Float Attach Bulkhead
Posted: 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
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