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aileron attachment concern

osaleh

Active Member
The inboard and outboard aileron attach points to the wing, an AN bolt and on other end the an365-1032 nut. Is this safe???? vibration or movement, will the nut not come loose???? anyone took some other kind of precaution that i need to be aware of???? ofcourse i will use the red past marker to make sure that i know if the nut is coming loose, but in flight???? scary.

Also the attach point of aileron to the w818 push/pull rode, is that not a very tight place for the AN nut??? i had to hold the nut with the wrench through the access hole and then tighten the bolt (instead of the nut as i usually do). anyone else had such problems??? or did i just screw up somewhere??

Thanks
Omar
 
never heard of one coming loose

I used torque seal on mine and inspect for during each preflight. I always use a new nut after disassembly
 
Since the bolt simply holds a fixed bearing in place without any rotation against the bolt, a simple locknut is good enough as is the case here. If the bearing isn't fixed, i.e. it rotates on the bolt, then a castle nut/clevis pin is needed.
 
Lock nuts

I'm changing the nuts in the hinge points and pushrods attach points to steel lock nuts. Most don't think it is necessary but I like the steel lock nut better.

My crude testing indicates it takes about 4 to 5 times the breakout force to overcome the locking mechanism of the steel lock nut. The fiber lock nuts turned at roughly a 2 in/ lbs and the steel lock nut turned at about 10 in/lbs.
 
I'm changing the nuts in the hinge points and pushrods attach points to steel lock nuts. Most don't think it is necessary but I like the steel lock nut better.

My crude testing indicates it takes about 4 to 5 times the breakout force to overcome the locking mechanism of the steel lock nut. The fiber lock nuts turned at roughly a 2 in/ lbs and the steel lock nut turned at about 10 in/lbs.

I agree, I only use the fiber nuts on secondary structure, trim, non-critical stuff. I also use a lot of "jap" locking nuts especially when the item is in shear.
 
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I follow the plans. Thousands of RV's flying never heard of a single one that had a fiber lock nut back out. I check them every preflight. Never seen one move.
If you are really that concerned, don't accept a lock nut at all. Put a castle nut on there and pin it. I have seen that done on very early RV's.
 

Yes, and these are the "jap" nuts: http://www.aircraftspruce.com/catalog/hapages/ms21042.php

ms21042.jpg
 
where will you get these steel lock nuts?

I'm changing the nuts in the hinge points and pushrods attach points to steel lock nuts. Most don't think it is necessary but I like the steel lock nut better.

My crude testing indicates it takes about 4 to 5 times the breakout force to overcome the locking mechanism of the steel lock nut. The fiber lock nuts turned at roughly a 2 in/ lbs and the steel lock nut turned at about 10 in/lbs.

where will you get these steel lock nuts?
 
Just to put a little perspective on this, there are THOUSANDS of RV's flying around with the fiber lock nuts, and I can't think of a single post (off-hand) here on VAF in the past seven years or so of an experience of one of them backing off from an aileron hinge.

Re-engineering for cause is a great idea - doing so "just because" might have other unintended consequences. If you want to use metal locknuts, I guess that's fine if you want to buy a bag, but not really necessary - I find that lots of the hardware gets replaced once in awhile due to rust here on the gulf coast. Oh - Louise's 22 year old RV-6 still has the original paint on the aileron hinge fiber nuts, so they've lasted that long.
 
Dash for diameter

which size of castle nut would we get Andrew?

Thx

The dash number will cross directly from the AN bolt used example AN3-5 bolt, dash 3 nut, AN4-5 bolt, dash 4 nut. Also found low profile castle fiber lock nuts, MS17826-
 
I do agree with Paul, there is really no need to change what is called out in the plans and there is nothing "wrong" with the fiber nuts. I happen to prefer steel lock nuts just because that is what I have used/seen used during my career, old habits is all.
 
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