Aileron Bearings / Pivots

[GrassStripFlyBoy]

During my past condition inspection I noticed the aileron pivot bearings are loose to the bracket, my impression is they have been this way a long time, and perhaps they have worn beyond point of loctite back in place.  Kind hard to gage how loose the gap is without taking everything apart, but based on "wiggle / giggle" feel I'm thinking I'd purchase new ones being 15 years old now.

Pulled up parts manual and find the only number is showing the whole bracket?  Is there a part number?  I plan to hit up FD USA, but also wanted some insight here on what I'm looking at.  Is replacement the best path, or does loctite generally address this?

[sandpiper]

I would first try a dab of loctite. If you do end up replacing your bearings you may find there are two types. The older ones being metal around the outside, the newer ones being fiber.

This is an important difference according to FD. The latest maintenance manual specifies, if I remember correctly, 80 inch pounds. That only applies to the metal ones. If you tighten the fiber ones to 80 you will not be able to move the controls without a lot of effort. Just snug up the fiber ones.

I asked Arian at FD why the manual has not been changed. He didn't know why. The book will also tell you not to lubricate thes bearings with anything. I think that is because most of the bearings are fiber and any petroleum based lube will possibly damage them, per Arian. He did say inbox is ok since it is not petroleum based

[Tom Baker]

There is a thread here somewhere that has the part number for the bearings. I have re-glued some before. I think I explained how I did them without getting glue on my fingers or the inner bearing race. If you can't find it I can explain again. I don't have the bearing numbers written down.

[Tom Baker]

Here is the installation I used. 

 

[Tom Baker]

There is a source for the bearings here. I don't know about a US source. 

 

[GrassStripFlyBoy]

Appreciate it Tom, I had recalled seeing some of this in past and had not search far enough to hunt these down - so thanks!  I'll probably order some new one's, good winter project.

[GrassStripFlyBoy]

I ordered the Loctite for gluing, and looking closer at the bearings perhaps only 1 or 2 are worn to point where gluing may result in more than the recommended 0.006" film thickness.  I could probably simply glue and move on, but as I'm planning to keep my CT for a long time and these have 15 years in service now, thought I'd order a full set to have on hand, shipping cost is really no difference with qty and navigated the German website via translating the pages copying/pasting into text translator - was fairly straightforward.  

So, if anyone needs a bearing, I'll have a stash on hand - hit me up.

[207WF]

Is a dry silicone spray lubricant OK for these bearings?    WF

[Roger Lee]

I see these lose quite often. I just did one on a CT 2 days ago. They are very easy to fix. Just remove the bolt and remove the black plastic bearing. Wipe it with laquer thinner and the same thing for the hole in which it sits. Then apply Loctite 480 around the outside of the bearing. All the way around, but not so much it wants to drip. Then I have it on one of my 6" allen wrench shafts and then put it up by the bearings bracket hole and slide it in. Make sure it's centered and not sticking way out to one side or the other. Let it sit and setup for about 10-15 minutes then put the bracket bolt back in place. Loctite 480 is the proper Loctite.

[GrassStripFlyBoy]

I've viewed the past posts on this topic - thanks Roger / Tom, and yes the Loctite ordered is 480.  A couple other bits of info, if anyone buys direct there is size selection drop down, don't purchase the smaller default bearing directly in the link of FlyRatz post, and to link it again here: http://www.igus.de/wpck/2492/igubal_Gelenklager_EGLM_mm  My '06 SW bearings checked 16mm OD / 8mm ID which lead me to part # EGLM-08:

The question of lubricant - I don't talk much of my work history here, have a BS in polymer science  / plastics manufacturing engineering.  I attempted to study what are the two base polymers in these, as well as what modifiers are included within the additive package of polymer (likely a lubricated resin at least on one side of the two components of bearing).  So the question is what impact will any given chemical have on the plastic for race, plastic for inner bearing, and any modifiers / lubricants that are in the mix of either plastic.  The website does not include direct info on the material they use as they are their own: igumid G for outer race and iglidur W300 on inner  

I'm curious to see what the fresh new bearings look / feel like compared to my existing ones that have had who knows what applied to them prior to me.  I have used INOX on these based on "forum knowledge" here.  I do question the use of INOX on these simply due to the spec sheet of INOX is over 50% secret ingredients and not disclosed, and I love INOX for lubrication of anything metal, plastics are a bit more concerning though.  These bearings being plastic do not require "corrosion protection" aspect of INOX.  However, what little info provided on site does appear to indicate there is decent chemical resistance:

FYI - the new bearings + shipping was ~ $60.  I noticed the bearing I removed to measure was tight to rotate the sphere in the race.  If dimensional creep has been occurring, or lubricants / dirt impacting looseness, and I find the new ones are nice and slick then I'll be swapping out every bearing with new.  This could be some aspect of why ailerons are tighter feel to controls, excessive forces in flap system, etc.  (Assuming the aluminum tube is not allowing the through bolt to rotate and the bearing center is having to spin relative to race, there is more to the assembly here I'm not expanding on how things can play out).  I had option of $9.50 for UPS ground shipping, or $11.50 for 2-day so opted for 2nd day.  Will report back when they arrive.

[Roger Lee]

"I do question the use of INOX on these simply due to the spec sheet of INOX is over 50% secret ingredients and not disclosed, and I love INOX for lubrication of anything metal, plastics are a bit more concerning though.  These bearings being plastic do not require "corrosion protection" aspect of INOX.  However, what little info provided on site does appear to indicate there is decent chemical resistance:"

 

I've been using Inox on these bearings and all bearings and hinges on CT's since 2006 and have never had any issues or even heard of any issues.

[Isham]

On my CTSW the Aileron Pivot #1 has a popping sound when I move the aileron.  I watched and watched but could not see any parts moving and the control end seems fine.  I tried tightening the fasteners but they do not budge.  Any idea what would cause this popping.  Sounds like it is right there where the bracket attaches to the aileron.

[Tom Baker]

There is something else that can cause the popping. I had one CTSW that I worked on that the ailerons would stick, and pop as you moved the stick. It would take some noticable force to get the stick to move, then it would be okay, until it would sit for a while again. There are some rollers inside the wing that supports the aileron pushrod mid span. The only access id the hole in the flap cove. It is a pain to lube, and I would venture that most of the airplanes have not been lubricated since new. 

[Isham]

I will check that. Thanks.

[DownUnderFlier]

On 11/5/2020 at 3:08 PM, Tom Baker said:

There are some rollers inside the wing that supports the aileron pushrod mid span. The only access id the hole in the flap cove. It is a pain to lube, and I would venture that most of the airplanes have not been lubricated since new. 

 

I discovered these GuideRollers in our CT2k when tracking down a slight scraping/rubbing sound when aileron-ing .. used a borescope + tube + fencing-wire to administer a spray of Inox, all quiet again now ..

Cheers,

David