T-10 Reserve line release

[kenneth21441 0]

Hello all,

I recently received a T-10 reserve and a MC1. For jumping.

When I went to go a pack the cheast reserve I noted these pip pins (l&R Line release) (PN: 500 FAA-PMA) attached from the connector links to gore's 23 / 24 and 1 / 2.

It is some sort of disconnector for these lines but the question I have is why? and what is the use for this?

Does any one know?

As all the T10 reserves that I've packed where in the Army and did not have these.

Any help would be appricated.


Thanks,
Ken

Kenneth Potter
FAA Senior Parachute Rigger
Tactical Delivery Instructor (Jeddah, KSA)
FFL Gunsmith

[mark 107]

The 4-line release is the easiest way to convert an unsteerable round to a steerable one; no sewing required. The back four lines release by pulling the release pins (L&R) or pulling out the daisy chain (Waters). The suspension lines adjacent to the released lines (alternatively, the rear risers) can be used to steer right and left. The result is a very stable descent, IMO much nicer than the alternative triple-doghouse.

Army T-10C reserves don't have 4-line releases because it doesn't help much to have a steerable reserve if your main is not steerable.

Some Air Force back reserves incorporated a 4-line release for steerability. The original modification, a 4-line cut, required physically cutting the four marked lines, something most pilots were reluctant to do, having discovered that if an emergency requires the use of your round parachute, you still have an emergency.

Mark

[kenneth21441 0]

Mark,

Thanks for the info as that was what I thought but just wanted to make sure. I am sure that if I ever have to use it I will not be doing to much steering but its nice to try.

Thanks for the input.

Until then
Thanks,

Ken..

Kenneth Potter
FAA Senior Parachute Rigger
Tactical Delivery Instructor (Jeddah, KSA)
FFL Gunsmith

[masterrig 1]

My first reserve, was a 26' Navy conical with 4-Line releases. I never had to use it but, the principle is to vent air out the rear of the canopy thus, reducing occilation. The flight of the parachute was more forward with the four lines released.


Chuck

[wmw999 2,587]

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I am sure that if I ever have to use it I will not be doing to much steering but its nice to try.

Having used a 4-line release (on a 24' though), I can assure you that you won't be doing much steering . It only barely fits the description of "steerable." You can eventually aim it in the right direction, and it won't oscillate too much. That's about it...

Wendy W.

There is nothing more dangerous than breaking a basic safety rule and getting away with it. It removes fear of the consequences and builds false confidence. (tbrown)

[mjosparky 4]

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masterrig

the principle is to vent air out the rear of the canopy thus, reducing occilation.

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wmw999


you won't be doing much steering……..and it won't oscillate too much. That's about it...

The purpose of early mods on round canopies was just that to stop oscillation. Any forward speed and direction control was a by product of that.

My idea of a fair fight is clubbing baby seals

[waltappel 1]

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The purpose of early mods on round canopies was just that to stop oscillation. Any forward speed and direction control was a by product of that.

I thought that was what the crown vent was for.

Walt

[mjosparky 4]

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The purpose of early mods on round canopies was just that to stop oscillation. Any forward speed and direction control was a by product of that.

I thought that was what the crown vent was for.

Walt

Jump a 24' flat unmodified or C-9 28' flat and see if the crown vent stops ocillation.

My idea of a fair fight is clubbing baby seals

[JohnRich 4]

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[I thought that was what the crown vent was for.

Jump a 24' flat unmodified or C-9 28' flat and see if the crown vent stops ocillation.

Okay then, so what is the crown vent for?

[masterrigger1 2]

John,
The crown vent allows some air to pass though so that the high pressure zone does not become an extreme high pressue zone and damage the canopy.
Hence the word "vent".


Blue ones,
MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[riggermick 7]

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[I thought that was what the crown vent was for.

Jump a 24' flat unmodified or C-9 28' flat and see if the crown vent stops ocillation.

Okay then, so what is the crown vent for?

It helps dampen ocillation but is also used to vent the canopy during deployment so it doesn't explode, it's kind of a dual purpose thing.


Mick.

[JohnRich 4]

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The crown vent allows some air to pass though so that the high pressure zone does not become an extreme high pressue zone and damage the canopy.

Thanks for that info. I learned something new.

Or else I had just forgotten something old that I used to know. And at my age and memory condition, I can't be sure of which.

[NickDG 23]

Since no one mentioned it . . .

Before the mechanical line release mods became the norm the military color coded the four lines to be released after opening. However, that was meant to be accomplished with a knife, and most pilots, or crewmembers, under a paradhute for the first time landed with them still attached.

After the military heard the same line over and over, "Hey, the parachute opened and I ain't cutting nothing with no knife!" they went to these mechanical releases.

NickD BASE 194

[Gary73 10]

If you make the crown vent large enough it will eliminate oscillations, but the descent rate goes from barely acceptable to not-even-that-good. Many rounds had a sort of neck above the vent with a stretchy O-ring that would allow pressure release during deployment then mostly close up to reduce descent rate once you slowed down. (Notice my use of the past tense here. That's where round parachutes belong! )

I'll definitely second the comments about the 4-line release. My first reserve ride was on an unmodified 24. The oscillations swung me through about a 90-degree arc. My second was on a 4-lined 24. A far, far better ride, with plenty enough steering and forward speed for someone who started on military-surplus rounds.

My third and fourth reserve rides were on a 26 conical with 4-line release. Not a good combo. No oscillations, but the thing wouldn't start turning without a major toggle pull, then it wouldn't stop! Number four got me my first (and let's hope only!) tree landing for that reason. I'm not sure why there was such a major difference between flat and conical canopies.

I can also second the comments about aircrew attitude toward cutting lines. I was going through Naval Flight Officer training after reserve ride # 2 and the instructor was describing that process. I was thinking "Oh, okay.", but everyone else in the class was going "Oh hell no!".
________________________

"Extraordinary claims require extraordinary evidence." - Carl Sagan

[mjosparky 4]

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but is also used to vent the canopy during deployment so it doesn't explode,

No more calls, we have a winner. With out the apex vent round canopies would be a nightmare during inflation. If they don't come apart from over pressure they tent to set up a rock and roll oscillation that will make you sick enough to puke.

My idea of a fair fight is clubbing baby seals

[JerryBaumchen 1,466]

Sparky & Mick,

I'm not a canopy designer; just a user.

If I remember correctly the Navy 26 ft conical had a fabric cap over the upper hem, this therefore means it had no vent. Anyone remember those canopies? Maybe I'm wrong.

Jerry

[mjosparky 4]

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Sparky & Mick,

I'm not a canopy designer; just a user.

If I remember correctly the Navy 26 ft conical had a fabric cap over the upper hem, this therefore means it had no vent. Anyone remember those canopies? Maybe I'm wrong.

Jerry

It works like a cat’s eye apex vent or a rubber vent ring. During the deployment when the pressure in the apex region gets too high it opens and “vents” the pressure. Then after deployment it closes off to increase drag.

If you remember on the Navy Con. You could pull the vent cap down over the vent hem to straiten the apex and apex lines. Then pull it back up with just the bridle poking out.

My idea of a fair fight is clubbing baby seals

[riggermick 7]

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Sparky & Mick,

I'm not a canopy designer; just a user.

If I remember correctly the Navy 26 ft conical had a fabric cap over the upper hem, this therefore means it had no vent. Anyone remember those canopies? Maybe I'm wrong.

Jerry

It works like a cat’s eye apex vent or a rubber vent ring. During the deployment when the pressure in the apex region gets too high it opens and “vents” the pressure. Then after deployment it closes off to increase drag.

If you remember on the Navy Con. You could pull the vent cap down over the vent hem to straiten the apex and apex lines. Then pull it back up with just the bridle poking out.

Pioneers KXX had a "cats eye" vent, when I was under one it looked like a large nylon vagina!! Seemed to work though.

Mick.

[mjosparky 4]

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Pioneers KXX had a "cats eye" vent, when I was under one it looked like a large nylon vagina!! Seemed to work though.

Mick.

The fill time on that little toy parachute was so small if they didn't put that big apex vent on it could be really bad. But with such a large vent it came out of the sky like a man whole cover. So they compromised and put on the “cats eye”. As I am sure you know, when dealing with anything, parachutes more than most everything is a trade off.

The last KXX I packed I could swear I could read the paper through it.

My idea of a fair fight is clubbing baby seals

[riggermick 7]

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Pioneers KXX had a "cats eye" vent, when I was under one it looked like a large nylon vagina!! Seemed to work though.

Mick.

The fill time on that little toy parachute was so small if they didn't put that big apex vent on it could be really bad. But with such a large vent it came out of the sky like a man whole cover. So they compromised and put on the “cats eye”. As I am sure you know, when dealing with anything, parachutes more than most everything is a trade off.

The last KXX I packed I could swear I could read the paper through it.

Yep, everything in skydiving is a trade off. My KXX (which I still have (with a Phantom 22 full stow diaper, not quite legal, but I dont use it as a reserve)) is in great shape!! I used it as a tersh (free bagged without the diaper being used) and it lands just fine!! Without the cats eye it would definatly land like a lead balloon!!

Mick.

[darkwing 5]

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Sparky & Mick,

I'm not a canopy designer; just a user.

If I remember correctly the Navy 26 ft conical had a fabric cap over the upper hem, this therefore means it had no vent. Anyone remember those canopies? Maybe I'm wrong.

Jerry

I believe you are correct. The Navy conicals I saw had (or were supposed to have) SOLID vent caps. During my master rigger practical I had to replace one that the owner had removed.

-- Jeff
My Skydiving History

[JerryBaumchen 1,466]

Jeff,

I'm with you on this; not as Mick & Sparky think.

Now we'll have to find one (any out there?) to 'know.'

Jerry

PS) Terry, you got one around?

[riggermick 7]

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Sparky & Mick,

I'm not a canopy designer; just a user.

If I remember correctly the Navy 26 ft conical had a fabric cap over the upper hem, this therefore means it had no vent. Anyone remember those canopies? Maybe I'm wrong.

Jerry

I believe you are correct. The Navy conicals I saw had (or were supposed to have) SOLID vent caps. During my master rigger practical I had to replace one that the owner had removed.

SOLID is a reiative term here (I do seem to remember them too) the canopy had the porosity of cheese cloth so it self vented. Continious suspension lines woukd keep it together in the event of an apex failure. I believe that's the only round canopy like that.

Mick.

[ripcord4 0]

I had a Navy 26' conical reserve and it most definitely DID have a "solid" vent cap. I cannot swear to the porosity of the fabric of that cap, however. Does anyone have an old Navy riggers manual. "Parachute Rigger 3 & 2' perhaps?

[ripcord4 0]

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I had a Navy 26' conical reserve and it most definitely DID have a "solid" vent cap. I cannot swear to the porosity of the fabric of that cap, however. Does anyone have an old Navy riggers manual. "Parachute Rigger 3 & 2' perhaps?

I just dug out my Crossbow harness and container. It has a Navy 26' conical canopy with the closed apex. It is most definitely standard 1.1 0z nylon material for the "cap" on the apex. For those inquiring minds that wish to know.