LIBIS KB-17 / LIBIS-17
Formerly known as the KB-17, this Yugoslav two seater high performance trainer was designed and built by the Letalski Institut Branko Ivanus, Slovenija - LIBIS at Ljubljana.
Of largely wooden construction, with a fabric covered welded steel tube fuselage, the LIBIS-17 has a cantilever single-spar high-set wooden wing, with a plywood covered leading edge torsion box supported by Styrofoam, the remainder of the wing being fabric covered. The fabric covered wooden Frise ailerons are also filled with Styrofoam, and there are Hiittertype wooden plate spoilers in the wing upper surfaces immediately aft of the spar. The angular tail unit is also a wooden structure filled with Styrofoam, and is made up of an all-moving one-piece fin and tailplane, each with a servo tab. The landing gear consists of a non-retractable unsprung Borovo main wheel and nose sheel in tandem, with a LIBIS mechanical brake. The two pilots are seated in tandem under a forward-hinged one-piece blown canopy; a ventilation system is provided and blind flying instrumentation, radio and oxygen equipment can be fitted if required.
It is cleared for looping, spinning and cloud flying as well as normal flight; it is also suitable for flying solo up to the Silver and Gold C standards.
The prototype LIBIS-17 first flew on October 1961, and the first production aircraft flew in June 1963; by 1972 there were 23 examples of the type on the Yugoslav civil register.
Span: 55 ft 9 in
Length: 25 ft 1 in
Height: 8 ft 11.5 in
Wing area: 237.9 sqft
Aspect ratio: 13.0
Empty weight: 739 lb
Max weight: 1,135 lb
Max speed: 138 mph (in smooth air)
Max aero-tow speed: 87 mph
Min sinking speed: 2.82 ft/sec at 47 mph
Best glide ratio: 27:1 at 58 mph