Ernő Rubik was a co-founder and the chief designer of the Aero-Ever aircraft company of Esztergom, Hungary, which was formed in 1938.

[1] The aircraft has a high wing braced by V-struts, with fixed leading-edge slots and retractable camber-changing flaps.

It has a conventional braced tailplane and a taildragger undercarriage with divided axle long-stroke oleo legs for the main gear, and a fixed tailwheel.

[3] It was powered by a Walter Major 4-I four-cylinder inline engine of 96.9 kW (129.9 hp) driving a two-bladed wooden propeller.

The third and subsequent aircraft, designated R-18c, c/n E-761, registered HA-RUC, had a Walter Minor 6-III six-cylinder engine of 116 kW (155 hp), which extended the fuselage length to 7.7 m (25 ft).