I set the bit high at first and profiled the tip bow in multiple passes. A little follow-up with the sanding block, and the tip bow looks better than I had hoped. I profiled the bow from the front spar back to the trailing edge. I only had one spot where I wasn't careful enough with the profiling jig, and the router cut a little deep on the inside edge of the bow. It's a small nick that will eventually be beneath a gusset, so no worries.
I also made the final glue joint where the bow attaches to the front of the front spar. The bow had a fair amount of spring in it to force it into the proper shape, so I added a small filler block to reinforce the joint. Eventually the leading edge skin will act as a gusset at this joint, but it will probably take some abuse from sanding and shaping before the L.E. skin is attached.
2 hr
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( 2.7 / 36 )When I first laminated the wing tip bow, I was disappointed that it didn't look like it would fit correctly. I thought I had layed it out in CAD correctly, but when I put the bow on the wing, it looked like it most of it would be trimmed away in the profiling. I was going to fix this by adding additional laminations to the inside of the bow so that there was sufficient material remaining for the desired stiffness after shaping.
A second look at the situation determined that the additional laminations would be unneeded. I trimmed the ends of the spars to match the 3/4" thickness of the bow. With minimal forcing, I could get the bow to fit the way I wanted, except possibly for the leading edge area. I trimmed the bow and glued it in place. The resulting cross section of the bow should be roughly trapezoidal in shape - 3/4" wide with the height tapering from 3/4" high on the inside to 3/8 of an inch at the outside.
1 hr
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( 2.9 / 20 )I trimmed the root end of the spars and trailing edge. Then I glued on the root rib.
In hindsight, this was a stupid way to make the root rib. I should have simply left off the ply and glued in the root rib with all the other ribs. Doing it the way I did requires more fiddling around getting things to fit properly. Same for the nose rib. The ply could have been attached afterwards. Since I already made the port side root rib, I don't even get the benefit of learning from this mistake.
1 hr
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( 3 / 15 )I cut and glued in the remaining top diagonals for the ailerons. The aileron end rib was also glued to the trailing edge.
1 hr
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( 3 / 20 )I cut and glued in about half of the top diagonal braces for the ailerons. I also made an aileron end rib that will form the outboard end of the aileron. The full rib at that location will remain intact as part of the wing tip, so a separate rib for the aileron was required.
2 hr
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( 3 / 20 )With the wing flat on the table and the trailing edge along the fence, I glued the trailing edge to the aileron ribs after trimming the ribs to length.
1 hr
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( 3 / 20 )I cut a form block out of some scrap birch faced 3/4" high density particle board. After clamping the aluminum panel to the block, I used a dead-blow hammer to work the flanges for the side panel around the edges of the form block.
The curved top of the tank did cause out-of-plane warping which was more than a match for my metal shrinking skills (nil). I don't have fluting pliers either, so I modified the form block with a depression between each rivet hole on the top edge. After placing the side panel back on the form, I hammered flutes into the depressions. The sides are nice and straight again.
2 hr
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( 3.1 / 19 )I glued the tail section of the ribs onto the rear spar.
1 hr
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( 3 / 15 )After cutting the ribs into two at the rear spar point, I glued the center sections of the ribs to the front spar.
2 hr
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( 3 / 15 )Using the mylar patterns, I cut out the tank side panels and bottom from 0.040 5052 aluminum sheet. I roughed the parts out using a snips, then cleaned up the cuts with a laminate trimmer bit in the Dremel following a straight edge (or spline in the case of the curved top pieces).
3 hr
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