REFLECTOR: Trim Spring and Triax

[pamberg@ibm.net]

OK Here's my 2 cents, one way to establish the correct width of the
elevator trim spring is to have all the elevator components assembled
and with the canard in the fuselage or perhaps set up on some saw
horses.
If you look up old reflector notes or talk to Scott you will hear that
you should have about 1 inch TE down travel with approx 16 to 18 pounds
of force applied to the elevators. First you need to establish a method
of measuring the amount of deflection, I simply taped a ruler from the
canard wing tip and set it up so that I could see when the elevator
moved an inch.  I used 2 plastic 1 gal containers that had about 8 lbs
of epoxy remaining in them, using filiment tape to distribute the load
across the TE of the elevators, I created a "fan" shape over the top of
both elevators and allowed 6 inches of tape to hang over the TE. Then by
"gathering" these together I simply wrapped them around the handle of
the bottle. So now you have 16 lbs pulling down of the elevators, and
you can measure the amount of deflection. At first with the full width
of the original spring this moved a half inch or so. Using a die grinder
or what ever you have you'll need to narrow the width of the spring, 
going from side to side until you get the spring weakened enough to get
the full 1 inch deflection. Since you are doing this "real time" you can
constantly monitor when you've gone far enough.
I looked at a number of springs and they vary quite a bit from plane to
plane. Some were clearly less than half an inch wide. Mine is probably
closer to 1 inch. 
Just make sure that you remove material evenly on  both sides and taper
as you get closer to the ends, so that the stresses get distributed  to
the attach points.

Now on the issue of triax, a simple rule would be to apply it so that
you see the uni bundles when it's applied. That is the only way I know
to see  if you get a lot of kinked fibers. Plus it lays "flatter" on the
surface it's being appied to, if the uni bundles are against the
bulkhead or whatever, I pretty sure that you would be trapping more
epoxy back there inbetween the bundles. Which brings me to my final
thought. Use peel ply where you know you will have a secondary layup,
and use it on the edges to prevent the meathooks, but don't cover an
entire surface, one reason as previously stated is that you won't see
air bubbles, but I'm convinced that you actually hold more epoxy
inbetween the uni bundles adding more weight.
Maybe just one more thought, Plan ahead look at other peoples work as
much as you can, I've been lucky to have been building in Florida, where
there are so many to see. But rather than use a lot of peel ply and have
a bunch of secondary bonds, I come from the school of thought that wants
to put in as many "wet" layups at one time to get true molecular bonding
and not worry about how well I sanded before putting on another layup on
top of another.  I feel that this can be particularly true when you put
in the massive gear bulkhead layups, and in the installation of the
canard bulkhead/ front gear layups and keel.