Step 4.7, Empenage tips

With the elevators complete, the last step of the empenage is to fit the fiberglass tips to the horizontal and vertical stabilizers and to the rudder and elevators as well.  The first step is to fit the tips relative to each other such that they are even on the outside edge and in alignment along their chord line.  A notch is made to clear the lead balance weight.

 On the forward end of the elevator tip there was a gap between the lead balance and the inside of the fiberglass tip.  I used epoxy mixed with 3M micro-spheres as a filler.  The micro-spheres are teeny weeny glass balls that are hollow and take up a lot of space when mixed with epoxy.  This makes a very light weight filler material called 'micro' in the aircraft builder's community.  The micro is the white colored material in the photo below.  One shouldn't miss the opportunity to chuckle at the irony of light weight filler bonded to a lead weight.

I have decided to smooth the transition between the fiberglass tips and the aluminum of the stabilizer with a strip of fiberglass and a very thin coat of glazing putty.  Although I am familiar with auto-body repair and fiberglass techniques, I was offered a chance to learn from a master builder from my local Experimental Aircraft Association chapter.  I visited Keith Peterson's shop and was treated to fiberglass 101.  We fit and glassed on the rudder top tip in a few hours, and in the process, I was given the information essential to continuing on my own.  Thanks, Keith.

To facilitate bonding, the fiberglass gel coat on the tip is roughed up with #40 grit and the aluminum with #80.  I'm using West System's 105 epoxy and 206 hardener.  Two strips of 9oz fiberglass cloth are cut the length of the tip and a thin layer of epoxy is painted on to insure complete coverage beneath the glass strip.  Then the glass is laid down and the brush is used in a stippling fashion to remove all bubbles.  The glass is completely 'wetted', but just barely so.

Once the epoxy is cured the fiberglass is smoothed out and blended down to a feather edge.  I used #60 grit for this process before the final step of applying a light weight glazing compound to smooth the transition even further. 

It would be difficult to overstate the tedium of working with fiberglass were it not for the sheer bliss of not having to think too much.  Lots of sanding and filling, sanding and filling.  But it's not particularly difficult and  I was ready for a break from the interpreting of plans thing anyway.  I find that a lot of my time goes into just standing in front to the plans set and I'm definitely enjoying my vacation from that.

So at the time of this posting, I've completed the rudder tips and one elevator tip, with the vertical and horizontal stabilizer tips still to go.

The big news is that I have received my first technical inspection from EAA 1175 technical counselor, Miles Bostic.  I am pleased to report that there were no issues.

Oh, and one more thing, I have received my wing kit...