Flight control assemblies

[N111YX]

I have never felt fore/aft (pitch) slop in the few Sonex aircraft that I have flown. For some reason, it's not a problem like with the left/right. The taper pins solve all slop...

Now if you use an AN4 bolt, you can tighten the crap out of it, deforming everything slightly, and introducing friction between the inner and outer tube which might be enough to prevent any feel of slop..

Overtightening this bolt didnt work for me. It possibly just squashes and ovals the 3/4" tube making the situation worse. ie Bigger gap top and bottom between the tubes.
I understand that fore and aft slop may also still be a problem with one taper pin. I think the fore and aft play here could be eliminated by using 2 small taper pins one from the left and one from the right. Providing there is enough room of course :?:

[N111YX]

I recall many YX'ers having this problem. I forget how many washers I used but I'll see if I can peek back there when I'm back home in a few days...

Tonight i started to rig my pitch control. The plans (this is for the Waiex only) say to place a 1/16" shim in between the stick frame and the spar box, and with the tail mixer fully forward drill the required bushing hole for the idler-to-mixer rod. I misunderstood what the plans meant by the 1/16" shim and did this at first.. it became obvious that it wouldn't work because the idler-to-mixer rod was in the wrong spot at the mixer end.



I didn't realize until this moment that the stick assembly goes over the spar when full forward. The instructions must have meant to put a 1/16" shim between the actual stick frame (and not like the forward most point of the stick like the above).



The problem that i ran into with this approach is that the entire assembly bottomed out at the idler before the stick frame was within 1/16" of the spar box. Because of this, i put a small shim in front of the idler and used this as my forward-most stick position for rigging. This made everything come out, from the best i can tell, correctly.



Now for the other problem i ran into. The ruder-vator push rods bottomed out by the spherical rod-ends hitting against their upper safety washer before the assembly moved all the way to the aft stop. Sorry about the bad photo.. it was very hard to get a picture of this:



You can see here more clearly what is bottoming out. In this photo, i have two standard washers above the spherical bearing and it still bottomed out (the prints call for only one). It took THREE washers above the spherical to get all the way to the aft stop, and i find this to be somewhat ridiculous.


Waiex builders, did you have this problem? what did you do?

[checkn6]

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[checkn6]

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[kmacht]

If I am reading it correctly your tube for the tailwheel bracket is larger than the diameter of the tailwheel titanium rod? My setups was like this. What I ended up doing was coating the titanium rod with some epoxy to fill the extra space and then putting the tube over it. The epoxy stays in compression since it is trapped in the tube and should hold up just fine. The bolt is still there to take any force placed on the connection. If I ever have to replace the tailwheel rod I will just also have to replace the bracket. If the epoxy breaks down I can just pull it all apart, clean it up and re-apply some new epoxy. I think a few people have also made shims to go in there but am not sure how they kept them in place.

Keith
#554

[falvarez]

I too was planning on filling that void with epoxy (and some flox, but that's just because I have some laying around). Just an FYI...epoxy will break down with extreme heat so if you want to take it back apart, simply heat the part with a heat gun and you should be able to separate them.

[checkn6]

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[sonex892]

For those that are in the know, perhaps this is a good place to ask about a minor concern.

I mounted my tail wheel bracket to the end of my rear fuselage and also drilled the titanium rod that fits inside. When I was done the bolt was nice and snug but there was a lot of play between the tube and the titanium rod. I'm not sure if a taper pin would help here because the rod is not a snug fit in the tube to begin with.

Would a taper pin help, or what are others doing/done to remove the excess play?

Thanks,

Chris
SNX 1372

Being an electrician I just wrapped insulation tape around the titanium tailspring and used bolts. :roll: 400 landings later still as tight as the day it was installed.

I used a taper pin on the tailspring on my sonerai, a similar setup to the sonex. It worked great. The spring wasnt a loose fit in the socket like the sonerai. The taper pin was just used to stop the rotational slop.
Steve 892

[142YX]

In my research on taper pins, i came across this RV builder who used a taper pin on his landing gear.. you could do the same thing for the Sonex tail rod.

http://www.matronics.com/wiki/index.php/Nose_Gear_Strut

Here is a source for shim stock. I was going to do this on my tail wheel (mine is very loose as well)

http://www.mcmaster.com/#standard-shims/=komc35

[142YX]

Worked on the Flap control Torque Tube tonight. I thought that the phenolic pillow blocks that i made had a great fit (i just stepped up to a 1" drill bit to cut the hole) but as soon as i tightened them into the fuselage with the torque tube in place, they bound really bad and it took all of my strength to get the tube to turn (obviously not acceptable).

Fearing the cost of a few oversized 1" reamers to try in hopes of improving things, i tried lightly opening up the holes with sandpaper, which probably would have worked, but was taking forever and i did fear that i would oval the blocks badly.

I then removed the powder coat paint from the area of the blocks (using the same blow torch method) to get the torque tube a little bit thinner.. this improved things but it was still much to tight.

The next thing i tried was a very silly idea involving gluing a paper spacer in between the blocks to make them ever so farther apart from one another. This did not work at all.




Then i though a little harder about it and actually came up with a good idea, and that was to use a brake cylinder hone like the one you can get from McMaster Carr for $16 http://www.mcmaster.com/#hones/=kp5t5z



The hone worked great. In just a few iterations i was able to dial the holes into a nice slip fit without making them go all eccentric, like what would have happened if i tried to do it by hand



With the proper fit done, i got to work with the die grinder cutting off the center bracket as i will not be installing a center flap handle.



I once again used the gun-blueing on the sections of bare metal that i have exposed, and then masked off the bearing area and have primer drying on the tube. After a top coat of paint, it will be ready for installation tomorrow.