In article ,
Stealth Pilot wrote:


btw dont be beguiled by the semantics.
the glue strength doesnt change with the glue area since it is a force
per unit area measurement.
the glue area directly changes the amount of total force that the rib
fabric join can stand.
a pound per square inch strength applied to a square inch can hold a
pound
a pound per square inch strength applied over a square foot can hold
one hundred and fourty four pounds.

Stealth Pilot
Australia

I'll bite into this topic from an intellectual curiosity perspective.
What are the forces acting on a rag plane that would tug against the rib
bond? Source? Direction? Magnitude? How common are such bond failures?
What is the cause? Poor surface prep or other application shortcomings?
Deterioration of the glue or fabric over time? Other?

If I take a 3" long piece of tape and stick it on my desk, and a 12"
long piece and stick it next to it, does it take more force to peel the
longer one, or just more time? I'd say a wider one would stick more
assertively, but not a longer one. Is this at all analogous to what's
going on in an airplane, or way off?

Has this been studied like wing loading, with safety margins built in?
Does an airplane fall out of the sky if the fabric starts letting go? I
guess eventually it would, if pieces started tearing and departing the
airplane. That would disrupt the airflow, I imagine. There was a
discussion of punch testing a short time back. Is there also a "pull
test" to see whether the glue bonds are getting ready to fail?

These are the things that I think about while I struggle valiantly to
smash two rivets to the same shape and size.