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Here it is in more detail.
Top cowling front spinner plate area was reinforced on the back side with
straight graphic fibers around the radius (Additional graphite fibers at the
center of the flange area where the most bending and flexure might occur. in
the inside corner covered with a 2 inch wide bid of graphite cloth around
three bid cut on the bias as our other bid tapes. Half of this bid was
attached to the backside of the spinner flange area over the graphite fibers
and the other inch to the underside of the front cowling. The right angle
three bid adds tremendous rigidity to that semi circle area thus avoiding
any flexure and diameter expansion which could occur when laying down the
cowling on the floor or other reasons. I needed to do this as the flange
area was split caused by hanger rash in storage. An obvious weak area.
Also wrap extra bid between the spinner area and the air intake area as
another flexure area. I used staggered three bid in this area. Results are
the cracking observed on other cowlings in these areas and that were present
on my cowling from hanger rash are not present now after 230 hours.
Yes, I went around the 180 degree arch with additional bids but applied more
bids on the top portion of that arch where the cracking appears most often.
Cracking around the front two cylinders are showing as per other postings on
this site. Clearances are about 1/2 inch so that heat and vibration and
perhaps occassional contact in high G maneuvers have cause cracking and
bubbling of the glass. Unfortunate but realities of lessons learned.
Bob Smiley
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