Re: Gluing them wings & a fuel system question.

One Sky Dog

In a message dated 4/14/2002 3:30:19 PM Mountain Daylight Time,
rayners@... writes:

Al, thanks for your informed comment on decalage and the fuel system
plumbing. I will follow your advice in both cases - well mostly anyway and
maybe completely after another question.

I am pleased you suggested hard lines for the fuel - I'm not happy about
plastic tube in the cockpit and would be pleased if someone could suggest an
alternative to the header tank sight tube. I have replaced main tank float
with an electronic one so it's removed that possible risk.

Surprisingly when looking through some early QBA mags, I found an article in
issue# 35 by Gene Cash. It said use Versatube - no question and the 3/8" AN
fittings. I do have a question though and it is - doesn't Al tubing
eventually fatigue harden and possibly crack? A/S also supply copper
tubing, wouldn't that be better - heavier I know, but there isn't much and
if it avoids a risk of cracking - that's good surely? Is there a down side?

To me, as a builder and new to some of this stuff, being able to seek advice
from you guys who have done and lived with their handiwork for many
(sometimes) hours flying - is worth a great deal. It's the reason I keep
reading all the messages and post some every once in a while.

PS. I'll be trimming to 0-0 with the wings.


Chris Rayner (compiling a shopping list for Aircraft Spruce - again!)

As a data point my Dragonfly 1989 was plumbed with both Al tubing and clear
plastic tubing. Aluminum looks really impressive and the cost is also
impressive, however unless the plumbing is supported just like in the real
airplanes to avoid stressing it, it will fatigue crack and break off. I
wondered where that strong gas smell was coming from after I fired it up. The
plastic turns dark and gets brittle and breaks.

The SAE fuel rated cloth reinforced DOT approved NAPA rubber fuel line has
replaced both in my airplane. For corner runs I put a light spring over the
tube so it cannot collapse. If that is not good enough check out the flexable
hose and fittings for fuel injection applications. 70 psi and the clamps are
rock solid.


One Sky Dog

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