What is this Bump on tail of my RV-7?

[az_gila]

Originally Posted by cajunwings

Can somebody post a photo of this area or the plans of a 4 or 6?

Don

The RV-6 stringers...



The smaller inspection panel...

[McDoogle]

Could the large inspection hole be causing a weakness in this area ?
The ones on my RV-6 are only half as big with 6 mounting screws.
Just thinking out loud .

Doug McMullin
RV-6
Ottawa, Ks.

[n82rb]

that looks like more than skin bulge to me. I would be pulling the vertical and horizontal off to check the bulkhead for damage. looks like it that could be wrinkled also.

bob burns
RV-4 N82RB

[Infidel]

Originally Posted by n82rb

that looks like more than skin bulge to me. I would be pulling the vertical and horizontal off to check the bulkhead for damage. looks like it that could be wrinkled also.

bob burns
RV-4 N82RB

Same thought here and suspect an anomaly that pronounced, would likely extend to the vertical and possibly horizontal stabs.

[RV6_flyer]

Originally Posted by Ironflight

To me it looks like a classic case of side-loading the tailwheel - it falls off the pavement and gets caught on an edge, or the two bolts that hold the socket to teh spring shear as the tail is being swung around and it falls off an edge. Either way, the tailwheel itself comes to a sudden stop while the fuselage is still trying to swing, and you put a slight kink in the fuselage structure. I've seen it on a couple airplane's, and both have had a sudden tailwheel stop event.

Just one possibility.

Paul

Originally Posted by rvbuilder2002

Look at the bottom of the rudder fairing. If there is not indication of contact damage from the tail wheel, then the scenario Paul described above is likely the cause.

N477RV (the RV-7 owned by Van's and used by Mike Seager for transition training) has spent its entire life based on a grass runway airport. It is just a few hrs shy of 4800 hrs T.T. and has had nothing like this occur (not to mention all of the plopped in landings it has endured during training).

The inertia of the induced by the tail swinging can induce huge twisting loads on the tail spring mount if the tail wheel comes to a stop suddenly.

Side load is what came to my mind when I saw the photo. Reading the thread I still think that may be the case and I am not the only one thinking the same way.

[sblack]

Is the tailwheel strut bent?

[JonJay]

DAN Miller hit it on the head. Ground loop induced side load has my vote. This is a difficult and challenging repair requiring complete disassembly of the empennage and inspection of all aft bulkheads.

[Boyd Birchler]

I have looked at a lot of RV7 and all I have seen so far have a bulge just below the access panel on each side. I think the answer is to put a angle as described just below the opening. The 7 was designed with access holes on each side that are larger than the single hole on the RV6.

The center part of the side skin just below the access opening is in compression from the weight of the plane on the tail spring transferred to the tail cone, that's what causes the bulge. If you pick up the tail by the horizontal and the bulge goes away it is likely harmless: however I think the angle stiffener added just below the opening is a superb modification that would prevent a hard landing from producing permanent deformation.

Another way to obtain the same objective would be to increase the thickness of the access cover and add several more nut plates around the opening so that the plate would become structural and carry some of the compression loads. Four screws is simply not enough to transfer the loads be across the cover panels.

[RV7A Flyer]

Originally Posted by Boyd Birchler

Another way to obtain the same objective would be to increase the thickness of the access cover and add several more nut plates around the opening so that the plate would become structural and carry some of the compression loads. Four screws is simply not enough to transfer the loads be across the cover panels.

It may not amount to anything without the addition of a stiffener as discussed, and I'm not at the hangar to check my aircraft, but aren't there *6* screws holding that plate on (two that go through the plate into the longeron which is tapped for those screws? (Might even be more, I dunno).

If so, they appear to be missing from the photo. Also, it looks to me like the flange on the aft spar of the VS is bent, too.

[Robski]

Originally Posted by Boyd Birchler

Another way to obtain the same objective would be to increase the thickness of the access cover and add several more nut plates around the opening so that the plate would become structural and carry some of the compression loads. Four screws is simply not enough to transfer the loads be across the cover panels.

Isn't a structural cover plate a contradiction in terms?

Good luck with the inspection and repairs, Dimitri.