was prepped, cleaned, etc. Did a bare hand pick up the tank skin? Did you
seal both the tank skin to the spar.. as well as the tank skin to leading
edge skin? When I do them I put the sealer around the permimeter of all the
tank parts (ribs, bulkheads, stringers, etc) and then on the tank skin I
coat the outside face at the main spar so it's ready when I slip it under
the leading edge.
I presume you put the bottom skin down first... and if so did you then get
inside and "butter" the sealer between the tank skin and the spar flange?..
as well as fillet everywhere inside the best you could?
Since you know the bottom skin is an obvious leaker.. and especially with it
leaking out through the main spar... I'd drill off the bottom tank skin....
build the "bath tub" out of the ribs and top skin having it all perfect to
put the bottom skin down again and then take a shot at putting the bottom
skin in place again, making sure that the scotchbrite x hatch comes out at
least 1/2" past the skin to spar flange overlap so it has room to bond well.
This all assuming you noticed no leaks at the top skin!! There's only two
stringers in the bottom... four in the top so that many less rivets doing
the bottom.
My fear if your front spar seam is leaking, which should be the easiest one
to seal up, how well did everything else seal?
I don't even bother with the extra rivet between each, as shown in the
manual, for the main spar and the root and outboard tanks. I just see them
as double the number of rivets to leak through and lack of these "holes"
hasn't caused me any ill effect on pressure tight tanks. (note this is a
Rebel manual thing for sure... I can't remember what the SR spelled out)
Here's a link to my current rebuild of a set of Rebel wings I'm in progress
on. I'll send you some pictures directly of the SR tanks I built in 2001
with less than a single can of PRC per tank.
https://www.facebook.com/media/set/?set ... 2f4b4f80dd
Wayne
----- Original Message -----
From: "Jerald Folkerts" <jfolkerts1@gmail.com>
To: <rebel-builders@dcsol.com>
Sent: Saturday, January 28, 2012 12:22 PM
Subject: [rebel-builders] Fuel Tank Woes in Missouri
Probably for Wayne, but anyone please jump in.
I'm building an SR 2500, stock Super Rebel with an extra
fuel bay (four bays total). Yesterday, I tried the balloon test on my
almost completed right wing and couldn't get the balloon to stay inflated.
I pretty well isolated the problem to the bottom corner near the fuel
filler
cap, in the first bay outside the tank (top wing skin is still removed)
near
the spar. I added approximately 10 gal of water to the tank, and yes,
found
water seeping out between the wing/leading edge skin and the bottom spar
flange in the first bay outside the tank. Next, I took my air gun and put
it next to the wing skin and spar flange while looking through the filler
cap with a flashlight. I had bubbles in four locations along the
spar/bottom tank skin mating area in the first bay. The last set of
bubbles
was next to the first rib over, so I have to assume I have a leak in the
next bay over as well. For some reason, I must not have good adherence
between the tank skin and the spar flange. Before assembly, I cleaned and
scotchbrited everything with good cross hatching etc. Perhaps I had an
area
such as the spar flange that never got sufficiently cleaned or something.
Don't know. I trusted the proseal, and there was an approximate 1/8" bead
evenly across the flange where it flowed out during riveting - perhaps too
much squeezed out? I didn't filet it up any more than that. I did cover
the rivet tails.
So, I have the top and bottom tank skins riveted on with a
problem on the bottom skin. Of course, the leading edge is also riveted
on
in the tank area. I have two access panels, already riveted on the bottom
in the 1st and 4th bay. Ted recommended I cut holes in the upper skin,
clean with dremel and roloc pad etc., then add a large filet where I have
the leaks. In looking at it, I don't believe I have sufficient access
between the stringers to get much of a hole and allow room for an overlap
(doubler). Another option might be to enter through the last fuel tank
rib
(up front), then add a doubler to it, but it would be on the outside. I
could probably reach the rivet tails through the fuel filler cap. That
only
works if my problem is confined to the first bay - something I can't
confirm. If I had to remove a skin, would you remove the top or bottom?
What are the risks involved in that? I need good ideas and am going to
ponder this a while before I dig in.
If anyone wants to call and discuss, my phone is
314-791-3536.
Thanks in Advance,
Jerry Folkerts
SR 2500 #093
www.mykitlog.com/jfolkerts
-----------------------------------------------------------------
List archives located at: https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
-----------------------------------------------------------------
-----------------------------------------------------------------
List archives located at: https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
-----------------------------------------------------------------
