The aircraft design office of the Letalski Institut Branko Ivanus Slovenija brought together teachers and students of the Ljubljana technical high school. The design office designed the KB-6 Matajur which was a two-seat light trainer and tourer that first flew on the 4 June 1952. The KB-6 was a cantilever low-wing monoplane with fixed tailwheel landing gear and an enclosed cockpit with side-by-side seating and dual controls. The aircraft was produced for use in aero-clubs until the mid-1960s.
Main production variant powered by a 136hp (101kw) Regnier 4L00 inline engine.