Saturday, June 27, 2015

Preparing F-1294A&B Tailcone Fairings For Drilling

The morning rains subsided during the afternoon which made it possible to cut and trim the F-1294A&B upper and lower tailcone fairings outside ... so as not to get fiberglass dust all over everything in the hangar. In addition, a little cutting was performed on the vertical stabilizer’s fairing as well.

Bolted up the rudder to the vertical stabilizer and checked the clearances between the VS-1213 stabilizer tip fairing and the R-1206 rudder tip fairing. Holding the upper bolt while inserting it into the bearing can be tough because there is not much room for fingers in the small opening on the rudder. A tactic I came up with that fellow builders can use to place bolts into tight places is to use a small piece of vinyl tubing with a long wire tie to grab and hold the bolt. When the bolt is inserted into the destination the wire tie can be pushed back through the tubing freeing the bolt.
A wire tie looped through a piece of vinyl tubing does a great job of allowing a bolt to be held while being inserted into a location too tight for fingers to easily maneuver.
Using the previously mentioned vinyl tubing & wire tie to hold a bolt so it can be inserted into the upper rudder bearing.

After the rudder was mated to the vertical stabilizer, the VS-1213 fairing was trimmed to the point that any tweaking will be done after the fairing is riveted in place to obtain a nice finished fit.

Moving on, the F-1294A&B upper and lower tail cone fairings needed to be cut and trimmed then sanded down to the scribe lines imbedded in the fiberglass. The Dremel outfitted with a cutoff wheel cut through the fiberglass like a hot knife through butter. Extra material was left beyond the scribe marks in the fiberglass and a Dremel with a sanding drum was used to get close to the line … hand sanding with a sanding block finished the process.

A time consuming error on my part …. typically, I make it a point to read ahead to obtain a better understanding of where things are headed.  Today was one of the rare times that I did not read ahead, and it cost me quite a bit if time. Basically, I left the upper and lower F-1294A&B fairings a little long with the exception of the forward edges that meet up with the tape lines on the tailcone. The thought was I would be able to make a fairly tight fit in the areas where the upper and lower fairings meet (and that was accomplished).

The F-1294A&B upper and lower tailcone fairings cut slightly beyond the lines so a tight fit could be (unnecessarily) achieved.

So the fairings were on and off, and on and off, quite a few times as the fit was slowly tweaked by hand sanding. After achieving, for the most part, tight fits all the way around with just a tiny gap in one area, I began reading ahead a little and came to realize all the time spent trying to achieve an O.J. Simpson glove fit was unnecessary. The plans instruct the builder to obtain a good fit, then drill the mounting tabs … after the mounting tabs are riveted in place, the areas where the two farings meet are to be filed to create a 1/32" to 1/16" uniform gap. Gee, I had that almost from the very beginning.
F-1294A&B upper and lower tailcone fairings were aligned to the red forward lines on the masking tape, then clamped and taped in place. The fairings are now ready for drilling of the mounting tabs that will secure the two halves together.