Different pull out design

[mr2mk1g 10]

Is it just me or is this design just freekin genious?: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?do=post_attachment;postatt_id=9086;guest=39794287

I was searching for ideas to help my decision to maybe change from throw out to pull out. I'm getting some problems I really should be having with PC in tow on low speed deployments and I'm looking for some solutions. Switching to pull out is one idea, though I'm still looking at what's behind the problem.

Anyway, I found this thread: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=496768#496768

In it there are posts about a system some are calling a "russian style" pull out PC:

1) The PC packs up into the BOC, same as a throw out... so there's no greater chance of floating pud/total than with a regular throw out PC.

2) The pin's only 18" from the handle so you pull your own pin, (hopefully solving my hesitation problems).

3) Because the handle's attached to the PC itself, just like a throw out, there's no more chance of the PC ending up in your burble than with a throw out, (good as I jump camera wings sometimes).


Am I missing something here or does this thing just tick all the boxes and combine the best of both a pull out and a throw out system, (appart from being different to everything else out there so you're the only one who knows how to pack it)?

Anyone see any problems with this design?
Anyone see any reason why it can't be made as a collapsable PC?
(The one in the pic appears to be from a CRW set up - presumably there'd have to be something like a small loop at the apex of the PC to cock it).

cheers

[NewGuy2005 53]

Maybe I don't know what I'm talking about, but it looks like a pull out to me.

Plus, if you're having trouble with hesitation, now, would you want the same hesitation with your container open?

[mr2mk1g 10]

Yes the picture shows a kind of hybrid between a pull out and throw out.

The problem I'm getting is with the pin not getting pulled. I solve it by reaching round and pulling my own pin with the bridle. The PC then pulls the d-bag out and deploys the main with no issues at all, so it presumably wouldn't happen at all with a pull out, though that is something to be considered.

As I said though, I'm also looking into the route cause of the problem with a view to solving that as well.

[riggerrob 643]

That reminds me of some of the weird deployment devices used by canopy formation (CReW) competitors. Suspension line - used for bridle - retracts (pulls down) the pilot chute to the top skin (during main canopy inflation), reducing the chances of entanglement - with other canopies.

However, having the container open (i.e. pin pulled) - but the pilot chute not pulling hard enough to lift the d-bag - scares me!

Start by checking if your old pilot chute has become porous over the years.
Secondly, ensure that your old pilot chute is large enough to lift the weight of your main canopy at sub-terminal airspeeds.
Third, ask the container manufacturer if that is the correct size of main canopy for that size of container.

[mr2mk1g 10]

PC is 28", ZP, in good condition, with only about 200 jumps on it. The container's sized for a 170 which is what's in it.

Already been in touch with the manufacturer and they're going to come back to me with some ideas once I send them some pics of the rig packed up.

I'm interested in comments on the deployment system design in my first post though for after I get to the bottom of the issues I've been having on deployment. For the sake of argument, assume those issues are solved when I install the above system, assuming I choose to in the end.

[darkwing 5]

Quote

... I'm getting some problems I really should be having with PC in tow on low speed deployments and I'm looking for some solutions. Switching to pull out is one idea, though I'm still looking at what's behind the problem.

The possibilities I see here --

1) Pilot chute is defective (apex pulled down too far)

2) bridle misrouted - I have seen this more than once, and the symptoms were pretty much as you describe.

3) bridle too short

-- Jeff
My Skydiving History

[MakeItHappen 15]

Quote

Is it just me or is this design just freekin genious?: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?do=post_attachment;postatt_id=9086;guest=39794287

I was searching for ideas to help my decision to maybe change from throw out to pull out. I'm getting some problems I really should be having with PC in tow on low speed deployments and I'm looking for some solutions. Switching to pull out is one idea, though I'm still looking at what's behind the problem.

Anyway, I found this thread: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=496768#496768

In it there are posts about a system some are calling a "russian style" pull out PC:

1) The PC packs up into the BOC, same as a throw out... so there's no greater chance of floating pud/total than with a regular throw out PC.

2) The pin's only 18" from the handle so you pull your own pin, (hopefully solving my hesitation problems).

3) Because the handle's attached to the PC itself, just like a throw out, there's no more chance of the PC ending up in your burble than with a throw out, (good as I jump camera wings sometimes).


Am I missing something here or does this thing just tick all the boxes and combine the best of both a pull out and a throw out system, (appart from being different to everything else out there so you're the only one who knows how to pack it)?

Anyone see any problems with this design?
Anyone see any reason why it can't be made as a collapsable PC?
(The one in the pic appears to be from a CRW set up - presumably there'd have to be something like a small loop at the apex of the PC to cock it).

cheers

With the attached pic you had, I see
- the possibility of getting a rightous PCIT if you loose the handle before extracting the pin or if the PC got deployed accidentally
- the overall length of the bridle line looks too short

For your original problem, you might try lengthing the bridle line so that it catches cleaner air further behind your body.

In standard pull-out systems, most hesitations are because of a too short bridle line or lazy throw. I always lengthen my bridle line by 3 ft on my Racer pull out.

"Because the handle's attached to the PC itself, just like a throw out, " is not true.
Throw outs have the handle attached to the APEX of the PC and pull outs have the handle attached to the BASE of the PC.

A longer bridle line on your current system will also help reduce hesitations when jumping a camera suit (and birdsuit too).

.

.
Make It Happen
Parachute History
DiveMaker

[sundevil777 102]

Very old Sweethog containers had a similar setup, except the PC was stowed in the backpad, and the handle was a martin baker style ripcord handle (but plastic) placed in the bottom corner of the rig. A coated cable entered the rig through grommets to get to the closing loop - no pin, just the cable served as a pin. The cable wasn't very rigid, so it required an elastic closing loop to avoid hard pulls.

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

[councilman24 37]

If you pull the PC out of the BOC but DON'T pull the pin you will have a PC deployed in the burble (short bridle) that may not inflate and if it does may not be able to pull the pin because it's a straight pin. (as best I can tell in the photo.) I think it very forseeable that you might end up with a pc in the burble, especially with a camera suit.

Real pull outs with the PC in the container you can't deploy the PC with out the pin being pulled. The handle is attached to the base of a pull out so you can't hang on to the PC with the container open.

This design was for CRW. Particularly for low speed exits where the TO PC may not reliably pull the pin for the crw team exiting very close and needing precise deployments. But still allows the sliding pin and suspension line bridle for the PC retraction system. I know that's your problem and this is a solution. But with the trade offs above.

I think you should fix the problem that shouldn't be happening. Is it really towing or just hesitating to open the container for a second or too? Neither should be happening but you may be too sensitive to PC delays. I wouldn't want to use this system on terminal low altitude openings. It serves a purpose on subterminal openings and up high you can deal with it. Not to mention the dawgs are crazy anyway.

Reminds me I need to pack my lightning.

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

[mr2mk1g 10]

Yeah I'm really towing the PC. I've done a couple of altitude hop&pops in the past and ridden the damn thing like a drogue for a thousand feet. On that occasion I dumped literally out the door, so there would probably have been no snatch force but still, that shouldn't happen!

One previous idea I've had was maybe that I was causing a problem with how I stow the bridle between the pin and the BOC, so I'm always very careful with that not to stow it too enthusiastically. Besides, I know when I reach round I find the bridle at the pin, not somewhere under the right hand main closing flap.

I've examined my PC using Bill Booths instructions posted elsewhere on here and it seems to check out fine - the apex is about 4" proud of the skirt when cocked, (and yes it's always cocked).

On a side note, any reason why a pull out can't have a curved pin rather than a straight one? One of the main problems we can identify with the system referenced in my first post is if for some reason I drop my deployment handle before pulling my pin leading to one hell of a PC in tow.

Assuming a curved pin on the system, this failure mode would essentially result in the same problem, and solution, as I have now at on low speed deployments. However it would be worth bearing in mind that with the above system there's also the potential for that happening at high speed!

Whilst that is obviously not a particularly nice thought, its exactly the same failure mode as with a pure pull out - drop the handle without pulling the pin and you've got nothing out.

I'm certainly going to be talking to my rigger about a longer bridle line as one possible fix in the meantime however.

[sundevil777 102]

If you are pulling the pin manually while the PC is in tow, then there is definitely something wrong, and going to a pull-out isn't a good way to fix it.

How long is your bridle? Is your closing loop really tight? Have you checked how much force it takes to pull the pin, perhaps a few times to get an average?

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

[mark 107]

Quote

I've examined my PC using Bill Booths instructions posted elsewhere on here and it seems to check out fine - the apex is about 4" proud of the skirt when cocked.

Usually the skirt of the canopy and the apex are at the same height when the pilot chute is cocked. Are you saying you have 4" slack in the center lines when the pilot chute is cocked?

Mark

[mr2mk1g 10]

Yes, pulling the pin manually, but only sometimes on low speed deployments. A few seconds delay for example and I would not usually see this happen. On a couple of occasions when it's happened and I've had altitude to spare I just waited and it popped on its own after I built up some speed. Deploying after freefall certainly never any issues.

Bridle is stock – 6ft from base of PC to the pin. Closing loop is not what I felt was overly tight: my pack jobs I get maybe an inch through clear of the grommets. My friend packed my rig the other day and felt I needed to shorten it as he had about 3 inches excess but I've never seen that much on my pack jobs.

I've pulled the pin on the ground a few times previously to try and replicate the issue and never felt the force required was excessive, though I confess I've never used a fish scale on it or anything. Pack closure is tight, (I freefly so I've always considered that to be good), but there's no rippling of fabric, straining of the stitching or anything and the grommets all line up fine for closure. Canopies are the correct size for the container.

It's pretty much a mystery to me – I wouldn't have posted here and written to ask the manufacturer if it was an obvious problem.

[mr2mk1g 10]

I've just measured it all laid out with a ruler rather than dangled and by eye. I have the apex as being 2" higher than the very seam of the skirt, (with higher meaning further away from the pin). That's with both the support tape and the center tape pulled tight. There's still a little slack in the kill line beyond that. All 4 "sides" of the PC are the same.

[MakeItHappen 15]

Quote

On a side note, any reason why a pull out can't have a curved pin rather than a straight one?

No matter what type of deployment system you look at there are very definitive reasons to choose a straight or curved pin.

When the pull force to extract the pin from the closing loop is parallel to the plane of the top grommet, you should use a straight pin.
When the pull force to extract the pin from the closing loop is perpendicular to the plane of the top grommet, you should use a curved pin.

If you use a curved pin when the pull force is parallel to the plane of the top grommet, then the pin may not clear.
If you use a straight pin when the pull force is perdendicular to the plane of the top grommet, the pin may not clear.

.

.
Make It Happen
Parachute History
DiveMaker

[councilman24 37]

Quote

One previous idea I've had was maybe that I was causing a problem with how I stow the bridle between the pin and the BOC, so I'm always very careful with that not to stow it too enthusiastically. Besides, I know when I reach round I find the bridle at the pin, not somewhere under the right hand main closing flap.

It's not the bridle between the pin and the BOC that's the problem. It may very well be the bridle between the pin and the BAG. It's very easy to either tuck the bridle in under the flaps while closing in such a way that the bridle beyond the pin and trapped under the flaps is loaded INSTEAD of the pin. That's why vectors (at least older ones I think they still do it) and many other rigs have a velcro tab on the top main flap above the pin and on the bridle. Mating this velcro insures that there is enough slack to load the pin first. Also simply misrouting the bridle around the flaps could cause the same thing. Get out the owners manual for the rig you have and follow the closing procedures and see what happens. If YOU can pull the pin using the bridle the PC can pull the pin, IF THE FORCE IS BEING APPLIED TO THE PIN. Even a ratty old PC should generate well over 50lbs pull. Generally over a hundred pounds pull. I certainly can't lift 100lbs pulling with one hand across the small of my back.

This problem just doens't happen any more with a properly packed and operated system. The local DZ had a PC in tow with reserve ride two weeks ago but the jumper opened the container and reclosed it with out removing the PC from the BOC. You CAN do this right but it's VERY easy to do wrong and misroute the bridle.

You should try to diagnose and fix the problem/error before changing system. Then change if you'd like.

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

[diablopilot 2]

Quote

I'm certainly going to be talking to my rigger about a longer bridle line as one possible fix in the meantime however.

If it's less than 9 feet or so I'd guess that may be the problem. How stuffed is your rig as well?

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

[riggerrob 643]

The local DZ had a PC in tow with reserve ride two weeks ago but the jumper opened the container and reclosed it with out removing the PC from the BOC. You CAN do this right but it's VERY easy to do wrong and misroute the bridle.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

On a related note, if you ever have to reclose a Vector Tandem, remember to pull the drogue out of the BOC and repack it as well. It is far too easy to mis-route the bridle (under a side flap) on a Vector Tandem, so easy that several DZOs will FIRE you if you reclose a Vector Tandem without also repacking the drogue.

[riggerrob 643]

Also simply misrouting the bridle around the flaps could cause the same thing.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Something as simple as stuffing the bridle too deep can also cause a hesitation. Merely stuffing the bridle past the corner of the bottom flap stiffener can cause it to wrap around the corner of the stiffener.
There is a good reason why the bridle cover - on newer Javelins - extends to the corner of the bottom flap stiffener.

[CReWLL 0]

It looks to combine the worst of both systems, into a neat little deadly package.

[sprtdth 0]

2) The pin's only 18" from the handle so you pull your own pin, (hopefully solving my hesitation problems).

Quote

Depends how long your arms are, mine's only 14"

3) Because the handle's attached to the PC itself, just like a throw out, there's no more chance of the PC ending up in your burble than with a throw out, (good as I jump camera wings sometimes).

Quote

The handle is not attached to anything. It floates inside the P/C. When you pack it you place the handle at the bottom of the P/C, stuff it in the BOC pouch and leave a little bridle and the P/C attachment point sticking out. Not a good idea for FF. But that's just my opinion.

Anyone see any reason why it can't be made as a collapsable PC?

Quote

Yes, because the bottom is sewn closed, no place for the kill line to go. It's built that way to allow it to go through the kill cone easier. You could re-engineer it and leave the bottom open, add a loop at the top, etc. for a kill line. Or, you could take the time that it would take to do that and instead find out what is causing the problems you are currently having.

CRW Skies
Frank
CRW Diva #58

• Quote

Share this post

---

Link to post

Share on other sites