No, the tail post bulletin does not assume there is a doubler around the Fus-30 as MAM does still not (to my knowledge) show the need for one in the manuals. (if someone has a new manual and they show one now let use know!) The only doubler MAM shows is the FUS-22 extensions that where added because people were buckling the tail, due to using that little hockey puck wheel supplied with the kit and NO FREE SWIVEL kit on it. I do not have these extensions on my aircraft, but have a Scott 3200 tail wheel and so far no damage to this area. ANYBODY that is still building though, you definitely should install these extensions in you new airplane as they help tie the FUS-30 to the tail cone! No need to buy them from MAM if you didn't get in your vintage of kit, as they are easy to make from raw sheet (as shown in a previous mail by Wray), but use posterboard to make your pattern first. The FUS-30 doubler that many of us builders have done since 1992 (started by Toby Riley I believe, not Me) does not do anything (may slow it down, but does not stop) to stop the 3 rivets from shearing or the Fus-31 from cracking. The first two Rebels I found the tail post problem on had a doubler on Fus-30, the others have not. The doubler on Fus-30's intended use is to stop the Fus-30 from buckling due to tailspring loads between the tail post and the tailspring attach bulkhead. The Service Bulletin doubler on Fus-31 that I had MAM issue, is due to the fact that when you go to the larger 3 rivets on the tail post (actually even if you don't) the Fus-31 starts to crack in the relief corners at the post area. Very fine cracks and you may need to lift with a screw driver blade in the corners with a good light shinning on the subject to even see them. When and if you do the Service Bulletin Doubler DO NOT put the relief's in it as show in MAM's drawing. Just bend the flange up out of your pie shaped piece of .032 and attach as shown. (Proseal under the whole thing will help bond it all together as an extra step) If you put the relief's in the corners, you are just giving it a place to crack again!
Take care and one of Our these trips south has got to be down to help you beat up that Rebel Alister! You are welcome to come and do the same to one of mine up here!
Wayne G. O'Shea
www.irishfield.on.ca
----- Original Message -----
From: A G Yeoman (yeoman@voyager.co.nz)
To: Murphy Rebel Builders List (murphy-rebel@dcsol.com)
Sent: Saturday, September 02, 2000 5:59 AM
Subject: Tail post bulletin
Hi Wayne,
What came first? the chicken or the egg?
I am unsure of the link, if any, between the tailpost bulletin fix and the doubler that wraps around the tail wrap (Fus 30).
My tail fell to bits a fair way back, I had flexing of the tail wrap and some cracking down low there, the three rivets in the tail post were sheared as well.
As a fix I placed a doubler around the tail wrap very similar to what you guys describe and replaced the three tailpost rivets with 3/16".( I did not do the bulletin horizontal doubler fix however )
I have been inspecting the area regularly, including the horizontal bulkhead, and the area seems to be holding up really well.
The doubler around the tailwrap seems to isolate very well the loads that create the shear that damages the horizontal bulkhead and tailpost rivets. It appears to me that the tail wrap doubler could be the primary area to attack to stop the shear in that area, and the bulletin fix may be hitting the symptom not the source of the problem and in time the problem come again or move elsewhere.
Does the bulletin fix assume that there is a doubler around the tail wrap already, or is this a fix for the area on its own?
You views would be appreciated.
Cheers
Alister
