This two-seater design was intended to fill the roles of training, solo flying and aerobactic flying and first flew in prototype form on 14 September 1960, duly going into service with the Romanian gliding clubs.
The IS-8 is of very similar plywood- and fabric covered wooden construction to the IS-3, and is characterised by cantilever shoulder wings with a distinctive 7° forward sweep at the 25% chord line,and with a rectangular centre section and tapered outer panels. The wings are all-wood single spar structures with a leading edge torsion box, 70% fabric covered, and the slotted wooden ailerons are plywood- and fabric-covered. The fuselage is a metal and plywood monocoque and has an air brake on each side of it, instead of in the more usual wing mounted position. The wooden tail unit is also ply and fabric-covered and there is an unsprung nonretractable monowheel without a brake, and a rubber-mounted skid. The pilot and pupil sit in tandem under a moulded plastic canopy.
Span: 43 ft 9.5 in
Length: 24 ft 1.5 in
Wing area: 166.3 sqft
Aspect ratio: 11.5
Empty weight: 463 lb
Max weight: 882 lb
Max speed: 112 mph (in smooth air)
Max aero-tow speed: 74.5 mph
Min sinking speed: 3.22 ft/sec at 43.5 mph
Best glide ratio: 23:1 at 53 mph