The LAK-15 was designed as a record breaking sailplane and so had a very large (25.6 m (84 ft 0 in)) span wing with an aspect ratio of 38.4.
There were high aspect ratio ailerons over at least half the span, with two flaps inboard.
[1][2] The oval section fuselage, built of composites, was deepest ahead of the wing with the pilot in semi-reclining position under a long single-piece canopy.
Behind the wing the fuselage was very slender and ended with an integral, trapezoidal profile fin.
[1][2] The LAK-15 landed on a retractable monowheel, equipped with a shock absorber and brake, and a fixed tailwheel.