The SZD-14X Jaskółka M was a single-seat glider designed and built in Poland at Szybowcowy Zakład Doświadczalny - Glider Experimental Works in Bielsko-Biała in 1954. This was an experimental prototype, and only one unit was constructed.[1]
Development
The SZD-14X Jaskółka M was developed from the SZD-8bis Jaskółka (Swallow) for research into the construction, control and characteristics of 'V' or butterfly tail surfaces.[2] Using the airframe of the second prototype SZD-8 a 'V' tail was added to the rear fuselage, with arrangements for the balance of the surfaces and the angle between them to be adjusted as required.[1] The designer was Tadeusz Kostia, the constructor was Władysław Okarmus.[3]
First flown by Adam Zientek at Bielsko on 23 July 1954,[3] the SZD-14 was found to be easy to fly with no vices, giving no indication that the tail layout was unconventional.[1] During spinning tests the rear fuselage was almost torn off, but the pilot (Dziurzyński) managed to regain control and recovered the aircraft to land safely.[2]
Up to the time of the SZD-14's debut, the 'V' tail system was rare, with few aircraft using the system devised by Eng. Jerzy Rudlicki and demonstrated on a licence-built Hanriot HD.14 biplane in the early 1930s.[4]
(in Polish) Babiejczuk, Janusz and Grzegorzewski, Jerzy. Polski przemysł lotniczy 1945-1973 [Polish aerospace industry 1945-1973]. Warsaw: Wydawnictwo MON, 1974
