Closing loop tension

[d123 1]

Does anybody know a way to test if your closing loop is long enough or is there a way to check if the closing pin tension is good enough?

I'm starting to think that mine is too slack but I have no way of really knowing it ...

Regards,
Jean-Arthur Deda.

Lock, Dock and Two Smoking Barrelrolls!

[CrazyL 0]

I assume your talking about the main closing loop. Read the manual and/or call the manufacturer. Learn how to make a closing loop, and know the type (name) of the line that the manufacturer recommends. Know how to tie the knot and install proper washer. Know when to replace the closing loop regardless of how many jumps are on it. The loop and the rubber bands are the 2 things that you (the end user) will be replacing from time to time without rigger supervision. Be good at it. If your freeflying, get a gear check by the highly experienced freefliers. Pin pressure should exceed the pressure it takes for the freefall wind speed to blow your bridle out from under the side flap and/or BOC and pull the pin. Scenario: Flying back to earth or butt down the pin cover flap blows open, bridle and pin get a heavy dose of 120mph+ wind beating. The wind whipping the bridle is what can pull the pin if the pin pressure is loose. You should have a curved pin on the main bridle, it'll pull in any direction. Brilliant innovation. On some rigs the bridle under the side flap is loose, the bridle is only sort of wedged up under the side flap anyway. You want the bridle that is tucked under the side flap to have pressure on it created from wedging the bridle up under the side flap till there is sufficient pressure (usually no higher than half the main container). So what if your pin was pulled while you're on your back arms and legs toward the sky and your pilot chute is still in the BOC? Gnarly horseshoe malfunction! Shorten the closing loop to be as tight as you can and still close the container, close the pin cover flap and do a pull test on the ground. There is much more to learn concerning loops, pins, bridle, boc, p/c, h/c, and aad choices for crw, rw, ff, cp, scr, scs,and zoo loads. Choose 'freefly friendly' gear. I took my Infinity to 246mph last month. Most gear is certified to go no faster than 150knots, close to 170mph. I would'nt want incidental main deployment at any freefall speeds. My pin pressure is tight.

[councilman24 36]

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Most gear is certified to go no faster than 150knots, close to 170mph. I would'nt want incidental main deployment at any freefall speeds. My pin pressure is tight.

Gear isn't certified for a freefall speed. The reserve and harness are certified for maximum weight and speed for deployment based on strength testing during the TSO process. Mains are not tested to any particular strength specification. And the H/C isn't necessarily tested as a complete unit with a main ready to deploy at any speed. (There are function tests for the reserve with the main full. But not necessarily airworthy and not necessarily at high speed.)

Many assumptions or marketing claims are made about the container designs being freefly (read high speed) friendly. No 'certification' testing is required.

When your going faster than the placarded deployment speed you in a realm where inadvertant opening may cause damage.

Perhaps TSO certification testing should specifically test the container integraty at high speed but it doesn't. And since the new TSO based on PIA Technical Standard TS-135 is scheduled to be published before Nov. 1 and it took 15 years to write it and have it adopted, I don't think high speed integrity will be added soon.

You can read the proposed TSO standard at pia.com, public documents. TS-135

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[RiggerLee 61]

Just for the record you are right to be worried. We recently had an incedent where one of our jumpers had transitioned from head down to a sit. He then had a preme. His normaly soft oppening canopy cracked the shit out of him and he now has a spinal injury. We are still waiting to see if he will ever wiggle his toes.

The simple truth is that the freeflyers have been exceading the speeds and some times the weights of what our gear has been designed for for a long time. I'm just surprised that there have not been more incedents, there have been some, before now. The reallity is that everything on the system from the harness and reserve all the way down to the main bag and PC were designed to opperate at normal speeds and altitudes. I remember haveing this conversation years ago with some one at Quincy where I predicted that we would start to see gear failures or in the case of Dinnis a failure of his body. Freeflying has become so prevolent it may be time to look at a full redesign of our gear and I mean more then just cool freefly colors and embrodery. It's time for people to learn to judge the marits of a container by more then just how shiny the hardware is.

Some thoughts:

Longer bridals should be standard alowing smaller PC and lower high speed snatch forces.

It's time to reevaluate how we are stowing our lines on the main bag. We may need to look at a more secure anti line dump bag for more possitive stageing. Lose the rubber bands and put heavy bungy stows on the locking loops. Two flaps that cover the lines and suport them from line dump.

The freefly puds have marret but some of the designs need a little more work.

A lot of the reserves out there were never built for this. We're finally getting a new generation of canopies hopefully they will be up to the chalange. I wouldn't be opposed to reducing the opening speed requierments. It's just too hard to build a canopy that oppens supper fast at low speed and doesn't blow up at high speed. That's what they did with tandoms. We're oppening higher then we did in the past. Low cut aways aren't as big a deal as they once were. You may have to pick your battles.

I've only seen a few harnesses dammaged but there have been injuries to jumpers. It might not hurt to pay more attention to the ergonomics, for lack of better word, and fit of the designs. Broken femors are not cool. I don't know if any thing could have saved Dinneses spine but we should keep in mind the protental for high g oppenings.

I'm sorry, I'm on a rant.

Oh, and for god sake can't people jump decent size gear! I'll go away now.


Lee

Lee
[email protected]
www.velocitysportswear.com

[NickDG 23]

Damn, nobody can give a simple answer anymore?

Pack up per normal. Lay the rig face down on the ground with the bridle and PC in your hand. While standing pull up very slowly on the bridle until you encounter the pin. Keep pulling gently and the rig should begin to rise ever so slightly before you hear an audible pop and the main container opens.

If you can pick the container anywhere near clean off the ground the loop is too tight. If the rig doesn't move at all and the pin just slides out of the loop with no pop at all (no resistance) it's too loose . . .

NickD

[skydiverek 54]

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I don't know if any thing could have saved Dinneses spine

Dacron lines, possibly.

Here is what BILL BOOTH has said on dropzone.com about DACRON LINES. Great source of info!:

"My tests show up to a 300% increase in opening shock felt by the jumper using Spectra vs. Dacron suspension lines. It is not always that much different. It depends on how quickly the force is applied...and canopy makers have done a good job of designing canopies that open slowly enough to allow the routine use of Spectra. However, when a rare hard (quick) opening happens, Spectra lines will definitely make it hurt more."

"Tandem canopies are public transportation. Little old ladies and parapelgics jump tandem. Dacron lines give lower opening shocks. It's that simple. This might not matter much on a "normal" opening, but if someone make a small mistake packing which results in a super fast opening, the Dacron lines could save somebody's grandmothers life. I know Dacron is bulkier, but I've seen no evidence that Dacron lined canopies have more malfunctions. In fact, I believe the opposite may be true."

"Anyone who doubts that suspension line stretch is a factor in reducing the opening shock felt by a jumper, should make a bungee jump...only replace the normal stretchy bungee cord with a stainless steel cable. What's going to happen when you hit the end of that steel cable? Your leg is going to be torn off, that's what. Now remember, Spectra line stretches about as much a steel cable."

"If you are not using Dacron lines, they would help. They stretch a little, and also slow the slider down due to surface friction. Spectra (micro) line does not. If you are already using Dacron lines, and still having hard openings, get a canopy that opens slower."

"The best way to avoid injuries from that occasional super hard opening (as well as the hard openings themselves), is not to jump no-stretch lines. Ask yourself, "Do I really need the (slight) advantages no-stretch lines offer?" If not, get Dacron. Your body will thank you, because even if you are not ever seriously injured on any single jump, each even slightly hard opening on no-stretch lines is damaging your body...and it all adds up."

"Spectra (micro line), Vectran, Kevlar, and HMA are "no-stretch" lines. They do not "absorb" opening shock the way Dacron does. This means that the same "hard" opening can hurt you a lot more. It's like doing a bungee jump with steel cable. The same force is applied...but a hell of a lot more shock is felt by the jumper. All the opening shock caused broken harnesses (two PDF tandem harnesses recently broke), injuries (a guy just broke both femurs), and fatalities (4 in the last two years that I know of) have all been on "no-stretch" line canopies, and could probably been prevented if Dacron line had been used. No stretch line is used because it is thinner, lighter, and has less drag than the same strength Dacron. While this is an "advantage" in a high speed swoop, it has no place in tandem. 85 year old grandmothers jump tandem. They, and many other tandem students, need the softest opening shock possible. This is why we only use Dacron line on our tandem products. Not to mention that our tandem equipment was NOT drop tested with no-stretch lined canopies.
I don't care if you have 1,000 jumps on a particular canopy with no-stretch lines with no problems. Ever canopy opens hard eventually. When that happens, I want some "bungee cord" between that canopy and the tandem passenger."

"One thing is for sure, if you jump "no-stretch" lines, especially Spectra (because it's so slippery, and reduces slider drag) your chance of being injured or killed by a hard opening shock is much greater than if you jump Dacron line, which stretches just enough to absorb some of that shock before it hits you."

"Spectra (or micro-line) is strong and tiny, so it reduces both pack volume and drag , which means you get a smaller rig and a faster canopy. Unfortunately, It has a couple of "design characteristics" (this is manufacturer talk for "problems") It is very slippery (less friction to slow the slider), and stretches less than stainless steel. This is why it hurt people and broke so many mini risers when it was first introduced. Now, I must say that the canopy manufacturers did a wonderful job handling these "characteristics" by designing new canopies that opened much slower than their predecessors. However, the fact still remains, that if you do have a rare fast opening on a microlined canopy, Spectra (or Vectran) will transmit that force to you (and your rig) much, much faster, resulting in an opening shock up to 300% higher than if you have Dacron lines. (It's sort of like doing a bungee jump with a stainless steel cable. At the bottom of your fall, your body applies the same force to the steel cable as it would to a rubber bungee cord, but because steel doesn't stretch, your legs tears off.)."

"Reinforced type-17 webbing risers rarely break. They have a new breaking strength of around 3,500 lbs. This is not that much less than type-8 risers breaking strength of 4,000 lbs. The real difference is whether you have mini rings or large rings...and the difference here is in cutaway forces, not breaking strength. While properly designed mini-ring risers can easily release even a 250 lb. jumper in a 3 or 4 "G" spin, the problem is that it is harder to manufacture mini-ring risers correctly. What causes any riser to break is usually a combination of a heavy jumper, a hard opening canopy, and no stretch (Spectra, Vectran, or HTML) line. Broken risers on Dacron lined canopies are very rare indeed."

"Single rear riser break is very rare. Risers usually break where they go around the large harness ring. It is obvious that since the "reinforcement" in type 17 risers is below the confluence, it does nothing to prevent this kind of damage. When this riser broke, it "released" a lot of energy, thus preventing much more serious injury of the jumper. Which is a good thing. The only way I know of to prevent "killer" opening shocks, is not to jump Spectra (Microline) or Vectran. They don't stretch at all, and therefore do nothing to help absorb the energy of a really hard opening. As long as we insist on jumping non-stretch lines, incidents like this are bound to happen. (Canopies with Dacron lines can still open hard, but much less shock is actually felt by the jumper.)."

[RiggerLee 61]

Booth is with out doubt a bright guy but as usual I don't fully agree with him.

It's all about kinetic energy. You have to do work to absorb it. Work is force over distance. Bunjies work becouse they streatch a long way. The force is absorbed over a long distance. Daccron does streatch but not that much. Even the hardest slammer is already ocuring over a distance measured in tens of feet. The streatch we're talking about is on the order of an inch. Even the body it self absorbs more energy then that.

Now where he's right is in the friction at the slider. It's hard to push a grommet down those fat lines at a fast rate. Keeping the canopy compressed has a far greater effect on mittigating the maximum forces of an oppening.

Personaly I think he had it right in the beggining with the large RW1 rings. That's why I was always so stoked about the Icon risors with the long center ring. Smartest thing I've seen in a long time. I wish they were the standard.

And he's right we're making too much out of this post. Bottom line guy, If you can close your container with out grunting then it's too lose.

Lee

Lee
[email protected]
www.velocitysportswear.com

[d123 1]

OK, so my closing loop is way too lose. Thanks for the input guys and I'll adjust it right away!
It also sounds like the pulling force should be around 10-15 pounds (to raise your rig up a bit before hearing the pin pop). Am I interpreting this right?

And is there a too tight closing loop that could create PC hesitation when doing H&P from Cessna or wing suit flight?

Regards,
Jean-Arthur Deda.

Lock, Dock and Two Smoking Barrelrolls!

[ZigZagMarquis 8]

Quote

Damn, nobody can give a simple answer anymore?

Pack up per normal. Lay the rig face down on the ground with the bridle and PC in your hand. While standing pull up very slowly on the bridle until you encounter the pin. Keep pulling gently and the rig should begin to rise ever so slightly before you hear an audible pop and the main container opens.

If you can pick the container anywhere near clean off the ground the loop is too tight. If the rig doesn't move at all and the pin just slides out of the loop with no pop at all (no resistance) it's too loose . . .

NickD

... and if you can pick your rig up by the PC bridle and swing it around over your head without the main pin being pulled, then that closing loop is "right out!"

[CrazyL 0]

Youre right. So how about the closing loop tension/ pin pressure? All gear does not have speed limitations, like my camera helmet or altimeter or shoes. Harness/ container and reserve canopies do have placard weight and speed derived from TSO tests. Many jumpers overspeed, some overweight and overspeed. Few pay the ultimate price for breaking the placard limits. Half a pilots body was broken for crossing into the realm of overweight/ overspeed. I get away with overspeeding the placard limits. I even do gnarly hookturns. Not sure which is most hazardous. Hookturns? cruising at over 200mph in freefall with gear not rated for such speeds? or jumping with a newbie that decides to sitfly with a loose closing loop wearing a demo rig with riser covers that just wont stay closed wearing a t-shirt and shorts jumping barefoot in the desert without a helmet? As I was trained at about jump 9 or 10 while in the static line program, I was taught how to 'track'. Was also taught how to 'flare' out of a 'track'. That training has paid off on pretty much every jump. Basically i'll slow down to a comfy speed for deployment whilst aiming my rig for the sky for deployment. Like in my quote in your post, ' I would'nt want incidental main deployment at any freefall speeds. My pin pressure is tight.' Gotta go change my BOC now, cycle and install my cypres, make sure my RSL is routed correctly, and when i pack my main i'll know it's tight enough when I make funny breathing sounds/ grunt a little.

[CrazyL 0]

Quote

OK, so my closing loop is way too lose. Thanks for the input guys and I'll adjust it right away!
It also sounds like the pulling force should be around 10-15 pounds (to raise your rig up a bit before hearing the pin pop). Am I interpreting this right?

And is there a too tight closing loop that could create PC hesitation when doing H&P from Cessna or wing suit flight?

Regards,
Jean-Arthur Deda.

Yes. While at the dz talk with the packers and rw jumpers and freefliers about how tight their loop is on the pin. For my wingsuit flights I change the loop to a length good for rw. I get hooked on wingsuits occasionally and will do several in a row. When it's time to go fast i''ll have a 'freefly tight' loop. I typically do hop and pops at random. For the quick hop and pops i'll open my riser covers and main pin cover flap and flip my pin so it stands on edge with the eye of the pin facing the BOC because of the 'freefly tight' loop. If i'm gonna take a delay on a hop and pop over 5 seconds I leave everything closed and tight partly because i'll exit in a spin of some sort.

[erdnarob 1]

I guess you are talking about main closing loop. It has to be quite thight for safety purpose. On a Vector III for instance, the closing loop is alright if the 2 biding tapes of the 2 last flaps (right and left) are just ovelapping.
A closing loop can easily becomes too long when the weather is more humid since the main canopy get smaller in volume due probably to less electrostatic electricity. Most likely seen in July and August. It's time then to readjust the closing loop length.
A too long closing loop is dangerous for you, for the airpane and everybody inside the since if you main container gets open in the door, the main parachute can be caught in the tail and rip it off if it inflates. I have seen a guy moving inside a Twin Otter and having when his main container opened due to a too long closing loop. We managed to close back the container and he could jump. On the ground I told him to have his closing loop shortened.

Learn from others mistakes, you will never live long enough to make them all.

[mjosparky 3]

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Most gear is certified to go no faster than 150knots, close to 170mph.

Most recent gear is tested and certified to the following:

---

a. Test weight = Maximum operating weight limit x 1.2
b. Test speed = Maximim operating speed limit x 1.2

However, test weight must be not less than 264 lb (119.7 kg) and the test speed must be not less than 180 KEAS (333.4 km/h) for reserve and emergency parachute assemblies; for dual harness parachute assemblies for test weight must not be less than 480 lb (217.7 kg) and the test speed must not be less than 210 KEAS (388.9 km/h).

---

That makes the MOW at least 220 lb. and MOS at least 150 KEAS or a little over 170 mph.

Sparky

My idea of a fair fight is clubbing baby seals

[popsjumper 2]

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And is there a too tight closing loop that could create PC hesitation...

No. A too-tight closing loop could create a PCIT. A weak throw is the most common cause of a PC hesitation.

WRTO all the gibberish....go back and read Nick's common sense information.

My reality and yours are quite different.
I think we're all Bozos on this bus.
Falcon5232, SCS8170, SCSA353, POPS9398, DS239

[d123 1]

Quote

A too-tight closing loop could create a PCIT. A weak throw is the most common cause of a PC hesitation.

True. I've meant to say PCIT.

I've shorten my closing loop to the point that I can't close the container unless I'm using the power tool. With the pull-up coord it's really hard. Its tight but I've seen tighter ones around my DZ.

From pitch to stand up I got around 1.0 - 1.5 sec. Is that too much? Dunno if my measurements are that accurate though ....

Lock, Dock and Two Smoking Barrelrolls!

[mjosparky 3]

Quote

From pitch to stand up I got around 1.0 - 1.5 sec. Is that too much? Dunno if my measurements are that accurate though ....

If you are using a curved pin, have the bridle routed correctly and can close the container without the use of a PLD a PC in good condition will extract the pin.

Sparky

My idea of a fair fight is clubbing baby seals

[jsaxton 0]

If your wife/girlfriend can close your rig, your closing loop it too long