FUS 31 Rivet Shear and cracking.

[Wayne G. O'Shea]

Forwarding to the list as this is a recurring problem with every aircraft I have worked on (EVEN ONES I DIDN'T BUILD, before someone goes there). On Charles Dixon's Rebel (ex Al Colburns) the FUS-31 cracks were so fine (but 5/16" long), that if I wasn't specifically looking for them I would not have seen them. Charles flew 11 hours+ (mostly in the rain) and took Commercial back to Mississippi, to have me do some refinements and modifications to his aircraft. I'm sure he is glad that his tail is not going to fall off now and this one item alone made it all worth while! Those that have looked at your flying aircrafts FUS-31's, look again!

Wayne

P.S I removed the picture attachments befoe I posted to the list!

-----Original Message-----
From: Wayne G. O'Shea <oifa@irishfield.on.ca (oifa@irishfield.on.ca)>
To: bgodden@murphyair.com (bgodden@murphyair.com) <bgodden@murphyair.com (bgodden@murphyair.com)>
Date: Thursday, May 04, 2000 10:14 PM
Subject: FUS 31 Rivet Shear and cracking.


Hello Brian,

Do not know if you are aware of this situation, but over the last 2 years I have found that every Rebel I have inspected with over 50 hours of flight on them (6 to date and I know of at least 4 others in the field) either have the 3 rivets that attach Fus-31 to the fin post sheared off, or the bulkhead is starting to crack at the flange reliefs on either side (or both). I advised Robin of this last year and he was to check the prototypes in Chilliwack (don't know if he did). I thought it was about time I touched base with the factory again, as I have found this situation again on Charles Dixon's Rebel that he flew up from Mississippi for me to do some upgrades and modifications to! I presume this shearing and cracking is being caused by torsional airloads on the stabilizers. I have repaired all aircraft involved by making a .032 doubler that goes from the tail post to the tail spring attach bulkhead, that has a flange to overlap the existing flange at the post. Also have been replacing the sheared RV1410's with RV1613's. Haven't seen any recurring problems after the "fix".

Brian, I know I'm not the greatest looking guy, but it can't be my ugliness that is cracking these FUS-31's, just because I pulled the fairings and looked inside!! I would highly suggest a Service Bulletin is sent out to address this problem before someone doesn't catch it before it's too late! (hate to say it, but a lot of people don't pull their fairings to do inspections like they should) Also note that if I didn't know what I was looking for, I would not have seen the cracks on Charles's Rebel. They were so fine (but about 5/16" long) that to make them show I had to lift up the area by inserting a screwdriver in the relief area.

This cracking/shearing has been found on aircraft that had the old "strap" style tail spring attach bulkhead, the new "motor mount" style bulkhead, with and without additional tail post reinforcing gussets etc. So none of these "improvements", or lack of, have any bearing on the shearing/cracking problem. It is not a tail wheel problem either, as I first found it on an aircraft that has only been on floats! I would highly suggest that the service bulletin advises to install the doubler and the RV1613 rivets during the building process to put an end to this possible Safety Issue!

Attached is 2 pictures. One of stop drilled cracks and one with the doubler in place.

Blue skies and Best Regards,
Wayne G. O'Shea
O'Shea's Irish Field Aviation
Rebels 230, 243, 385, 386 and numerous others!
www.irishfield.on.ca
705-527-1124 fax-527-0874

[rebelair]

Hi Wayne

Thanks very much for the 'heads up' on this critical point. I will have a look this weekend & let people know what I find.

Regards

Brian #328R

-----Original Message-----
From: Wayne G. O'Shea [mailto:oifa@irishfield.on.ca]
Sent: Thursday, May 04, 2000 10:35 PM
To: murphy-rebel@dcsol.com
Subject: Fw: FUS 31 Rivet Shear and cracking.


Forwarding to the list as this is a recurring problem with every aircraft I have worked on (EVEN ONES I DIDN'T BUILD, before someone goes there). On Charles Dixon's Rebel (ex Al Colburns) the FUS-31 cracks were so fine (but 5/16" long), that if I wasn't specifically looking for them I would not have seen them. Charles flew 11 hours+ (mostly in the rain) and took Commercial back to Mississippi, to have me do some refinements and modifications to his aircraft. I'm sure he is glad that his tail is not going to fall off now and this one item alone made it all worth while! Those that have looked at your flying aircrafts FUS-31's, look again!

Wayne

P.S I removed the picture attachments befoe I posted to the list!

-----Original Message-----
From: Wayne G. O'Shea <oifa@irishfield.on.ca (oifa@irishfield.on.ca)>
To: bgodden@murphyair.com (bgodden@murphyair.com) <bgodden@murphyair.com (bgodden@murphyair.com)>
Date: Thursday, May 04, 2000 10:14 PM
Subject: FUS 31 Rivet Shear and cracking.


Hello Brian,

Do not know if you are aware of this situation, but over the last 2 years I have found that every Rebel I have inspected with over 50 hours of flight on them (6 to date and I know of at least 4 others in the field) either have the 3 rivets that attach Fus-31 to the fin post sheared off, or the bulkhead is starting to crack at the flange reliefs on either side (or both). I advised Robin of this last year and he was to check the prototypes in Chilliwack (don't know if he did). I thought it was about time I touched base with the factory again, as I have found this situation again on Charles Dixon's Rebel that he flew up from Mississippi for me to do some upgrades and modifications to! I presume this shearing and cracking is being caused by torsional airloads on the stabilizers. I have repaired all aircraft involved by making a .032 doubler that goes from the tail post to the tail spring attach bulkhead, that has a flange to overlap the existing flange at the post. Also have been replacing the sheared RV1410's with RV1613's. Haven't seen any recurring problems after the "fix".

Brian, I know I'm not the greatest looking guy, but it can't be my ugliness that is cracking these FUS-31's, just because I pulled the fairings and looked inside!! I would highly suggest a Service Bulletin is sent out to address this problem before someone doesn't catch it before it's too late! (hate to say it, but a lot of people don't pull their fairings to do inspections like they should) Also note that if I didn't know what I was looking for, I would not have seen the cracks on Charles's Rebel. They were so fine (but about 5/16" long) that to make them show I had to lift up the area by inserting a screwdriver in the relief area.

This cracking/shearing has been found on aircraft that had the old "strap" style tail spring attach bulkhead, the new "motor mount" style bulkhead, with and without additional tail post reinforcing gussets etc. So none of these "improvements", or lack of, have any bearing on the shearing/cracking problem. It is not a tail wheel problem either, as I first found it on an aircraft that has only been on floats! I would highly suggest that the service bulletin advises to install the doubler and the RV1613 rivets during the building process to put an end to this possible Safety Issue!

Attached is 2 pictures. One of stop drilled cracks and one with the doubler in place.

Blue skies and Best Regards,
Wayne G. O'Shea
O'Shea's Irish Field Aviation
Rebels 230, 243, 385, 386 and numerous others!
www.irishfield.on.ca
705-527-1124 fax-527-0874