Tag Archives: wiring

CF – Upholstery, Painting & Wiring

Upholstery work takes a bit of courage and determination – at least for me it does. A big part of the work involves trimming the vinyl leatherette-like covering to fit the center console and then bonding pieces of material to some rather sizable and awkwardly shaped panels – everything is frighteningly sticky with spray adhesive.

I got through it and it all seems to look rather nice. I can’t say I’d do it the same way again, but at the same time, I don’t exactly know what I’d have done differently. You’ve just got to do the best you can.

All of the center upholstery pieces came in a kit, along with fiberglass-backed side panels, seat and seat back cushions, and carpet panels for the floor and luggage compartment. The seats cushions are covered with genuine leather and stitched by professionals. I got to choose the colors. Methinks it’s going to be a rather sporty and plush setup for this little 2-seater. Oh well! What can I say?

Once the rear portion of the center console was covered, it seemed a good time to put it into position. The inside seatbelts pass through, so it was time to assemble those to their anchors. I haven’t riveted the rear console yet – just clecos for now.

The front console panels have 3 sections. The top panel of the LH side is removable for inspections, as are 4 other square panels – 2 of which are covered with the vinyl. The 2 forward most panels are painted, along with 2 panels for the baggage area.

Bonding the covering to the RH side panel was the biggest challenge. The section of material was large enough to be unwieldy. Working conditions inside the CF were awkward. I did, however, manage to lay in the material and get it satisfactorily positioned. I’m happy to have that task in my rearview mirror.

This seemed a good time to complete more of the wire connections to the rear fuselage (RF) section for the tail beacon and electric pitch trim servo. The PVC jacketed wires in the RF were routed and secured as part of the factory quick-build (QB). My custom avionics harness was provided with “pigtail” connectors. I connected the wires of the pigtail to the fuselage wires with Raychem D-436 series butt splice connectors. The connectors are a bit expensive and a special crimp tool is required. I believe the resulting connections are more than satisfactory. As usual, I insulate and protect the connections and secure them from movement.

Wiring Harness Placement

After careful study of the wiring harness, I think I generally understand how it should be positioned. All of the connectors and each of the individual wires have labels that match the names of the LRU connectors and appear in the schematic wiring diagrams that came with it all. Sweet!

The harness has a central “gooseneck” from which various connector bundles extend. The several sub-harness bundles have been made to reach corresponding LRUs where they are mounted behind the panel. Other portions of the harness extend to places in the center and rear fuselage to connect with lights and autopilot servos.

There are probably several ways that some of the harness extremities could be routed within the center fuselage (CF). Some routes are undoubtedly better than others. I’ve tried to find what I consider to be the most natural – and if you will – most elegant way to dress and eventually secure the wiring, while always considering guidance in FAA AC-43.13-2B.

So far, so good.

In the interest of keeping things both lightweight and tidy, I’ve opted to replace a heavier and bulkier firewall-mounted circuit breaker enclosure with a simple bracket. I also decided to locate the battery and pitot heat power C/Bs and the ammeter shunt on the LRU rack instead of inside the engine compartment.

VS Skin – Prep and Test Fit

I spent several work sessions to make sure I can expect good results when it comes time to close up the VS by riveting the skin to the underling structure. By that time – the VOR antenna, its RG-400 coax cable and the tail strobe wiring must be in place and will be expected to last the lifetime of the aircraft. No pressure!

Holes around the edges of the skin were typically large enough to accommodate 3,2 x 8mm domed rivets, but the holes in the skin at the interfaces with the ribs were smaller and needed to be enlarged with a #30 straight flute chucking reamer. All holes in the skin were carefully deburred. Overall, the concentric alignment of holes in skin and structure were pretty good, but a few will need to be match-reamed during the final fit, immediately prior to the riveting.

The antenna base required 4 recesses be machined into the plastic-like material that allow shortened rivets to fit without interference. My trusty Dremel Tool did both jobs handily – shortening the rivets and creating the recesses.

Starting Off On the Right Foot

I ordered my quick-build kit in July and I’ve had my empennage sub-kit since August, but have yet to pull my first rivet. I’m finding that it’s taking many hours for research and for me to learn enough background information to make confident choices that will set the direction and metrics I will endeavor to satisfy as I build. I think that’s part of the fun.

Surface priming – materials and techniques – is a significant matter. I’m still wrangling a bit with that, but have determined that I have to be practical, or I’m never going to put pen to paper, so to speak. My priming standards are going to fall somewhere closer to the minimum of bare aluminum rather than the extraordinarily high level demonstrated by the truly awesome work of Pascal Latten for his Sling 2 build. Spray painting can be a messy and tedious business. I’m not a professional and I want to keep things clean and simple as possible, while achieving a worthwhile result. In a nutshell, I’m going to use RustOleum self-etching aerosol primer for most internal mating surfaces. For more exposed areas, such as the hinge areas and outward facing structure of the horizontal and vertical stabilizer assembies, I’ll use Alumiprep 33 and Alodine 1201, coated with more durable PTI 2 part epoxy primer – and ultimately the final color top coat.

Wiring, VOR antenna and external lighting choices figure in early for the empennage build.

Aveo Engineering produces what I think is the best option for the anti-collision light atop the rudder. For reasons that included fit, features and color, I’ve opted for the aviation red Posistrobe MiniMax to complement Aveo 3-in-1 nav/position/strobe lights on the wingtips – exact model number of the wingtip lights TBD. Without a huge amount of work, and or ready access to a completed Sling 2, it’s really mostly an educated guess that the overall lighting results will satisfy FAR 23.1385 – 23.1401. Hopefully it will and the DAR will agree.

Rudder Cap Strobe Mounting Area – small, even for the 1.74in wide MiniMax Light

Working through the electrical current requirements of the LED rudder strobe against AC 43.13B, I’ve tried to determine the necessary gauge and then acquire M27500 shielded cable to replace the TAF-supplied PVC jacketed wire in the kit. Based on actual experience with such wire in my Warrior, I’m not impressed with its suitability for aircraft applications. Based on my calculations, I think readily available 22 gauge conductors would be sufficient to handle peak current less than 3A over a run of 20ft. But, based on some data from the awesome builder I mentioned earlier, it’s possible that 20 gauge wire would be a better choice. I ordered some M27500-20TG4T14 from WireMasters. The minimum order was 100ft. This wire may turn out to be overkill for the small LED light. We’ll see.

You’ll find a chart like this in AC 43.13B

The VOR/GS antenna gets built into the vertical stabilizer, so I have to make a commitment to that, even before I’ve settled on my avionics choices. I’m hopeful that conformance with FAA TSO: C34e, C36e, C40c will make my choice compatible with whatever I finally choose for a VOR/GS receiver. Keeping the antenna price down will also make it easier to go with only a GPS navigator. At least the antenna and wiring will be in place. I’ve opted for the Rami AV-520 which has 2.5in diameter base “puck” with removable whips, built-in balun and coax connection.

I’m aiming for an advanced IFR all-Garmin EFIS panel with autopilot. We’ll see where it ends up.

I’ve ordered a bunch of stuff and it will be here next week. I’m perilously close to the official start my Sling 2 build.