SAFETY: Modify your bridle!

[remko 0]

At Lake Wales I saw 3 and heard of 1 entanglement with deployment bags/pilot
chutes. I think we need a 'Y' finger-trapped tab modification on the bridle to hook
behind the middle ring after opening to preclude the pilot chute + bag to extend
when the canopy collapses during a rough dock or when the canopy is
hard pointed. I just got mine modified.

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Everything you know is wrong. But some of it is a useful first approximation.

[teamhypoxia 0]

My bridle is short enough that about half of my pilot chute gets sucked into the middle ring. It's always there after landing and walking back, so I doubt it'd ever come out from a rough dock or hard point

[remko 0]

relyon wrote in thread 835373: `IIRC, the Lightning bridle is 79" long for 176s and smaller.'

I gave this some more thought and had some correspondence with Rusty Vest about it. Lightning canopy sizes evolved over time and PD just used a few different bridle lengths. It was simply never an issue (in the past). Recently I came up with a formula to calculate proper bridle length using the 176 as a base:

113 : 64"
126 : 67" (flight tested)
143 : 71"
160 : 75"
176 : 79" (standard PD length)
193 : 83"
218 : 88"
235 : 91"
253 : 95"

These should leave about up to 1 inch between the pilot and the middle ring. I am very confident about the numbers but I say `should' because I have flight tested it only for the 126. My advice is to have it checked in flight first before you have it trimmed. Feedback is highly appreciated. Enough data to back it up will bring it into main-line.

These lengths are ok for all configurations: throw-away or pull-out, tail-pocket with optional kill-cone or deployment-bag with large or small grommet.

Now there are still two ways to go about fixating the bridle in the retracted position and collapsing the pilot. The Y-finger-trap modification (see attachment) with kill-cone or large grommeted bag, or having the pilot pulled into the middle ring. There are some cons to the latter:

- Not all pilot chutes will pull smoothly into the middle ring.
- The tension on the bridle may deform the canopy.
- Not suitable for deployment-bag systems with small grommet.
- Bridle gets awfully short on a 113 (57" or less).
- They are not interchangeable.

If you do choose the pilot in ring method, lightly pull the bridle and see if and how far it will go into the ring. 6-8 inches should be enough, no more than 12.

Conclusion:
1) Make sure your bridle has a correct length.
2) Make sure it stays retracted, no matter what happens to your canopy.

A little investment in time and money might prevent a cut-away and loss off or damage to equipment, or worse...

Fly safe,
Remko

[cwn 0]

Quote

- Bridle gets awfully short on a 113 (57" or less).

You can use a longer bridle if you attach it to the center ring and route it from one side to the other then back through the center ring.

[remko 0]

Quote

You can use a longer bridle if you attach it to the center ring >=8

I don't know about that. Anybody has any experience with it? It wouldn't work for the ring-kill though. The attachment of the bridle to the center ring will be in the way for the pilot chute to enter it.

A possible solution would be to attach it to the webbing that holds the ring but the deformation of the webbing has consequences for the strength of that construction (concentration of forces to the outer stitches). I wouldn't advise it.

Remko

--
Everything you know is wrong. But some of it is a useful first approximation.