Sharpening the Arrow

Posted January 2018

One of the things your Fly Baby should have are wing "arrows".  These are small dowels that attach about half-way out on each set of flying and landing wires.  You can see a typical example on the landing wires of C-FRDA:

The dowel is attached to all four wires in the set, by a tie-wrap, safety wire, or whatever. 

What are they for?  It's really rather simple.  They damp out the shaking of individual wires.  It's impossible to get the wires EXACTLY the same tension, which means the loosest one might want to shiver a bit.  By attaching it to the other three wires in the set, this tendency is reduced.

But....sometimes I hate the guy who built my airplane.

Most guys use ordinary dowel, or even real arrows, with safety wire or tie-wraps to hold them in place.

Not my guy. He took a ~3/4 inch dowel, sharpened it fore and aft, SPLIT IT LENGTHWISE, cut two inch gaps front and back set about an inch and a half from the ends, and glued every else back together.

Slots were routed out to match the cables, and the removed gap sections clamp back into place using two #6 screws and nuts each (four per arrow).

Oh, then he ran it through the sander one more time to give it an oval cross section.

Better him than me, eh? They look impressive, and didn't take any work for me.

One problem: He didn't glue them back together very well. Not long after buying the plane, I was fiddling with one arrow when the top half of the front popped right off. I glued it back, and tested the others. Reglued a couple.

But I missed one. Couple years back, I noticed the top of the front of the left wing flying wire arrow was gone.

Finally got around to replacing it. I cut a short segment of 5/8 poplar dowel, slit it LENGTHWISE, rough cut the shape, epoxied it in place, then hand-sanded it to shape.

Ron Wanttaja

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