Origin of Pulled down Apex?

[everymansaved 0]

Hey all, I'm doing pre-questions for my upcoming rigger A course, and I have one question of thirty still plaguing me. The question is about who developed the pulled down apex. I've found the term referanced several times in the design of hte PC etc... but never its origins. Can someone give me a hint, or a clue as to where to look in my Poynters manual? I just thought all you guys that are so well versed in vintage gear might have a better idea than I. Thanks!!

God made firefighters so paramedics would have heroes...and someone can put out the trailer fires.

[bozo 0]

Quote

Hey all, I'm doing pre-questions for my upcoming rigger A course, and I have one question of thirty still plaguing me. The question is about who developed the pulled down apex. I've found the term referanced several times in the design of hte PC etc... but never its origins. Can someone give me a hint, or a clue as to where to look in my Poynters manual? I just thought all you guys that are so well versed in vintage gear might have a better idea than I. Thanks!!

--------------------------------------------------------

that would be cheating.

bozo
Pain is fleeting. Glory lasts forever. Chicks dig scars.

[everymansaved 0]

No!! It specifically says in our instructions that it's an open book assignment, and we can draw on other people. We just have to reference the poynter manual. Now PLEASE!!! hehe

God made firefighters so paramedics would have heroes...and someone can put out the trailer fires.

[JerryBaumchen 1,063]

Hi every,

Back in the '60's there was talk of the Italians using a seperate line attached to the apex of their 'normal' round canopies so that they could pull the apex waaaay down to increase the descent rate; they then would let go of the line just before touchdown. Might be an old urban myth.

The first I knew of the pulled down apex was on the lifting canopy designed by the Frenchman Lemoigne. He owned the rights to the design and Pioneer bought them from him for use in this country; resulting in the ParaCommander.

However, the first canopy on the market with a pulled down apex was Security's CrossBow.

HTH,

Jerry

[everymansaved 0]

Thanks, I think I've found it!

God made firefighters so paramedics would have heroes...and someone can put out the trailer fires.

[ripcord4 0]

Quote

Hey all, I'm doing pre-questions for my upcoming rigger A course, and I have one question of thirty still plaguing me. The question is about who developed the pulled down apex. I've found the term referanced several times in the design of hte PC etc... but never its origins. Can someone give me a hint, or a clue as to where to look in my Poynters manual? I just thought all you guys that are so well versed in vintage gear might have a better idea than I. Thanks!!

I believe the US Air Force developed the pull down vent line to decrease the opening time of its 28' diameter emergency chutes. The Army and Air Force also use pdvl's to allow for faster inflation of air drop cargo chutes to allow lower drop altitudes.

[everymansaved 0]

Awesome! Thanks!

God made firefighters so paramedics would have heroes...and someone can put out the trailer fires.

[pchapman 262]

Quote

Back in the '60's there was talk of the Italians using a seperate line attached to the apex of their 'normal' round canopies so that they could pull the apex waaaay down to increase the descent rate; they then would let go of the line just before touchdown. Might be an old urban myth.

Here's a pic from ParachuteHistory.com where there's a page on it.

[vpozzoli 0]

Quote

Hi every,

Back in the '60's there was talk of the Italians using a seperate line attached to the apex of their 'normal' round canopies so that they could pull the apex waaaay down to increase the descent rate; they then would let go of the line just before touchdown. Might be an old urban myth.

Nope, not a myth. A friend of my father's went through airborne school in the '60s all the way to his instructor rating and, as an instructor, he he had to get rated for that type of 'chute as well. I don't recall what they where called and have no idea whether they're still in use today.
Obviously the rationale behind this mod was to spend less time playing shooting target for the enemy when dropping into a hot area. In reality it only caused a lot of preventable injuries as a result of its own peculiar brand of "low pull contest" (in this case a "low release" of the mod line).

Cheers,

Vale

[CReWLL 0]

Canopy Apex Retraction
Originally conceived and tested as a reefing method, retraction of the canopy apex with an axial control line has more recently been used as a means of both shortening the filling time and increasing the effective drag area of the fully inflated canopy. For this purpose the apex retraction line is made a fixed length which will pull the apex down a distance in the range of 0.25 – 0.40 times the nominal diameter.
There is an AIAA paper on the subject, AD 764 364, May 1973.

[JerryBaumchen 1,063]

Last year Dan Abbott, who designed the entire CrossBow system, stayed with me for a night. He said that when they went to determine just how much to pull down the apex on the CrossBow canopy they had not a clue. So they took an old C-9 that they had made for some contract, pulled the apex down to the skirt and had some guy jump it. He said that it knocked the beejeesuuus out of the guy. Plan B was to raise the apex 2 feet and rejump the C-9. It worked and that became the final design for the CrossBow canopy.

Real high tech design/development work; "OK, where can I find a %&#@& dummy?"

Jerry

[riggerrob 558]

The first I knew of the pulled down apex was on the lifting canopy designed by the Frenchman Lemoigne. He owned the rights to the design and Pioneer bought them from him for use in this country; resulting in the ParaCommander.

However, the first canopy on the market with a pulled down apex was Security's CrossBow.

HTH,

Jerry

[WGore 0]

Quote

The first I knew of the pulled down apex was on the lifting canopy designed by the Frenchman Lemoigne. He owned the rights to the design and Pioneer bought them from him for use in this country; resulting in the ParaCommander.

However, the first canopy on the market with a pulled down apex was Security's CrossBow.

HTH,

Jerry

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>.

Remember that LeMoigne was primarily interested in towed canopies ala. Para-Sail.
Americans at Pioneer and GQ Security perfected PDA for freefall deployment.
I have also repacked a few ejection seat parachutes that included PDA to speed inflation at low altitudes and low airspeeds.

[riggerrob 558]

A number of years ago I modified a round reserve with a PDA for BASE jumping and we tested it at 100ft and got reliable openings with Oscar (our drop dummy). It was used at 217ft by the owner off of a bridge.

[WGore 0]

That would make for a snappy opening. Sure wouldn't want much speed there.

GUNFIRE, The sound of Freedom!