# Rigging a Helicopter



## gafftaper (Mar 6, 2022)

On the way home from USITT, @dvsDave and I spent a couple of hours at the Udvar-Hazy Air Museum near Dulles.

Umm I wasn't so sure about walking under this.


Yep it's a single hanging point. Zooming in...


Zooming in further from a side catwalk location. Is it just me, or is the mouse missing?


Nearby they had one of the original Flying Tigers hung and you could see the mouse. 



@egilson1 @What Rigger?


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## jtweigandt (Mar 6, 2022)

If it goes it will autorotate to a soft landing no?


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## gafftaper (Mar 6, 2022)

jtweigandt said:


> If it goes it will autorotate to a soft landing no?


A serious answer to an excellent quip... They did have a very small line on the tail to prevent rotation couldn't have been more than 1/4"


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## What Rigger? (Mar 6, 2022)

Just riffing: we know it's dry- no fuel or fluids. The engine itself may not even be in it. So there's some possible weight savings. My curiosity is the design factor. Did they use one, or go with the MBS? Let's say that's 1/2" 6x19. MBS is 13+ tons or so, and WLL is about 2.5 tons approximately. So, yeah, definitely curious about the most important thing: how much does it weigh sitting on the ground?

Also I freaking LOVE that museum.


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## MNicolai (Mar 7, 2022)

What Rigger? said:


> Just riffing: we know it's dry- no fuel or fluids. The engine itself may not even be in it. So there's some possible weight savings. My curiosity is the design factor. Did they use one, or go with the MBS? Let's say that's 1/2" 6x19. MBS is 13+ tons or so, and WLL is about 2.5 tons approximately. So, yeah, definitely curious about the most important thing: how much does it weigh sitting on the ground?
> 
> Also I freaking LOVE that museum.



Empty weight is 5,083 lbs, 2.54 tons, assuming they didn't strip any of the interior or engine.


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## gafftaper (Mar 7, 2022)

Also, it was a long way up there and looked pretty heft from a distance. It could easily be 3/4" or larger cable.


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## What Rigger? (Mar 7, 2022)

gafftaper said:


> Also, it was a long way up there and looked pretty heft from a distance. It could easily be 3/4" or larger cable.


Okay, so....3/4" _could _be 5.5 ton "capacity" depending on what manufacturer website we look at (i'm bouncing around several because I'm too lazy to go pull the Wire Rope Users Manual off the shelf. I have coffee here. Don't judge me.) and I'm looking at Fastenal right now. They don't list any MBS that I see. Some tables online show 6X12 as having a 4.9 ton capacity, and again not finding a whole lot of MBS or WLL info at the moment (again, I'm being very Dude about this). 

So, as usual, when it comes to rigging something, the answers aren't always cut and dried and "it depends" plays a factor. Would I personally walk under it? Sure. Because I actuall already have when I was there last (ok, this aircraft wasn't there, but I walked under all that other stuff up in the air). I'm also pretty sure that the one person here who has "picked an actual spacecraft" on his resume will show up and illuminate us some more.


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## Van (Mar 7, 2022)

Man! Talk about a point load!


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## gafftaper (Mar 7, 2022)

I'm still worried about the lack of mousing. The first thing in my brain is, if that simple step isn't done correctly, and it sure appears that way, what else isn't done correctly. @dvsDave did you get a picture that shows the shackle on the helicopter more clearly than mine? Do you see mousing?


What Rigger? said:


> I'm also pretty sure that the one person here who has "picked an actual spacecraft" on his resume will show up and illuminate us some more.


Last I heard he was hanging out at a rest stop in Jersey listening to Janet Jackson.


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## sk8rsdad (Mar 7, 2022)

gafftaper said:


> I'm still worried about the lack of mousing


Just speculating but would loctite be appropriate for semi-permanent installations? If so, would it be visible from the ground?


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## egilson1 (Mar 7, 2022)

Mousing a shackle is one of those things that can be hotly debated. Most shackles not in water tend to tighten under load, not loosen. Using a shackle on a wire rope choke might lead to loosening if the pin is used against the down leg of the choke, but that’s a specific application where even then it’s unlikely to roll the pin out. 

Point being, the evidence that shackle pins work themselves out is anecdotal at best. If it was a real issue, every road shot and tour would mouse their shackles every load in.


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## gafftaper (Mar 7, 2022)

egilson1 said:


> Mousing a shackle is one of those things that can be hotly debated. Most shackles not in water tend to tighten under load, not loosen. Using a shackle on a wire rope choke might lead to loosening if the pin is used against the down leg of the choke, but that’s a specific application where even then it’s unlikely to roll the pin out.
> 
> Point being, the evidence that shackle pins work themselves out is anecdotal at best. If it was a real issue, every road shot and tour would mouse their shackles every load in.


Interesting, I had not heard that. The more you know!


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## brucek (Mar 7, 2022)

egilson1 said:


> Mousing a shackle is one of those things that can be hotly debated. Most shackles not in water tend to tighten under load, not loosen. Using a shackle on a wire rope choke might lead to loosening if the pin is used against the down leg of the choke, but that’s a specific application where even then it’s unlikely to roll the pin out.
> 
> Point being, the evidence that shackle pins work themselves out is anecdotal at best. If it was a real issue, every road shot and tour would mouse their shackles every load in.


OK, teach me: "Most shackles not in water tend ..." 
What is the water effect? All I can think of is that the water will take weight off so the pin has no weight holding it down and increasing its friction.


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## What Rigger? (Mar 7, 2022)

sk8rsdad said:


> Just speculating but would loctite be appropriate for semi-permanent installations? If so, would it be visible from the ground?


Loctite would not be visible at all, because it fills the voids in the threads. You may be thinking of "torque stripe" aka anti-sabotage lacquer (one of my fave terms to use), which will be visible used as an external indicator of something starting to move or rotate.


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## kicknargel (Mar 7, 2022)

My least favorite bit might be the weld tab it's hanging from on the roof truss.


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## dvsDave (Mar 7, 2022)

kicknargel said:


> My least favorite bit might be the weld tab it's hanging from on the roof truss.


Just for clarification, the pipe that that tab is on is about 12" in diameter. It's hard to tell from here, but the roof truss is freaking enormous. There's a minimum of 2-3 meters between each pipe of the triangular truss. The scale is hard to fathom, but in the next couple of weeks, maybe I'll get out there again and shoot some more pics. Maybe I'll even grab a zoom lens.


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## egilson1 (Mar 7, 2022)

brucek said:


> OK, teach me: "Most shackles not in water tend ..."
> What is the water effect? All I can think of is that the water will take weight off so the pin has no weight holding it down and increasing its friction.


So in water you have the flow of the water itself, the potential lack of load, as well as the movement of all the hardware that can position the pin in a valuable position. And the. There is the lack of ability to easily visually inspect the pin.


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## gafftaper (Mar 7, 2022)

dvsDave said:


> Just for clarification, the pipe that that tab is on is about 12" in diameter. It's hard to tell from here, but the roof truss is freaking enormous. There's a minimum of 2-3 meters between each pipe of the triangular truss. The scale is hard to fathom, but in the next couple of weeks, maybe I'll get out there again and shoot some more pics. Maybe I'll even grab a zoom lens.


You live 5 minutes away. We need better photos of the helicopter's rigging and the truss.
...And bring a banana for scale!


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## dvsDave (Mar 7, 2022)

gafftaper said:


> You live 5 minutes away. We need better photos of the helicopter's rigging and the truss.
> ...And bring a banana for scale!



I'll bring a zoom lens, a tape measure and a laser rangefinder. The zoom lens is actually the hardest part, I sold all my big camera gear.


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## Amiers (Mar 7, 2022)

Maybe see if you can chit chat with the facilities guy. Im sure it has to be inspected on a somewhat regular basis. Just find an employees door and walk around with a clipboard til they scoop you up.


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## dvsDave (Mar 7, 2022)

Amiers said:


> Maybe see if you can chit chat with the facilities guy. Im sure it has to be inspected on a somewhat regular basis. Just find an employees door and walk around with a clipboard til they scoop you up.


I will look through my email to see if I still have the contact info for one of the docents there.


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## RonHebbard (Mar 7, 2022)

gafftaper said:


> You live 5 minutes away. We need better photos of the helicopter's rigging and the truss.
> ...And bring a banana for scale!


Drone shots from a variety of angles could be useful. Photos of you salivating over your banana wouldn't be necessary. 
Toodleoo! 
Ron Hebbard


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## gafftaper (Mar 8, 2022)

gafftaper said:


> You live 5 minutes away. We need better photos of the helicopter's rigging and the truss.
> ...And bring a banana for scale!


And a banana for scale. You might blind someone with a laser range finder. Bananas are safe.


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## JChenault (Mar 8, 2022)

dvsDave said:


> I'll bring a zoom lens, a tape measure and a laser rangefinder. The zoom lens is actually the hardest part, I sold all my big camera gear.


I think my daughter has a 300mm Nikon if that helps


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## dvsDave (Mar 8, 2022)

JChenault said:


> I think my daughter has a 300mm Nikon if that helps


We should plan a meetup at the museum! Have you been yet?


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## DaveySimps (Mar 8, 2022)

This is one of my favorite attractions in the DC area. Worth the trip away from the mall area. I liked going to the top of the tower, hearing the tower feed from the new(er) airfield, then seeing the plans land. Being able to get so close to the aircraft was a pretty cool expirence. 

~Dave


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## TimMc (Mar 8, 2022)

gafftaper said:


> And a banana for scale. You might blind someone with a laser range finder. Bananas are safe.


There are no safe bananas, only safer banana practices. /nudge, wink


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## JChenault (Mar 9, 2022)

dvsDave said:


> We should plan a meetup at the museum! Have you been yet?


No I did not know it existed

but I won’t be out there for several months


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## Ted jones (Mar 9, 2022)

Amiers said:


> Maybe see if you can chit chat with the facilities guy. Im sure it has to be inspected on a somewhat regular basis. Just find an employees door and walk around with a clipboard til they scoop you up.


Yeah. Its a federal facility. They won't mind....

T


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## Ted jones (Mar 9, 2022)

egilson1 said:


> Mousing a shackle is one of those things that can be hotly debated. Most shackles not in water tend to tighten under load, not loosen. Using a shackle on a wire rope choke might lead to loosening if the pin is used against the down leg of the choke, but that’s a specific application where even then it’s unlikely to roll the pin out.
> 
> Point being, the evidence that shackle pins work themselves out is anecdotal at best. If it was a real issue, every road shot and tour would mouse their shackles every load in.



I'm with Ethan on this. It also depends on if the shackle was tightened enough that the threads are buried into the female side of the shackle and that the bow was compressed. I've looked at thousands of shackles that are part of rigging systems installed by us and other companies. The ones that are tightened with a properly sized wrench don't seem to come loose. Finger tightened shackles often are backing out. I have our guys wrench tighten all of our shackles.

What I saw was a nylon tie on the other shackles. Possibly the nylon decomposed and fell off. Maybe there was a crack in it? I would be interested to see if the tie is sitting in the top rotor. Possibly, the pin is loosening due to building vibration and has broken the tie?

The above said, yearly inspections and maintenance should catch all of this. I don't know what the protocols are at the Udvar. Especially if they were closed for a couple of years.

I forwarded this conversation to a friend that may have rigged this Sea King, or at least he may know who did it to see if he has thoughts on it. I'll let you know. Or he will.

T


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## Chase P. (Mar 9, 2022)

I’m not a rigger, but is it ok to side load a master link like picture 4/4?

I’m pretty sure the 2014 Ringling incident was from a side loaded carabiner. Is a master link stronger material, or is it the lack of a gate that makes it less probe to breaking?


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## Ted jones (Mar 9, 2022)

Ted jones said:


> I'm with Ethan on this. It also depends on if the shackle was tightened enough that the threads are buried into the female side of the shackle and that the bow was compressed. I've looked at thousands of shackles that are part of rigging systems installed by us and other companies. The ones that are tightened with a properly sized wrench don't seem to come loose. Finger tightened shackles often are backing out. I have our guys wrench tighten all of our shackles.
> 
> What I saw was a nylon tie on the other shackles. Possibly the nylon decomposed and fell off. Maybe there was a crack in it? I would be interested to see if the tie is sitting in the top rotor. Possibly, the pin is loosening due to building vibration and has broken the tie?
> 
> ...


My friend did not rig this ship. So no news.


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## egilson1 (Mar 9, 2022)

Chase P. said:


> I’m not a rigger, but is it ok to side load a master link like picture 4/4?
> 
> I’m pretty sure the 2014 Ringling incident was from a side loaded carabiner. Is a master link stronger material, or is it the lack of a gate that makes it less probe to breaking?



1) the term is cross load, not side load. I mention this because the term side load has a specific meaning with industrial lift hardware that doesn’t mean what we think it means. 

2) yes, mast link rings like that are able to deal with the cross loading. 

3) the Feld Ringling Brothers failure in RI was due to triaxial loading of the carabiner. Although similar to what is in image 4, the big difference is the master link is designed for the use, and carabiners are only to be loaded along the major axis.


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## kicknargel (Mar 9, 2022)

Gosh, even if everything is properly rated, engineered and installed (and I have no reason to believe it isn't), the single point of failure just gives me the heebies. Big fan of redundancy.


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## Benjamin Fink (Mar 10, 2022)

kicknargel said:


> Gosh, even if everything is properly rated, engineered and installed (and I have no reason to believe it isn't), the single point of failure just gives me the heebies. Big fan of redundancy.


I'm right there with you on the need for redundancy in our work, but helicopters are no strangers to single points of failure: https://en.wikipedia.org/wiki/Jesus_nut. (I much prefer the Jesus nut on a C-Clamp that just skins your knuckles when it gives out.)

I've heard it put that airplanes want to fly, but helicopters are just so loud and ugly that the earth repels them.


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## What Rigger? (Mar 10, 2022)

Ted jones said:


> I'm with Ethan on this. It also depends on if the shackle was tightened enough that the threads are buried into the female side of the shackle and that the bow was compressed. I've looked at thousands of shackles that are part of rigging systems installed by us and other companies. The ones that are tightened with a properly sized wrench don't seem to come loose. Finger tightened shackles often are backing out. I have our guys wrench tighten all of our shackles.
> 
> What I saw was a nylon tie on the other shackles. Possibly the nylon decomposed and fell off. Maybe there was a crack in it? I would be interested to see if the tie is sitting in the top rotor. Possibly, the pin is loosening due to building vibration and has broken the tie?
> 
> ...


Curious regarding the reasoning to put a wrench on a shackle to tighten it. What kind of wrench? Does the MR require or suggest this? What torque setting are you looking for? Are we talking anchor shackles, or bolt/nut/cotter pin styl set ups?


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## egilson1 (Mar 10, 2022)

kicknargel said:


> Gosh, even if everything is properly rated, engineered and installed (and I have no reason to believe it isn't), the single point of failure just gives me the heebies. Big fan of redundancy.


Redundancy from an engineering standpoint doesn't always mean multiple of something. Sometimes it's in the design factor. Cranes for instance do this, as they often are a single point failure concern.


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## What Rigger? (Mar 10, 2022)

egilson1 said:


> Redundancy from an engineering standpoint doesn't always mean multiple of something. Sometimes it's in the design factor. Cranes for instance do this, as they often are a single point failure concern.


The maillon rapide that holds a rope access harness together below the sternal point, for example, is also redundant because of (yep) engineering. No double required.


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## kicknargel (Mar 11, 2022)

Benjamin Fink said:


> I'm right there with you on the need for redundancy in our work, but helicopters are no strangers to single points of failure: https://en.wikipedia.org/wiki/Jesus_nut. (I much prefer the Jesus nut on a C-Clamp that just skins your knuckles when it gives out.)
> 
> I've heard it put that airplanes want to fly, but helicopters are just so loud and ugly that the earth repels them.


Woah, I'd only ever heard "Jesus Nut" in the c-clamp context (and it's not even a nut). I wonder if the term was borrowed from the helicopter context. Not very appropriately as the Jesus Nut on a c-clamp is not a single point of failure. But it does tend to make people blaspheme.


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## kicknargel (Mar 11, 2022)

egilson1 said:


> Redundancy from an engineering standpoint doesn't always mean multiple of something. Sometimes it's in the design factor. Cranes for instance do this, as they often are a single point failure concern.


Content warning: internet semantics quibbling 

I and this wikipedia article:







Redundancy (engineering) - Wikipedia





en.wikipedia.org





. . .define redundancy as being a "duplication of critical components or functions of a system" as a fail-safe to prevent critical failure in the event of component failure. Redundancy and design factor both mitigate risk, but in different ways. Design factor wouldn't protect against an un-caught manufacturing error, but redundancy would. The two ideas can play together. You could hang something from two points, with enough design factor that either one would suffice.

I think design factor is about preventing component failure, and redundancy is about what happens when component failure occurs.


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## Footer (Mar 11, 2022)

The entire thing was designed to be picked up at the main rotor when in flight... so why not rig from there. 

Adam Savage did a whole thing on how they do it with one of the people that does it... not a ton of info but interesting none the less.


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## Jay Ashworth (Mar 11, 2022)

Van said:


> Man! Talk about a point load!


Seems worth pointing out here that the Jesus Nut on a helo *is* the point-load spot; all the non-spinning weight hangs from that spot.


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## Jay Ashworth (Mar 11, 2022)

Ted jones said:


> The above said, yearly inspections and maintenance should catch all of this. I don't know what the protocols are at the Udvar. Especially if they were closed for a couple of years.



Well, if they were closed for a couple years, and did *not* precede the reopening with a complete set of rigging inspections, I'll want heads on my desk on Monday morning.


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## Benjamin Fink (Mar 11, 2022)

kicknargel said:


> Woah, I'd only ever heard "Jesus Nut" in the c-clamp context (and it's not even a nut). I wonder if the term was borrowed from the helicopter context. Not very appropriately as the Jesus Nut on a c-clamp is not a single point of failure. But it does tend to make people blaspheme.


My guess is that it’s a parallel construction, especially since I’ve also heard it affectionately referred to as the F*** nut (I.e. what you say when you skin your knuckles instead of who you pray to when it gives out.)

Although that wouldn’t be the first thing stagehands picked up from the navy. I’ve heard theories that’s where the taboo on whistling came from.


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## Jay Ashworth (Mar 11, 2022)

Benjamin Fink said:


> My guess is that it’s a parallel construction, especially since I’ve also heard it affectionately referred to as the F*** nut (I.e. what you say when you skin your knuckles instead of who you pray to when it gives out.)
> 
> Although that wouldn’t be the first thing stagehands picked up from the navy. I’ve heard theories that’s where the taboo on whistling came from.


It's not a parallel construction... We are talking about a helo here, are we not?

It appeared to me that that hoisting point was fastened to the rotor assembly, did I misread the photograph?


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## Benjamin Fink (Mar 11, 2022)

Oh no, parallel construction of the two uses of Jesus nut. (I.e. the phrase was developed by helicopter pilots and lighting techs separately.)

To take the thread even further from the original topic, it’s like how nature evolved crabs about five separate times.


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## gafftaper (Mar 12, 2022)

Jay Ashworth said:


> It appeared to me that that hoisting point was fastened to the rotor assembly, did I misread the photograph?


Maybe. From my point of view my thought was that the cable was secured to the chopper internally and then routed around and through the rotor. But I was far from close up.


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## videographer (Mar 16, 2022)

Benjamin Fink said:


> I'm right there with you on the need for redundancy in our work, but helicopters are no strangers to single points of failure: https://en.wikipedia.org/wiki/Jesus_nut. (I much prefer the Jesus nut on a C-Clamp that just skins your knuckles when it gives out.)
> 
> I've heard it put that airplanes want to fly, but helicopters are just so loud and ugly that the earth repels them.


Or: You can trim an airplane to fly itself, but a helicopter is always trying to kill you.


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