Forming the Leading Edges

To form the leading edges, the instructions say to get a 2x8 and a couple 2x2s, attaching the 2x2s to the 2x8 with about an inch-and-a-quarter between them (enough for the pipe to fit between). Then just lay the aluminum across the jig and press the pipe down between the 2x2s to form the leading edge. It says you'll need to back the pipe with a 2x4 to keep it from flexing. The pipe is so massive, I couldn't believe it would flex. Well, I had a thing or two to learn. Using the captions for the photos below, I'll describe the process and how I ended up making the leading edges (Hint: not at all how the instructions said to do it!).

My original leading-edge-forming jig, according to the instructions.

1 1/4" pipe. It has an inside diameter of 1". Buy a ten-footer.

Cutting the sheets to size. I ordered them 18" wide, but cut off another 1/2". I also cut them down close to their final length. You need extra length for attaching the wing tip bow.

If you score the aluminum several times with a razor blade, you can just bend it back and forth a couple times, and it breaks off, leaving a nice, clean edge.

It was very easy to bend this small test piece. Unfortunately, when trying to bend the entire sheet, I discovered that would be pretty much impossible. I banged on the pipe with a small sledge hammer, and even stood on it. It wouldn't budge. I understand now why the instructions said to use a 2x4 to back the pipe so it didn't bend. When I clamped the ends, it definitely flexed, despite it's being a pretty beefy pipe.

Put a mark on your test piece right at the leading edge (note the red line on this piece of metal). Use this piece to mark the appropriate location at both ends of your final piece so you know where to line up the pipe that you clamp down over the aluminum sheet. It's not quite symmetric due to the different curvature on the top and bottom of the nose ribs, so you want the bend to be in a pretty specific location on the sheet. You can't just clamp the pipe right down the middle of your aluminum edge sheet.

So, I decided to try something else. After mulling over it for a couple days, it occurred to me to clamp the pipe over the metal, then move the 2xs in from the sides. I was going to buy more wood, but then decided I would just  clamp the pipe directly to my work bench and use the 2x8 that I was using as a base and the 2x4 that I had bought to back the pipe to squeeze in from the sides.

My first attempt at a new method of bending the leading edge material.

You can't see it in this photo, but the 2x2s were a little too flexible and didn't squeeze the metal all the way in out in the middle.

I had to keep taking bites until full squeezage was achieved. After reaching the limits of my clamps, I would hold things together with a second clamp, then unscrew the main clamp, slide the other end in tight, then screw this end down again. It took probably three or four bites.

My ultimate solution. Clamp the pipe over the aluminum directly to the work bench. Then use the 2x8 and 2x4 to squeeze in from the sides. I would recommend buying a 1" pipe ten feet long, and two 2x6s eight feet long. That should be all you need to bend your leading edges, other than several good clamps.

You can see that I'm using different clamps now. My pipe clamps are quite long and therefore unwieldy.

The end result (almost).

After I had the clamps squeezed tight against the lumber (and, therefore, pipe), I went down the length of the aluminum, up and down both sides, pushing in with my hand to get a little tighter bend in the aluminum. I didn't need to push too hard, but got the optimum bend, I think.

Cool!!!

Making the Wing Rib Corner Blocks

After all the compression tubes and drag wires are in place and adjusted, I'll glue corner blocks in place around each rib, turning the wing into a stiff, strong, G-pulling monster. Just make sure things are lined up before that!

Several places throughout the instructions, you'll read something like "These are available from B.O.A.C." (Barney Oldfield Aircraft Company) Yeah, right! Of course, they don't exist anymore and Aircraft Spruce (who owns the rights to the plans) doesn't have and can't make some of these things. One of the things in question is the corner blocks for the upper wings. Remember, those wings are swept 6°. So, half the corner blocks need to be 96° and the other half 84°. Gotta make 'em yourself. I just used the piece of wood I made on the table saw which I used to cut the angles in the nose ribs for the upper wing. I cut the long (6-foot) pieces of corner block material in half to make it more manageable and, after sanding it on my oscillating belt sander, chopped it into small pieces.

Sanding the 84° angle.

Making the 96° angle.

The chop saw is one tool I would highly recommend for anyone building an airplane.

Blocks of different lengths for different locations. Still need to make some
really short ones for where the leading edge spruce strip fits into the nose ribs.

Finishing the Drag Wire Assemblies

Getting ready to paint the compression tubes and drag wires with zinc phosphate

Bend the fitting apart and slide it on to the wire so that the threads are sticking out past the end. I forgot to put a washer on. Put that on first. Then screw two nuts on and tighten them against each other with about three threads showing at the end. I also added Loctite to them. They won't be adjusted or moved after this.

Add a drop of oil where the washer rests against the fitting. This will allow the wire to turn more easily during adjustment. Also, the instructions say to put one inch of threads on this end. I don't see why. Most of that isn't used. Since I'll be re-making all the drag wires (since Aircraft Spruce sent me 6061 instead of 2024 and I didn't realize it until I was done making these), I think I'll put only about a half inch of threads on the next set.

This is the end where you put about an inch-and-a-half of threads. First screw two nuts all the way on and lock them against each other. I also used Loctite on these as they are permanent. These are used simply to get a wrench on to adjust the drag wire tension. You turn the nuts to turn the wire. When I re-make these wires, I'll be careful not to get paint on the threads. I would feel better if the nuts were riding on clean metal.

After the locked nuts are in place, put on the fitting. Then add a washer and the nylon lock nut.

I just set the nylon lock nut in the fitting—don't forget the washer—and lowered it onto the wire. Then you can just tighten the nut by hand.

Here's how that end will look after you've assembled it (sans washer). Put a drop of oil where the washer will bear on the fitting. You install this into the wing as an assembly. To tighten a drag wire, simply grab the nylon lock nut with something like the pointy vise grips with the big 90-degree jaws, or maybe even just stick a big screwdriver in next to it, and turn the wire via the two locked nuts.

Compression Tubes

The compression tubes are one of the easiest things I've made so far. I simply cut them a little long on my chop saw—carbide slices through aluminum like hot butter—then shorten them a little at a time on the oscillating belt sander using a miter fence to keep the end square. When I assemble the wings, I may need to take a tiny bit more off. You want the ribs not to bind after you tighten down the drag wires. If the compression tubes are either too long or too short, they will.

Drag Wire Fittings

To make the drag wire fittings, I just followed the steps that Tony Bingelis outlines in his book Sportplane Construction Techniques.

Basically, you clamp the metal in a vise with a piece of hard wood, bang on it with a hammer until there's a 90-degree angle. Then flip it on its side with another piece of hard wood and bang some more. Then you've got a U-shaped piece. At that point, drill the hole in the end. Then, clamp it back in the vise with a triangular piece of wood inside it (the two ends of the U are in the vise jaws) and bang yet more. At this point, you've got the basic shape. After that, drill and ream the hole for the bolt and grind the square corners off.

Unless you're a much better metal worker than I, I don't see how you'll make it look as nice as the diagram in the plans. Still, once it's bolted into place on the spar, I think mine will look pretty good. When they're just sitting there, however, they're not closed up tight on the end. I can get them to close up, but then the end where the nut will pull is not flat.

By the way, the info pack is not clear at all about the material you need for these. Aircraft Spruce sent me stainless tubing. Huh? After looking at the materials list (which is in the info pack), I could see their confusion. The plans spell out the material needed for these. Make sure that's what you get.