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The properties of latex / was Re: [GPSL] COVID-19 and GPSL

Hank Riley
 

Joe,

When you say "many many" I'm curious why you did those tests?  Any special reason other than curiosity?

Do you have any tables or graphs you could provide, or write up for this list?

Hank
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On 3/22/2020 3:29 PM, Joe WB9SBD wrote:

We have tension tested many many samples of latex

Joe WB9SBD
 

I was just wondering what the tensile strength on the average actually was. So then even when fully inflated how much pressure it could actually generate before failing.

I had all the formulas for pressure vs diameter skin effect it was a pretty complex formula,

Funny thing was my bench tests came in very very close to the tests that someone made with a pressure gauge!

Joe WB9SBD

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On 3/22/2020 8:36 PM, Hank Riley via Groups.Io wrote:
Joe,

When you say "many many" I'm curious why you did those tests?  Any special reason other than curiosity?

Do you have any tables or graphs you could provide, or write up for this list?

Hank
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On 3/22/2020 3:29 PM, Joe WB9SBD wrote:

We have tension tested many many samples of latex

BASE_DePauw
 

This conversation reminds me of some work my students did several years ago.  Attached are a few slides from our presentation at the 2013 GPSL in Pella.

That work was inspired by Ron K6RPT's long duration floaters and relates to Joe WB9SBD's comments about the stretching of latex.

If you revisit CNSP (Ron's) flight to Morroco, the float altitude increased each daylight period.  A  simple explanation would be that the strong UV in the stratosphere degraded the latex, reducing its tensile strength, and eventually allowing the balloon to reach burst diameter.

Howard, KC9QBN
BASE_DePauw