Specs for bungy cord pc?

[RTB 0]

I have a friends bungy cord collapsible pilot chute where the old cord is worn out.
Does anyone have specs for how much force should be required to stretch it when new?
As a rigger would you refit a pc with a new bungy cord or just have them buy a new pilot chute?

[Dumpster 0]

I'm not a rigger, but I would reccomend replacing the bungee cord PC with a kill-line PC. I understand bungee PC's don't work well in sub-terminal deployment situations, like one might encounter in an aircraft emergency.

Easy Does It

[masterrig 1]

I agree with Dumpster. Replace the bungee pilotchute with a kill-line collapsible pilotchute. The bungee type, stays collapsed until enough wind speed is reached to open the pilotchute. The bungee collapses the pilotchute when the canopy is fully opened due to the lower wind force. The kill-line collapsible is 'cocked' open and stays open until the parachute is inflated then, the pilotchute collapses. Hope, this helps.

Chuck

[jerry81 10]

I believe there are specifications for bungee cord length for different pcs that should be followed. Probably best to contact the manufacturer.
Besides the possible hesitations at subterminal deployments (if it's possible, I cock the bungee pc if I'm packing a rig with one), my biggest gripe with bungee pcs is that I've seen more than a couple of them (partially) reinflate at high-speed landing maneuvers, which kinda defeats the purpose of a collapsible pilot chute...

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[riggerrob 643]

Replace the old bungee cord with new cord of similar thickness. Start by tying it, so that there is a two inch gap between the apex and the end of the bridle. The do a few test jumps to confirm your setting.

As for fears that bungees will not work during hop-an-pops ... I have used them on dozens of hop-and-pops and have only experienced one hesitation, and that only lasted a couple of seconds.

[mjosparky 4]

Rob is right. A properly made bungee PC will open just find down to speeds of about 40/45 mph. This myth that they do not work on H&P's is just that, a myth. I have used them on H&P exits out of a Wilga at 50 mph on demos.

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(if it's possible, I cock the bungee pc if I'm packing a rig with one),

How do you "cock" a bungee PC?

Sparky

My idea of a fair fight is clubbing baby seals

[jerry81 10]

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How do you "cock" a bungee PC?

This would be easier to explain with pictures. On some bungee pcs, it's possible to wedge the lower end of the cord in the channel through which it passes into the pilot chute. (Come to think of it, I've seen most of these on PdF rigs.) That way the pc is 'cocked' when you pitch it, but collapses like normal when the canopy's out.

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[usskydiver 0]

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Rob is right. A properly made bungee PC will open just find down to speeds of about 40/45 mph. This myth that they do not work on H&P's is just that, a myth. I have used them on H&P exits out of a Wilga at 50 mph on demos.
Sparky

And if they work at 40/45 mph, they reinflate at those same speeds therefore affecting the flight characteristics of a high performance canopy. I tell someone a couple of times a year that they need to adjust their know because their PC is reinflating.

As a side note, I used one on my Raider would would not even think of using one on any of my Velocity 103's.

Tim T.

[mjosparky 4]

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And if they work at 40/45 mph, they reinflate at those same speeds therefore affecting the flight characteristics of a high performance canopy. I tell someone a couple of times a year that they need to adjust their know because their PC is reinflating.

As a side note, I used one on my Raider would would not even think of using one on any of my Velocity 103's.

Tim T.

I agree, they should not be used on smaller, high performance canopies. But I was addressing the fact that they work well and are safe for H&P jumps.

Sparky

My idea of a fair fight is clubbing baby seals