Re: Superpressure balloon valve / was Re: [GPSL] K5NOT-11 WSPR Balloon Failure

Bill Brown

I managed to float a couple of 1200 and 1500 gram balloons by putting a PVC pipe with an end cap in the neck of the balloon and drilling a 1/16" hole in the end cap (two 1/16" holes were too much as were larger size drill holes). The ones with the single 1/16" hole all floated all night long over 100,000 feet or so. 

- Bill WB8ELK

-----Original Message-----
From: BASE_DePauw <hlbrooks@...>
Sent: Tue, Jul 21, 2020 9:27 pm
Subject: Re: Superpressure balloon valve / was  Re: [GPSL] K5NOT-11 WSPR Balloon Failure

I suggest reaching out to Michael K5NOT (ARBONET) who did the presentation at GPSL 2010.

Another investigator was James Flaten with his students at the University of Minnesota who shared their results at the Academic High Altitude Conference that same summer at Taylor University.

I cannot find copies of either presentation in my files tonight.

Howard, KC9QBN

On Tue, Jul 21, 2020 at 10:12 PM Mark Conner N9XTN <mconner1@...> wrote:
I searched my Gmail archive and there are fragments of a discussion on this topic based on an ARBONET balloon flight in the summer of 2010 which may have measured this.  There may even have been a GPSL presentation that summer on it.  If you look in the archived messages from ~June-Sept 2010 you may find something.

GPSL 2010 was in Hutchinson KS.

73 de Mark N9XTN

On Tue, Jul 21, 2020 at 7:40 PM Dennis Klipa - N8ERF <klipadk@...> wrote:
I am curious.  Many of us have measured the atmospheric pressure versus altitude.  I have wanted to, but haven't, measured the pressure inside the latex balloon as it rises.  Has anyone measured the pressure differential (inside vs outside) of the latex balloon as a function of altitude?  How much difference are we talking about trying to control with this valve.  If the balloon were a fixed volume you could do the calculation, but the latex balloons are not.

Best Regards,
Dennis Klipa, N8ERF

Howard L. Brooks
Professor of Physics and Astronomy
241 Julian Science and Mathematics Center
DePauw University
2 E. Hanna Street
Greencastle, IN 46135

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