Rust prevention: Inside fuselage

"Michael Horowitz" wrote

It's a rag and tube a/c and we're talking holes in the steel.
I can send you an illustration via e-mail showing the hole in the
landing gear strut if you're interested - Mike

That goes against convention, for rag and tube aircraft, from everything I
have read.

The tubes should have holes at joints, so all of the insides of the tubes
are connected to each other. All of the tubes should not be open to the
outside air. That is the only way that rust inside of the tubes can be
prevented.

Linseed oil is (one of the most popular things) used, because of the ability
to coat the inside of the bare metal tubes, and because the oil oxidizes
(binds with the free oxygen) and that leaves an environment inside the tubes
that prevents the steel from rusting. If you are capable of keeping the
inside without free oxygen, there can be no oxidation (rusting) of the
tubes.

Some aerobatic rag and tub aircraft have a air fill valve, and a pressure
gauge where it can be checked at every pre-flight. It is then filled with
some gas, like nitrogen or argon. If the pressure is lower, or at
atmospheric pressure, there is a crack somewhere, meaning that it might not
be structurally sound, especially for high G loads.

I think you have some decisions to make, as how to proceed with your
airplane. It would seem to me that you need to be able to see if the tubes
are still sound, and that you need to seal that sucker up and coat the
inside with something.

JMHO.
--
Jim in NC