Chapter 7: The Wings

Now onto the wings. After hoisting the HS and elevator combo up to the ceiling, I started making the cradles. Fortunately, the experience here was a good one. The blueprints, hence the cradles, too were perfect. This time I used angle iron for the span-wise braces. The wing is a pretty large task and gets broken up into 5 subtasks:

1. Core
2. Flap
3. Aileron
4. Close out
5. Clean up and trim

1. The Core

The core comprises mounting various things onto the wing itself. The main pieces are slosh doors, fuel probe, fuel return line, fuel pick-off, fuel drain, fuel cap, fuel vent line, glide-slope antenna, Pitot tube, conduit, flap hinges, and various other bits and bobs. All went quite straightforwardly with few surprises. Things, which I did differently, were...

• Bought the upscale fuel caps. Look a whole lot nicer and are of significantly better quality than those that come with the kit.

1. the vent line (aluminum) would be a good reflector at VOR frequencies, and

Fast build is the way to go if one wants to fly the plane in one's lifetime. Often during drilling, hacking, and swearing I thought about the amount of work required installing all the ribs, shearing webs etc. Glad it’s not me!

The conduit filled up pretty rapidly, 6 runs of 14AWG for the landing lights and pitot heat, multi-core cable for the strobe and position light, coax for the antenna and pitot tube, and finally 22AWG for the trim tab servo.

 2. Flap

After completing the core, I, for some inexplicable reason, proceeded to build the flap. The manual has the flap construction following the wing core, but says not to do it until the wing is closed. OK, so I guess it isn’t quite inexplicable, I missed the note. GOOD THING TOO! (See later) The flap construction went pretty well, with again, few surprises and the "joy" of peel ply. It comprises fitting ribs and spars to the skin, building ribs and spars, and fitting the bottom skin. One interesting technique was the fabrication of hard points to bolt the hinges onto the ribs. This was performed by removing one of the plies and the core from the rib and bonding* a phenolic insert into the rib. Quite a neat technique.

Now in fitting the bottom skin to the flap and to build the rib and spar caps, I noticed that the outboard edge of the flap protruded about ¼" higher than the adjacent rib cap on the wing. Oh No! Where did I goof? Back to the blueprints, check the cradles, check the flap ribs, where did I screw up? Re-check, re-measure. OK, let’s put the cradle top on and see what gives? Well, would you believe it? The wing is wrong! Yet again a part of inferior quality.

Another fiery call made to Carsten. He was, understandably skeptical. So, I emailed him a few pictures, which convinced him. It turned out that the all the ribs and spars, on the trailing edge half of the wing, were undersized. The error was negligible at both the extreme inboard and outboard edges, and increased toward mid-span with the greatest error at the flap/aileron junction, where it was about 3/8".

The fix was to build spacers, using pieces of tongue depressors, to lift the bottom skin until it touched the top cradle. Then place a release tap on the bottom skin and spread loads of epoxy/flox over the effected caps, place the bottom skin in position and let it cure. Pop the skin off and voila! It is done! Infinitely easier than discovering the problem after closing the wing (see how to fix that in Chapter 4: the horizontal stabilizer).

Carsten did offer to help fix it, but I was in too much of a hurry to wait for him to come over. He did come a week, or two, afterwards and took photos. I was hoping for an offer of a free lifetime supply of epoxy in compensation, but all I got was "You did a good job, Pat!" (I was relieved that Pat had handled the problem well, and an "expert" confirmed that it was well done) I guess I could have been a little harder... errr-- nosed, yeah, that’s it, -nosed, about it. But I wasn’t. I just assumed it comes with the home building turf. (That comes from coming from a society, which is not litigious and much more subservient that US society)

The rest of the flap building was uneventful. (I was thankful for that, I could just see that when we finally got to fly, the wing would--fall off, snap off, shear off--whatever else can happen to wings!)

The aileron is made of carbon fiber and proves to work a lot easier than E glass. This was immediately noticeable when removing the ubiquitous peel ply. Another advantage of buying the L-IVP kit! It is also easier to cut, sometimes too easy. The challenges with the aileron were the trim tab, the thickness of the aileron, and balancing.

The trim tab was extensively modified. The manual calls for embedding one side of about 12"s of hinge into the trailing edge of the aileron and letting the other side dangle in the wind. It looks really cheap and hokey. Many moons ago (this is the kind of language born of too many John Wayne movies seen in a misspent youth), when I was a CompuServe subscriber, I used to visit Avsig and read stuff in the homebuilder’s library. One contributor, a Dr. Fopp in the UK, an L360 driver, didn’t like the aileron trim tab either. He built a regular trim tab. I followed his lead and built an embedded trim tab. This proved to be quite a task. One problem was the distance between the servo and the trim tab crank is now greatly reduced. I had a special clevis made to fit in the available space. Remember to mount the mini spars and hinge prior to closing the elevator.

The thickness of the aileron at the leading edge is also a challenge. I guess I should have trimmed the counterbalance lever off the aileron, reduced the thickness of each half by about 1/8" and then reattached the lever arm. But I didn’t--so I wound up with a slightly oversized aileron. Oh well, nothing’s perfect and the drag should be a little less as there isn’t a depression where the aileron meets the wing. (God, how would we survive without rationalizations?)

The act of balancing the aileron turns out to be a real balancing act of patience and fury. To tell the truth, it’s still not balanced and is stored away in a dark hole waiting for my patience to be restored. The problem is there are three variables:

1. Balance
2. Weight
3. Travel

In order to use the least weight possible, one tries to get the lead as far forward on the balance arm as possible. In doing this, one increases the thickness of the balance arm and limits the travel of the aileron as it makes contact with the wing skins. Thus, one moves the weights back and thus there is insufficient weight. Add more weight, fouls with the wing skin. Move more back, add more weight, on and on. The aileron weighs an incredible amount right now and is kinda balanced and kinda meets the travel specs. But I think it could be lighter. Stay tuned.

The final stretch!

"The area upon which one has to spread epoxy and then epoxy/flox is huge and the manual recommends getting friends to help, I fortunately had a few builders among my motley crew. The manual also gives various options to use depending on the ambient temperature. I used the first in both cases (Left and right wings) i.e. Hysol on the leading and trailing edges, epoxy/flox everywhere else. The biggest problem we had with the first wing was the supply of epoxy, we had 5 people spreading, 3 mixing and one pumping, as I only have one pump. This turned out to be a severe bottleneck and almost led to disaster, but we made it. With the next wing I focused on improving the supply of epoxy and did the following...

Left wing closeout crew

Right wing closeout crew

Now here’s where Weston Aerospace went International. My brother, Alan, who lives in Cape Town, South Africa, came to Portland and helped with the building of the left wing. He came once more to help with the clean up and trim of the same wing. This was a long thankless task of filling channels with micro and tons of sanding. (Alan, being an African easily fell into the role of Pat's indentured "slave, and was incarcerated in the "facility" from morning until dark and his only reward was being taken to dinner at a local pub--I was visiting with my parents in South Africa at the time. Alan seemed to enjoy his "servitude" and soon it became clear that he had become "Master Builder" rather than "slave.")

I was really fortunate, in that, he did an excellent job. The trailing edges are as straight as a rifle shot. The leading edge as smooth as a baby’s errrr… cheek, yeah, that’s it… cheek. Which cheek is left to the imagination of the reader? (Is Pat becoming PC? Good grief how age affects one's thinking. At 21 he would have said, "bum" and have thought nothing of it. But now at 50-plus it's a "hum and an errr…")

We (he) applied the primer coat, PPG K200, with a roller. We left it on, more as a protection than anything else. Sanding to come later. (All I know it that the paint was bought at Baxter's of Beaverton [Pat has pointed out the store to me on several occasions as though it should be put down in the historic building register] and that it was costly--Pat was quite floored by the cost. That's because he has grown insensitive to prices thanks to their costliness in all that is aviation. One really does become numb when ordering, or buying, for anything in the aviation sector--even though this paint is, in fact, for auto use. It's all so expensive and there really is very limited competition around. I believe it's due to the litigious nature of the public--or so I have been told. However, tell Pat that a dress cost $40 and he faints with shock--I suppose he doesn't believe that people sue clothing companies for poorly fitting dresses, or for dresses, which fail to hide our generous bodies sufficiently so that we never look sylph-like.)