Forums: Skydiving: Gear and Rigging:
Heavily wingloadings, line strength and peak forces

 


Jiggs  (F 745)

Aug 26, 2012, 9:17 PM
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Heavily wingloadings, line strength and peak forces Can't Post

Hi guys,

Is anyone aware of testing in the durability of line strength under heavy loadings? Historically, most line breakage has been on openings. With higher loadings and even higher performance canopies we are generating even more power and even more stress in the system. I know PD did some but can't see anything published?

E.g. has anyone looked at the forces that are generating with on opening and swooping canopies at very high loadings and how this compare to the max strength of the lines? Is there any hard data on this? There are few big boys loading up quite high these days - Is there any info on the relative strengths of the different version of HMA that we actually use?

FYI - I am wondering whether or not to reline a 69 sized canopy used for XRW with 500 HMA from the current 300. Current wingloading is 3.6
Or if I was to obtain a smaller main and run with less lead and still keep the thinner line.

Thoughts?

PS. Will download some data and see if I can figure out maximum speeds from Flysight - might be an idea / proximate on some of the forces?


RiggerLee

Aug 26, 2012, 10:12 PM
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Re: [Jiggs] Heavily wingloadings, line strength and peak forces [In reply to] Can't Post

I was amazed at all the work being done with data recording that was being presented at PIA. There's actually a lot of hard data being gathered out there. They don't normally share it but most people aren't really interested. Try Peek. He was kind of at the for front of all of this. He has a good bit of data and he's writen papers and shit. He was really into this for a while and I'd bet he'd be happy to talk to you. Nice guy.

Lee


mchamp  (D 32129)

Aug 27, 2012, 8:52 AM
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Re: [Jiggs] Heavily wingloadings, line strength and peak forces [In reply to] Can't Post

If you do find further information about what you asked please post it here if you can as this topic is really intriguing to me!


skydiverek  (C 952)

Aug 27, 2012, 12:37 PM
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Re: [Jiggs] Heavily wingloadings, line strength and peak forces [In reply to] Can't Post

http://www.pcprg.com


JohnSherman  (D 2105)

Aug 28, 2012, 8:11 AM
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Re: [Jiggs] Heavily wingloadings, line strength and peak forces [In reply to] Can't Post

Parachute Labs. has extensive data in this subject area. Exactly what do you want to know?
We use a PDAS system which will record everyyhing you ask for on any given jump.
See: http://www.jumpshack.com/...s/PDAS%20Brocure.pdf. BTW: We provide these systems to the U.S. Air Force which they use for evaluations of their systems.
Give me a specific request for data and we will try to provide it for you. If is involves equipment from a different manufacturer we would be happy to test it for a fee.

John

BTW: Ther are math models which do a fair job of predicting most of this type of thing.



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