C.Jerzy Polish Aircraft 1893-1939 (Putnam)
Lotnia Gliders. Taking his favourite bird, the stork, as the master pattern, Tanski began developing a primitive man-carrying glider almost at the same time as his work on flying models. The machine, which was progressively improved and tested in three versions, became known as the Lotnia. According to his own account, Tanski began construction of the glider in Janow Podlaski in 1894 with the help of a carpenter.
Work on the Lotnia seemed to have progressed rather slowly. The first attempts to fly it were made in June 1896, in Janow Podlaski, but these proved the inadequacy of the device and its operating technique. The glider, consisting only of a crude frame and a stork-like wing, had to be held by its 'pilot' with his hands above his head. The 'pilot', imitating a heavy bird, had to run quickly against the wind, bounce his feet off the ground and become airborne. During the first tests the original Lotnia proved unstable and uncontrollable; in spite of several attempts Tanski was unable to hold it at the desired angle and during his last run he lost his grip on the machine and it crashed upside down. The damaged glider was repaired and improved, modifications including the addition of a small adjustable horizontal tail to improve stability. Realizing the futility of his efforts to lift from the flat ground, Tanski built a 3.5 m (11 ft 6 in) high wooden scaffold, but jumps from it were also inconclusive.
The first and second variants of the Lotnia possessed a divided 'stork-type' monoplane wing with an area of 7 sq m (75.3 sq ft), which consisted of the leading-edge limewood spar and osier ribs and supplementary stiffeners. The single-surface wing, covered with silk gauze pasted over with tissue-paper, was attached to the top frame longerons and braced by short inverted V struts to the lower part of the frame. Each wing panel, easily detachable, was set at a pronounced dihedral angle. The 'fuselage' frame was a sledge-like structure built up of lime and aspen. One triangular vertical surface on each side at the rear of the frame, and the horizontal plane above them, were covered with gauze for stabilizing purposes. The second variant of Lotnia was provided with an adjustable fan-shaped flat-section tailplane. The approximate span of the glider was 8.6 m (28 ft 2 3/4 in), the length (with the tail added) 3.2 m (10 ft 6 1/4 in) and the basic weight 18 kg (40 lb).
Due to frequent damage in various crashes and accidents the Lotnia was constantly repaired and rebuilt, and in the years 1897-98 Tanski evolved and constructed a considerably revised third version of the design. Coming to the correct conclusion that the original wing was too small to support him, he enlarged its area to 12 sq m (129.2 sq ft) and, to improve stability, lengthened the whole structure, adding the bigger horizontal tail, which had an area of 1 sq m (10.8 sq ft). He also covered two forward vertical areas of the frame (one on each side) with gauze, in addition to the rear areas. According to Uminski's contemporary articles and estimates from photographs, the span of the third Lotnia version was about 10.8 m (35 ft 5 1/2 in) and overall length 3.8 m (12 ft 6 in). Its basic weight was about 25 kg (55 lb).
In 1898 the improved Lotnia made numerous gliding attempts from the previously mentioned scaffold, as well as from a flat meadow in Janow Podlaski, several of them being witnessed by the designer's friends, Kocent-Zielinski and Lukawski. About the tests from fiat ground, Tanski wrote himself: 'From the moment of the first step forward the machine became lighter and during my run I not only did not feel its weight, but on occasions became supported by it. Running against the wind long jumps were possible. I had the proof of how difficult this operation really was, when two of my friends, Zielinski and Lukawski, came to visit me. None of them could hold the machine in his hands even in light wind' and the device 'either overturned or hit the ground with its fore end'. During one of these prolonged jumps in 1898 Tanski was said to have reached a height of some 2 m (6 1/2 ft) and covered a distance of some 30 m (98 1/2 ft), this being claimed as the world's first ascent by a man from flat ground without assistance from any source of power.
Describing his jumps from the scaffold, Tanski said: 'I mounted the scaffold by a ladder, holding my machine above my head. The main difficulty was to gather speed and position the machine correctly. The platform was short and not very secure ... Moments of jump and descent very short ... However, further experiments gave me the chance to feel and utilize the lifting force of my big wings. Some jumps became longer and descent was markedly slower.' These flights, although very short and inadequate, were nevertheless a great pioneering achievement and the first in Poland on a heavier-than-air device to be historically documented.
At that time Tanski was thinking about transferring his experiments to hilly regions and began to evolve the design for a new, more advanced glider, which was to be provided with twin pusher airscrews driven by the pilot's feet, but a disastrous financial situation forced him to postpone these projects and concentrate on painting so as to repair his resources. During the next five years (1899-1904), living in Warsaw, Paris (1901-02), and then again in Warsaw, where he settled permanently, Tanski devoted most of his time to painting. However he soon turned part of his Warsaw studio into an aviation workshop and in 1904-05 resumed design work on a man-carrying glider.
Experimenting with the general concept for the new project with the help of models, he prepared a study for a full-size tail-first machine and for a muscle-powered foot-operated propulsion system driving two pusher airscrews, which was later to be installed in it. It is interesting to note that, contrary to the common practice of contemporary designers of the muscle-powered aircraft, Tanski intended to use muscle power only to propel the airscrews and never to flap the wings. About the same time he became progressively interested in the helicopter idea, but as his limited funds did not permit him to build both machines, he eventually abandoned the tail-first glider in favour of the latter.
News items about the Lotnia and Tanski's glider experiments inspired Ryszard Bartel (later a well-known aircraft designer) to follow in Tanski's footsteps, and in 1911, at the age of 14, he evolved his first glider, which in certain respects resembled Tanski designs.
In 1956, on the 60th anniversary of Tanski's first pioneer gliding attempts in Poland, the Aeroclub of the Polish People's Republic established the Tanski Medal, which is awarded yearly to a Polish glider pilot for the most outstanding gliding achievement of the year.