. The design crystallized in 1909, and construction of the airframe began towards the end of that year. The machine, called by the designer the Mono-biplan I, was the first Polish composite design and the first to use steel tubes in the structure. Apparently inspired by the French Obre aeroplane of 1908, it employed an unusual configuration which embodied a main monoplane wing with a short-span supplementary wing on top.
The Mono-biplan I was built in the workshops of one of Lwow's largest locksmiths, and the airframe was ready in May 1910. The aircraft was equipped with an indigenous 48 hp four-cylinder air-cooled radial engine, constructed in Lwow, and drove, by means of chain transmission, a two-blade sheet-aluminium tractor airscrew with a diameter of 2.4 m (7 ft 10 1/2 in). Some parts of the engine were made by Zieleniewski Machine Factory in Krakow and only the cylinders were ordered from abroad, from the 'Kabel' Steelworks in Germany.
Libanski obtained permission to use the Lwow military exercise field and erected a hangar there, but the first flight attempt, undertaken by him about June 1910, ended in a mishap. During the take-off one of the cylinders exploded and the Mono-biplan I fell back on the ground, breaking both wheels. The front of the fuselage frame and the forward elevator were also damaged by the explosion, but the pilot escaped injury. Libanski then thought about fitting the machine with a Daimler or Korting engine, but came to the conclusion that the whole structure was rather fragile and not rigid enough, and he abandoned the Mono-biplan I completely. In the autumn of 1910 he began work on a vastly superior design, which later became known as the Jaskolka. His damaged Mono-biplan I, less its forward outrigger structure, was displayed at the First Aviation Exhibition in Lwow, which was open from 1 September until 15 October, 1910.
Construction: The Mono-biplan I was a single-seat multi-bay sesquiplane of the open-frame, lifting-tail variety. The airframe was a composite structure, all supporting areas being of wood, and the fuselage and landing gear framework, of welded steel tubing. The main wing, a divided two-spar structure with a chord of 2.5 m (8 ft 2 3/4 in), was attached to the upper fuselage framework at a slight dihedral angle and provided with pivoting wingtips, which controlled lateral stability. The straight one-piece supplementary wing, with a span of 4 m (13 ft 1 1/2 in) and chord of 2.5 m (8 ft 2 3/4 in), was carried above the main wing on four pairs of struts, the interplane gap being 1.6 m (5 ft 3 1/4 in). Both wings were covered with fabric on both surfaces. The combined gross area of all lifting surfaces (wing and tail) was given as 40 sq m (430.5 sq ft). The fuselage consisted of a rectangular-section forward part, which merged into a single vertical frame at the rear, the engine being mounted at the front of the fuselage and the pilot's seat situated at the rear of the rectangular section. All controls were operated by a steering wheel on a steering column. The tail unit, of biplane type, consisted of two similar horizontal surfaces, having a span of 3 m (9 ft 10 1/4 in) and chord of 1.5 m (4 ft 11 1/2 in), and a single rudder in between. The lower horizontal surface was fixed, while the top movable surface was linked with the forward elevator which was carried on outriggers in front of the wings and operated in conjunction with it to control longitudinal stability. The rear rudder was also linked with two movable vertical surfaces, one between the arms of each forward outrigger, which acted as supplementary rudders. The landing gear comprised a pair of mainwheels and a tailwheel. The whole airframe could be easily dismantled into large sections for transport. The overall span of the Mono-biplan 1 was 11 m (36 ft 1 1/4 in) and the overall length (estimated) 9.5 m (31 ft 2 1/4 in). The basic weight of the airframe less engine was 170 kg (375 lb). The loaded weight was 300-320 kg (661-705 lb) and wing loading 8 kg/sq m (1.6 lb/sq ft).
(Except for the overall length, which is estimated from photographs, all the above details and dimensions are taken from a comprehensive technical description of Libanski's aircraft in contemporary Austrian sources recently unearthed by the author).