Wayne/Gary:
Before I got into major surgery, I decided to get an idea of the size of
this leak, so I'd know how long to test it before I decided it was fixed. I
put a balloon on the inlet, blew it up as hard as I could with lung power,
and let it sit. It's been there for four hours with no visible change in
the balloon, so we're not talking about a big leak - certainly nothing light
would shine through.
Now, thinking about it, the only time I noted the leak was when the airplane
was in the hangar over the winter. The tank was full. So perhaps (a) the
leak is at the top of the tank, and (b) it's so small that in warm weather
the gas evaporates before it becomes visible. It's even possible that the
leak has always been there, but is small enough that the balloon test does
not detect it over 24 hours.
So I'm starting to re-think this thing. My idea is to operate the airplane
over the summer as is. The season is short enough, for sure. I'll use the
time to try to characterise the leak. I'll start by filling the tank half
way, and see if there's any sign of a leak. I'll then add gas in 5 gallon
steps, and see if and when the leak shows up. If it is near the top of the
tank, I may even live with it, by only filling the tank immediately before a
flight, and running off the leaky side for the first hour.
At the end of the season, I can take the wing off and work on it over the
winter in a heated area, if I decide that it's troublesome enough to be
worth the bother.
Does this make sense?
Al
-----Original Message-----
From:
mike.davis@dcsol.com [mailto:
mike.davis@dcsol.com] On Behalf Of Gary
Gustafson
Sent: Thursday, May 27, 2010 4:26 PM
To:
rebel-builders@dcsol.com
Subject: RE: [rebel-builders] Fuel Leak
I did use a 50/50 mixture of toluene and MEK. I did slosh MEK inside
first and let it dry for several days. The Proseal/MEK/toluene mixture
was a bit thicker than engine oil but not by much. It flowed slowly. I
used a small cup on a rod to transport a bit of the mixture to each
section and had the wing tilted so that when I poured the mixture would
land just above the rear J panel. Once I sealed the opening in the rib
next to the fuselage, I applied 4 PSI to the inside of the tank (measured
with a water menometer for about 5 hours. I do not know how long it
will last as I did not scuff up the areas where the leak(s) were
occurring.
However, I would listen to Wayne as he has had much more experience than
my one patch. Mine did not leak much and I could see no light from the
outside when a small LED flashlight was inserted on a rod. My wing tanks
passed the pressure test (glove inflated for 24 hours) but have now
developed weeping leaks that take a day to notice. I have noticed that
the doors initially opened and closed easily and now stick or are hard
to close. Which leads me to wondering if the plane 'settles' or moves
slightly as it is broken in. The other thing is that I wonder if the
leaks in the tanks could have developed via thermal expansion and
contraction here in the hot Florida sun.
-----Original Message-----
From:
mike.davis@dcsol.com [mailto:
mike.davis@dcsol.com] On Behalf Of Alan
Hepburn
Sent: Wednesday, May 26, 2010 8:58 PM
To:
rebel-builders@dcsol.com
Subject: RE: [rebel-builders] Fuel Leak
Thanks for this. I have no visible leaks, so I figure it must be somewhere
on the rear bulkheads. I had thought about putting an access plate in the
root rib as you describe, but I'm wondering why you wouldn't just stand the
wing trailing edge down and pour about a pint of diluted Proseal through a
tube towards the rear bulkheads, then move the tip up and down and the
leading edge backwards and forwards. Then pump off the excess Proseal and
ventilate it to evapourate the excess solvent. I'd also planned to use some
gentle pressure to try to force the stuff into the leak. How long did it
take the Proseal to cure? Did you use the same 50:50 toluene:MEK mix, and
how thin did you make the sealant? I'm thinking about like engine oil. I'm
told you should rinse the tank thoroughly with MEK first.
This leak appeared after about 4 years in service. I've tried looking for it
with a flexible inspection camera through one of the flap hinge access
covers, but can't be sure of having seen the source.
Al Hepburn
-----Original Message-----
From:
mike.davis@dcsol.com [mailto:
mike.davis@dcsol.com] On Behalf Of Gary
Gustafson
Sent: Wednesday, May 26, 2010 7:31 PM
To:
rebel-builders@dcsol.com
Subject: RE: [rebel-builders] Fuel Leak
I would go with Proseal diluted with 50/50 solution. It is a heck of a
job to de-rivet. What I did was cut a hole into the rib next to the
wing, made a cover along with two doublers to cover the hole, then
poured the diluted Proseal mixture near the rear spar in each section
and tilted the upside down wing at an angle so that te Proseal would
run down to the trailing edge where the spar and skin come to gather
while alternating lifting the wing tip and the fuselage end of the wing
to ensure an even flow. I then Prosealed both doublers and riveted
them in place, then Prosealed around the cover plate and riveted it
in place. No leaks from the top trailing edge or the access plate
that I riveted in. However, after about 2 weeks of flying the top
outside edge near the filler cap started to weep (gradually seep out
over a 24/48 hour period). I mention this as one might put the diluted
Proseal all around the top edge of the tank.
Good luck
-----Original Message-----
From:
mike.davis@dcsol.com [mailto:
mike.davis@dcsol.com] On Behalf Of Alan
Hepburn
Sent: Wednesday, May 26, 2010 7:03 PM
To:
rebel-builders@dcsol.com
Subject: [rebel-builders] Fuel Leak
Well, I just got back from playing ring around the volcano on a
Transatlantic trip. Delivered four airplanes (not Murphies) safely to Paris
on schedule. So no I'm trying to figure whether to slosh my leaky tank with
Proseal diluted with 50:50 toluene/MEK, or de-rivet the rear lower skin at
the TE and try to localize the leak. What would you do?
Al
-----Original Message-----
From:
mike.davis@dcsol.com [mailto:
mike.davis@dcsol.com] On Behalf Of Wayne
G. O'Shea
Sent: Wednesday, May 26, 2010 5:27 PM
To:
rebel-builders@dcsol.com
Subject: Re: [rebel-builders] Rebel / Elite - Dipstick clearance on
Dynafocal mounts
Hey Al !!! Where the hell ya been??? ;O)
----- Original Message -----
From: "Alan Hepburn" <
g.alan.hepburn@gmail.com>
To: <
rebel-builders@dcsol.com>
Sent: Wednesday, May 26, 2010 4:46 PM
Subject: RE: [rebel-builders] Rebel / Elite - Dipstick clearance on
Dynafocal mounts
My mount was wrong and Murphy replaced it - but that's about 5 years ago.
Al Hepburn
-----Original Message-----
From:
mike.davis@dcsol.com [mailto:
mike.davis@dcsol.com] On Behalf Of
Wayne
G. O'Shea
Sent: Tuesday, March 23, 2010 11:45 PM
To: Murphy Rebel Builders List
Subject: [rebel-builders] Rebel / Elite - Dipstick clearance on Dynafocal
mounts
Someone asked if it was a common issue that his dipstick tube was hitting
the mount a while back....
.. .. so while bolting up the latest (O-320-E2D) engine installation
today,
I took a picture after everything was tightened up.
This has been the typical clearance on every Dynafocal engine I've mounted
to a Murphy made mount. About 3/16 to 1/4"....so not sure why the fella
had/has issues.
http://www.irishfield.on.ca/gallery/dip ... omount.jpg
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