Flaperon mixer bolt safety wire

[LetMeFly]

Hi All,
I searched the forums and couldn't find a post that covered this subject.

I'm safety wiring the bolt to connect the flaperon mixer assembly to the airframe. The manual says to wrap the wire around the shaft of the flap bellcrank. Below is what I'm thinking for this. I'm using cheap copper wire for practice so this is not the final wrap. How does it look? I can find tons of info on safetying but not something like this.
24999

[Delta Whisky]

Greg - that's how I did it. I'm working from memory here but I went back and did that safety wire task again when I noticed the bolt stayed put until the safety wire forced it to turn. I'm pretty sure that the wire should ensure the bolt stays put in regards to the weldment to which it is tied - to make sure the movement occurs where it is supposed to. Probably wouldn't make a difference in the life of either the plane or the owner but my CDO kicks in once in a while.

[PapuaPilot]

Why wouldn't you just use a cotter pin? That is the standard practice with a bolt and castle nut.

[avidflyer]

I was thinking the same thing, and trying to remember what I did on the 2 Kitfox 4s I've set up. Looked in the Kitfox 4 manual, and it shows the bolt going the opposite way, and having a castle nut and cotter pin. Wonder what they learned to change it., JImChuk

[efwd]

That is how mine is done.

[jiott]

Greg - that's how I did it. I'm working from memory here but I went back and did that safety wire task again when I noticed the bolt stayed put until the safety wire forced it to turn. I'm pretty sure that the wire should ensure the bolt stays put in regards to the weldment to which it is tied - to make sure the movement occurs where it is supposed to. Probably wouldn't make a difference in the life of either the plane or the owner but my CDO kicks in once in a while.

I think DW has it. The weldment with the safety wire has very small bearing area around the bolt, so you don't want the movement/wear at that point. The airframe has much more bolt bearing area, so grease this area and force the bolt to turn there. My 2 cents.

[109JB]

The bolt should go in from that side. Not the nut. Once fabric is on I don't think you would be able to remove the bolt without cutting fabric if you had to.

[efwd]

If I ever need to remove that bolt I will cut the bolt head off before I cut any fabric.

[jiott]

The bolt should go in from that side. Not the nut. Once fabric is on I don't think you would be able to remove the bolt without cutting fabric if you had to.

I don't think so; that would defeat the purpose of the safety wire-see my post below.

[jiott]

Its all clear in the assembly manual for the SS7: Fuselage Assembly, Section B, page 26, step 70. It agrees with Delta Whiskey's assesment.

[efwd]

Odd though, that they didn't just use a bolt with a drilled head. Unless you put a hole in the fabric that bolt wont go back in I suppose.

[LetMeFly]

I've created conflict! :eek:

[jiott]

I'm sure you could get the bolt far enough out to regrease it if necessary.

[Dave S]

Jim has got this....

May be different in the pre S5 aircraft; however, the manual is clear on which way it goes on the later craft. I'd reinforce the thought the reason is to have the smooth shank of the bolt rotate on the larger bearing. I am also not convinced that extracting the bolt would be impossible - it will come out a ways without touching the fabric; and, the fabric is not inflexible and can likely be deflected (carefully) enough to get the bolt out with the span of fabric that exists between the hard points.

So far I have not needed to remove the bolt; and, the recommended lubrication procedure seems to adequately take care of that anyway. I'd guess the fabric will be replaced in 25 years before the bolt needs to come out.

[Shadowrider]

So I installed this the way the manual describes, even though seemed more dangerous than a cotter pin. Saftey wired it and bolt moved with linkage as described in the manual. On my recent condition inspection the bolt was no longer moving freely. The bolt would stay until the saftey wire caught and then moved the bolt with it. Eventually I think the saftey wire would fail with possibility of the nut coming off. So I decided to just use a cotter pin. I slightly loosened the nut to allow it to rotate with the linkage freely. This seems much safer to me? Even if the bolt stops rotating like it’s suppose to, the likelihood of wearing things out in my lifetime seems unlikely. Seems less likely to have something fail?

[JayHenry]

The Factory uses a cotter pin on their builds.