The question below and Scott's answer explains very plainly and graphically
why hinged attachments using Carbinge is the best answer for cowl fastening.
Shameless plug, but experience - Scott's in this case - is often the best
teacher.  

www.carbinge.com

John Barrett
Leading Edge Composites

Rob, et al,
 
I use SS camloc devices from Skybolt.  There have been 2 issues:
 
1. Camloc style fasteners are spring loaded and do not provide a rigid
attachment even though I used a little tighter spacing than the plans called
out.  The combined positive pressure in the cooling plenum and the low
pressure over the top of the cowling puts a great upward strain on the
cowling.  I have frequently found bug residue in a half inch sliver on the
top face of the cowl because it did not stay in line with the spinner.  I
have somewhat resolved this problem by epoxying small phenolic blocks to the
top inside of the cowling that are stops against the fuselage upper forward
deck joggle leading edge.  This has reduced the ability of the cowl to lift
up and slide back on the upper fasteners.  Myself and others have had to
reinforce the bottom center most holes in the cowling after in flight strain
has worn those holes.  
 
2. Most of my original Camloc SS fasteners were installed with pinch washers
whose fingers firmly held the camlocs in place in the cowling.  When I
replaced these with the Skybolt SS equivalents, the fastener body was made
of much harder SS and the pinch washer fingers could not hold them in place
(could not grip the body).  I was forced to use the split washers that allow
the Camlocs to pull back out to the latch pins in the tip and thus
contributing to paint wear and chipping around the holes.
 
Were I to build another cowling, I would prefer a more rigid set up - either
by making some use of hinge-type fastenings or better and tighter fasteners
(whatever those might be).
 
Scott Krueger
 
In a message dated 4/27/2009 6:51:57 P.M. Central Daylight Time,
rwolf99@aol.com writes:
Tw years ago I asked a group of three aircraft designer / builder /
manufacturers which were the best fasteners to use for my Lancair cowling.
These guys were:

Carsten Sundin (of Lancair fame)
Chuck Harrison (Composites Universal in Scappoose Oregon)
Mark Bettosini (AirBoss Aerospace)

They all said the same thing, in unison.  "Skybolt Fasteners"

I have read Brent Regan's discussion of LiveLock fasteners and I'm certain
that they are very good.  My recollection was that they were far more
expensive than Skybolt with marginal extra "niceness" (yeah, that's a
technical term...)  This is the Tridair offering, is it not?

As for Camlocs, these are the originals and will certainly do the job, but I
think the Skybolts look nicer.  I did not want to save an insignificant
amount of money for something that would be so readily visible to a
non-aviator that was already nervous about riding in my "toy glued-together
airplane".  Those types judge the workmanship solely by the appearance of
the paint and interior (we all know better, right?) so I figured they would
benefit from the shiny fastener...

Your mileage may vary.  All of them will work.  Read Brent's missive on the
Livelocks in the archives and choose for yourself.

- Rob Wolf
(Cowling presently held on by clecoes...)