I used 1/8" bore nylon tubing from a compressed air fitting supply
company (ASI Airflo in Sheffield) when I retrofitted the XS pitot to my
classic wings. I needed the small diameter to fit in the classic flap
close out corners. The tubing works well - there is no lag in the ASI as
I thought there might be and, being nylon, it is much tougher and likely
to last longer.
Apart from having a larger bending radius than PVC, which is not really
a problem, I found it difficult to find suitable fittings to connect it
to a short length of PVC tubing at the ends. (PVC tubing is necessary at
the ends to slide over the barbed quick - connect fittings). There are
commercial "olive" fittings which terminate with a 1/4"? NPT fitting -
but these are quite bulky. I found that heating the nylon carefully with
a heat gun and using needle nose pliers as a reamer it was possible to
enlarge the nylon tubing end sufficiently to be an interference fit on
1/8" bore brass tubing. In effect the brass tubing forms the join
between the PVC and the nylon. I covered the entire joint in heat
shrinkable adhesive lined tubing (from Maplin) and produced a small,
neat, airtight joint.
If the PVC ends subsequently age, harden and crack I will simply cut
through the adhesive shrink down tubing and remove the pvc at the brass
tubing.
Regards
Roger Mills
141
-----Original Message-----
From: forum-owner@europaclub.org.uk
Subject: Tubing to Pitot Head
I'm just about to fit my pitot head to my wing and I remembered that I
had seen something on the forum regarding doubts about the longevity of
the PVC tubing supplied to connect to the pitot head assembly. Looking
through the forum archives, there seem to be two trains of thought:
install a larger bore tube in the wing so that the pitot tubing could be
replaced if necessary or find a better tubing with a longer life. I am
inclined toward the second option, but I would like to know if anyone
has done that, particularly in the UK, and if so, what tubing was used
and where did you get it?
Cheers
Rick Sivier
|