One way you can fix a leak is:
If it's physically small and you can isolate its general location...
Mix up some runny micro. Smear it over the area. Pressurize.
The pressure will force the runny micro into the hole. After it
sets, recheck. Repeat as needed. I used this approach with vacuum in
sealing some pinholes in my fuel bays. There I just used runny epoxy
since the holes were multiple, but very small individually.
Ted Noel
N540TF
On 9/19/2013 7:43 AM, John Barrett
wrote:
Many of you have supplied very useful tips in response to my
questions. Since then I've found some substantial leaks that
are probably the issue. I wonder if others have had leaks in
the tunnel under the spar box that hydraulic and fuel lines go
through? I have a significant one here and I fear I will have
to stop it in order to get adequate pressurization. Has anyone
else dealt with this after the lines are all in and the a/c is
flying? I think I can seal up the tunnel front and back but it
will likely take a good bit of some kind of goop to do it.
Thanks for any advice.
John Barrett
Hi John,
Attached is a pic of the wedge. I used controller rather
than outflow valve throughout my first posting on this.
Outflow valve is a better description. You interpreted my
suggestions correctly.
Here is a pic of the wedge. Length from the bend is 4".
The slot is 7/8" wide and the short angle section is 1". The
overall width is 4". The slot is 2.5" deep. The piece is
scrap from something on a IV..... sorry I have forgotten
what but hopefully it is still lying around your shop. the
other two bits are what I used to set the tension holding
the outflow valve closed.
I noted a suggestion that you block off the outflow valve
tub from the top and fly the airplane. Keep in mind that the
over pressure pop off valve will also be disabled if you do
this since if is normally in the tub. I would double check
that you can't over pressurize the cabin and damage it
before trying that suggestion. I assume but don't actually
know that the pop off valve protection is required if the
outflow valve jams closed.
My mixing box came from Lancair with the pressure dump
and temp mix levers only partially tightened. One of my
early discoveries was that the pressure dump flapper worked
intermittently until I tightened the lever securely. You
have either a big leak, bad outflow valve, or leaky pressure
input to the cabin if you are only getting 1/2 PSI. I was
able to get 3.5 PSI before I found my last significant leak.
It was easily found with two shop vacs but not with one.
Hope this helps.
Jack
<IV Pwedge.jpeg>
On Sep 5, 2013, at 6:01 AM, Lancair Mailing List
wrote:
Subject: IVP pressurization
Date: September 4, 2013 7:42:10 AM EDT
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