Thursday, March 6, 2014

Vertical Stab Fairing

Yesterday and today I worked on the forward fairing for the vertical stab.  I installed the forward portion of the vertical stab.  I held the PVC fairing in place and marked the location of the holes. The 2-forward most holes on each side of the vertical stab fairing will be used to hold the small PVC fairing in place.  I drilled the holes and used the squeezer to countersink the holes for the flat head screws used in that location.  I installed the small PVC fairing.  The forward most holes squeeze the forward part of the PVC fairing in and it looks bad. 
I removed the 2-forward most screws and began to consider various solutions to the problem of how to attach the PVC fairing without deforming it.  I considered attaching some kind of aluminum bracket to the top of the fuselage and then putting a screw down through the top edge of the fairing to hole it in place.  After working with some scrap aluminum and attempting to make 2-different brackets I decided that was not a good solution.  The problem with the fairing is it is too wide at the forward screw attachment points.  I considered stacking some washers between the PVC and the aluminum fairing but that seemed to be a difficult solution.  What I decided to do is mix some body filler and put a dab inside the PVS fairing at the forward screw holes to form a spacer inside of the fairing.  I installed the forward most screws in the aluminum fairing and taped some plastic over the fairing.  
Next I mixed some body filler.  There are a couple of very minor dents in the aluminum skin.  One on the top of the left wing and one on the top of the right half of the stabilator.  I sanded the dents with a Scotch Brite pad and filled them with body filler.
Next I put some filler on the inside of the forward screw holes on each side of the PVC fairing and installed it over the aluminum fairing.  The filler material oozed out of the holes so I am sure there is a good spacer formed on the inside. After the filler has cured for a day I will remove the fairing and redrill the forward holes and see how it fits on the airplane.  By installing the 2-forward most screws on each side of the fairing it will be securely attached to the airplane.
While at the hangar yesterday I also drilled the hole in the wing for the AOA sensor.  I will install the sensor (a ball inflation needle) on the wing and hook up the 1/16th inch plastic tube that runs to the instrument in the fuselage.