Aileron assembly has been delayed by ignorance and procrastination. It’s amazing how long it took me to decide to lever $20 out of my pocket for a tool. There’s an anchor nut that gets attached to a rib with a couple of stainless steel rivets that have a 120 degree countersink. I was reluctant to spring for a 120 degree, #40 pilot cutter. This left me pondering various alternative ways I might proceed to attach the anchor nuts. The door was left open because the construction manual doesn’t say anything about it. But, I did have reference examples – other builder’s and identical anchor nuts mounted in my quick-build fuselage. I finally ended up getting the stupid pilot cutter and then mounted the anchor nuts as I knew they should be from the very beginning.
Another self-inflicted setback has been in play. Sometime earlier, I’d riveted one of the aileron hinge bracket and rib sub-assemblies together. Unfortunately, something I’d noticed, but dismissed during initial fitting, had to be corrected. The bolt holes on the inner and outer aileron hinge brackets were not in alignment. To compound the problem, I reasoned that it would probably be ok to ream the bolt holes a little – make them oblong – and somehow that work out ok. Wrong! The result was better alignment, but at the cost of precision (proper) fit.
Sloppy fit for the outer aileron hinge just isn’t going to cut it. What could I do? Eventually, I did what I I should have done in the first place – ask the factory for guidance. I sent an email and got an overnight response directly from Mike Blyth – designer of all Sling Aircraft models. The outer bracket just needs to be bent a bit more. So simple! That absolutely did not occur to me. Sadly, I’d ruined (by reaming) the inner and outer brackets for one aileron and needed new ones. TAF USA rushed me replacements. Fantastic service!
With new brackets in hand, I slightly increased the bends on the outer brackets for both ailerons, removed the old brackets from one of the ribs and riveted all of the sub-assemblies together. Beautiful! I can sleep again. No more worries thinking about how I would try to rationalize wobbly ailerons to myself, the DAR, my technical counselors and everyone else.
With a now ample supply of 4,8mm rivets in both 15 and 10 mm lengths, finishing the lefthand flap could proceed. I did, however, have to make a decision about how to address hole misalignment involving the short ribs of the hing-rib subassemblies. The solution I chose was hole enlargement and larger 4mm rivets.
I’ve learned that perfect factory bends are required in order to get relaxed fit and freedom from structure twists and wags on the trailing edges of control surface skins. Knowing what to look for during inspection is essential. It had been months since I’d received the quick-build wing kit components and done my inspections. I was reasonably confident the skins were good, yet there was a huge sense of relief to see them actually fitting very nicely.
For the flaps and ailerons, it is common practice to initially rivet only the bottom surface of the skins to the ribs and brackets. The top surface and the row of rivets at the leading edge of the control surface remain free until they are fitted to and the trailing edges are perfectly aligned with the each other and the wing.
Assembly of the adjustable seats has been straightforward. They’re made up of 2 hinged panels that have a simple channel structure, sandwiched with identical skins – top and bottom. Inside the seat base is spring-loaded lever and cable mechanism for the slide locking pins. I opted to adapt some clevis pins instead of using the kit-supplied (large) solid rivets to assemble the linkages. The rivets proved difficult to deal with. It took a few days of pondering, but I eventually realized that custom fabrication of clevis pins were the way for me to go.
The only metal preparation I did was deburring and scuffing with a Scotch-Brite pad. I may or may not paint the seats as they’ll be almost entirely covered by the upholstery. The structures and panels fit perfectly and went together quickly. Sling 2 seat design has apparently changed over the years. The recently manufactured parts I had didn’t exactly match the construction manual, but understanding and dealing the differences was not difficult.
There are now at least 2 ways that the piano hinge can be mounted between the seat base and back, so that it can folded forward to access the luggage compartment area. The deciding factor seems to be how far beyond perpendicular to the seat base the seat back will naturally recline. The construction manual shows the hinge on the surfaces, riveted across step transitions where the side channels overlap the skins. The hinge, mounted to the back and bottom edges of the seat panels just seems more appropriate and allows for about 21 degrees backward and no restriction (until the panels meet) in the forward folding direction. That’s perfect. Seat recline angle is set by side-straps anchored to brackets at the edges of the seat panels.
The seats slide on rails mounted to the center fuselage. Clearances are pretty close, but appear to be perfectly aligned. Finding that helps to confirm that the center fuselage is built straight and square. Oh let me tell you that’s good news!