Letov LF-107 Luňák

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LF-107 Luňák
Lunak 02.jpg
Role Aerobatic glider
Manufacturer Letov
First flight 25 June 1948
Number built 75

The LF-107 Luňák (English: Kite) is a Czech aerobatic glider designed by Rudý Letov in the late 1940s. The design was developed within a prolific group of aeronautical engineers and sailplane pilots, including K. Dlouhý, J. Matejcekm, and B. Bocek.

Design and development[edit]

LF-107 at Old Warden, 2013

The first flight of the prototype took place on June 25, 1948 and a second prototype flew in July. The prototype participated later in the same year in an aerobatic competition in Grenchen, Switzerland, and in Ziar, Poland in 1949, where its good aerobatic and gliding characteristics drew considerable attention.

Unfortunately serial production was disrupted by geopolitical developments, as the factory was charged with production of MiG-15, MiG-19 and MiG-21F aircraft, and access to Western civil export markets was progressively hampered by the emergence of the Iron Curtain. Therefore, only 75 examples of the Luňák were produced in all.

In 1950, a variant with simpler construction and a revised cockpit, among other changes, was developed. This LF-107 Luňák of wooden construction, designated Letov VT-7 under the military training system, was instrumental in the development of gliding and aerobatics in the Czech Republic. The LF-107 was also used for aerobatic training in the Soviet Union, Bulgaria, Romania and Poland.

XLF-207 Laminar[edit]

The Letov XLF-207 Laminar, a derivative of the Luňák, holds the distinction of being the first glider in the world to have a laminar flow wing.[citation needed] Its maiden flight took place in Praha Letnany in August 1951. Research into laminar flow wings was carried out by the XLF-207 Laminar, a LF-107 fitted with laminar flow wings. Presently there are only nine airworthy Luňáks, two of which are in the United Kingdom. A Luňák is displayed in the American Museum of Flight.

Variants[edit]

Lunak kitted out for aerobatics at Old Warden, June 2014
Lunak doing aerobatics
Lunak landing
LF-107 Luňák
The initial production version of this aerobatic glider, 75 built.
VT-7
Simpler construction with a revised cockpit for use by the Czech military.
XLF-207 Laminar
The Letov XLF-207 Laminar holds the distinction of being the first glider in the world to have a laminar flow wing. Its maiden flight took place in Praha Letnany in August 1951.

Specifications (LF-107 Luňák)[edit]

Data from [1]

General characteristics

  • Crew: one
  • Length: 6.78 m ( ft in)
  • Wingspan: 14.27 m ( ft in)
  • Wing area: 13.38 m2 ( ft2)
  • Aspect ratio: 15.22
  • Empty weight: 205 kg ( lb)
  • Gross weight: 310 kg ( lb)

Performance

  • Maximum speed: 300 km/h ( mph)
  • Maximum glide ratio: 24 at 80 km/h (43kts)
  • Rate of sink: at 65 km/h 0.85 m/s (at 35kts 167 ft/min)

See also[edit]

References[edit]

  1. ^ Simons, Martin (2006). Sailplanes 1945-1965 (2nd revised ed.). Königswinter: EQIP Werbung & Verlag GmbH. ISBN 3-9807977-4-0. 

Further reading[edit]

  • German Wikipedia article de:Letov LF 107 Luňák
  • Peter Mallinson and Mike Woollard, Handbook of Glider Aerobatics

External links[edit]