Monthly Archives: December 2020

QB Fuselage Rework – Part 2

Sometimes you have to go backward to go forward. Drilling out rivets is one of those things you have to do sometimes when building and airplane. Fortunately, I’ve had to do very little reverse-assembly. But, there are a couple of parts I needed to add and I’ve opted for an upgrade to the cowling fasteners that calls for replacement of narrow, factory-mounted parts, with wider aftermarket replacements. Drill baby drill!

There’s a reinforcement plate, near where the ballistic parachute rocket canister mounts. The plate rivets to the RIB that forms the back wall of the parachute compartment. Several rivets had to be drilled out and removed so that the plate could be positioned and riveted. Done.

There was also a missing attachment angle for the top right edge of the parachute compartment. It should have been installed at the factory. It’s going on now, but a few rivets had to be removed before the angle was riveted using those same holes.

To go along with the other rework, I’ve opted for an upgrade to the factory-supplied cowl fasteners. I want to use Camloc fasteners rather than the Dzus fasteners that come with the kit. The Camloc parts are more user-friendly when it comes to unfastening and re-fastening of the cowling. For best results, getting the fasteners a little farther away from the edges of the fiberglass cowl is a good thing to do. That involves replacing the factory cowl fastener strips with wider parts that I ordered from Midwest Sky Sports. They make these wider strips and use them for the planes they build and they seem like a good idea to me.

The rivets holding the factory-strips needed to be drilled out. I did it. Now I don’t have that to contemplate anymore. I did a quick fit of the new cowling fastener strips. They look like they fit pretty well. That’s a relief after removing the factory parts.

Rudder Pedals – Trial Fit

The sight of rudder pedals in their proper home makes the whole project seem like it’s on track to be a finished airplane. That’s important for me to realize, now and again, and helps to reinforce the idea that finishing the airplane is possibly doable.

My Sling-branded rudder pedals are an option that I knew about, liked, and deliberately ordered with the quick-build kit. When my QB kit was delivered, the pedal parts I ordered were not there. Most of the related parts I got were for toe-brakes. It took more than 6 months to get things sorted out with the factory and finally get all of the parts for the pedals I ordered — all good now.

The typical braking configuration for Sling airplanes is a simple, single hydraulic master cylinder, lever-operated mechanism that evenly applies the Matco disc brakes for both main wheels. Toe-brakes are a necessity for Sling tail-draggers, but are available as an option for us lowly nose-dragger pilots. Space is pretty tight for 4 independent toe-brake master cylinders with all of the plumbing. From what I’ve been able to determine, Sling pilots find they like the hand-brake, even if they’re used to toe-brakes. I’m going for simplicity. My Piper Warrior has toe-brakes. They’re fine, until they leak all over your pedals and carpet and demand maintenance. I’ve been there, done that and got the T-shirt – thank you very much. Simplicity is a virtue. I’m going through the simple-is-better phase of my life now. You can have toe-brakes in your Sling.

I had hoped that I’d be done with this pedal mounting business – the final assembly. But, it’s turned into a trial attempt. The pedal tubes, bushings and brackets fit nicely, but I did find some clearance issues with the pedal stops that I’ll need to address. That means the whole pedal assembly has to come out again, except for the permanently riveted floor brackets. As I moved the pedals I heard squealing. It’s a little hard to explain, but the edges of the lower hands of the stops can (and do) occasionally touch the edges of the control arms where the nose-wheel pushrods and rudder cables attach. I have to do something. Exactly what, I don’t quite know. Something will come to mind. That’s where procrastination comes in.

Fortunately, I’ve elected to retain the top bushing brackets with M4 x 12mm SS cap screws, washers and elastic stop-nuts. That makes for straightforward disassembly. (I may eventually be forced to use 4mm pulled rivets, if the retainers show any signs of movement, but for now the M4 screws seem reasonable. Space is very tight and riveting would be a challenge – explanation below.)

Typically, the rudder pedal floor brackets, tubes and stops are fitted and mounted much earlier during fuselage assembly, with just the CF floor sitting ever so conveniently on the workbench. For my factory-assembled QB project, this didn’t happen and I’m doing the fitting and assembly work inside the completed CF structure. It’s certainly more challenging to do this work while kneeling and reaching into the cockpit foot wells.

CF – Rivnut Mounting

Setting rivnuts in the center fuselage (CF) area had been on the TODO list for a long time, but it took until now for me to summon up the nerve to actually do the deed. It turned out to be rather easy. I was in the right frame of mind and it all went very well.

A few of the rivnuts are in locations where I couldn’t use my drill-mounted (Astro ADN14) setting tool – particularly one of the M4’s for the A/P bracket nearest the main spar, and two M5’s that will serve to anchor the rudder return springs to the rear spar carry-through member. Fortunately, I’d acquired a nice hand tool (Astro 1443B) and it worked brilliantly for those. Concern about these rivets were what kept me dragging my feet until I’d worked up my courage to attempt the work.

Each of the holes where a rivnut goes, were enlarged to the proper size. This takes several steps, but it’s the same process I’ve used elsewhere. In places where I can’t see the back side of the mounted rivut, I use a mirror to inspect the crimp. They all looked great.

Various panels and covers in the CF that need to be removable, now have their mountings in place.