Ripcord pull force (re Poynter's manual)

[johnmatrix 21]

I came across this bit in Poynter's parachute manual that I'm curious about:

p423 (Section 7.46)
"On some side pull containers, pulls of as much as 80 lbs have been recorded and this is particularly disturbing after reviewing an Air Force report on muscle strength: 50% of the male Air Force personnel tested could not pull 22 lbs (the FAA maximum as set forth in NAS-804) to the side, 95% couldn't pull 43 lbs and 5% couldn't even pull 12 lbs."

Does anyone know how it came to be that the FAA max of 22lbs was set that high?
Or was this set for a different system before side pull containers became widely used?

The google is struggling with NAS-804. From what I can see it began in 1949 alongside TSO-C23b. Is that right?

[masterrigger1 2]

Quote

Does anyone know how it came to be that the FAA max of 22lbs was set that high?
Or was this set for a different system before side pull containers became widely used?

Good question!
I have no idea...

Also, remember that the B-12 was allowed to have a pull force up to 28 lbs also.

I would have to look it up but i think it was the only military rig to allowed that high of a pull force.

The NB-6 could be also included, but I simply do not remember for sure.

MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[steve1 5]

I think I may have already told these hard pull stories. I hate to sound like a broken record all the time. But I'm about out of old stories.....

Anyhow, I remember a small girl in the 70's who couldn't open her B-12 container on two different jumps. She had an awful time just opening her belly reserve. She ended up with the nickname of "Total".

Most people were trained to pull with two hands if one didn't work. I'd think that most could pull more than 22 pounds, with two hands.

I remember one jumper who survived a midair collision with another plane. A year later he had a hard pull, couldn't open his main....(It may have been a b-12). He thought there could have been a piece of gravel in his rip cord housing. He openned his round belly reserve, and found it full of holes. He ended up in the hospital.

A year or so after that, he was killed in a plane crash, on a snowy day. I guess he ran out of luck....

[JerryBaumchen 1,364]

Hi john,

Quote

The google is struggling with NAS-804. From what I can see it began in 1949 alongside TSO-C23b. Is that right?

It works sort of like this; a committee writes a standard, i.e., NAS 804 and submits it to the FAA. They then consider it, maybe change it, and publish it as the reference document for the TSO.

The standard becomes a part of the TSO.

Just my thoughts on this.

If you would like a copy of TSO C23b, drop me a line with your mailing/postal address & I'll send you one.

As for why the 22 lbs, way before my time. But it did get changed in C23c & d for chest packs.

Hope that this helps,

JerryBaumchen

[JerryBaumchen 1,364]

Hi steve,

Quote

I remember a small girl in the 70's who couldn't open her B-12 container

We had a rather small girl jumping with us at Mayfield's dz in ~ 1969-70 or so. At a competition at Snohomish, on a hop-n-pop she went to pull her main ripcord (B-4/B-12) and could not get the pins to clear. So she went to her chest pack and could not pull it. She then went back to the main ripcord (very lucky to find again) and pulled with both hands. She was swinging in the saddle in the mid-100's.



JerryBaumchen

PS) As I remember, that was her last jump.

[dks13827 3]

PS) As I remember, that was her last jump.


Good thinking !!! On both counts.

[johnmatrix 21]

Thanks Steve! I remember reading that in the 'scary stories' thread and was thinking I might have to read the entire thread again to find it.

There is an APF RAC concerning the pull force for female parachutists here:
http://hq.apf.asn.au/images/5/5d/502B.pdf

It seemed from that that the max had been set right for the majority of men (but unfortunately too high for some women) but that passage from Poynters indicates the limit was set too high for a large percentage of men too. I had a vision of the regulations being drafted quickly one afternoon by a 250lb drill instructor who thought 44lbs was a reasonable pull force, and never being further looked at.
I guess we're talking about a time here where things didn't work as they do now and there was a bit of trial and error to work through.

There is more info on other studies in Poynters 9.3.2 but not much more about the side mount systems.

http://bit.ly/ofR4gx

From what I can see about the side pull chest mount systems it would have been a bit harder to get another hand on it.
Thanks for the responses.

[johnmatrix 21]

Thanks Jerry! So the TSO is the primary document and then NAS-804 was like an appendix or something?
The TSO gets mentioned a lot on this site but not the NAS, I think I saw somewhere it was superseded by one of the later TSOs....?

[mjosparky 4]

Good question!
I have no idea...

Also, remember that the B-12 was allowed to have a pull force up to 28 lbs also.

I would have to look it up but i think it was the only military rig to allowed that high of a pull force.

The NB-6 could be also included, but I simply do not remember for sure.

MEL

[JerryBaumchen 1,364]

Hi Sparky,

Re: http://www.baesystems.com/...ndv_durachute_af.pdf


I talked to them at a PIA Symposium a few years ago. At that time, IIRC, they said that they had developed it under a Navy contract and that was the only way to get one.

Anything new that you know of?

JerryBaumchen

[mjosparky 4]

Quote

Hi Sparky,

Re: http://www.baesystems.com/...ndv_durachute_af.pdf


I talked to them at a PIA Symposium a few years ago. At that time, IIRC, they said that they had developed it under a Navy contract and that was the only way to get one.

Anything new that you know of?

JerryBaumchen

Yes I do. The company I worked at the time, AERO, conducted most of the tests using a King Air. I did most of the live jumps on it for the TSO. We test the standard aircrew, one for the E2-C and one for the P-3 Orion. We spent over 2 years doing testing on various configurations of the system.

Sparky

http://i397.photobucket.com/albums/pp55/mjosparky/Skydiving/LiveTest2.jpg

http://i397.photobucket.com/albums/pp55/mjosparky/Skydiving/HighAltitude3-1.jpg

The original company was Simula Inc.

My idea of a fair fight is clubbing baby seals

[likestojump 3]

I just got a Durachute (P22P). Pretty cool LITTLE thing. Feels like a brick with a vacuum sealed canopy. A EXTREMELY noticeable different from the old NB's

[mjosparky 4]

Quote

I just got a Durachute (P22P). Pretty cool LITTLE thing. Feels like a brick with a vacuum sealed canopy. A EXTREMELY noticeable different from the old NB's

How did you manage to scam on of those?

Sparky

My idea of a fair fight is clubbing baby seals