Cracks aft of ramp area

There have been many post about cracking on the underside just aft of the ramp area around rivets. My 8A is starting to show similar cracking around 3 rivets and all have been stop drilled, one twice. Has anyone got pictures/specs of the external doublers they have used for this problem. Also has Vans posted any repairs for this problem.

Pat Stewart
RV8A
J3Cub

Hi Pat. I hope Alabama is treating you well. I don't have any pictures or drawings, but after I stop-drilled the cracks on the one rivet where this has happened on my -8 I haven't seen any further cracking. That was 2 years ago.

Chris

Cracks

Chris,

Good to hear from you and Alabama is ok. I do miss the weekly BCS flyouts though. For a year or so I had two smal cracks both stop drilled with success however as of last week one of them starting cracking again which required a second stop drill. I think over time this will just get worse. I have seen a few 8's at flyins with external doublers but did not pay a great deal of attention. Im just looking for what others may have done.

Thanks,

Pat

Are you guys talking about the rivets that attach one (or both) of the hinge halves, or something else?

FWIW, I copied Jim D. here and used a .040 angle. I wonder if the slop/play in the hinge rings-to-pin fit is the culprit. I know the hinges are tight but they are 3 seperable pcs., therefore not solid.


http://home.comcast.net/~jwdmac/Fuselage12/pic7.html

For me the cracks were from the outer rivet holes over the rib that is between the hinge and firewall.

My ramp used to vibrate a lot. I could feel it through the floor. I could make it stop by putting my feet at the right place on the floor. I think this was because my exhaust exited more horizontally than it should have. The exhaust pulses must have been hitting the ramp even though there was a fairly large angle between it and the pipes.

Last year I moved the exhaust around so that the pipes exited as vertically as I could get them. The change was not that noticeable in appearance but the vibration went away completely and so did the cracking. This was not before several large cracks and loose rivets.

AC-43 chapter 4 describes how to do a patch.

Luis Luciani
RV8

Cracks

These cracks are aft of the ramp area in the flat section. There are 3 stiffeners on the inside of the skin however its like a drum, not very strong. Lots of RV8's have this problem.

Pat