Stab Farings

This blog covers the installation of the intersection fairing for the elevator and rudder.

Installation

Trial fit of the rudder and elevator stab fairings
Note: Components have been trimmed to factory guide lines

Trial fit of fairings

Both factory supplied fairings were trial fitted onto the starboard side but the builder could not work out how the intersection was to be created. 

The factory replied that the fin fairing was installed over the elevator fairing but again an acceptable method of assembly could not be found.

After much thought it was decided that the best way forward would be to make the components fit by placing the rudder fairing under the elevator fairing.

Work started on fixing each component onto the airframe before undertaking any modifications.

Masking tape was applied over the areas to be marked allowing an installation scheme to be developed and with rivets securing the skin to the ribs on the same line care was required not to drill at or near a rib flange. This issue arose at the lower side resulting in two broken drills

It was decided to install the mounting points on the rivet line for the rib starting at the nose rib centering about rivet group [pitched @ 30 mm], then pitching the other holes at 90 mm along the top side. The location off the holes in the fin is a projection of the location of the holes on the elevator. 

Ruler

With all the marking out the most useful tool proved to be a cardboard ruler. This was made from a piece of scrap cardboard with a base at 90 degrees and pitches at 10,15,20,30,40 and 90 mm.

The bottom side was more difficult but in general the same philosophy was followed but with a slightly more uneven distribution based on the restrictions created by the rivet locations on the underside.  

Fixing point currently selected with all parts fixed with 3/32'' clecos
Underside shown at the top of image

Note: Do not attempt to drill in the area of the skin line seen running through
the hole without a cleco - it intersects with the stringer and just breaks drills
This single line defines were the fixings cannot be installed

Marking out the port side using the starboard fairing - rivets on nose
ribs located on rib rivet center line

Note: Approx location of the rivets [circles] - location is
about rivet group center seen in gap between to tape runs.

Stab clecoed to turtle deck at a pitch of 90 mm
starting at the nose

Intersection of elevator faring was cut to allow it to be brought into contact
with the fin faring, this area is glassed with 100 mm tape x 5 layers

Note: Two [2] 1/8'' clecos installed to hold the loose components
onto the fin faring

Comment

All the trimming used a Dremel motor tool with a extension shaft with a quick change plastic disc. It was found that discs marked for plastic set at about 15000 rpm gave the cleanest cut.

Sanding was all done using 80 grit aluminum open cut paper and a flat hard sanding board.