Purpose: To test designer’s experimental wing.
Design Bureau: Aircraft constructed by BOK to design of S S Krichevskii.
Sawa Syemenovich Krichevskii, called ‘a talented designer’ by historian Shavrov, spent the early 1930s trying to create the most efficient aeroplane wing. He made many tunnel models, eventually settling on a wing of high aspect ratio constructed in front and rear sections. The rear part was hinged to the front
with a small intervening gap acting as a slot. In flight, the intention was that the pilot would select the optimum angle for the rear portion, Shavrov commenting that ‘this wing could always be flown in a drag-polar envelope’.
Krichevskii secured funding to build a research aircraft, called RK (Razreznoye Krylo, slotted wing) and designated BOK-2 by the construction bureau. The BOK-2 was completed in 1935 and flew successfully, but Krichevskii died shortly afterwards. Documentation on this aircraft has never been found.
The BOK-2 was an extremely neat cantilever monoplane, with a single M-l 1 engine rated at 11 Ohp. Shavrov comments that ‘The wing skin was polished to mirror brilliance [suggesting all-metal construction]…it is hard to say if its excellent performance was due to its drag-polar envelope or to its perfect aerodynamic shape’.
Despite its apparently excellent performance the RK appears to have had no impact on the Soviet aviation ministry.
No data available.