While waiting for some riveting assistance on the ailerons, I started in on the flaps by deburring the flap spars. Nothing tricky or visually interesting here, so no pictures.
Category Archives: Wings
Right landing light wiring
Spent the last couple of days routing wires from the landing lights into the now-permanent conduit. Nothing tricky here, except that I routed the wires through the outboard spar lightening holes and that meant some extra work securing the wire.
Nothing particularly sexy on the right side except the use of some heated and hand-formed poly tubing to keep the wire from rubbing against anything…
The right side wire is bundled with pneumatic lines from the Advanced Flight Systems AoA probe. This actually made it easier to run the line, because I was able to use a Click Bond standoff.
I used self-fusing silicon tape to seal the holes and prevent chafing where wiring enters the plastic conduit. With all this fun complete, I went back to working on the ailerons.
Made the conduit installation permanent
I had already pulled lengths of Van’s corrugated black conduit through the wings, but hadn’t bothered to permanently attach them. Didn’t have anything else to do today, so I mixed up some proseal and made the conduit installation permanent.
Prosealed conduit
I also caught up on one smaill detail. I had previously installed local ground studs in each wingtip for the landing and nav lights, and had used steel AN hardware to make those studs. I had a sneaking suspicion that galvanic corrosion could result from running electrical current through steel fittings in contact with aluminum, and after some digging in AC43.14, I found that was indeed the case. I ordered some special aluminum washers from GAHCo and reworked the grounds so that only those washers are in contact with wing structure. Problem solved.
Wrapped up work on the heated pitot
I wrapped up work on the heated pitot by wiring up its electrical connector. I purchased the pitot as used-serviceable from our local flying club; got a great price, but the connector wasn’t with the pitot. That meant buying one from Aircraft Spruce for the exorbitant price of $57.75. But it has an inspection stamp on it, so it must be worth the price. Soldering the pins on the connector was no problem; 14 gauge Tefzel wire was chosen to support the expected 10 amp current draw from one of the cockpit electrical busses. Here are the soldered pins…
Connector pins soldered
The only tricky parts here were routing wires to the connector so that it could be removed with the pitot tube, and installing the ground such that the crimp connector could be visually inspected and disconnected if necessary. Some plastic tubing and a couple of tie-wraps made a good standoff.
Pitot heat wiring
Left wing’s pitot line plumbing
Over the last couple of weeks decided to take a break from the ailerons and start working on the left wing’s pitot line plumbing. I was considering two ways of doing this; per Van’s plans with a piece of aluminum tubing and some bulkhead fittings, or with the plastic lines and push-to-seal fittings that came with the SafeAir pitot-static plumbing kit. The fact that I’m installing a heated pitot actually made it impossible to use Van’s original design, since it only calls for a simple aluminum tube pitot connected to a bulkhead fitting. On the flip side, the heated pitot could melt the SafeAir plastic tubing. So…I came up with a hybrid approach.
The pitot tube end was easy. I just moved Van’s original bulkhead fitting from the wing underside to the wing rib just inboard of the pitot tube, then bent and flared a short piece of tubing to connect the pitot tube to the bulkhead fitting. This is to allow the pitot tube to be disconnected and removed for maintenance in the future via access from the outboard inspection hole. Although you can’t see it in the first picture, there’s an AN fitting hidden by the pitot mast.
Pitot-to-bulkhead connection
The other side of the bulkhead is attached to a piece of aluminum tubing that extends inboard under the aileron bellcrank and into the middle inspection bay…
Bulkhead-to-line connection
…and is connected there to an AN-to-1/4″ NPT fitting (available from GAHCo) onto which is threaded a SafeAir’s push-on connector. Plastic line is run inboard from there through the wing root. The short piece of aluminum tube acts as a heat sink, keeping the plastic tube from melting. And using the plastic line inboard will make it easier to route the line through the wing root area to the cockpit.
Aluminum-to-plastic connection
Why no bulkhead fitting at the aluminum tube’s inboard end? Pretty simple.
Away on a work trip
My website updates are happening so infrequently these days that I doubt anyone still hits the site. I’ve been away on a work trip for most of the last month, acting as program manager and test director for a large DoD interoperability test event in the beautiful – but damn hot – California desert. Here are the folks and airplanes involved during a checkout flight test at NAS Patuxent River, Maryland. I’m in there somewhere…
Bits-and-pieces work
Took advantage of the long holiday weekend and did some more bits-and-pieces work. This time it was installing rod-ends into the pushrods and setting them to the right overall length. I also test fitted the bellcrank spacers in each bellcrank and made sure there was no binding with the bellcrank mounts. I also started fitting pitot lines in the left wing, and final-drilled the pitot tube attachment holes in the SafeAir pitot tube mast.
Bellcrank spacers
Did a little pickup work fabricating aileron bellcrank spacers; sorry, no pictures.
Pushrods
I’ve been on travel for a week or so since the last entry. I decided to work slowly, surely and patiently on the large aluminum pushrods, measuring two or three times and taking great care in cutting and drilling. The result this time was much more successful. Here’s one end of a pushrod with the threaded end match-drilled in place, done after the interior of the tube was primed.
After deburring, the threaded ends were wet-riveted in place with pulled rivets. Why the wet-riveting? Those pulled Cherry rivets are steel, and I didn’t want any galvanic corrosion working on those pushrods.
After riveting, both pushrods got a final coat of primer.
Welded aileron pushrods
So…after those job-stress-induced issues, I ordered new parts for both the large and small aileron pushrods. Rather than go through another trial-and-error process of riveting rod-ends on the small steel pushrods, I decided to have them welded on by a local welder who does work on certified airplanes. Here’s the final product, after priming.