Crack found in my Xenos's tail post channel.

[Xenos29DN]

During a pre-flight I was able to move the top of the rudder (the small one) side to side. Closer inspection found a vertical crack in the tail post channel right at the bend line of the c-channel. Not sure if the Waiexs have same channel, but certainly something to check on the Xenos inspections. It is in the process of being replaced - fun job. I would post a picture if I can figure out how to do it.

[Rynoth]

Thanks, I'll take a close look at this on my Waiex. Looks like a very similar part. It attaches to the fuselage side-skin and has the rudder hinge on the inside, correct?

I'll add a side-note here... when I made my Waiex rudder I missed the detail that the piano hinge is the different/stronger closed-loop piano hinge material. If I were in your position I'd use the opportunity to change out the piano hinge material to the correct one. I'm closely monitoring that piano hinge and it's been fine so far, but I'll add to that inspection to check the channel as well.

[N111YX]

That's an interesting failure. I once had to hit my brakes hard enough to where my tail came up and slammed back down causing the tailwheel rod to contact the rudder. It actually stressed some of the rivets near the very bottom of the rudder hinge and I replaced the hinge.

To see such stress in your case from the top down really makes me wonder(?).

[Rynoth]

To see such stress in your case from the top down really makes me wonder(?).

Same here, I'd always figured that the highest stress on that hinge would be at the bottom near the drive horn. I've also never dimpled a piano hinge, though I imagine many Xenos builders do the flush-rivet build. All that to say, I'm very curious to know what might have caused the channel to crack in this fashion. One thing that comes to mind is how the piano hinge pin is safety wired. I.E. might it be possible that the hinge was binding at the top if the safety wire/hinge pin end was getting jammed up in some way.

[racaldwell]

Thanks for the heads up to check this spot on preflight. It would be useful to know if the hinge pin was binding or tight to get it inserted.

My pin was very difficult to slide in the last two inches because of the solid flush rivets when squeezed slightly bent the hinge. I used the extruded hinge that is thicker than the rolled hinge so it can be machine countersunk and the skin & channel dimpled. So I got a drill rod a couple thou smaller dia. and that works. I'll just pull it out every so often once I get flying to check if the pin is wearing. I doubt it would as the drill rod is harder than the original stainless steel pin.

Rick Caldwell
Xenos 0057

[Area 51%]

Speaking of that hinge pin, the way it's safety wired to the hinge half on the rudder causes pin rotation within the hinge attached to the fuselage. Seems like a better deal if the pin remained stationary at the fuselage, and the wear occurred at the rudder.

Maybe there's not enough wear to matter?

[Fritz]

Wow! Definitely not a crack you want to see happen. What does that do to the structural integrity of the rear spar?

Thanks for the heads up, I'll certainly add that to the Waiex preflight.

[Sonex1517]

Did anyone contact technical support about this?

[XenosN42]

Am I the only person that doesn't see a crack in the posted photo?

[Fritz]

One leg of the "C" channel looks like it's split at the bend.

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