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Reserve / PEP ripcord pull forces

 


fcajump  (D 15598)

Dec 7, 2012, 10:39 AM
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Reserve / PEP ripcord pull forces Can't Post

Before getting repremanded for thread drift, I figured I'd open the discussion here.
---------------------------------------------

I'd be curious to know how many riggers routinely test the pull force of the rigs they see in their loft, how they do their testing and what pull forces they see.

1 - regs: within the US, I understand that all reserve/emergency systems must deploy at or below 22-lbs. Yet, one rigger I know references (old?) that a three pin rig has a higher allowance than a two pin... Anyone? Other countries?

2 - pull force technique - I use a scale with max-force needle. (would like a digital, graphing with peak force and averaging functions, but until one of you give me one, its what I've got...) Checked once a year to ensure its still reporting accurately.
When its an option, I have someone wear the rig and have the scale pull in line with the housing.
When I don't have someone to wear the rig I place it on the table (PC up) and arrange the yoke/shoulder to have ~ the same arc as if it was being worn (often with another rig playing the roll of "shoulder")
I have heard some insist that it should be in a different direction... references?

I do my tests with the seal removed.

I test at the handle. However, I've heard some say it is the force at the pins that "counts" and the measurement should not include housing resistance at all. (when discussing "legal limits")

In the extreme out-side-the-norm, I've seen old loops come in with 3-5 lb pulls and factory packs come in at 30-50lb pulls. Most repacks seem to run 12-18 lbs on rigs that have their loops changed regularly and their PC launches without hesitation and moderate-strong.

I'd like to see what y'all see...

JW


mark  (D 6108)

Dec 7, 2012, 10:58 AM
Post #2 of 7 (1054 views)
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Re: [fcajump] Reserve / PEP ripcord pull forces [In reply to] Can't Post

In reply to:
<snip>
2 - pull force technique - I use a scale with max-force needle. (would like a digital, graphing with peak force and averaging functions, but until one of you give me one, its what I've got...) Checked once a year to ensure its still reporting accurately.
When its an option, I have someone wear the rig and have the scale pull in line with the housing.
When I don't have someone to wear the rig I place it on the table (PC up) and arrange the yoke/shoulder to have ~ the same arc as if it was being worn (often with another rig playing the roll of "shoulder")
I have heard some insist that it should be in a different direction... references?

I do my tests with the seal removed.

I test at the handle. However, I've heard some say it is the force at the pins that "counts" and the measurement should not include housing resistance at all. (when discussing "legal limits")

<snip>

TSO-C23f (TS-135), para 4.3.3(b) "a load applied at the handle of not more than 22 lbf (97.9 N), applied in the direction of normal design operation." The note in TS-135 4.3.3.1 states that the seal must be installed.

There is similar language regarding pull force, pull direction, and seal for TSO-C23d (AS 8015B, 4.3.2.1 and 4.3.2.5) and for TSO-C23c (AS 8015A 4.3.2.1 and 4.3.2.2).

TSO-C23b just says 22 pounds, without specifying direction or seal.

The direction of pull in normal design operation is probably straight out (90-degrees from the end of the cable housing) instead of straight down (aligned with the cable housing).

Mark


piisfish

Dec 7, 2012, 2:24 PM
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Re: [mark] Reserve / PEP ripcord pull forces [In reply to] Can't Post

In reply to:
The direction of pull in normal design operation is probably straight out (90-degrees from the end of the cable housing) instead of straight down (aligned with the cable housing).
Hi Mark, please allow me to not completely agree with that last statement/supposition. I agree with the "not straight down" but 90 degrees seem exaggerated, and would be glad to accept a happy medium at around 45 (and we are not talking Pullmonauti here). Will try and analyze my pulls at next repack Smile


riggerrob  (D 14840)

Dec 7, 2012, 2:31 PM
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Re: [fcajump] Reserve / PEP ripcord pull forces [In reply to] Can't Post

...

1 - regs: within the US, I understand that all reserve/emergency systems must deploy at or below 22-lbs. Yet, one rigger I know references (old?) that a three pin rig has a higher allowance than a two pin... Anyone? Other countries? ...

..........................................................................

First time I have heard that!
But I have only been a rigger for 28 years. ...

Rob Warner
FAA Master Rigger (back, seat and chest)
Canadian Rigger Examiner


mark  (D 6108)

Dec 7, 2012, 3:04 PM
Post #5 of 7 (965 views)
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Re: [fcajump] Reserve / PEP ripcord pull forces [In reply to] Can't Post

In reply to:
1 - regs: within the US, I understand that all reserve/emergency systems must deploy at or below 22-lbs. Yet, one rigger I know references (old?) that a three pin rig has a higher allowance than a two pin... Anyone? Other countries?

Military personnel systems (e.g. MC-4/5, etc) can be used by civilians. If the military spec allows a higher pull force, say, 27 pounds, the rig is legal to jump at any pull force from 5 to 27 pounds.

There may be a particular military-approved 3-pin container that is okay with a higher pull force than 22 pounds. An MC-3, perhaps. It's up to your rigger friend to provide the citation.

Many chest-type reserves are (were) 2-pin systems. Chest reserves are allowed a max pull of 15 pounds. If the 3-pin container is part of a back-type system and the 2-pin container is part of a chest-type, then the 3-pin could be legally allowed to have a higher pull force than the 2-pin.

Additionally, there is no maximum pull force specified for opening a main container.

Finally, I don't know of any case where pull force is measured at the pin.

Mark


fcajump  (D 15598)

Dec 7, 2012, 4:26 PM
Post #6 of 7 (934 views)
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Re: [riggerrob] Reserve / PEP ripcord pull forces [In reply to] Can't Post

In reply to:
...

1 - regs: within the US, I understand that all reserve/emergency systems must deploy at or below 22-lbs. Yet, one rigger I know references (old?) that a three pin rig has a higher allowance than a two pin... Anyone? Other countries? ...

..........................................................................

First time I have heard that!
But I have only been a rigger for 28 years. ...

Rob Warner
FAA Master Rigger (back, seat and chest)
Canadian Rigger Examiner

I am just guessing that he got that from NB-6 era...
I'll try to ask him next time I see him.

JW


JerryBaumchen  (D 1543)

Dec 7, 2012, 9:16 PM
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Re: [mark] Reserve / PEP ripcord pull forces [In reply to] Can't Post

Hi Mark,

Quote:
Chest reserves are allowed a max pull of 15 pounds.

Depends upon which TSO standard you are referring.

Not to be negative towards you, but there are different req'ments in each of the TSO standards.

If I remember correctly ( I was there Crazy ) the 15 lbs for gut pack came with C23c.

Other than the 15 lbs for gut pack, I know of no other definition for specific pull req'ments for types of containers, i.e., some number due to quantity of pins, etc.

JerryBaumchen



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