Spoke to dad last night and he described the Blanik as more sophisticated in design, and he does recall getting stuck inside the fuselage of one after having crawled inside it with a tape measure!!!! Suffered a panic attack and had to be dragged out by his ankles.!!!
The reason for the parallel chord wing was to use one universal rib with pressed flanges and the rivet holes in the flange were the datum so that the ribs were the same in both wings
Financial problems were a big issue at Slingsbys after the death of Major Shaw, the original chairman and shares were sold to pay death duties.