In designing the Pilis, Ernő Rubik was influenced by the arrival in Hungary of a German Göppingen Gö 1 advanced trainer, itself a response to the Grunau Baby.

All were mounted on top of the fuselage and had a single spar with plywood covering forward of it around the leading edge, forming a torsion resistant D-box.

The first two production variants, like the prototype, had no airbrakes but these were introduced on the R-08d, initially designated R-09, mounted on the rear of the spar between the tapered section and the drag strut.

[2][4][5][6] The Pilis's fuselage was a ply semi-monocoque structure with strengthening frames and stringers, roughly oval in section but with sharp junctions above and below.

All production models had similar tails, with tapered and round-tipped horizontal surfaces mounted just above the fuselage, to which the tailplane was braced with a single strut on each side.