Forums: Skydiving: Gear and Rigging:
1 and 2 pin Pop Top pull forces

 


crapflinger2000  (D 15756)

Jan 5, 2004, 7:09 PM
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1 and 2 pin Pop Top pull forces Can't Post

Yo!

I am more or less out of the rigging game, but back in the day, realizing that if you set the pin(s) on a Reflex or Racer, THEN tightened down the pop top, you were setting someone up for a hard pull, I used a simple technique to avoid this:

Tighten down the pop top with the temp pin(s) IN. THEN insert the ripcord pin(s) in the normal manner. My theory was that if you can put the pin in using only a packing paddle and knee plate, the pull forces should be acceptable. It may be above the 22lbs, but not in the "impossible to pull" range.

To be sure, getting the ripcord pins in while the loops are tightened down is a bitch, but it IS doable. Mainly you have to be creative with knee plate placement.

Am I just dumb?


hookitt  (D License)

Jan 5, 2004, 7:35 PM
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Re: [crapflinger2000] 1 and 2 pin Pop Top pull forces [In reply to] Can't Post

Something I've always done is put both the ripcord pin and the temp pin in the closing loop then cinch it down. Once it's tightened down properly pull the temp pin and the pull up cord out.

This seems to result in very consistant pull forces.


pilotdave  (D License)

Jan 5, 2004, 7:44 PM
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Re: [crapflinger2000] 1 and 2 pin Pop Top pull forces [In reply to] Can't Post

I'm not a rigger, but I own a reflex. On mine anyway, I haven't found a rigger that could tighten the thing down too much. Never tested the pull force, but also never had a hard pull when I've brought it for a repack. Sometimes mine needs to be tightened after the first jump or two after a repack, as the reserve bulk shifts around a little.

I helped tighten mine down once. I sure as hell couldnt get it too tight! That's not easy!

edit: When I've seen it done, the temp pin and the real pin were in at the same time to prevent bending the reserve pin.

Dave


(This post was edited by pilotdave on Jan 5, 2004, 7:45 PM)


ChileRelleno  (D 24868)

Jan 5, 2004, 7:53 PM
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Re: [crapflinger2000] 1 and 2 pin Pop Top pull forces [In reply to] Can't Post

I have a one pin poptop (reflex) which can be tightened down in the field by the jumper or a rigger. I've heard it discussed before about pull forces on reserve pins being in excess after doing this or when closing the reserve in the loft, doubtless it happens.
I'd just like to say that after almost every repack within a short time I need to tighten the poptop and I do so myself, I've found that it takes a bit of a tug to snug it down.
Which had led me to question the pull force for the pin, I always put my rig on and pull my handles when handing the rig over to the rigger and never had a remotely hard pull.
And have used a spring scale just for yucks to see what it takes just to get the pin to slide, its been within limits.
My conclusion is that some people must be exerting some considerable pressure when closing or tightening reserve poptops.


Hooknswoop  (D License)

Jan 5, 2004, 9:06 PM
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Re: [ChileRelleno] 1 and 2 pin Pop Top pull forces [In reply to] Can't Post

I heard a story recently from another rigger. They had packed a pop top rig and the owner had it tightened by another rigger. They brought the rig back to the first rigger because they were concerned about pull forces. They told the jumper not to worry and to prove it, had the jumper put the rig on and put a spring scale on the reserve handle and began to pull. 35 lbs.-nothing. 45 lbs- still no PC launch and the jumper complained that it was begining to hurt their shoulder. Finally at 55 lbs. the PC launched.

Derek


Premier GravityGirl  (D 18897)

Jan 5, 2004, 10:33 PM
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Re: [ChileRelleno] 1 and 2 pin Pop Top pull forces [In reply to] Can't Post

I had a VERY hard pull on my Reflex. This dates back to the first batch of rigs to come off the line. I had a loose Pop Top and asked a rigger to have a look. He tightened it down while we were all out to eat that night.

Next morning, I got up to do a jump before the paying customers arrived. I pulled at 3500. Was spinning on my back. Chopped at 3200. No RSL. No Cypres (well dead batteryCrazy). Grabbed Silver with one hand. Tug. Nothing. Okay. Two hands. One more time like you mean it! Nothing. By the time I got the handle out, I was on my back digging in with my knees and everything I had. I had an open parachute just under 700 feet.

When we looked at my gear, the reserve pin was slightly bowed. I'm not sure what the pull force was, but I'm not exactly a tiny girl.


pilotdave  (D License)

Jan 6, 2004, 7:08 AM
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Re: [GravityGirl] 1 and 2 pin Pop Top pull forces [In reply to] Can't Post

Well, I'm no expert, but it seems to me that your problem was a bent pin, not just a tight poptop. Tightening the pop top can bend the pin if done incorrectly, but that's something you could have caught before jumping, right?

Dave


Hooknswoop  (D License)

Jan 6, 2004, 7:16 AM
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Re: [pilotdave] 1 and 2 pin Pop Top pull forces [In reply to] Can't Post

Quote:
Well, I'm no expert, but it seems to me that your problem was a bent pin, not just a tight poptop. Tightening the pop top can bend the pin if done incorrectly, but that's something you could have caught before jumping, right?

Over-tightening the pop top can bend the pin. It is very difficult to see a bent pin while it is still through the loop.

I had to replace a ripcord on a reserve that another rigger had (because of the ripcord SB) pulled to test it. It didn't break and didn't look bent, so he OK'd it. It was very bent.

Derek


rigging65  (D 21921)

Jan 6, 2004, 8:25 AM
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Re: [crapflinger2000] 1 and 2 pin Pop Top pull forces [In reply to] Can't Post

I think one of the most unfortunate (or fortunate, depending on how you look at it) things about pop-top style rigs, is that your rigger really needs to be familiar with the system to do his/her best work for you. There are certain tricks and tips that make packing pop-tops easy. Unfortuantely, too many riggers don't take the time and go out of their way to learn them for the one or two pop-tops they see. In my travels, its been very rare to see poorly packed pop-top rigs on DZs with large, busy lofts. The riggers get more experience with them and they become easier to pack.

This weighs in with this discussion because a competent rigger shouldn't have any problem telling when he's getting close to "the edge" with tamping a loop...whether on initial closing or when re-seating. From what I've seen, more common than not it's the customer tamping down their own pop-top that make it too tight. They're worried about getting the cap all the way seated, not understanding that you shouldn't be using the loop to make the cap sit down, rather the loop is there to keep the cap in place once you get it in position.

If people work off the theory that the loop is only there to hold things in place after you put them in place, I think you'd see heavy pulls on pop-tops go away, for the most part.


ChileRelleno  (D 24868)

Jan 6, 2004, 8:44 AM
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Re: [Hooknswoop] 1 and 2 pin Pop Top pull forces [In reply to] Can't Post

Quote:
My conclusion is that some people must be exerting some considerable pressure when closing or tightening reserve poptops.

I think alot of riggers/jumpers put maximum downward force on the poptop and tighten it as hard as they can thinking its the only way to get a good seat on the containerCrazy.
When all they need to do is apply enough pressure to seat the poptop and snug the closing loop.


(This post was edited by ChileRelleno on Jan 6, 2004, 11:06 AM)



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