Skyhook

[mirage62 0]

Don't want to start a shit storm here but.....

The debate about lowering your decision height would be dumb and generally I don't think anyone is saying that.

I think there is a legitmate question as to IF YOU FUCKED up and you got yourself way in the basement with a main malfuction how low would you cut away with and without a skyhook.

Picture: Your at 700 feet (I'm using my number you pick your on low number) with a spinning main. Do you a) fire your reserve getting as much shit above you? b) Attempt a canopy transfer c) Cut away with a skyhook?

PLEASE I understand the real solution is to NOT get there, but I think the skyhook does perhaps offer another option than "A" or "B"

Again don't get there and you don't have to decide.

Kevin Keenan is my hero, a double FUP, he does so much with so little

[billbooth 10]

dudeman17

***...but it has certainly been the most "trouble free" device I have ever invented...

It's distressing that I have to write this, but historical accuracy demands it. I have been skydiving for 35 years, and I am as big a fan of Bill Booth as anybody, and in no way do I mean to denigrate him or his contributions to our sport. But he did not invent the skyhook. He may have redesigned it for skydiving rigs, but the first MARD system was invented by Mark Hewitt, on a base rig called the Sorcerer, and Bill knows this. Credit is deserved where credit is due.

The inventive idea in the Skyhook is not simply the idea of hooking the cutaway main to the reserve bridle. It is how to do this in such a way that the connection releases and gets out of the way when it is not needed, but stays connected when it is. A little history.

If you will look at the beginning of our "Skyhook Promotional Video" (#2 on UPT's website) you will see video evidence that I started working on MARDs in the early 1980's. The reason the skyhook didn't come out until 2003 was that it took me all those years to work out all the problems that need to be solved before such a device would be safe enough for sport jumping. During the 80's and 90's I designed and jumped several primitive MARD's, but none of them worked well enough to satisfy me. The Sorcerer system came out during this time period, but required a hand deployed reserve pilot chute, had no automatic release system, and wouldn't work with spring loaded, ripcord activated reserve systems. As has been noted elsewhere on DZ.com, I included mention of the Sorcerer in my patent application. Some of my first devices involved pins and loops similar to the Sorcerer, but these systems weren't reliable during rapidly spinning malfunctions.

You see, the MARD connection pulls on the reserve bridle near the midpoint, which means that it is pulling on both the bag and the pilot chute. If there is a lot of horizontal speed involved (spinning malfunction), then the pilot chute often generates enough force to prematurely release a simple pin/loop system, which will release as soon a the pilot chute loads at all. I needed to work out a system where it took a lot more force from the pilot chute to release the MARD connection in a partial malfunction than in a total malfunction. This is where the Skyhook lever/cam design came in. It is designed to require 5 times more force from the pilot chute than the weight of the packed freebag (25 - 60 lbs.) if you have a partial malfunction, yet release with a force of between 4 and 8 lbs. if you have a total malfunction. And it has to figure this out instantly, with no input from the jumper.

The lever idea worked well, but there was one more serious problem to address. Simply - What happens if the RSL side riser releases BEFORE the non-RSL side riser. This is a bad situation even with a "normal" RSL, and has resulted in several deaths due to main/reserve entanglement. But with a MARD, the situation practically GUARANTEES a fatality. I was stumped, so I put the Skyhook on a back burner for nearly 10 years. Then one day I was discussing the problem with a young engineer I had hired straight from Georgia Tech. After thinking about it for a moment he said," Why don't you simply connect the RSL riser to the cutaway cable leading to the other riser? I was stunned. There was the answer I had been looking for dropped right in my lap. The young man's name was Kyle Collins, and that's how the Collins' Lanyard, a necessary component of ANY MARD system was born. We had a working model that day, and you will notice that it is his name, not mine, on the patent.

So I put out the Skyhook immediately right. WRONG. I didn't want to put two new reserve related systems at once, so I fitted all of my existing and new tandem rigs with the Collins' Lanyard. I then waited the requisite 5 years to see if the Collins' Lanyard worked as expected. It did. Then, and only then, was I ready to release the Skyhook. The whole process took nearly 20 years from inspiration to implementation, but I think the result was worth it.

[lyosha 46]

billbooth

You see, the MARD connection pulls on the reserve bridle near the midpoint, which means that it is pulling on both the bag and the pilot chute. If there is a lot of horizontal speed involved (spinning malfunction), then the pilot chute often generates enough force to prematurely release a simple pin/loop system, which will release as soon a the pilot chute loads at all.

Hi Bill, thank you for the detailed explanation. I'm having trouble visualizing the quoted material - in a spinning mal, isn't there substantial centripetal force that would force a sideways reserve deployment? Or are you suggesting that the MARD starts deploying the reserve, but pops the pin on the pilot chute which goes at ~90 degree angle to the skydiver and the pull in the 90 degree angle disconnects the pin system?

Is there a video somewhere that could illustrate that scenario?

Thank you in advance!

[billbooth 10]

It's a mater of airspeed and the direction of the relative wind. Pin and loop systems simply release too easily with very small pilot chute loads. As I said, the Skyhook lever solves this problem.

[Deyan 31]

lyosha

Is there a video somewhere that could illustrate that scenario?

I don't know about the pin MARD video, but you can see how "good" SKYHOOK is working in the same spinning mal scenario.

https://www.youtube.com/watch?v=mEau0dc67e4

There are a few more. You just have to search

"My belief is that once the doctor whacks you on the butt, all guarantees are off" Jerry Baumchen

[vision 0]

Hi Bill,

Love your work.

I prefer to have skyhook on all my descents now be it tandem or otherwise including camera jumps.

one thing however is the weakness of the RSL/Skyhook Collins lanyard in a bag lack situation.

Releasing the RSL in a bag-lock should be (imo) an integral part of training which it is not.

There have been a few situations now that this procedure would have avoided ugly situations. The recent one in Romania comes to mind.

Without a main it seems this system does not have enough pull force to shear the Velcro when a head low position is achieved.

Can you comment on this to clarify your view of the matter?

[Hellis 0]

vision

Without a main it seems this system does not have enough pull force to shear the Velcro when a head low position is achieved.

Can you comment on this to clarify your view of the matter?

Wouldn't a shrivelflap work on the RSL?
But I guess in a true headdown there will still be an angle that a shrivelflap might struggle with.

[jerolim 7]

Hi,

I have heard (correct me if I am wrong), that in some number of cases, that skyhook disconnects, and reserve is deployed only by reserve PC. I am not talking about total mal. I am talking about partial main malfunction, and after cutaway handle is pulled, shorter RSL bridle pulls reserve pin, reserve PC launches, and this res. PC launch force actually sometimes disconnects skyhook lanyard from skyhook, and reserve PC has to take over and deploy reserve. As I have understanded fix for this was red seal thread, but it still happens sometimes.
Can you tell us how often this can happen in percentages, and is this reason why you said that skyhook should not be justification for someone to lower hard deck altitude and to cutaway lower than usual?

Regards,
Jerolim

[base698 1]

Anyone have any numbers on skyhook saves where not having it would end in death?

[BigMikeH77 0]

It's really not possible to accurately gauge events that didn't happen.

[base698 1]

You can make an educated guess. Ie cutaway less than 600 ft it likely increases the probability of surviving. I'm more interested in how often that happens vs the complications. I've seen super low cutaways that were in my mind saved by the rsl.

[gregpso 1]

billbooth

******...but it has certainly been the most "trouble free" device I have ever invented...

It's distressing that I have to write this, but historical accuracy demands it. I have been skydiving for 35 years, and I am as big a fan of Bill Booth as anybody, and in no way do I mean to denigrate him or his contributions to our sport. But he did not invent the skyhook. He may have redesigned it for skydiving rigs, but the first MARD system was invented by Mark Hewitt, on a base rig called the Sorcerer, and Bill knows this. Credit is deserved where credit is due.

The inventive idea in the Skyhook is not simply the idea of hooking the cutaway main to the reserve bridle. It is how to do this in such a way that the connection releases and gets out of the way when it is not needed, but stays connected when it is. A little history.

If you will look at the beginning of our "Skyhook Promotional Video" (#2 on UPT's website) you will see video evidence that I started working on MARDs in the early 1980's. The reason the skyhook didn't come out until 2003 was that it took me all those years to work out all the problems that need to be solved before such a device would be safe enough for sport jumping. During the 80's and 90's I designed and jumped several primitive MARD's, but none of them worked well enough to satisfy me. The Sorcerer system came out during this time period, but required a hand deployed reserve pilot chute, had no automatic release system, and wouldn't work with spring loaded, ripcord activated reserve systems. As has been noted elsewhere on DZ.com, I included mention of the Sorcerer in my patent application. Some of my first devices involved pins and loops similar to the Sorcerer, but these systems weren't reliable during rapidly spinning malfunctions.

You see, the MARD connection pulls on the reserve bridle near the midpoint, which means that it is pulling on both the bag and the pilot chute. If there is a lot of horizontal speed involved (spinning malfunction), then the pilot chute often generates enough force to prematurely release a simple pin/loop system, which will release as soon a the pilot chute loads at all. I needed to work out a system where it took a lot more force from the pilot chute to release the MARD connection in a partial malfunction than in a total malfunction. This is where the Skyhook lever/cam design came in. It is designed to require 5 times more force from the pilot chute than the weight of the packed freebag (25 - 60 lbs.) if you have a partial malfunction, yet release with a force of between 4 and 8 lbs. if you have a total malfunction. And it has to figure this out instantly, with no input from the jumper.

The lever idea worked well, but there was one more serious problem to address. Simply - What happens if the RSL side riser releases BEFORE the non-RSL side riser. This is a bad situation even with a "normal" RSL, and has resulted in several deaths due to main/reserve entanglement. But with a MARD, the situation practically GUARANTEES a fatality. I was stumped, so I put the Skyhook on a back burner for nearly 10 years. Then one day I was discussing the problem with a young engineer I had hired straight from Georgia Tech. After thinking about it for a moment he said," Why don't you simply connect the RSL riser to the cutaway cable leading to the other riser? I was stunned. There was the answer I had been looking for dropped right in my lap. The young man's name was Kyle Collins, and that's how the Collins' Lanyard, a necessary component of ANY MARD system was born. We had a working model that day, and you will notice that it is his name, not mine, on the patent.

So I put out the Skyhook immediately right. WRONG. I didn't want to put two new reserve related systems at once, so I fitted all of my existing and new tandem rigs with the Collins' Lanyard. I then waited the requisite 5 years to see if the Collins' Lanyard worked as expected. It did. Then, and only then, was I ready to release the Skyhook. The whole process took nearly 20 years from inspiration to implementation, but I think the result was worth it.

yes it was worth it Bill Thanks for doing it !!

I tend to be a bit different. enjoyed my time in the sport or is it an industry these days ??

[diablopilot 2]

base698

You can make an educated guess. Ie cutaway less than 600 ft it likely increases the probability of surviving. I'm more interested in how often that happens vs the complications. I've seen super low cutaways that were in my mind saved by the rsl.

I think that the advantage is not as much low cutaways, but rather decreasing tumbling deployments. At least that's what I like about it, especially in the tandem world.

----------------------------------------------
You're not as good as you think you are. Seriously.

[jumpwally 0]

Ok,,one guy made a commercialy viable product the other guy didn't do much with it,,i've been around since 77' and i never heard of it....there is a difference.....

smile, be nice, enjoy life
FB # - 1083

[Skydivesg 6]

champu

I'm not convinced, however, that the Collin's lanyard addresses anything other than gear maintenance / construction errors and I'm not comfortable with the added complexity and potential failure modes it creates.

Hey Ryan, will you please explain what you mean by "potential failure modes it creates"?

Be the canopy pilot you want that other guy to be.

[gowlerk 1,903]

I don't know if the man who knows is still following this thread, but here's a question I'm wondering about. The Skyhook lanyard is supposed to be held on by a single turn of seal thread. Twice lately I've opened rigs and found doubled (2 turns) of thread, which takes a lot more force to break by hand at least. I know this is a finely tuned system, how serious is this seemingly small error?

Always remember the brave children who died defending your right to bear arms. Freedom is not free.

[pchapman 261]

I once found 4 turns of thread, taking something like 45 lbs to break, and started a thread.

http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=3744788;

The great bearded one did reply further down the thread, and basically said that in a normal skydive it's gonna pop fairly soon anyway from the pilot chute drag, so it isn't normally all that dangerous. Still, it could be dangerous in rare situations -- say a low emergency exit from a balloon.

[craddock 0]

vision

one thing however is the weakness of the RSL/Skyhook Collins lanyard in a bag lack situation.

Releasing the RSL in a bag-lock should be (imo) an integral part of training which it is not.

There have been a few situations now that this procedure would have avoided ugly situations. The recent one in Romania comes to mind.

Without a main it seems this system does not have enough pull force to shear the Velcro when a head low position is achieved.

Can you comment on this to clarify your view of the matter?

Two things that come to mind reading this. I do not have any knowledge of the prior incidents you speak of but it would seem odd to cutaway in a head low position from a bag lock in the first place? I had a bag lock where the bag never got out if the first or second stow(tight tube stows) as I remember it and while it didn't cause the drag I have seen on videos I tried to sit up and get it to release for a second before getting rid of it. I guess I don't know why one would go head low before cutaway when if anything it would seem inclined to try the opposite. But forget that for a second because it apparently has happened per the incidents you mentioned. Just seems odd on a sport jump to me

The adding a step in emergency procedures to release rsl during one particular malfunction seems questionable to me. While some jumpers may be able to adapt to the complexity of that I do not see the entire population as a whole handling that well at all. My bag lock didn't even sit me up but regardless it is always an extremely high speed malfunction. I believe it took me an extra second to realize it was not a pilot chute hesitation(again I had very low drag) before I reached up and shook risers quick before a bang bang on the pillows.

If anything perhaps just sitting up before cutaway if that will solve the problem you mentioned of the Velcro not releasing in a head low position? Does anyone else recommend teaching this extra rsl release step to sky-hook sport jumpers for emergency procedures?

That spot isn't bad at all, the winds were strong and that was the issue! It was just on the downwind side.

[gowlerk 1,903]

Thanks Peter. That was an interesting read. Still wonder a little about even a short hesitation in an AAD fire situation though.

Always remember the brave children who died defending your right to bear arms. Freedom is not free.

[JerryBaumchen 1,046]

Hi Peter,

Quote

4 turns of thread, taking something like 45 lbs to break

That is consistent with some testing I did back in '08 with two turns of red rigger's thread.

I conducted five seperate tests. The high value was 26 lbs, the low value was 23 lbs and the average was 24 lbs.

JerryBaumchen

[Hellis 0]

craddock

***
one thing however is the weakness of the RSL/Skyhook Collins lanyard in a bag lack situation.

Releasing the RSL in a bag-lock should be (imo) an integral part of training which it is not.

There have been a few situations now that this procedure would have avoided ugly situations. The recent one in Romania comes to mind.

Without a main it seems this system does not have enough pull force to shear the Velcro when a head low position is achieved.

Can you comment on this to clarify your view of the matter?

Two things that come to mind reading this. I do not have any knowledge of the prior incidents you speak of but it would seem odd to cutaway in a head low position from a bag lock in the first place? I had a bag lock where the bag never got out if the first or second stow(tight tube stows) as I remember it and while it didn't cause the drag I have seen on videos I tried to sit up and get it to release for a second before getting rid of it. I guess I don't know why one would go head low before cutaway when if anything it would seem inclined to try the opposite. But forget that for a second because it apparently has happened per the incidents you mentioned. Just seems odd on a sport jump to me

The adding a step in emergency procedures to release rsl during one particular malfunction seems questionable to me. While some jumpers may be able to adapt to the complexity of that I do not see the entire population as a whole handling that well at all. My bag lock didn't even sit me up but regardless it is always an extremely high speed malfunction. I believe it took me an extra second to realize it was not a pilot chute hesitation(again I had very low drag) before I reached up and shook risers quick before a bang bang on the pillows.

If anything perhaps just sitting up before cutaway if that will solve the problem you mentioned of the Velcro not releasing in a head low position? Does anyone else recommend teaching this extra rsl release step to sky-hook sport jumpers for emergency procedures?

I don't know the incident either, but if you have a uncocked PC and baglock maybe it creates so little drag that you could end up head low?
Also I'm thinking of baglocks on tandems? Does that create a head low position? With the drouge collapsing before the bag opens.
Or maybe that is not on all tandemrigs?

[vision 0]

Quote

Two things that come to mind reading this. I do not have any knowledge of the prior incidents you speak of but it would seem odd to cutaway in a head low position from a bag lock in the first place?

So when you remove your arms from the free-fall position and have your hands in to pull handles and deal with other complications you 'might' end up head low.

With a complicated mess with little drag behind you and/or a freaking out passenger in front of you, you could even end up on your side or back...

here is one incident.

http://www.dropzone.com/forum/Skydiving_C1/Incidents_F14/Bag_lock_on_Sigma_P4155226


there are more.

[skydiverek 54]

pchapman

I once found 4 turns of thread.

From Bill Booth:

http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=3745043;search_string=turns%20red%20;#3745043

[pchapman 261]

Yup, that was in the thread I started. (But you conveniently linked directly to Bill's reply rather than to the whole thread as I did.)

[craddock 0]

vision

With a complicated mess with little drag behind you and/or a freaking out passenger in front of you, you could even end up on your side or back...

here is one incident.

http://www.dropzone.com/forum/Skydiving_C1/Incidents_F14/Bag_lock_on_Sigma_P4155226


there are more.

If you were specifically talking about tandems than my post should be disregarded both in the head low position and the questioning the added rsl disconnection. I was thinking of adding this step to a standard sport jump with say a much lower ~2500 container opening.

That spot isn't bad at all, the winds were strong and that was the issue! It was just on the downwind side.