Here's a vintage glider which could be seen in the Slovenian mountain areas around 1937-38. The original designer of this paper model is Mitja Sersen Erman, and his original design in ca 1/25 scale can be downloaded from his site
ultralajt.webs.com (scroll down until you get to the Inka model).
Mitja very kindly allowed me to rearrange, rescale & repaint his original uncolored model, and publish it here, in the downloads section (links in following posts). The model design is based on the original drawing below from
Narodna Krila (National Wings) magazine, December 1948:
Mitja tells me that the Inka glider was designed by Dr. ing. Anton Kuhelj in 1937-38. Intended for schools and gliding clubs with little or none previous building experience, it was a much simplified version of the Grunau Baby. An early version of the Inka even had square wing tips:
Almost every Inka glider built differed from each other in various details such as the extent of plywood covering of the fuselage. Some builder gropus enlarged the rudder area, after reports of insufficient rudder control if built according to the original plans. I have used this as a license to create a division between plywood-covered sections of the aircraft and fabric-covered structure which was to my own liking. It may not represent a typical Inka, but in any case it was theoretically possible...
The glider was used for slope-soaring in the Bloke mountain area of Slovenia up to the outbreak of WWII. The starting method was the common one of the era, several club members tensioning two strands of thick bungee cords, while others held the glider back until no more tension could be achieved.
The glider was hauled back to its starting point by attaching a couple of barrel wheels to the landing skid. Gliding in those days was great exercise for everybody involved!
Data (original):
Wing span: 12,3 m
Fuselage length: 6,3 m
Height: 2,05 m
Wing chord: 1,4 m
Wing area: 16.35 m2
Root airfoil: Go 549
Tip airfoil: NACA M6
Empty weight: 130 kg
Take off weight: 219 kg
Best glide: 17
Minimum sink: 0,85 m/s @ 50 km/h
Original photos and drawing provided by Mitja Sersen Erman.