I recently bought one of theses Yaks from Hobby King's Aus warehouse. It arrived within a week and I set about following the advice of others who had built the same plane.
It certainly looks as if there was a shortage of glue at Hyperion when this was put together and I ended up adding epoxy to every joint I could reach. The instructions comprised a series of pictures which in some places didn't match reality at all and in others there were gaps where I needed to figure it out for myself. Changes I made along the way:
Epoxied the elevator connecting wire in place
Bent, cut and epoxied the tail wheel wire in place (the instructions didn't even include a tail wheel - just a skid).
Taped around the carbon fibre wing spar to make it a tighter fit in the tube.
Strengthened all around the motor mount and front bulkhead
Strengthened the undercarriage where it mounts to the fuse. Will probably need to do more in this area, but not sure what at this stage.
Ignored the instructions on fitting the wheel spats as they were completely back to front. Mine are much better fitted.
Replaced the aileron pushrods and clevises with threaded rod and good quality swivel ends as the original items would never cope with the changing angles due to the horizontal servo arm. A better solution would be to use proper wing-type servos where the arm operates in the vertical plane, which would be more natural for the aileron throws. It would take some serious rebuilding of the