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SZD-14x Jaskółka M
Role	Glider aircraft
National origin	Poland
Manufacturer	SZD; Władysław Okarmus
Designer	Tadeusz Kostia
First flight	23 July 1954
Number built	1
Developed from	SZD-8 Jaskółka

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]

Specifications (SZD-14x Jaskółka M)

Data from http://www.piotrp.de/SZYBOWCE/pszd14.htm

General characteristics

Crew: 1
Length: 6.48 m (21 ft 3 in)
Wingspan: 16 m (52 ft 6 in)
Height: 1.3 m (4 ft 3 in)
Wing area: 13.6 m² (146 sq ft)
Aspect ratio: 18.8
Airfoil: NACA 23012A
Empty weight: 288 kg (635 lb)
Gross weight: 373 kg (822 lb)

Performance

Maximum speed: 250 km/h (155 mph, 135 kn)
Stall speed: 59 km/h (37 mph, 32 kn)
Maximum glide ratio: 26.3 at 80 km/h (43 kts/50 mph)
Rate of sink: 0.70 m/s (138 ft/min) at 69 km/h (43 mph/37 kts)

References

^ ^a ^b ^c "SZD-14x Jaskółka M (PL)". www.piotrp.de. Archived from the original on 2003-07-31.
^ ^a ^b Simons, Martin. Sailplanes 1945-1965 2nd revised ed. EQIP Werbung und Verlag G.m.b.H.. Königswinter. 2006. ISBN 3-9807977-4-0
^ ^a ^b Babiejczuk, Grzegorzewski. Polski przemysł lotniczy 1945-1973, p. 120
^ Cynk, Jerzy B.. “Polish Aircraft 1893–1939”. London, Putnam. 1971. ISBN 0-370-00085-4

Taylor, J. H. (ed) (1989) Jane's Encyclopedia of Aviation. Studio Editions: London. p. 29
Cynk, Jerzy B.. “Polish Aircraft 1893–1939”. London, Putnam. 1971. ISBN 0-370-00085-4
Simons, Martin. Sailplanes 1945-1965 2nd revised edition. EQIP Werbung und Verlag G.m.b.H.. Königswinter. 2006. ISBN 3-9807977-4-0
(in Polish) Babiejczuk, Janusz and Grzegorzewski, Jerzy. Polski przemysł lotniczy 1945-1973 [Polish aerospace industry 1945-1973]. Warsaw: Wydawnictwo MON, 1974