During 1905-07 Tanski concentrated on the development of a helicopter. After tests with models, which were used to study the stability and lift values of helicopter-type designs, he began construction of a full-size helicopter. This was built in his workshop at Mazowiecka Street and completed in 1907. It consisted of a metal-tube mast composed of two co-axial shafts to which two two-blade rotors, rotating in opposite directions and set one above the other, were fixed, a very progressive configuration by the then standards (on the other hand the machine did not possess any means of control and was designed simply to rise and descend vertically). The rotor blades, with leading-edge limewood spars and osier ribs, were covered with silk gauze pasted over with tissue-paper on the upper surface only. Each blade was braced with two struts to the metal mast above. The 'pilot' was attached to the mast by a special belt harness and operated a hand-driven gearbox propelling the rotors. The approximate overall span of each rotor was 8m and the overall height of the mast (including its harness extension fixture) 2m.
Tests indicated that the pilot's muscle power gave a maximum lift of only about 12kg which was not nearly sufficient to raise the machine and its operator. In 1909 Tanski adapted the machine for a 2.5hp Anzani two-cylinder vee engine, but this powerplant also proved inadequate and, according to the designer, the cylinders of the engine became red hot after a short while because of the complete lack of cooling. Later, Tanski was thinking of installing a small, light but more powerful engine, and in the autumn of 1910 he asked his son, who was in France, to look for a suitable powerplant. His helicopter survived as a museum piece until the last war and was displayed at the Lwow Aviation Exhibition in 1938.
During the inter-war era Tanski returned to the problem of vertical llight and in 1927 built and tested four experimental helicopter models.
This work, however, did not seem to offer a sound basis for a practical full-size machine and appeared to be limited only to the study of a primitive rotor concept. In 1934 a special commission of I.B.T.L. (The Institute of Aviation Technical Research) investigating his helicopter proposals said in an official statement: 'The works of Mr C.Tanski from the period of the beginnings of world aviation, because of the era when they were accomplished and their successful form, are today of great historic importance for Poles. They can be regarded as the first successful efforts in corresponding fields in world aviation. Mr Tanski's collaboration in the field of helicopters now offered would be of no use at the present time."
Early in 1939 Tanski again proposed undertaking work on an experimental helicopter and asked L.O.P.P. (The League of Air and Anti-gas Defence) for a subsidy for the project. In April 1939. the L.O.P.P. Central Committee replied that it could not grant such a subsidy before examination and approval of detailed calculations and project design drawings, but these were never submitted.
Jerzy B. Cynk "Polish Aircraft 1893-1939", 1971