Left Wing VIII

11/25/2006

I wanted to fit a pitot-static tube under the wing due to the chances of it getting broke off if mounted in the leading edge. Other possibilities were i) upper wing [troublesome when routing long tubes down through cabanes etc], ii) on the I-strut [still exposed to kiddies hands and extra tube routing].

I fitted a cleat for the pitot outboard of the I-strut. I had trouble researching what depth along the wing chord the pitot should sit. The general consensus is that it has to be a minimum of 5 inches below the wing so as to be in clear air, and not further back than 35% of chord. I also popped down to Georgetown airport to go look at some pitot positions, I found 2 planes with underwing pitots and noted their positions.

Aileron hinge brackets were fitted next. I then focused upon the aileron well. The spaces between the aileron-well ribs, and any cloaking of the aileron well is not referenced on the plans. But it was obvious the spaces between these ribs needed bridging. I did this with 1/4 birch ply. I used popsicle sticks as a kind of nailer while the T-88 cured. The wing was then turned over and any protruding 1/4 ply was routered flush. You could also not bother bridging within each rib with 1/4 ply, instead you could notch-out a 1/4 x 1 profile in all the wing aileron-well ribs and span the whole length with 1/4 x 1 ply. I didn't do this because I knew I was cloaking over the top of everything with a V shaped alum trailing edge.

The trailing edge for the aileron wing well is alum sheet, it was bent it in a break [see Right Wing V on my site for more details of this stage], and it fits lovely...thus providing a solid straight edge for the fabric to wrap around when the time comes. The alum angle was over-bent so as to force the fit of it to the rib tails, therefore keeping the alum flat along the length of the well. The trailing edge glued on with T-88 and not screwed or riveted, I figured that as long as the trailing edge was tight against the tips, coupled with the fact that the eventual fabric tautness will keep all in place. At the underside, the alum trailing edge has the added benefit of creating a lip on the 1/4 ply, this lip is great when fitting the radiused 1/32 ply because you can press the 1/32 ply against the lip and seat/coax the bend of the ply without it slipping off. An added bonus is that the 1/32 ply sits flush against the alum' too. After notching around drag blocks and hinge brackets, the ply was glued in place. 2 coats of clear coat were then applied.

Next, I wanted to cut and fit the small tip bow to the aileron. In order to get an accurate flow of the whole tip bow through to the aileron tip bow, I first mounted the aileron in the wing well, ensured it was in a final position, and marked off the tip bow accordingly [The mini tip bow was the drop-off from when I cut the main tip bow a while back].

While the aileron was dry-set and perfectly lined up with the wing at the trailing edge [use builders string for a straight line], I dry fitted the hinges. The smaller aileron hinge bracket positions were 1/16 short [i.e., bolting them on would draw in the aileron 1/16, ruining the wing-to-aileron trailing edge alignment], so I glued into the aileron wells 1/16 ply shims.