LAK-12 "Lietuva" (not in production)



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LAK 12 in action!
This data are from book "All Jane's Aircraft - 1993"

Short History of LAK-12 LIETUVA (LITHUANIA)

The Lietuva was the first all-plastics sailplane produced in the BK-7/7A/7V/7S, LAK-9/9M and LAK-10 early versions can be found in the 1982-83 Jane's.
The LAK-12 become the sixth production version. Compared with the earlier versions originated by Mr. Boleslovas Karvyalis, it was considerably redesigned under the leadership of Mr. Kestutis Gechas. It is intended as a training aircraft for high class pilots participating in all-Soviet and international events, and for record attempts. Compared with LAK-10 it has a more comfortable cockpit, with improved instrument layout, a better positioned control column, and a one-piece canopy. Streamlining of the airframe is enhanced, the wings are lowered to a mid position, the fuselage and horizontal tail surfaces are of completely new design, and construction makes extensive use of composite materials, including carbonfibre for the wing spars and other components.

First flight of the LAK-12 took place on 21. December 1979. Flight testing was completed in 1980, and deliveries of production aircraft began later that year.

Description of LAK-12

TYPE: Single-seat Open Class Sailplane. AIRFRAME: Centilever mid-wing monoplane. Wortmann wing sections: FX-67-K-170 from root to junction with outer panels, than tapering to FX-67-K-150 at tip. No wing fillets. Main wing spar is a carbonfibre T beam. Trailing-edge flaps and interconnected ailerons are attached to auxiliary rear spar. Airbrakes on upper surfaces only. Wings, split flaps and ailerons have a skin of three ply glasscloth, with foam plastics infill between each layer; carbonfibre tape is used to reinforce flap construction. Fuselage and integral fin, are of glassfibre construction, reinforced with carbonfibre tape. Slightly swept fin and rudder, and non-swept low-mounted tailplane and elevators (all of Wortmann FX-71-L-150/25 section), are of similar construction to wings. Rudder and elevator are mass balanced. Retractable monowhell, with mechanical brake and and oleo-pneumatic shock absorber; non retractable shock absorbing tail bumper. One-piece cockpit canopy. Provisions for 190 liters water ballast in wing leading-edge tanks.