15 & 16 May 2024

Based on the information provided by other builders, I decided to move the one control stop from the co-pilot's joystick to the pilot's side, so both are on one joystick. Apparently, this allows for much easier final assembly adjustment.

Installed both joysticks. This was a painstaking exercise and took quite a few hours. The Vesconite bushes are preinstalled and cannot be adjusted, plus the 16mm stainless steel machine screws holding them in place at the rear are too long to be inserted from the top as per the KAI, so installing and removing the nuts was painful. I made this easier - and saved wear on the nyloc nuts - by using some standard nuts for temporary installation during testing. Far quicker and easier to install and remove the standard nuts. I needed to use a deburring tool to remove the primer and a tiny bit of material on the inside of the brackets holding the rear Vesconite bushes on the joysticks in order to release a bit of clamping pressure and permit smooth motion. Based on the advice of another builder, I carefully bent the top flanges of the main spar control brackets up a little bit at a time whilst test fitting each joystick. Eventually I got both sides correct and now have butter-smooth motion.

I really don't like the Vesconite bushes though, they seem very prone to locking up if the adjustment isn't absolutely perfect, which makes one wonder what could happen should something shift / come under load during flight. For critical flight controls, Sling really should be using bearings and securing the ribs and brackets a lot more firmly so that they cannot flex at all, which can cause the bushings to misalign and lock up. In addition, locking rings are used in many areas adjacent to the Vesconite bushings - the problem with this is that as you drill them they have a tendency to move around a bit, and when riveted in place sometimes don't sit 100% aligned with the tube they're attached to.