The Rubik R-15 Koma (Godfather) was a side-by-side seat Hungarian training glider designed to introduce pilots to winch-launching techniques.

Constant chord flaps and Handley Page slotted ailerons together filled the whole trailing edge, mounted on a light-metal tube false spar and fabric-covered.

This carried the two side-by-side seats, provided with dual controls, in an enclosed cockpit under a generously glazed, centrally hinged two-part canopy.

It also mounted, on its underside, a semi-recessed monowheel, placed under the trailing edge on production aircraft (it was further forward on the prototype) with a short, rubber sprung landing skid ahead of it.

From the aft of the beam a metal tube strut reached upwards and rearwards to support the boom that formed the rear fuselage.

The upward sloping tailboom was a rectangular section, wooden, ply-covered structure mounted on the centre of the rear semi-circular frame, braced with wires from the inner wings as well as the metal tube from the lower fuselage.

Its trials showed average students needed landing speeds reduced and so flaps were added to the R-15b Koma, first flown in June 1950, which went into series production.