Aileron bellcrank hardware

[MrPilotRon]

On my Companion QB, we are struggling to stitch together tidbits from the BH5, BH4, and Patrol to fill in some of the missing details that a first time builder needs. Hardware callouts don't seem to line up with what came in our hardware kit and some of the build photos contradict the text. I don't want to mess this up so hopefully some pics will help. I don't understand the reason for AN970 washers called out under the rod ends. Is this just to create a bit of tilt limitation? In the pics I attached, these are assembled as I understand they should be, but in several cases I am just making something up due to lack of clear guidance. The only thing I am sure I missed here is cotter keys for the castle nuts. Aside from that, is this how others assembled the hardware?

[AZBearhawk272]

Looks correct.
The large dia washers keep the parts properly located should the spherical bearing or race fail.

I would be inclined to use them on the bellcrank pivot bearings also.

Kevin D
N272DG
KCHD

[gregc]

In cases where you need full movement of the bearing, I like this beveled version used in the auto racing world -

https://www.pegasusautoracing.com/productselection.asp?Product=3068

[noema]

I would use a shorter bolt in place of the one with the three washers. It's one thread too many for my taste. If I had to keep the long bolt and I was sure the nut is not bottoming out I would move two of the washers to the other side to maximize the clearance to the structure.

Interestingly, on the Patrol the rod end bearing is at the very end of the bellcrank which benefits from two big washers for a benign failure mode. Maybe that's why your bolt has the length to accommodate two as well.

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[Bcone1381]

What you have is fine. The following text is not science, or law. Its just commentary. It's stuff I've picked up about hardware that you can take or leave. BTW, every builder can have an opinion....be critical about an install. I want to come across helpful and maybe some can take something away to help there build. When I see part of what I built years ago, I see growth in my building. Craftsmanship is all about improvement and its fun to collaborate, see things, improve and hang out with others to pick up little improvements.

Some of what follows comes from the weight of my hardware stash. When I pick up a tackle box of my bolts, or nuts, or washers and move it I think about how much it weighs and look at my airframe and wonder if I can shave any weight off. Some extra attention to detail might shave off a few pounds from my airframe in the end.

Turn Buckle Bolt:
-Washers under the head of a BOLT are handy for protecting the paint surrounding the bolt. If they are not installed under the head then a socket will mess up the paint. So, I like having washers under bolt heads where appearance is important to me. Otherwise, I see those washers as extra weight and extra expense and unnecessary.

-The thread exposure on the The turn buckle bolt looks perfect to me At least One Thread should be showing on a bolt. I had a very talented nit-picky mechanic say its 1.5 threads. Its not...one thread is IAW AC43.13. But, I try to hit 1.5 threads and will use different thickness washers to hit 1.5 threads to give my install a barrier against those nit-pickers who might say "Looks like He only has .8 threads showing."

-A clevis pin is also an option in this location.

Aileron Push Rod Bolt
-You used two standard washers and one thin washer to accommodate the longer bolt. Thin washers are 1/2 as thick as standard washers. (.031, not .062).

-The AN970 fender washer....I want to echo what Kevin said about Spherical Rod End Bearings. A failure mode of them is they fall apart. When they do, the bolt head is not large enough to keep them in place and they will fall off. So the oversize washer will keep the rod end in place. The industry standard plans this and you'll apply this where ever They are used.

-That bolt is a long bolt. Make sure you have good clearance as the threaded bolt end moves under the steel aileron drive linkage frame. Consider a slightly shorter bolt to improve clearance and remove the extra washers.

-I document desired changes like this kind of stuff on a shopping list and my "issues" list, so when I buy the shorter bolt on my next order, and it shows up in four weeks, I can recall where and why I did it.

-Shear nuts (thinner nuts than standard tension nuts) will save a bit more weight, and improve that clearance. I used a lot of them in my build wherever they could be applied.
Screenshot 2025-02-17 at 8.12.52 AM.png

[MrPilotRon]

-The AN970 fender washer....I want to echo what Kevin said about Spherical Rod End Bearings. A failure mode of them is they fall apart. When they do, the bolt head is not large enough to keep them in place and they will fall off. So the oversize washer will keep the rod end in place. The industry standard plans this and you'll apply this where ever They are used.

-That bolt is a long bolt. Make sure you have good clearance as the threaded bolt end moves under the steel aileron drive linkage frame. Consider a slightly shorter bolt to improve clearance and remove the extra washers.

That long bolt was the shortest one in my hardware kit and that's long enough to work. It's also a non-drilled bolt so no castle nut and cotter pin. I see most of the other pics for this location show a drilled bolt and castle nut, which I feel would be a better choice for this location. Technically, there is no rotation on this bolt because the bearing centers are clamped and stationary. In my head that means a nylock nut should be acceptable, but in the event of a bearing failure, there might be some rotational movement against this. Perhaps I'm over-thinking this... The same story applies to the other bolt that mounts the bellcrank to the cross bar.

Ron

[Bcone1381]

I agree with everything you say. Your thinking is right on except I don’t think you’re over thinking it. Don’t let this stuff slow your build. Install what you’re comfortable with. If you’re in doubt about the nylon lock nut change it out.

Ya know, keeping an inventory of drilled bolts plus non-drilled bolts adds hassle factor. I Just buy un-drilled bolts and use a tool/jig to drill them in my shop.