Letov LF-107 Lunak / VT-7 / XLF-207 Laminar
The Czech aerobatic glider LF-107 Lunak was designed by Rudy Letov and further developed by a group of sailplane pilots and aeronautical engineers. 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 the serial production was disrupted by geopolitical developments, as the factory was charged with production of MiG-15, MiG-19 and MiG-21F aircraft and the access to Western civil export markets was progressively hampered by the emergence of the Iron Curtain. Therefore, only 75 examples of the Lunák were produced in all. Production models were used in local clubs for sailing and aerobatics as well as for training jet pilots.
In 1950, a variant with simpler construction and a revised cockpit, among other changes, was developed. This LF-107 Lunák 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.
The Letov XLF-207 Laminar, a derivative of the Lunák, 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. Research into laminar flow wings was carried out by the XLF-207 Laminar, a LF-107 fitted with laminar flow wings.
In 1990 there were only nine airworthy Lunák, of which two are in the United Kingdom. A Lunák is displayed in the American Museum of Flight.
Length: 6.78 m
Height: 1.47m / 5ft
Wingspan: 14.27 m
Wing area: 13.38 sq.m
Aspect ratio: 15.22
Empty weight: 205 kg
Gross weight: 310 kg
Maximum speed: 300 km/h
Maximum glide ratio: 24 @ 80km/hr (43kts)
Rate of sink: @ 65km/hr 0.85 m/s (@ 35kts 167 ft/min)