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Post by CalmBlueSkies on Apr 29, 2023 5:26:35 GMT
Is the aileron control rod on anyone else’s Tecnam held onto the aileron by just one regular nylon locknut? If that one nut slipped off, you’d lose that aileron and I’d imagine would make directional control extremely difficult. I’m very surprised to see the absence of a cotter-pin locked bolt in such a location. Is anyone else?  |
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Post by ChiMike on Apr 30, 2023 17:56:30 GMT
What aircraft type is this?
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Post by Flocker on Apr 30, 2023 18:03:01 GMT
Based on previous posts by this Member, I'm going to guess an Astore.
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Post by Ed Midgley on Apr 30, 2023 18:12:30 GMT
That’s normal as the rod end’s center is clamped tight. You only need a castle nut and cotter pin if the bolt can rotate freely as in a clevis type connection.
Ed
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Post by CalmBlueSkies on May 1, 2023 4:59:32 GMT
That’s normal as the rod end’s center is clamped tight. You only need a castle nut and cotter pin if the bolt can rotate freely as in a clevis type connection. Ed I don’t understand. Why’s that matter? If that one nut falls off, you’ll lose control of that aileron. |
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Post by Ed Midgley on May 1, 2023 12:09:52 GMT
Well, if the nut falls off the bolt at the bottom of the wing strut on my P2008 I die.
If we built planes as strong and safe as we wanted they would be too heavy to leave the ground.
Your elevator controls are probably attached the same way.
Ed
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Post by CalmBlueSkies on May 1, 2023 15:13:06 GMT
Well, if the nut falls off the bolt at the bottom of the wing strut on my P2008 I die. If we built planes as strong and safe as we wanted they would be too heavy to leave the ground. Your elevator controls are probably attached the same way. Ed But this is why cotter-pin bolts exist. I don’t understand why they weren’t used on the primary flight controls. On my Cessna, there’s a cotter-pin bolt on every primary flight control and it comes like that from the factory. |
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Post by LSA Flyer on May 2, 2023 1:20:09 GMT
I'd trust a single use Nylock fastener in this application not to back off. Not saying it's better than a cotter pin and a common nut but corrosion and vibration can weaken any fastner. I can imagine the plastic insert Nylock will time out at some point due to environmental exposure and lose its compression but S.S. Nylock fasteners have been used in marine environments for at least 50 years without backing off issues. They also effectivly eliminate the risk of under torque by the installer.
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Post by pcushman63 on Jan 16, 2024 13:22:20 GMT
I look at those nuts during my pre-flight everytime.
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Post by nohippychicks on Jan 28, 2024 2:19:04 GMT
I missed this thread when it started, so I'll chime in now!
While it's common to have a split pin and castle nut in most aircraft (in my humble experience), it's not required. AC43.13-1b suggests that it's standard to have a locking device like this on any connection that has rotational force applied, like your aileron, if the manufacturer and/or Administrator decide that another method is needed, it overrides advisory information.
I maintain about 30 various Tecnam aircraft for a flight school and, while I don't care for their plain metric hardware choice, in many many thousands of flight hours in our fleet I've never seen one of these back off, break torque stripe or give any warning of failure.
A fiber locking nut is a pretty good choice (Even given that there exist fiber locking castle nuts that would be a great choice) for something that doesn't see a lot of wear. That is to say that the locking feature on that hardware CAN wear out but only if it's removed and installed often. It's not going to wear out during normal use.
On your pre-flight, reach up and try to unscrew that nut. If you can't turn the nut with your bare hands, it's not going to end your flight.
Otherwise, if you use bear hands, you just may get some movement from that nut...
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Post by Ed Midgley on Jan 28, 2024 12:16:45 GMT
I agree on their choice of bolts. I have noticed a few places where they used AN bolts.
I do wonder about the lower wing strut bolts on the P2008. They use 8mm bolt while all the strutted Cessna’s use dash 6 (3/8) bolts. I’m sure 3/8s bolts on a Cessna 152 is overkill. The lower strut bolt in in double sheer and when I did a rough calculation of the loads it looked like other parts of the plane would be breaking up first.
Ed
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Post by ronin5573 on Jan 29, 2024 15:19:16 GMT
I missed this thread when it started, so I'll chime in now! While it's common to have a split pin and castle nut in most aircraft (in my humble experience), it's not required. AC43.13-1b suggests that it's standard to have a locking device like this on any connection that has rotational force applied, like your aileron, if the manufacturer and/or Administrator decide that another method is needed, it overrides advisory information. I maintain about 30 various Tecnam aircraft for a flight school and, while I don't care for their plain metric hardware choice, in many many thousands of flight hours in our fleet I've never seen one of these back off, break torque stripe or give any warning of failure. A fiber locking nut is a pretty good choice (Even given that there exist fiber locking castle nuts that would be a great choice) for something that doesn't see a lot of wear. That is to say that the locking feature on that hardware CAN wear out but only if it's removed and installed often. It's not going to wear out during normal use. On your pre-flight, reach up and try to unscrew that nut. If you can't turn the nut with your bare hands, it's not going to end your flight. Otherwise, if you use bear hands, you just may get some movement from that nut... If your concerned, Why not just put another nyloc nut so there are 2?? |
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Post by nohippychicks on Feb 6, 2024 2:00:16 GMT
If your concerned, Why not just put another nyloc nut so there are 2?? I'm not worried about it. I mentioned that I've never seen broken torque stripe or any other signs of loosening at this location. The rest was just pedantic rambling that there could be better hardware choices made; "Good enough," is good enough for me here.
Of all of the questionable decisions in these aircraft, a fiber locking nut at the aileron control rod is way down the list of my things to complain about.
If you want a real answer, though, I don't think the IPC doesn't call out two nuts there...on the other hand, I'm reasonably certain it doesn't actually call out one nut...
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Post by technammech on Feb 6, 2024 21:52:31 GMT
I'm not worried about it. I mentioned that I've never seen broken torque stripe or any other signs of loosening at this location. The rest was just pedantic rambling that there could be better hardware choices made; "Good enough," is good enough for me here.
Of all of the questionable decisions in these aircraft, a fiber locking nut at the aileron control rod is way down the list of my things to complain about.
If you want a real answer, though, I don't think the IPC doesn't call out two nuts there...on the other hand, I'm reasonably certain it doesn't actually call out one nut...
Oh did I just bust out. Struggle is real. |
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