Rigging a Helicopter

dvsDave

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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.
 

dvsDave

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DaveySimps

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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
 

Ted jones

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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
 

Chase P.

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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?
 

Ted jones

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

egilson1

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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.
 

Benjamin Fink

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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.
 

What Rigger?

I'm so fly....I Neverland.
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
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?
 

egilson1

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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.
 

What Rigger?

I'm so fly....I Neverland.
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.
 

kicknargel

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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.
 

kicknargel

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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:

. . .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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