Rear Vertical Fin/Fuselage Modification:
Rear Bulkhead and Vertical Fin assembly. I had the unfortunate pleasure
of experiencing a problem with the vertical fin and rudder system. One of
the hinges had popped
loose and started to flutter the entire right vertical fin on a high speed
fly by. I managed to land the aircraft without any further damage. The whole
fin was violently swaying back and forth on the fuselage, so I had presumed
that it was completely dislocated. I found out however that the fin was
completely attached to the fuselage still. The fuselage where it had attached
to the rear bulkhead had come loose and the fuselage was warping back and
forth during the flutter in flight. Small cracks in the joint ( fin and
fuse) were repaired with epoxy and a syringe. I had placed 1/4 wooden dowels
pegs to help anchor the fin when I constructed it originally and they were
still in place and holding well. I would suggest doing the same for your
bird as well, if they weren't there, the plane would have been history.
I reattached the rear bulkhead to the fuselage with an epoxy fillet and
then laid 2oz glass strips across that to secure it all in. I also drilled
and pegged the vertical fin spar to the bulkhead as well, it was just epoxied
before hand. Ahead of the rear bulkhead, I crisscrossed 4oz glass/carbon
cloth strips about 1 inch wide and about 5-6 inches long, from the side
to the center of the fuselage. it is now a lot stiffer than it was. The
whole area back there is not very deep, in fact is very shallow, no more
than half an inch or so. So you have to reinforce with out adding weight
and bulk.
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