Saturday, August 8, 2015

34-14 glassing canopy fairing

Well, I’ve been dreading this page for a year or two, and I’m still pretty keyed up about it.  Recall that long, long ago I came across the fact that Viking Aircraft produced a pre-molded aircraft skirt that eliminated the angst associated with this step.  I purchased it and it’s in my garage but I recently (few months ago) realized that it was not allowed since I was planning on certifying ‘012 as an E-LSA.  

(A thought just jumped into my head.  More recent reviews on the Viking Shield commented that it was flimsy and prone to wind noise.  My version (see below) is ugly and may not be  long enough to cover the lower edge of the canopy supports but it is probably very stiff (lots of epoxy).  I may investigate getting my certificate, flying off the 5 hours, then bonding the nice smooth Viking shield over mine.   Hmmm. Food for thought.)

Anyway,  this is the ‘before’ picture showing the smoothed foam, and scuffed up aluminum skirt and leading edge of the canopy.  BTW, it really felt weird to deliberately scratch & scuff that expensive plexiglass!

IMG 4555

Just prior to glassing


The canopy is still mostly wrapped in its original sticky plastic.  The blue painter’s tape covers the area between the double layer of electrical tape and the plastic.  The ‘grey’ region in front of the black tape is actually dulled canopy.  The black electrical tape is the 2nd layer, as called out by The Book.  Since the instructions say to sand through the 2nd layer to achieve a nice feathered edge, I placed red electrical tape as the 1st layer so I’ll easily be able to tell when i’m making the transition.

The foam blocks are very fragile where they are tapered out around the bolt holes.  Ask me how I know  :-(     I used some expoxy/flox to glue the remnants back into place so there wouldn’t be a big void right there on the leading edge where wind loads will probably be pretty high.  I think I may inject some epoxy/flox into the back side of that area when I get the canopy off for trimming.


IMG 4556

Right Side after glassing

IMG 4557

Left Side after glassing

This was far and away one of the more stressful days of the project.   Cutting the fiberglass wasn’t too bad, but the long narrow strips (next page) were very challenging when they were very narrow.  I think I may have made a mistake by cutting the long strips parallel to the weave of the cloth; perhaps cutting them on the diagonal would have worked better.

The dry fitting of the 1st ply nearly panicked me into thinking I had made some major mistake in cutting.  It didn’t look like the intended shape at all.  I was eventually able to stretch it into something that resembled an intended shape and proceeded.  I wasn’t able to get the ‘tails’ to extend as far as I thought they should.  As I type this, I realize that I was trying to maximize the fore-aft direction of the plies and this probably resulted in shrinkage of the up-down dimension. It’s not too bad here on the left, but the plies are definitely too short on the right.  I’m going to have to work on a remedy for that.  Later.

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