Float Attach Bulkhead

Wayne G. O'Shea · Post by **Wayne G. O'Shea** » Fri Feb 17, 2012 8:40 pm

Working away on a new Rebel fuselage, here in the shop, and thought I would share my latest (well not really, I also installed it in Bob's XWI well over a year ago) "mod" with everyone.

I have noticed that on about 80% of the Rebels on floats that the lower corner wrap, above the rear float attach fitting, just below the side skin will pucker (or slightly buckle) over time. This skin area is located directly on top of where the half circle "cut out" is located on the bulkhead. What is happening after a few (hard?) landings is that this smaller area, of the bulkhead, is deforming slightly (in worse cases cracking) and causing the skin to pucker. I have been cutting out a piece of .063" x 6061-T6 to fit the curved section of the bulkhead, that continues out in both directions along the straight sections for about 2 1/2" beyond the "cut outs". Then, after drilling, installing this reinforcement piece with 5 x RV1613 rivets in a cross pattern on each of the 2 1/2" sections beyond the cut out and using AN3 bolts through the reinforcement, the two bulkheads, and the float attach fitting (in place of rivets). This allows the airframe loads (from the rear float strut) to get transferred past these cutouts, into the full width of the bulkheads and should put an end to this area "working" due to the weak link at the cut out. I have been putting these "plates" only on the "A" bulkheads and leaving the extra "float fitting" bulkhead as is, as that would be overkill in my honest opinion.

OF course, if you ditch now (GOD FORBID!), the airframe will sustain more damage as it will rip out more of the bulkhead instead of just pulling out the section between the "cut outs".

AS ALWAYS, this is just another one of my "suggestions", brought about from 8 years of building and maintaining (numerous) Rebels, and you are free to do what ever the $#LL you want to do with your own personal Rebel!

Best Regards,
Wayne G. O'Shea
www.irishfield.on.ca

Bob Patterson · Post by **Bob Patterson** » Fri Feb 17, 2012 8:40 pm

Thanks Wayne !!

We've heard several reports of problems starting at those cutouts
in the fuse bulkheads - Angus McKenzie just recently finished an extensive
rebuild because of buckling & cracks starting near the rear landing gear
pickup bulkhead....

Putting doublers over the cutouts as you suggest is probably
"A GOOD THING"(tm) ;-) Likely, even .025 doublers in other areas
would not hurt ....

.....bobp

---------------------------------orig.---------------------------------------
At 09:11 PM 2/2/01 -0500, you wrote:

Working away on a new Rebel fuselage, here in the shop, and thought I would

share my latest (well not really, I also installed it in Bob's XWI well over
a year ago) "mod" with everyone.

I have noticed that on about 80% of the Rebels on floats that the lower

corner wrap, above the rear float attach fitting, just below the side skin
will pucker (or slightly buckle) over time. This skin area is located
directly on top of where the half circle "cut out" is located on the
bulkhead. What is happening after a few (hard?) landings is that this
smaller area, of the bulkhead, is deforming slightly (in worse cases
cracking) and causing the skin to pucker. I have been cutting out a piece of
.063" x 6061-T6 to fit the curved section of the bulkhead, that continues
out in both directions along the straight sections for about 2 1/2" beyond
the "cut outs". Then, after drilling, installing this reinforcement piece
with 5 x RV1613 rivets in a cross pattern on each of the 2 1/2" sections
beyond the cut out and using AN3 bolts through the reinforcement, the two
bulkheads, and the float attach fitting (in place of rivets). This allows
the airframe loads (from the rear float strut) to get transferred past these
cutouts, into the full width of the bulkheads and should put an end to this
area "working" due to the weak link at the cut out. I have been putting
these "plates" only on the "A" bulkheads and leaving the extra "float
fitting" bulkhead as is, as that would be overkill in my honest opinion.

OF course, if you ditch now (GOD FORBID!), the airframe will sustain more

damage as it will rip out more of the bulkhead instead of just pulling out
the section between the "cut outs".

AS ALWAYS, this is just another one of my "suggestions", brought about from

8 years of building and maintaining (numerous) Rebels, and you are free to
do what ever the $#LL you want to do with your own personal Rebel!

Best Regards,
Wayne G. O'Shea
www.irishfield.on.ca

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<META http-equiv=Content-Type content="text/html; charset=iso-8859-1">
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<DIV><FONT face=Arial size=2>Working away on a new Rebel fuselage,

here in

the shop, and thought I would share my latest (well not really, I also

installed

it in Bob's XWI well over a year ago) "mod" with everyone.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I have noticed that on about 80% of the Rebels on
floats that the lower corner wrap, above the rear float attach fitting, just
below the side skin will pucker (or slightly buckle) over time. This skin area
is located directly on top of where the half circle "cut out" is located on

the

bulkhead. What is happening after a few (hard?) landings is that this smaller
area, of the bulkhead, is deforming slightly (in worse cases

cracking) and

causing the skin to pucker. I have been cutting out a piece of .063"
x 6061-T6 to fit the curved section of the bulkhead, that
continues out in both directions along the straight sections for

about

2 1/2" beyond the "cut outs". Then, after drilling, installing this
reinforcement piece with 5 x RV1613 rivets in a cross pattern on each of the 2
1/2" sections beyond the cut out and using AN3 bolts through the
reinforcement, the two bulkheads, and the float attach fitting (in place of
rivets). This allows the airframe loads (from the rear float

strut) to

get transferred past these cutouts, into the full width of the bulkheads and
should put an end to this area "working" due to the weak link at the cut

out. I

have been putting these "plates" only on the "A" bulkheads and leaving
the extra "float fitting" bulkhead as is, as that would be

overkill in

my honest opinion. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>OF course, if you ditch now (GOD FORBID!), the
airframe will sustain more damage as it will rip out more of the bulkhead
instead of just pulling out the section between the "cut outs".</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>AS ALWAYS, this is just another one of
my "suggestions", brought about from 8 years of building and
maintaining (numerous) Rebels, and you are free to do what ever
the $#LL you want to do with your own personal Rebel!</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Best Regards,</FONT></DIV>
<DIV><FONT face=Arial size=2>Wayne G. O'Shea</FONT></DIV>
<DIV><FONT face=Arial size=2><A
href="http://www.irishfield.on.ca">www.irishfield.on.ca</A></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV></BODY></HTML>

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