From about 1950 to his death in February 1981, Iosif Șilimon was Romania's most prominent glider designer, his aircraft distinguished by his initials.
Its slotted ailerons, which filled about half the span and were divided into two pairs, were ply skinned but with an outer fabric covering.
Its tandem two seat cockpit stretched from the extreme nose to behind the wing leading edge, enclosed by a long, two part perspex canopy following the lines of the fuselage.
The horizontal tail was straight tapered in plan with squared tips, raised a little above the fuselage on a fin fillet and constructed in the same way as the ailerons.
[2] Development of it ceased when it was decided that the IIL IS-8, another Silimon designed two seater but with a smaller span, would be operationally simpler and more economical to run.