Skyhook downsides?

[snowdude1 0]

I was wondering if people would mind listing the downsides of the skyhook system...i am interesting in getting gear in the next few weeks and i am debating between jav and rws. i like the idea of the skyhook and have heard the pros, cons though??
thanks
Marc

[snafuhere 0]

line twist on main => line twist on reserve
not a big problem however

https://www.facebook.com/1skydive/

[MB38 0]

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line twist on main => line twist on reserve

Here are a few quotes from Bill Booth on the issue:

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In the last few years, we have filmed dozens of spinning cutaway tests on the Skyhook system. On a few of these tests, we have recorded rotation rates up to 360 degrees per second, post cutaway. What's worse, is that the relative wind, right after cutaway, is often "horizontally" across the jumpers body. On a standard RSL, this would result in uneven line lengths at line stretch. Combine line twists with uneven line lengths, and you might just get a spinning reserve canopy. As noted above, post cutaway spin rates that high are rare, but they would give me pause before jumping a standard RSL with a very high performance canopy. The Skyhook solves this problem placing the reserve canopy, not into the relative wind, but right where the main was a half a second before, directly in line with the jumpers body. So, even if you have a twist or two, you will not be spiraling from uneven line lengths.

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...the only line twists we have ever filmed in the whole Skyhook test program were on the simulated total malfunction jumps, where the reserve was deployed by the pilot chute, not the Skyhook. We get letter after letter about Skyhook breakaways from BAD spinners that result in NO reserve line twists. After watching hundreds of reserve deployments on video, I can safely say, believe it or not, that Skyhook deployments, even from spinning malfunctions, yield far fewer line twists than stable pilot chute deployments.

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I never liked the "standard" single-sided RSL because if the RSL side riser releases prematurely for any reason, the reserve will be deployed into the still partially connected main, which has killed people in the past. The Collins' Lanyard (part of the Skyhook RSL system) cured that. Beyond that, I always pull very high, and figured I had plenty of time to get my act together after a breakaway. Rightly, or wrongly, I do worry about stability before I deploy my last chute. The Skyhook doesn't allow time for instability after a breakaway, even from a bad spinner. It also deploys your reserve in a direct line to the "vertical" axis of your body (where your main just was), guaranteeing equal line length at line stretch.

By comparison, a pilot chute deploys your reserve into the relative wind, which may or may not be the "right" direction depending of body position. (When you're "sliding" sideways after a spinning malfunction breakaway, the reserve deploys "across" your body plane, resulting in apparent differential line lengths which makes for "sloppy" openings.) Also, RSL deployed pilot chutes lift the bag off very "slowly" at low speeds, giving the bag a chance to spin, resulting in a better chance of line twists.


The Skyhook always pulls with the same force, in the same direction, regardless of your malfunction, yielding amazingly consistent openings. Simply put, after watching literally hundreds of video reserve deployments over the years, the Skyhook deployments simply look "cleaner" than the non-Skyhook deployments, and that makes me feel better.

As for downsides to the Skyhook? The usual camera/RSL entanglement issues remain. Is it reason enough to not get a Skyhook or RSL? Talk to people that know.

I suppose that there is a bigger risk of somebody improperly rigging your reserve with a Skyhook but that is what it is. Anybody can improperly rig anything, reserves don't always work, etc. I would hope a rigger is just as attentive packing a Skyhook equipped rig vs. a non-Skyhook equipped rig. If shit happens, aim for their car.

I really don't know what I'm talking about.

[Ronaldo 0]

I may be wrong but I think the Skyhook does not increase the chances of line twists on your reserve even if you cut away under a spinning main. As far as I understand the concept, the reserve reaches line stretch fast enough to avoid most of the twists to develop. Anyway, I think it is better to have a reserve above your head faster even with a few twists than wasting a couple hundred feet trying to get stable.
The downsides I can think of right now are adding a little bit of complexity (and maybe potential mistakes) during reserve packing. Also, in some cases where you need to delay your reserve opening (such as in collisions and/ or entanglements).
IMO it is a fantastic idea. If I was getting a new container I would seriously consider a Vector because of it.

Engineering Law #5: The most vital dimension on any plan drawing stands the most chance of being omitted

[Mathyaz 0]

I did a demo this summer with one of RWS skyhook demo rigs. I jumped my Velocity 84, released one of the toggles and put a lot of weight on one side leaning in my harness. That gave me a spinning velo. :-) I cut away, the reserve came out suuuper fast and suuuper clean. Not even a question about linetwists in my case.

[Ronaldo 0]

Wow! Was this demo rig equipped with 3 canopies? Do you have a picture of it? Is it necessary to do a full reserve repack after each jump? Do you have to pay for these repacks?
Sorry if these are dumb questions but I got really curious about the set up. We rarely see demo gear here in Brazil.
Safe skies!

Engineering Law #5: The most vital dimension on any plan drawing stands the most chance of being omitted

[brabzzz 0]

Two at the back, one at the front and a few more handles. I think you normally need to pay for (or do) the reserve repack (and in Gap, you had to pay for a vidiot too). It was tempting, but the expense meant i just did 5 normal jumps instead!
It looks unremarkable (read: therefore damn effective) from the ground. Pretty much an instant reserve canopy.

---------------------------------------
Ex-University of Bristol Skydiving Club
www.skydivebristoluni.com

[Mathyaz 0]

You have a "normal" rig with 3-rings on the reserve risers, a cut-away handle for the "main"-reserve and a belly reserve on the front. If you have the chance to do a skyhook demo you should definately do it! Also, check out the skyhook video here

The reserve needs a repack after the jump, normally you would have to cover that your self. With the skyhook installed in your rig you will have a major safety upgrade of your equipment, in my opinion.

[Remster 24]

I adds complexity to the system, and like any other layer of complexity, it can create more problems: incorect installs for example.

Remster

[aironscott 3]

Bag strip.
It is a very real and potentially lethal issue. Does it make a skyhook equiped rig less safe? I don't think so. But I'm still on the fence with the skyhook. Part of me thinks that it is overkill. A RSL should be enough. But I've also watched some of my bros cut away a Sorcerer and have a canopy right now and that has impressed me.

But you do loose the crystal ball on tandem rigs if they are skyhook equiped. Personally I like having the ability to pull the reserve from the right hand side.

Aaron

“God Damn Mountain Dew MotherFuckers!”

[skydiverek 55]

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Bag strip. It is a very real and potentially lethal issue.

From Bill Booth:

"Let me answer both questions. At first I worried that the Skyhook would put "too much" force on the reserve bridle, causing a bag strip in certain extreme situations, like an accidental main deployment on the tailgate of a C-130, that broke the right main riser, and caused the Collins' lanyard to breakaway the left riser, resulting in a both fully open, and "fast" main canopy dragging out the reserve bag via the Skyhook. To make sure this would not happen, I did drop tests from PD's tower to determine how much force was necessary to cause a bag strip, then designed the red Skyhook lanyard to break before that force could be applied. That's why it breaks at 400 lbs."

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But you do loose the crystal ball on tandem rigs if they are skyhook equiped. Personally I like having the ability to pull the reserve from the right hand side.

Little background from Bill Booth:

"The reason I have removed the right hand reserve ripcord (crystal ball) from Sigma tandem systems with the Skyhook, is that if you pull the "Crystal Ball", you pull the RSL, which pulls the Skyhook hardware, which pulls a bight of freebag bridle out of the container just under your right ear. While this will not stop the Skyhook from releasing during bridle stretch, it just might put your reserve bridle in a position to entangle with your helmet. I know this is far fetched, and we can't make it happen on the ground, but I'm not willing to take the chance."

and

"The "crystal ball" right hand reserve handle was originally put on Vector tandem systems when we were using the red, outward facing, PILLOW reserve handle on the left side. Now Vectors and Sigmas come with a forward facing red loop reserve handle on the left side, which you can pull with your right hand if need be. It isn't particularly easy, but neither was the "crystal ball". So, you really don't have to make a choice between the Skyhook and the Crystal Ball. Besides, does anyone know of a Tandem Instructor who actually used the Crystal Ball to save his life?"

[skydiverek 55]

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Two at the back, one at the front and a few more handles.

Picture here: http://www.relativeworkshop.com/images/skyhookdemo.jpg

[tdog 0]

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Bag strip.
It is a very real and potentially lethal issue.

A TI friend of mine had bag strip on a skyhook equipped tandem rig...

After the cutaway, the reserve stayed in the tray without the freebag.

He reached back and grabbed the fabric/risers from the reserve tray and threw it out into the wind and "shook it out until it inflated"

I still have a skyhook on my sport rig, but this TI did point out that the mass of the tandem reserve and the force of a fully inflated tandem main, does make him wonder about skyhook tandem rigs and the possibility of bag strip.

[skydiverek 55]

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line twist on main => line twist on reserve

You are probably assuming that the spinning motion and the twists from the main will transfer thru the bridle on to the reserve (like the spinning motion and the twists transfer from your hand, thru the screwdriver, on to the screw). The difference is that the bridle is not stiff (like a scredriver) and will "absorb" the twists (=get twisted itself), rather than transerring the twists on to the reserve.

Also, each TSO-D reserve was testdropped with THREE 360 twists. They fly straight...

[Danne 0]

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A TI friend of mine had bag strip on a skyhook equipped tandem rig...

After the cutaway, the reserve stayed in the tray without the freebag.

He reached back and grabbed the fabric/risers from the reserve tray and threw it out into the wind and "shook it out until it inflated"

I still have a skyhook on my sport rig, but this TI did point out that the mass of the tandem reserve and the force of a fully inflated tandem main, does make him wonder about skyhook tandem rigs and the possibility of bag strip.

Are you really sure about this? Did the safety stow break? Was the correct safety stow used? Is it reported to RWS?

/D

[billbooth 10]

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A TI friend of mine had bag strip on a skyhook equipped tandem rig...

After the cutaway, the reserve stayed in the tray without the freebag.

He reached back and grabbed the fabric/risers from the reserve tray and threw it out into the wind and "shook it out until it inflated"

I still have a skyhook on my sport rig, but this TI did point out that the mass of the tandem reserve and the force of a fully inflated tandem main, does make him wonder about skyhook tandem rigs and the possibility of bag strip.

Are you really sure about this? Did the safety stow break? Was the correct safety stow used? Is it reported to RWS?

/D

Yeah. Me too! We have never heard anything about this. The only way this can happen is if the safety stow breaks. That is why I made the red Skyhook lanyard weaker than the safety stow. This has been tested many times on the dynamic drop tower, and Skyhook lanyard always breaks before any "line dump" can happen.

[psychoswooper 2]

From Bill Booth:

So, you really don't have to make a choice between the Skyhook and the Crystal Ball. Besides, does anyone know of a Tandem Instructor who actually used the Crystal Ball to save his life?"

[freekflyguy 0]

We had a baglock malfunction on a Sigma here at Netheravon a few weeks back.

The Skyhook depolyed the reserve, unfortunately due to the lack of seperation the freebag landed ontop of the tandem and was entangled with the lines.

Fotunately the tandem instructor who is not only very experienced, but also one coolheaded coucumber was able to untangle the lines and gather the main in and land safely.

Buzz

It's nice to be important, but it's more important to be nice.

[skydiverek 55]

You meant 'main deployment bag', not a 'feebag', didn't you?