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SZD-17X Jaskółka L
	SZD-17x in the Polish Aviation Museum
Role	Glider
National origin	Poland
Manufacturer	SZD
Designer	Jan Dyrek, Tadeusz Kostia
First flight	9 March 1956
Introduction	1956
Number built	4
Developed from	SZD-14x Jaskółka M

The SZD-17X Jaskółka L was a single-seat high-performance competition glider designed and built in Poland at Szybowcowy Zakład Doświadczalny (Glider Experimental Works) in Bielsko-Biała in 1955.

Development

The SZD-17X Jaskółka L (Swallow Laminar) drew on the experience gained from developing the SZD-11 and SZD-14X gliders combined with new laminar flow aerofoil sections and flaps, as well as provision for water ballast^[1] and a fully retractable undercarriage.^[2] Main designer was Tadeusz Kostia, main constructor Jan Dyrek.^[3] Construction of the SZD-17X was of conventional wooden semi-monocoque fuselage and thick skinned wooden wings with wooden spars, retaining the Jerzy Rudlicki's butterfly tail of the SZD-14X. First flight of the SZD-17X took place at Bielsko airfield, flown by Adam Zientek, on 9 March 1956.^[3]

Four aircraft, (reg'n no.'s SP-1504 to SP-1507), were built for use in 1956 World Gliding Championships, but performance fell short of expectations and they finally were not used there.^[4] Despite the disappointing performance, Tadeusz Góra was able to establish a cross-country speed record on 9 May 1956 whilst flying SP-1506.^[4] SP-1506 was used until 1977, then it was given to the Polish Aviation Museum.^[5] The glider was nicknamed laminarka, due to its laminar flow profile.^[6]

Specifications (SZD-17X Jaskółka L)

Data from The World's Sailplanes:Die Segelflugzeuge der Welt:Les Planeurs du Monde^[1]^[7]

General characteristics

Crew: 1
Length: 6.8 m (22 ft 4 in)
Wingspan: 16 m (52 ft 6 in)
Height: 1.26 m (4 ft 2 in)
Wing area: 13.6 m² (146 sq ft)
Aspect ratio: 18.8
Airfoil: NACA 65₂512a
Empty weight: 340 kg (750 lb) equipped
Max takeoff weight: 540 kg (1,190 lb)

Performance

Never exceed speed: 250 km/h (160 mph, 130 kn)
Aerotow speed: 140 km/h (76 kn; 87 mph)
Winch launch speed: 120 km/h (65 kn; 75 mph)
g limits: +7.9 -1.9 at 186 km/h (100 kn; 116 mph)
Maximum glide ratio: 31.2
Rate of sink: 0.8 m/s (160 ft/min) at 87 km/h (47 kn; 54 mph)
Wing loading: 39.7 kg/m² (8.1 lb/sq ft)

Note: A. Glass^[6] quotes different specifications: maximum glide ratio 30.5 at 98 km/h; best sink rate 0.86 m/s at 93 km/h; wing loading 31.2 kg/m² (40 with ballast).

Notes

^ ^a ^b ^c "SZD-17x Jaskółka L (PL)". Archived from the original on 2009-08-21. Retrieved 2009-08-05.
^ Simons, Martin (2006). Sailplanes 1945–1965 (2nd revised ed.). Königswinter: EQIP Werbung und Verlag G.m.b.H. ISBN 3-9807977-4-0.
^ ^a ^b Babiejczuk, Janusz; Grzegorzewski, Jerzy (1974). Polski przemysł lotniczy 1945–1973. Warsaw: Wydawnictwo MON.
^ ^a ^b "SZD-17X Jaskółka L". Retrieved 17 June 2013.
^ Krzyżan, Marian (1983). Samoloty w muzeach polskich. Warsaw: Wydawnictwa Komunikacji i Łączności. pp. 139–140. ISBN 978-83-206-0432-0.
^ ^a ^b Glass, A. (ed) (1965), p.64-68
^ Shenstone, B.S.; K.G. Wilkinson; Peter Brooks (1958). The World's Sailplanes:Die Segelflugzeuge der Welt:Les Planeurs dans Le Monde (in English, French, and German) (1st ed.). Zurich: Organisation Scientifique et Technique Internationale du Vol a Voile (OSTIV) and Schweizer Aero-Revue. pp. 124–128.

References

Shenstone, B.S.; K.G. Wilkinson; Peter Brooks (1958). The World's Sailplanes:Die Segelflugzeuge der Welt:Les Planeurs dans Le Monde (in English, French, and German) (1st ed.). Zurich: Organisation Scientifique et Technique Internationale du Vol a Voile (OSTIV) and Schweizer Aero-Revue. pp. 124–128.
Piechowski, Piotr. "SZD-17x Jaskółka L". Retrieved 17 June 2013.
Krzyżan, Marian (1983). Samoloty w muzeach polskich. Warsaw: Wydawnictwa Komunikacji i Łączności. pp. 139–140. ISBN 978-83-206-0432-0.
Babiejczuk, Janusz; Grzegorzewski, Jerzy (1974). Polski przemysł lotniczy 1945–1973. Warsaw: Wydawnictwo MON.
Simons, Martin (2006). Sailplanes 1945–1965 (2nd revised ed.). Königswinter: EQIP Werbung und Verlag G.m.b.H. ISBN 3-9807977-4-0.
"SZD-17X Jaskółka L". Retrieved 17 June 2013.
Glass, Andrzej (ed) (1965) Konstrukcje lotnicze Polski Ludowej [Aviation constructions of People's Poland], WKiŁ, Warsaw, p. 64–68 (Polish)