On Fri, 21 May 2004 00:49:17 GMT, Richard Lamb
wrote:

And you glued eight yards of fabric to a wood skinned wing?
How did that turn out? Real smooth, huh?
Ah, question? How are you going to iron it out?
If the glue releases at 250 degrees,
but the fabric needs 350 degrees to reach working tightness???

I can answer that question, or at least give an example of something
very similar. The double covering technique, which was developed for
extremely high power and big propped aerobatic airplanes like the
Pitts model 12, involves laying the top layer of fabric on top of the
initial layer and rolling polytach on top of it. You put it on thick
and roll it through the fabric. You can see that it's saturating the
fabric when you do this. The top layer of fabric is usually the same
weight and weave as what you use for tapes, and in effect is one
gigantic tape.

Then you iron the top layer using a 250 degree temp iron. This is
enough to smooth things out and eliminate any bubbles or slight
ripples. Using the rolling on technique, there aren't many
imperfections to correct.

As mentioned above, this process is being used on extreme machines,
but has also been applied to three Beech Staggerwings with a field
approval. You end up with a very very smooth covering and very close
to the the same weight as a covering using traditional tapes and
filler.

Corky Scott