His Dupla was intended as a light, low cost basic trainer to replace his widely used R-26 Góbé, which was coming to the end of its useful life having entered service in 1963.

He began its construction in his own garage but later the Hungarian Defence League (Magyar Honvédelmi Szövetség or MHSz) offered help in their Budaörs workshops.

The half-wings were built around single dural spars with Rubik's characteristic corrugated skin, first used some twenty-five years earlier on the R-23 Gébics, ahead of it around the leading edge forming a torsion resistant D-box.

Behind the wing the fuselage was a slender cone covered with dural plate and tapering to a conventional tail with a short but broad fin.

Its performance was poorer than that of the Góbé it was intended to replace, its handling characteristics did not prepare students for gliders like the SZD-30 Pirat and vibration problems persisted at all speeds, so testing was terminated in 1986.