NIAI RK

RK
Role	Telescopic Wing Research Aircraft
National origin	USSR
Manufacturer	NIAI (Naoochno-Issledovatel'skiy Aero-Institoot - scientific test aero-institute)
Designer	Grigorii Ivanovich Bakshayev
First flight	1937
Number built	1

The RK (Razdvizhnoye Krylo – extending wing) (a.k.a. LIG-7) was a two-seat cabin aircraft designed and built in the USSR from April 1936.

Development

In 1930 the LIIPS ( - Leningrad institute for sail and communications engineers) formed a UK GVF ( - training centre for civil air fleet), in turn the UK GVF formed the NIAI (Naoochno-Issledovatel'skiy Aero-Institoot - scientific test aero-institute) which became the focus of several good design engineers who were given command of individual OKB (Osboye Konstrooktorskoye Byuro – personal design/construction bureau).

Along with contemporary aircraft designers, in the USSR and abroad, Grigorii Ivanovich Bakshayev was interested in the concept of variable geometry aircraft, where the size and/or shape of wings are altered according to the stage of flight, or desired characteristics. There are many methods of achieving this but one of the simplest is the telescopic wing, where wing sections of bigger area and, possibly, aerofoil section, are telescoped out over the original wing. Bakshayev designed the RK to use a telescopic wing with six sections, of gradually increasing size, extending outwards from the fuselage to the demands of the pilot.

The airframe of the RK was a simple structure of steel tube fuselage and a wire braced monoplane wing of constant M-6 section constructed of wood. The extending wing sections were each 460mm wide and were extended by the observer in the rear cockpit operating a hand-crank, cables and pulley system to pull each section out in turn, with each section pulling the next behind it, over 40 secs. Flight tests starting in 1937 were successful leading to authorisation for a fighter with telescopic wings to be designed and built;The RK-I (Razdvizhnoye Krylo - Istrebitel – extending wing fighter).

Specifications (RK)

Data from Gunston, Bill. "Encyclopaedia of Russian Aircraft 1875-1995". London:Osprey. 1995. ISBN 1-85532-405-9

General characteristics

• Crew: 2
• Length: 7.34 m (24 ft 1 in)
• Wingspan: 11.3 m (37 ft 0-3/4 in)
• Wing area: 16.56 to 23.85 m² (178.25 to 256.72 ft²)
• Empty weight: 667 kg (1,470 lb)
• Gross weight: 897 kg (1,978 lb)
• Powerplant: 1 × M-11, 85.75 kW (115 hp)

Performance

• Maximum speed: 150 km/h (93 mph)

See also

Aircraft of comparable role, configuration and era

• Gérin 'Varivol'
  

Related lists

• List of aircraft
  

References

• Gunston, Bill. “The Osprey Encyclopaedia of Russian Aircraft 1875 – 1995”. London, Osprey. 1995. ISBN 1-85532-405-9