J.Zynk Polish Aircraft 1893-1939 (Putnam)
Zbigniew Babinski was a close friend of Wladyslaw Zalewski. They both lived in Milanowek near Warsaw and shared an active interest in aeronautics. Following his friend's example. Babinski built a man-carrying glider in the first half of 1912. The design, a huge boxkite-type biplane, was evolved to the ideas and instructions contained in the book How to Build a Glider by Michal Krol.
The glider was first tested in June 1912, three friends, Babinski, Zalewski and Woyna, being involved in this exercise. Zalewski recollected: 'We set off at dawn for the small hills in the meadows on the outskirts of Grzedow, which lay between the Krolewska highway and the railway line. Despite its huge size, the machine was very light and the three of us carried it tail up without too much effort. We made our gliding attempts in a very light westerly wind of only about 2 m/sec (4.4 mph). The lifting capability of the design was very great; when two of us holding the tips of the bottom wing let them go after a brief run and the third lifted his feet up, the aircraft made a pleasant glide at an even height above the very gentle slope of the hill, covering some 30 to 40 m (98 to 131 ft) at a stretch. Babinski glued in new sheets of tissue-paper, repairing the pieces torn during landings and each of us took his turn at making glides. After about two hours I and Woyna had to leave, and Babinski stayed behind alone with the aircraft.'
With the help of a few shepherd boys, Babinski continued to fly his glider as a kite, without a pilot, launching it higher and higher. During these operations the aircraft, which rose to some 40 m (131 ft), was suddenly caught in a strong wind and one of the wires by which it was being pulled slipped loose from the hands of the boy holding it. The glider lost its equilibrium and was completely wrecked on hitting the ground.
The glider was an equal-span biplane constructed of wood and trussed with steel wires. The airframe consisted of two-bay wings, which were covered on the bottom surfaces with gauze pasted over with tissue-paper, a simple open frame fuselage and a cellular tail bay. A cambered aerofoil section was employed and the lifting surface area exceeded 40 sq m (430.5 sq ft). The pilot, with his armpits supported by special fittings, hung in the uncovered centre section of the lower wing and controlled the balance by movements of his body. No other data are available.
In 1913 Babinski built a smaller glider (less than half the lineal size of the previous machine), which, whilst employing a flat, instead of cambered, aerofoil section, was in all other respects exactly similar to the earlier design. However, with the flat wing and small supporting surface, this aircraft was far less stable and more difficult to fly. In spite of this the designer and his friends, including Zalewski, carried out several short glides on it, 14-year-old Kazimierz Wasiutynski, small and light, making by far the largest number of successful flights. The overall span of this second glider was 6.8 m (22 ft 4 in) and its empty weight was 25 kg (55 lb).