New Service Bulletin 00053

[rv9builder]

Originally Posted by bobnoffs

i would like to know a lot more about the failure and why the other bulkheads won't follow . from what i read so far i think i would use the gusset vans is supplying and use it for a model to make brackets for the other bulkheads. crawling back there once more is bad enough.

To prevent cracks in the other bulkheads, the service bulletin says to add clips to all three bulkheads. The F-1208 and F-1209 bulkheads get two clips, and the F-1210 bulkhead gets one clip. All five clips are included in the 00053 service bulletin parts kit.

[mturnerb]

Originally Posted by rv9builder

That's an interesting idea, Turner. The ceiling is too low to try this in my garage, but maybe the tail cone could be moved outside on a day when there isn't any wind!

My thought was definitely under very controlled conditions with assistance, and more like supported relatively close to floor, crawling in to stand up - probably not a great idea overall.

[bobnoffs]

uh, upon closer inspection........

[Jcurry]

Originally Posted by Tacco

I’m with you Jim. Why not just put three doublers on from the outside and be done with it, cracks evident or not.

I'm with Steve and Jim. I wish Van's would re-think this repair/SB. I am not an engineer but the "clips" do not look robust enough and I suspect cracks will form even with the clips installed. I'm in favor of the external doublers cracks or not.

[rgmwa]

Checked the three bulkhead locations on my tail cone today and they were fine, but I have the SB on order and will install it. It would be interesting to know how many aircraft have experienced these problems and their time in service. Any in flight schools?

[rgmwa]

Originally Posted by Jcurry

I'm with Steve and Jim. I wish Van's would re-think this repair/SB. I am not an engineer but the "clips" do not look robust enough and I suspect cracks will form even with the clips installed. I'm in favor of the external doublers cracks or not.

We can assume that Vans have done their analysis on the effectiveness of the clips, and personally I would prefer to install those than have to install and paint an external doubler, which by itself might not be enough to fix the problem. If it was, Vans may have gone that route as they did with the wing skin doublers. Without more information, we're just guessing.

[Kahle76]

Originally Posted by mturnerb

I wonder how hard it would be to support the tailcone vertically and stand inside to do the work?

We just riveted the top panel of the tailcone yesterday.

[ravenstar]

Well, I guess now I feel like an aircraft owner rather than a collector of oddly shaped metal parts. I also just closed out my tailcone and am waiting for wings. I guess I'll have something to keep me occupied for a while.

[JDAviator]

I'm not a structures engineer, and I didn't stay at a Holiday Inn Express last night

That being said, I believe the cracks are caused by vibration and movement of the bulkhead, leading to the skin flexing - hence causing the fatigue cracks. An external gusset would transfer loading, but would probably just move the cracking to another location. It seems the clips are designed to support the bulkhead and reduce/eliminate the relative movement to the skin.

Just my .02

And FWIW - I'm 5'7" and go about 230# on a good day. I've no idea how I'm going to accomplish this feat!

[Dgamble]

5' 10" and 134 pounds. A walking broomstick, but it comes in handy now and then.

My entire USAF career working on SR-71s and RF-4Cs was a clamor of "Go get Gamble - that little &^%$ can fit anywhere!"