Folding Tail Fairing
By Tony Burton
I’ve been folding and unfolding the tail of my RS-15 for 22 years with no significant problem. I see two possible sources of excessive wear:
1. During construction the taper pin hole of the upper pin was not reamed with the axis of the reamed hole lined up with the front spar bolt.
2. Too much tail movement available when folded in the trailer.
I finally had to fix a little excessive wear two winters ago—and it was the *front* spar bolt hole that had got slightly out-of-round allowing some fore and aft slack in the fin. This was fixed by carefully drilling out to the next largest *metric* bolt size (only a few thou more than 3/16").
By the way, a significant amount of tail taping hassle can be eliminated if you build a glass fairing permanently affixed to the fuselage. Advantage -- nice double-curved fairing, one piece of tape. Disadvantage—front spar attach bolts harder to access.
Short description of method:
1. Fill space between fin and fuselage with temporarily glued layers of hard foam.
2. Form to pleasing shape with slight recess at fin edge.
3. Remove fins and glass the foam (including the area between the top and under-surfaces) using some release material on fuselage surface.
4. Remove the glassed foam, chew away foam from glass, beef up inside of glass where required for strength.
5. Bond fairing to fuselage, fill, smooth, etc. A short (1/2") narrow slot has to be cut in the fairing to give clearance for the front spar folding. The slot can be ¼" wide or so which can be covered with a bit of tape.
A removable panel will have to be made at the top rear of this fairing for access to the taper pins. I made mine out of a piece of aluminum attached by a couple of screws into two tabs with captured nuts. It all looks very sexy and your old floppy fairings and box of tape can be tossed.