The bolts that hold our wings on.

If the wings are moving that much.....maybe you have termites in there? o_O
 
Velocity173 said:
Forget the bolt, you’ve got intergranular corrosion all over the spar. Replace ASAP!
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So you know I'm totally going to Google that and then I'm going to be private messaging you a bunch of times going you're just kidding right?
 
SixPapaCharlie said:
I do too! I kind of checked to make sure no one's watching when I do it. I feel silly doing it. But every flight LOL
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If you feel self conscious about it, just tell yourself you are wiggling the fuel in the tanks to make sure you catch any water when you sump.
 
SixPapaCharlie said:
So you know I'm totally going to Google that and then I'm going to be private messaging you a bunch of times going you're just kidding right?
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Good. When you get a chance, go back and pull those rear seats out and check your flap actuator clearance with the spar. Mine was rubbing on the top of the spar and over time it created a huge crack. I repaired it myself with JB Weld but it didn’t hold for long. Out practicing steep turns one day and the wings folded up on me. Sucks, I know but just a common problem with Grummans that you should be overly concerned with.
 
bnt83 said:
Its funny because a lot of those have a torque check after a period of operation like 10 hours if removed or found to turn at a sceduled inspection torque check.
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I'm a former UH-1N crew chief with "all-systems QA" and "safe-for-flight" designations. The procedure for torquing the "Jesus nut" was to torque it up to some ridiculous number I can't remember exactly. But, something like 600 ft/lbs, wait 10 minutes, then retorque. You keep doing this until the PowerDyn torque reading stays at the specified torque for the full 10 minutes.

This is "PowerDyn Torque Multiplier".

s-l300.jpg

The Jesus Nut has teeth around the perimeter that engage with a keeper that is itself bolted with an AN bolt and torqued to standard value (I think about 25 ft/lbs) and safety wired.

main-qimg-95af477c4d3c2fa740bb0cc6c2c4b5d6-c


The weakest link is not the Jesus nut. Its the Mast that the Jesus nut is torqued to. In a condition called "mast-bumping" the rotor head can contact the mast with enough force to damage it, leading to a catastrophic in-flight failure in which the rotor head separates from the helicopter. And, the helicopter tears itself apart inflight. Extremely rare. But, something I'd worry about sooner than I'd worry about the Jesus nut; at least on an aircraft that I maintain anyway.
 
Whenever I've had structural concerns, I've gone back and looked at the NTSB report history, where I've determined that the probability of a structural failure is far lower than the probability of me being an idiot and crashing because of my own stupidity.
 
If you zoom in, that bolts looks loose to me. Meh, I am sure it's fine. flY on.
 
wilkersk said:
I'm a former UH-1N crew chief with "all-systems QA" and "safe-for-flight" designations. The procedure for torquing the "Jesus nut" was to torque it up to some ridiculous number I can't remember exactly. But, something like 600 ft/lbs, wait 10 minutes, then retorque. You keep doing this until the PowerDyn torque reading stays at the specified torque for the full 10 minutes.

This is "PowerDyn Torque Multiplier".

s-l300.jpg

The Jesus Nut has teeth around the perimeter that engage with a keeper that is itself bolted with an AN bolt and torqued to standard value (I think about 25 ft/lbs) and safety wired.

main-qimg-95af477c4d3c2fa740bb0cc6c2c4b5d6-c


The weakest link is not the Jesus nut. Its the Mast that the Jesus nut is torqued to. In a condition called "mast-bumping" the rotor head can contact the mast with enough force to damage it, leading to a catastrophic in-flight failure in which the rotor head separates from the helicopter. And, the helicopter tears itself apart inflight. Extremely rare. But, something I'd worry about sooner than I'd worry about the Jesus nut; at least on an aircraft that I maintain anyway.
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Yeah, I always laugh when pilots over emphasize the Jesus nut. “If it fails, we’re dead!” Well jeez, if the split cones on the mast fail we’re dead. If the mast separates from the transmission, we’re dead. Heck, if the bolts holding the transmission to the roof fail or they rip from the roof itself, we’re still dead. All things that are so remote, it’s not even worth bringing up.

That being said, always check the keeper on preflight...if I can find it under all the pro seal. ;)
 
Ted DuPuis said:
Whenever I've had structural concerns, I've gone back and looked at the NTSB report history, where I've determined that the probability of a structural failure is far lower than the probability of me being an idiot and crashing because of my own stupidity.
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“He died doing what he loved.”

“Being stupid?”

And that’s how the fight started at the funeral... ;)

Alternate answer...

“Flying something with a structural engineering flaw?”

:)
 
Timbeck2 said:
I've seen (removed and installed new) the two bolts that hold a Cessna 182 wing on, okay four if you count the strut.
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The bolts in the strut are what really carry purd near all the weight of the airplane and will let the wing fold instantly if either one fails. So, yea. I would count those.
 
wilkersk said:
I'm a former UH-1N crew chief with "all-systems QA" and "safe-for-flight" designations. The procedure for torquing the "Jesus nut" was to torque it up to some ridiculous number I can't remember exactly. But, something like 600 ft/lbs, wait 10 minutes, then retorque. You keep doing this until the PowerDyn torque reading stays at the specified torque for the full 10 minutes.

This is "PowerDyn Torque Multiplier".

s-l300.jpg

The Jesus Nut has teeth around the perimeter that engage with a keeper that is itself bolted with an AN bolt and torqued to standard value (I think about 25 ft/lbs) and safety wired.

main-qimg-95af477c4d3c2fa740bb0cc6c2c4b5d6-c


The weakest link is not the Jesus nut. Its the Mast that the Jesus nut is torqued to. In a condition called "mast-bumping" the rotor head can contact the mast with enough force to damage it, leading to a catastrophic in-flight failure in which the rotor head separates from the helicopter. And, the helicopter tears itself apart inflight. Extremely rare. But, something I'd worry about sooner than I'd worry about the Jesus nut; at least on an aircraft that I maintain anyway.
Click to expand...


I participated in R&R of the rotor assembly on a UH-1 in A&P school. They had a pretty big chain hoist welded to the roof structure in the hangar, it looked sketchy but it worked. They actually traded that helicopter for a different training aid beings it was just too big and a PITA to move around.


My middle brother is huge into heli maintenance so I hear about all kinds of creepy things in the MRO side of a huge medivac operator. Like a tiny clip missing that holds the gas strut onto one of the crew doors, pilot opens the door which goes beyond limits as the strut fell off, rotor strikes door and damn near totaled the whole ship. A whole lot of pressing in bearings stories, training note from school at Bell etc. He was a transmission overhaul tech then a hydraulics specialist. Now he's just a QA dude. Oldest brother was electrician & enviro specialist in the Airforce and did lots of work on different rotory wing models on TDY but really was a fixed wing dude.

I'm a fixed wing guy lol.
 
denverpilot said:
“Flying something with a structural engineering flaw?”
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The nice thing is that by the mid 1950s they'd figured out how to build our spam cans pretty well from a structures perspective.

It seems like experimentals are the primary ones that have structural failures these days, but even then they seem to be aggravated by aerobatics or build flaws rather than true design flaws.
 
PPC1052 said:
If you feel self conscious about it, just tell yourself you are wiggling the fuel in the tanks to make sure you catch any water when you sump.
Click to expand...

If any body asks, just "What are you talking about, I didn't do that. "
 
I was walking across the ramp with the med crew once after we finished a trip. I saw a lug nut, obviously from one of the ancient C-60 fuel trucks, laying on the ramp. I picked it up as FOD removal. One of the girls asked me, "What is that.??"

I couldn't resist...... "It is the nut that holds the propeller on, it must have fell off as I shut the engines down.."

They were not amused....
 
Is that a wooden spar??

I painted the bolts on the canard that are visible for preflight so I can tell if they’ve moved.

Take a sharpie, paint pen, nail polish, or torque putty and mark it if it makes you feel good.

Keep
Calm
and
Paranoid
On
 
Timbeck2 said:
I've seen (removed and installed new) the two bolts that hold a Cessna 182 wing on, okay four if you count the strut. That's why I'd rather fly my Cherokee.
Click to expand...

The aluminum spars would rip apart before those bolts would shear. They're big enough. A strut-braced airplane can get away with smaller hardware than the cantilevered wing like the one on your Cherokee. It's all about leverage. A 182's wing tries to pivot up under load, forcing the wing root inward and pulling on the struts, but those points are 40" apart or so. The Cherokee's bolts are only maybe eight inches apart, putting far more force on the spar roots and the hardware. That's why it's so beefy compared to the Cessna.
 
I like beefy. I'm skeert of flimsy and flimsy is all in the eyes of the beholder.
 
Ted DuPuis said:
Whenever I've had structural concerns, I've gone back and looked at the NTSB report history, where I've determined that the probability of a structural failure is far lower than the probability of me being an idiot and crashing because of my own stupidity.
Click to expand...

As always, the most critical fastener is the loose nut behind the yoke.
 
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Dan Thomas said:
The aluminum spars would rip apart before those bolts would shear. They're big enough. A strut-braced airplane can get away with smaller hardware than the cantilevered wing like the one on your Cherokee. It's all about leverage. A 182's wing tries to pivot up under load, forcing the wing root inward and pulling on the struts, but those points are 40" apart or so. The Cherokee's bolts are only maybe eight inches apart, putting far more force on the spar roots and the hardware. That's why it's so beefy compared to the Cessna.
Click to expand...
The design loads dont bother me, its qc vs the lack of redundancy. An ancient strut bolt - was it xrayed? Ultrasonic? Magnafluxed? Or none of the above? Then add 40ish years of use to let the hidden internal defect grow.

I try not to think about it. I feel better in the cherokee, but the citabria is too much fun to stay away.
 
SixPapaCharlie said:
I've determined I'm an aviation hypochondriac.

Ever since the EARU arrow incident, I swear I'll be flying along and see my wing wiggle out of the corner of my eye.

I turn to look at it and of course it stops wiggling.

I had some down time. Imagine that. So for grins I decided to open an access panel and get some peace of mind.

I couldn't wait to find a sea of bolts and cotter pins.

2 bolts.

This is my wing spar. There is a bolt in front and one in back. They hold the wing tube to the spar. I don't see any attach points near the LE or TE. In fact their is a gap all the way around the wing by design. Nothing tightly affixing the wing to the body.

I get that it it is engineered and even over engineered but maybe a cotter pin or another couple bolts... Even a bit of safety wire...

This thing is going to be full on flapping out of the corner of my eye now.

I'm fully convinced if I ever designed a plane it would be too heavy to get off the ground.

View attachment 64465
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That's a good size bolt there, Bryan-with-a-Y. My Mooney, like all the rest of 'em built the last 50-odd years, has two little 1/4" bolts that hold the entire tail section to the fuselage. Wanna go for a ride? It's OK, with no back window you can hardly see even the tip of the horizontal stabilizer.
 
Hank S said:
That's a good size bolt there, Bryan-with-a-Y. My Mooney, like all the rest of 'em built the last 50-odd years, has two little 1/4" bolts that hold the entire tail section to the fuselage. Wanna go for a ride? It's OK, with no back window you can hardly see even the tip of the horizontal stabilizer.
Click to expand...
Ugh...
 
Hank S said:
That's a good size bolt there, Bryan-with-a-Y. My Mooney, like all the rest of 'em built the last 50-odd years, has two little 1/4" bolts that hold the entire tail section to the fuselage. Wanna go for a ride? It's OK, with no back window you can hardly see even the tip of the horizontal stabilizer.
Click to expand...

And for some serious entertainment, go stall a Tomahawk and watch the stab...
 
SixPapaCharlie said:
I believe they have to be replaced once and then inspected every 100 hours.
Click to expand...

My understanding is inspect within 100 hours of the announcement of the AD (should already be done since it was 2005, I believe) and then a SB RECOMMENDS inspecting every 500 thereafter.
 
Did you see this?


The pilot was quoted as saying "We barely tapped that wing when poof! The bolt that holds the spar sheared off, and the wing pulled itself out. They should make that area more beefy, like bolts all over, not just two. That design, Piper got from Grumman, and I think they should revisit it."
 
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As long as you don’t tap a helicopter or hit any large fowl Bryan, you should be good. They don’t call them “Iron Works” for nothin.
 
Cap'n Jack said:
https://en.wikipedia.org/wiki/Jesus_nut
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That reminds me.

I don't remember exactly what grade I was in...early...likely 1st or 2nd...

And, my oldest brother, Joe, comes home on leave. He was in chopper training at the time (he later flew Hueys in 'nam) and he tells dad and I the story about the "Jesus nut" on a chopper.

And, the next day at school there happened to be a multi-grade religion assembly and I excitedly told all the kids and nuns about the Jesus nut! The nuns were not amused and I was sent home for the day.

Thanks, Joe, you've always been such a great influence and role model! ;)
 
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When I last applied wing root tape to my Sky Arrow, I inserted some clear plastic so I could view the wing attachment bolts:

7425409566_2cc051f34a_z.jpg


They’re certainly not very big.

Gives one pause, but I have to assume they’re properly sized and sourced. I don’t think the wing attachment bolts on my Citabrias were much larger.

As an aside, after the fatal accident in my Citabria, the NTSB found evidence one of the wing attachment bolts was missing. Seemed impossible, since we had just completed an annual, where they were inspected, and not removed as a matter of course. Their evidence was lack of any indication of shear at the attachment point. It was suspicious enough it was referred to the county Homicide division, but no action was forthcoming. Still, always made me wonder about an intentional act being involved.
 
I would more worried about the rust that is growing on the inside of that tube and on the bolts. Every flight just think that metal is getting thinner and thinner. thats why I dont want to look at the insides of the plane or under a Thai street walker's skirt. Just better to not know.
 
I think a lot of times we forget just how strong bolts really are, and how little force these spam cans have exerted on them. If you figure a 2,000 lb max gross weight to make the math easy, even at 6 Gs you've only got 12,000 lbs of load, and that should never be concentrated on a single fastener. A fine thread 1/4" grade 8 bolt is rated to over 5,000 lbs tensile strength. No, this is not engineering analysis, but

While airplanes aren't built as tough as trucks are buildings, they don't need to be and they're still pretty tough. Structural failures are rare unless a pilot gets disoriented in IMC or there's something that is grossly wrong with the plane. For the most part, though, what you find is a pilot who got disoriented and yanked on the controls too hard.
 
Salty said:
Four of these 1/4" bolts is all that holds the engine on my mooney...

AN4-27A.jpg
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Your Mooney's engine weighs about 400 lbs or so, and isn't exactly going to rip itself off of its engine mount.

Those 4 1/4" bolts are just fine.
 
What really makes it seem small is that the bolts holding the engine to the mount are beefy 7/16" bolts, and then you hold the mount to the firewall with those itty bitty 1/4" bolts....
 
Salty said:
What really makes it seem small is that the bolts holding the engine to the mount are beefy 7/16" bolts, and then you hold the mount to the firewall with those itty bitty 1/4" bolts....
Click to expand...
Shear force vs. Tensile force.
 
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