Wing X-bracing install

Stringing the Kevlar X-bracing through the wing

We started putting the Kevlar X-bracing through the wing sections, after having previously cut the holes with a laser alignment tool.

You have to keep track of a lot of fibers and lay them out neatly when you are starting the first few runs of the cord, so that they don't get tangled.  Each time through, you tighten each pass of the Kevlar line by pulling as hard as possible while someone supports the other end of the wing.  You must make sure that each of the individual strands is pulled tight through the sailing thimble before clamping that tension in place and beginning to string the next pass through.

We're using 7100 Denier Kevlar tow that consists of 5 separate strands of 1420 Denier tow, so sometimes one or more of the separate strands gets caught up and doesn't get pulled to the same tension as the others.  A careful pull on each strand will sort it out.

Once all 4 passes of the X-bracing have been done, we terminate it by gluing the free end onto the previous strands with Cyanoacrylate glue.

You start by tying the Kevlar tow to one of the sailing thimbles at one end

Pulling through before tensioning

Tensioned strands with loose strands ready to be threaded through

Kevlar Wrangling

The elaborate system of laying out the Kevlar tow to avoid tangling

Getting ready to tension the next run of tow, with previous run tensioned with clamps

Pulling on both parts of the X-bracing simultaneously before clamping

One must pull quite hard to keep the tension in the line before clamping

Both sides clamped

Clamping close-up

Clamped strands being glued in place

Glued joint after trimming excess free end -- all 4 passes in place

We are going to hold the wing sections together with aluminum wing connection brackets in a tang and clevis configuration, one set on the front of the wing section in front of the spar, and one set at the rear spar.  The machined parts just got finished, and will be glued into the wing sections soon.

Some of the wing connection brackets, fresh from machining

Showing how they will fit together (with hole drilled through both, and pin in place, evenntually)