Topsy-Turvy

5/18/2008

Center Bow

To finish off shaping [narrowing] the ends of the bow, where they meet the trailing edge, I turned the wing vertical and placed on the purpose made stand. This position gave me a good comfortable sanding action. The bow is thicker than the trailing edge thickness, so it has to be tapered down to finish flush with the trailing edge. For this I used a 7" sanding block.

Tip: Originally I had cut the bow to fit snug up to the tail rib where the alum' trailing edge terminates, but I realized that I needed a small radius at that corner...this doesn't work too well trying to smooth the edge of an alum' extrusion. So, I planted in a 1/4" piece of spruce between the bow-ends and the tail rib. This gave me a wood-buffer-zone which I could round-over.

Tie-Downs

Before storing away the recently purchased required I-strut AN4 bolts, I remembered that I needed to look at the tie-down options available. what I decided to go with was, cutting the eye off an eye bolt and welding that to the lower forward I-strut attach bolt. This seems a very good way to go, since the eye is minimal and requires no extra attachment hardware except the already required I-strut attach bolt.

Cabane Fairing Prep

The most practical method of working with the cabane glass fairing was unfortunately to have the plane upside down. This seems a daunting task at first, but it turned out to be a real no brainer with the help of three other hangar ratz. I made a small trestle for resting the fuselage on, and the whole process was over and done with within 3 minutes. The wing frame you see on the ground in the pics is just the previously made vertical hanging frame turned downwards [lucky me!].

Now I will be in a comfortable position to mess around with the fairing, which bye the way has to be cut into three pieces to fit around the cabanes neatly [a lot of fiddling around, hence my inverted 'quest']. I had decided to buy a ready made fairing from Steen, because my glass skills are nil. The quality seems excellent. I need to now make a thinner female mold from this fairing which I will use as a sacrificial template to get around all the nooks and crannies the cabanes and any wires will dictate. I know a guy who could do this for me, but I am tempted to have a go myself seeing as it's only a template...

Compression Tube Woes

Way back when I was rigging the incidence of my top wing, I had dropped the spar center line slightly past the spar/cabane brackets a touch. This has come back to haunt me. As you can see by the inset pic, the belly of the ply clashes with the tube, causing it to sit high from where it should be. I need 3/16 off from somewhere. Taking this off the tube will really not give me much tube left, channeling a groove in the ply is a no-no since it is considered structural. So I have decided to move the tube by adding two triangular steel gussets and mounting a tube between them [see pink in pic]. The cabane fairing is tall enough to cover everything.