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WenEng

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Practicing safety wiring now that I drilled the actuator shaft and I don't know if either of these are ok or neither of these are ok. Any comments please. I'm using .041 safety wire and really don't know if I should be trying to twist between the the bearing and shaft hole or not. I've seen literally every kind of combo when I search on this.
Thanks.
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I did not drill through the rod end. The safety wire should go through the lip of the jackscrew and the wraparound the bolt that hconnects the rod end to the weldment. At least that's the way I read the SB.
 
Lock Wire Nuts

I wouldn't drill any flight control rod, your inducing the possibility of failure at the critical point of the rod. If it comes from the manufacturer that way then all good.

You can use a AN nut that has lock wire holes drilled on the flats for this purpose, The AN drilled nut replaces the jam nut on your set up, you need to lock the nut to the rod, Look at using .032" lock wire, it will be a lot easier to use.

I'll look up the lock nut part number tonight at work and get back to you.

Nick.
 
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I think drilling does weaken the rod-end, but I dont know if it matters because under flap load its in compression (if I remember right). Seems like a smaller hole and .032 wire would make my eyes happier. The top wiring job looks correct although the plans don't call for for the drilled rod-end.
 
hmmm

I looked at this when I got to it in my build and decided to just install the rod end with jam nut tighten then I drilled straight through the screw housing and the rod end (threaded portion) and put a cotter key there.



bird
 
From previous post.....I looked at this when I got to it in my build and decided to just install the rod end with jam nut tighten then I drilled straight through the screw housing and the rod end (threaded portion) and put a cotter key there.

I like this idea. What fixture is best to start the hole on a cylinder?
 
drill press

I used a drill press and a piece of angle iron and a vise. Clamp the angle iron in the vise, lay the assembly in the angle iron and clamp. This keeps it from moving, mark the spot and pilot drill with a small bit then step it up to correct size and voila', its done and no worries about broken safety wire.

bird
 
flyinga said:
I did not drill through the rod end. The safety wire should go through the lip of the jackscrew and the wraparound the bolt that hconnects the rod end to the weldment. At least that's the way I read the SB.
Click to expand...

Yes, and the safety wire will flex every time the flaps are actuated.

Not the usual mode for safety wire...
 
Damage

You have damaged the rod end. You only need to keep the jam nut from rotating.
 
Back from Sun N Fun and found a related thread...

http://www.vansairforce.com/community/showthread.php?t=82498
Van's service bulletin on the bearing unscrewing from the jack screw shaft called for the hole in the edge of the shaft and a looping safety wire around the connecting bolt as mentioned by flyinga. This would allow a loosened jam nut to still permit unscrewing of the bearing but the safety wire would prevent total unscrewing unless it breaks. Many build sites show drilling the bearing and a couple say it was ok with Vans. I don't know that for a fact and will find out. This jack shaft movement differs from the other typical rod end bearings. If the jam nut loosens at all, the entire bearing can unscrew from normal action. Some builders locktite the bearing threads and with the torqued jam nut have never reported a problem. Some builders reported .035 wire breaking. No one I can find reported .041 breaking. I think I like drilling through the shaft and threaded portion of the bearing with a cotter pin as the best solution. We'll see.
 
az_gila said:
Yes, and the safety wire will flex every time the flaps are actuated.

Not the usual mode for safety wire...
Click to expand...

Actually the safety does not move. The loop of safety wire around the bolt rotates with the actuator not the bolt.
 
moves

It does move if and when its purpose comes into play, when the rod end and or jam nut loosen, then the rod end rotates and the safety wire stops it in each direction therefore fatiguing the wire, leading to breakage.

bird
 
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