lines and connector links

[voltage 0]

Question from a student:

When you start out with your first gear, means you start on a bigger canopy, what type of lines and connector links would you order?

What would you think about that decision:

190sqf Spectre with Dacron lines and Slinks for a jumper about 180 pounds out of the door

I mean I got unsure of my decision when asked by a gear shop person "do you really want Dacron on your canopy? Nowadays people don't use that anymore".

But as I understand it Dacron will help me save my back in case of those few hard openings. I have learnt on a canopy with Spectra lines and one time got an opening that I could feel in my back for several days. Nothing permanent, but I do care for my body and don't want to experience that again when avoidable.

So what do you think about my choice? Will the drag do very much on a 190sqf Spectre and will it be alot bigger to pack?

Thanks for comments,

Andi

[skydiverek 63]

From my different post to a skydiver who needed soft openings (previous back injury):

"Hi there,

Yeah, Spectre would be perfect. Also, opt for Dacron lines, which strech more than Microline and have more friction when the slider grommets slide on them. Here is Performance Designs' opinion on them (from their website):

"Why would anyone want to use Dacron line on their canopy?

Though most people prefer the lower bulk and drag of Microline or Vectran, Dacron is often the best choice for some applications. Dacron is a fairly elastic line, so it gives a little when there is a sharp "spike" to the opening force. This elasticity won't change the really good openings very much, but it can take the edge off those occasional abrupt openings where your packing was a little off or your airspeed was a little high at opening time. Dacron may be preferable in a student operation, where unusual body positions can compound opening issues. Some camera flyers with very heavy helmets also prefer Dacron lines. Older jumpers, who may not want to subject their bodies to hard openings, may want Dacron to help reduce the impact should something get a little out of control at opening time."

Also, Bill Booth made some comments on that issue, too:

"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.)"

Moreover, you can opt for lighter, brass slider groomets, instead of heavier, stainless steel slider groommets. Lighter mass equals less momentum (speed) down the lines. BTW, Precision Aerodynamics favors them, saying they contribute to softer openings.

Also, on their website Performance Designs says that "larger Spectres open slower than the smaller models".

So, to sum up, if I were you my choice would be large Spectre, Dacron lines, and brass slider grommets. Careful packing and deploying at no faster than 120mph (and not while tracking, especially steep tracking) will help, too. Some people also say that Psychopacking helps, but I am not sure about this.

Good luck and welcome back
Bart"

Drag on 190 will be no issue. It will pack one size larger (on the safe side).

[billvon 3,116]

>what type of lines and connector links would you order?

Dacron can indeed mitigate the damage a slammer can cause, but generally canopies are not as prone to slammers as they once were. The Spectre is legendary for soft and consistent openings. If you're ordering new I'd tend to stick with spectra for the simple reason that the resale value will be higher and you probably won't have the larger canopy for very long.

At those loadings drag won't be too much of an issue, but you will still see some minor degradation in glide performance with dacron.

Connector links don't matter too much. For smaller canopies where you have to collapse the slider and pull it down I'd go with slinks, but for larger canopies again it doesn't matter as much. You can still pull the slider down if you wish.

Hard links are easier to change out if you'll be switching risers/canopies often. Slinks are less likely to damage the slider if you don't take care of your slider bumpers.

[AggieDave 6]

Firstly we need to wonder if this student jumper has talked to his instructors and is local rigger yet? Regardless of what we consider to be good information, there's no way for him to verify our opinions as a trusted source.

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Hard links are easier to change out if you'll be switching risers/canopies often. Slinks are less likely to damage the slider if you don't take care of your slider bumpers.

Slinks are stronger then the metal connector links and if they fail they fail, instead of bending open for an unsuspecting dump of a group of lines at 75ft.

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generally canopies are not as prone to slammers as they once were.

Any canopy can give you a slammer opening. With that said I don't have dacron on my velo, I have tiny Vectran on my Velo and am going to even smaller HMA. It is about choice and what your desired result is.

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for larger canopies again it doesn't matter as much.

An uncollapsed or even a collapsed slider on your lines at the connector point increases the wear on the lines at that point. However, a slider that is pulled down but is allowed to "creep" back up can do all sorts of bad things to your vision and possible controlability issues. There's also the obvious factor of having a slider come down over your toggles during deployment.

Like most all things in skydiving, everything is a trade off.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[billvon 3,116]

>An uncollapsed or even a collapsed slider on your lines at the
>connector point increases the wear on the lines at that point.

Yes, which is why you MUST pull down the slider if you use regular slinks. The bumpers used on hard links protect the lines from that wear, and also keep the slider up out of trouble.

[AggieDave 6]

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The bumpers used on hard links protect the lines from that wear

Not really. The slider still rests on some part of the suspension lines and vibrates (flaps) in the wind to a degree. Rubbing on the lines, creating friction and heat, etc.

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also keep the slider up out of trouble

Yes.

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Yes, which is why you MUST pull down the slider if you use regular slinks

Quantify that.

You MUST pull the slider down if you use regular slinks without the "pilgram hat" bumpers (when using PD slinks).

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[billvon 3,116]

>The slider still rests on some part of the suspension lines . . .

With silicon slider bumpers, the slider generally rests on them. The motion eventually wears through the bumpers, but they are easier to replace than lines.

[AggieDave 6]

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>The slider still rests on some part of the suspension lines . . .

With silicon slider bumpers, the slider generally rests on them. The motion eventually wears through the bumpers, but they are easier to replace than lines.

I have seen both happen independantly of each other.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[voltage 0]

Thanks guys for the information pro/con dacron and about the links, surely helps to make an informed decision, even in addition to the plenty of information already available by searching here.

That decision would still be dacron with slinks for me.

I got a nice PDF from PD's website regarding how to install slinks. Is this something you normally do yourself (changing main canopies) or let your rigger do?

Andi

[skydiverek 63]

You can also get Slinks bumpers (hats), too:

http://www.performancedesigns.com/docs/SlinkInstructions_RCI.pdf

Useful with Type 17 (narrow, 1-inch) risers.

BTW, they are included with every Slinks purchase.

[rushmc 23]

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Thanks guys for the information pro/con dacron and about the links, surely helps to make an informed decision, even in addition to the plenty of information already available by searching here.

That decision would still be dacron with slinks for me.

I got a nice PDF from PD's website regarding how to install slinks. Is this something you normally do yourself (changing main canopies) or let your rigger do?

Andi

Have you been trained in line continuity? Do you have the tools to tack the slinks in the riser?

If you don't understand these questions, work with your rigger. Most riggers are more than happy to show you what is going on.

It is acceptable by rule for you to do it however. (on the main)

Good luck and I want to comment on you raising some very good questions and asking for clarifications. Good Job!!

"America will never be destroyed from the outside,
if we falter and lose our freedoms,
it will be because we destroyed ourselves."
Abraham Lincoln

[phoenixlpr 0]

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I got a nice PDF from PD's website regarding how to install slinks. Is this something you normally do yourself (changing main canopies) or let your rigger do?

I don't think that you are certified to modify, repair skydiving equipment.

[sundevil777 102]

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I got a nice PDF from PD's website regarding how to install slinks. Is this something you normally do yourself (changing main canopies) or let your rigger do?

I don't think that you are certified to modify, repair skydiving equipment.

Installing slinks is not modification or repair, and there are no limitations on mods/repairs done to mains.

People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

[phoenixlpr 0]

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Installing slinks is not modification or repair, and there are no limitations on mods/repairs done to mains.

So do you recommend students to do this kind of "updates"?

[sundevil777 102]

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Installing slinks is not modification or repair, and there are no limitations on mods/repairs done to mains.

So do you recommend students to do this kind of "updates"?

No, I wouldn't recommend it, but that is a different question than what you posed. It depends on the student. Some first time students would be quite capable of doing it with only the instructions to guide them. Others would be dangerous even if they have a thousand jumps. What is really important is that people know their limitations - as Clint Eastwood would say.

People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

[phoenixlpr 0]

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What is really important is that people know their limitations - as Clint Eastwood would say. Laugh

Ok. Regulations can depend on the actual country. I guess you are in US, he is in Germany and I'm in Finland.

[mark 107]

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[T]here are no limitations on mods/repairs done to mains...

except for what's in FAR 65.111(b). Are there any other limitations?

Mark