SonexBuilders.net

JCollinet wrote:Bryan,
What's that line going right across your control horn???

You mean the line that is almost vertical WRT the picture? That is the end rib I think.

Ah I think I see it...you slid the control horn INSIDE the rib? Mine is riveted to the bottom of that rib...or it was before it tore off.

This is obviously no god but i dont think you would have lost full rudder authority since the rudervator of the y tail function as a rudder, That being said you would def have reduction of rudder authority, by what amount i cant say that would require some analysis. That being said thats still pretty scary.

lakespookie wrote:This is obviously no god but i dont think you would have lost full rudder authority since the rudervator of the y tail function as a rudder, That being said you would def have reduction of rudder authority, by what amount i cant say that would require some analysis. That being said thats still pretty scary.

The airplane in the video with the failed rivets was a Onex, not one of the extra cool Y tails. I do agree a Waiex would fare better for this failure.

Looks like the onex rudder drive connection to end rib is a totally different configuration to a sonex. Hopefully this is a one off builder error..

Not at all uncommon, I´m affraid!

I reported a similar incident on my Legacy #0525 rudder, built according to the drawings, after some 500 flight hours a couple of years back.

What happened was that the rudder bracket, riveted to the underside of the of the bottom rib, started to pull the rivets through the rib. There was no rivet failure- just the rib material giving way. And the increasing gap between bracket and rib was clearly there for all and sundry to see. I blamed it on my home strip surface. Many years ago Sonex stated that the gear as a whole was not intended for rough grass field operation.

So off came the rudder, and out with all the rivets holding bracket to rib and rib to rudder. Then a 1/8 bolster plate was shaped to go on the inside of the bottom rib. New, longer rivets to sandwich the bottom rib between bracket and bolster. And of course rivet the bottom rib back in place.

It has been sitting there for apprx 150 hrs now- still looking healthy. But there is always still that nagging doubt, so the assembly gets an extra look during every DI.

One more documented occurrence doesn't make it common. But I would like to hear some numbers from Sonex.

Kai wrote:Not at all uncommon, I´m affraid!

I reported a similar incident on my Legacy #0525 rudder, built according to the drawings, after some 500 flight hours a couple of years back.

What happened was that the rudder bracket, riveted to the underside of the of the bottom rib, started to pull the rivets through the rib. There was no rivet failure- just the rib material giving way. And the increasing gap between bracket and rib was clearly there for all and sundry to see. I blamed it on my home strip surface. Many years ago Sonex stated that the gear as a whole was not intended for rough grass field operation.

So off came the rudder, and out with all the rivets holding bracket to rib and rib to rudder. Then a 1/8 bolster plate was shaped to go on the inside of the bottom rib. New, longer rivets to sandwich the bottom rib between bracket and bolster. And of course rivet the bottom rib back in place.

It has been sitting there for apprx 150 hrs now- still looking healthy. But there is always still that nagging doubt, so the assembly gets an extra look during every DI.

If your legacy Sonex was built as you describe above it was not built to plans.

I flew my Cleanex this morning (the plane performed flawlessly - again) and took special note during preflight to inspect the area of the rudder drive horn, especially the assembly of it, and then compare it with the plans. The set of authenticated plans I have for Serial # 1319 shows the rudder drive plate is mounted on top of the bottom rib of the rudder ... not below it. You cannot see the drive plate under the rudder as in the video of the OneX posted by the OP.

I don't know if the OneX build is the same in this area. But if the plans call for it to be assembled the same way as the Legacy Sonex rudder is - then a few people need to openly and loudly offer an apology to Sonex LLC for shouting fire in a crowed theater. How about a follow up video describing how the plane was inncorrectly built and that the problem is poor workmanship, not Sonex LLC.

When properly assembled according to the plans and proper hardware is used for the drive rod to keep the geometry correct and prevent binding - there is not a problem here!

Scott Todd wrote:One more documented occurrence doesn't make it common. But I would like to hear some numbers from Sonex.

Yup- you´re right!

More than a few are needed before this could be called common. As previously stated, I did not suspect anything wrong with the plans. I blamed my loose rivets on forces on the bracket from the (original) steering rod (has since been rebuilt with spherical joints), and the rough ground conditions at my home field.

I checked my plans- to DaleandDee I can only say that the horn on my (original red stamp) drawings is shown to go under the bottom rib, so for me the setup is (was, by now) built according to the #0525 plans. Looking at other pictures in this thread it stems more than mine have been built that way.

But,

Since we are scrutinizing the Sonex tail- how many of you have come across this one?