February 14, 2013 - Triplane: Tapering Spar
Flanges |
| The spar
flanges stock is two inches wide. But they don't need to be two
inches wide all the way out to the wingtip. For weight and
flexibility reasons, the spar flanges get tapered starting a few
feet outboard of centerline until they are only 3/8" wide at the
wingtip. |
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I had to do a lot of measuring to
figure out how to lay out my jig. The laser "line" came in handy for
this job. |
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| The tapering was
very similar to the scarfing. I made a new, much longer, jig but
otherwise, I did everything the same as when I made the scarf cuts. |
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A flange spar ready to meet Mr.
Tablesaw blade. |
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| A rare action
shot. I have a very healthy respect for the tablesaw, so I always
wear eye and ear protection, and use a guide to keep my hands away from
the blade. |
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| Here we go! |
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| Some of the spruce
stock wasn't perfectly straight so I used some clamps to keep it straight
up against the jig. |
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Like the scarf jig, I used a couple
of screws to secure the work to the jig. |
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| The piece that is
removed from the spar flange gets trimmed and then spliced to the end of
the spar flange. |
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I saw amazed at how much sawdust the
tapering produced. |
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| That's a lot of
sawdust! |
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| The miter saw was
perfect for cutting the spar flanges to the proper length. |
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I tapered all 24 spar flanges. Then I had trim the
wingtip pieces, and scarf both them and the main inboard
pieces. Lot of work that took me about a week. But it went
very well and was fun. I did make a mistake on one piece out of 24,
so I had to order another 3/4" x 2" x 9' piece from Wicks. I needed
some more spruce to finish up the swallowtail blocks anyways, so I ordered
that too.
The spar flanges are now ready to get glued together. |
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