Helium loss
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rich.m.legrand@...
Hey everybody,
We're interested in some extended flights (several days) using simple latex (chloroprene?) balloons such as the ones from Kaymont. We have a ballast/gas release system that we're designing... One piece of information we haven't been able to find is how much helium we can expect to lose over time. Does anyone have some metrics or know where to grab them? thanks! |
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I don't think Kaymont sell any chroroprene balloons (Totex KA and
TX series are both latex I think). For long duration Chloroprene
would be better for UV degradation (and I think helium diffusion
too). If you want chloroprene a good source would be the Pioneer (Qualatex / ToyTex) Cloudbusters - (as used for cluster ballooning) - but only available in sizes up to about 600g. You should consider using HiFloat to reduce helium diffusion (on both latex and chloroprene according to manufacturer). Helium diffusion seems to be highly dependent on a number factors
- loss on the ground is considerably different than at altitude
(cold and humidity). You should probably seek guidence form previous ballast/gas flight folk (like the
Stanford guys). My
longest Chloroprene floater flight was only about 18 hours I'm
afraid. Steve G8KHW/AJ4XE
On 22/09/2022 20:22,
rich.m.legrand@... wrote:
Hey everybody, |
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rich.m.legrand@...
Hi Steve, thanks for the information! That's an interesting suggestion about Hifloat -- it looks like it could make a significant difference.
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Joe WB9SBD
If I remember correctly Hi
Float is just HE and air , nothing special. so the HE will still
escape just as fast and left with an envelope filled with air.
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Joe WB9SBD On 9/22/2022 3:52 PM,
rich.m.legrand@... wrote:
Hi Steve, thanks for the information! That's an interesting suggestion about Hifloat -- it looks like it could make a significant difference. |
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? Steve
On 22/09/2022 21:53, Joe WB9SBD wrote:
If I remember correctly Hi Float is just HE and air , nothing special. so the HE will still escape just as fast and left with an envelope filled with air. |
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Although we did not take the time to do repeated trials, earlier this summer we filled a 200 gram Cloudbuster with helium indoors and set it for an initial 200 grams of positive lift. 24 hours later the lift was only 100 grams. After an additional 24 hours the lift was 50 grams. One more day and there was no lift at all. We did not treat the balloon with the HiFloat solution. Howard On Thu, Sep 22, 2022 at 5:21 PM Steve G8KHW / AJ4XE <steve@...> wrote:
--
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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rich.m.legrand@...
A 200 gram cloudbuster filled to 200 grams of positive lift isn't much stretch for that size balloon, but that's still really useful info -- thanks!
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As the picoballooners have found - gas loss through diffusion on
the ground is completely different in floating flight. A foil
balloon might loose 1g of lift (out of the 10g or so it was filled
with) over 24 hours on the ground under no pressure - yet stay up
for months in the air - under 0.2 psi differential pressure. Steve G8KHW
On 22/09/2022 22:49, BASE_DePauw wrote:
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