LK stand for, Leningradskii Komsomolyets, (Liningrad young communist).
100 hp Shvetsov M-11 five-cylinder air-cooled radial engine
Four version of this aircraft were produced. The first was a sesquiplane with a cantilever lower wing. The second version had the upper wing moved back and the lower wing moved forward. The third version was a parasol monoplane. The fourth version was a low wing monoplane with strut braced wings.
First version of the LK-4, known as LK-4-I.
Third monoplane version of the LK-4, known as LK-4-III.
