[Discuss] Near space: Gas

James Hukill EMAIL HIDDEN
Tue Jan 24 12:23:53 PST 2012


Other upside, much easier to have an emergency down option.
Small spark in the balloon and it will decelerate

;-)

On Tue, Jan 24, 2012 at 12:20 PM, Laura Harris <EMAIL HIDDEN> wrote:

> Here are the relative boyancies:
>
>
>    - Gross buoyant lift of hydrogen: 1.1399 Kg/m^3,
>    - Helium is 1.0565 Kg/m^3.
>    - The difference is 10 grams (~.35 oz) more lift per cubic meter of
>    gas. Another way to look at it is that it takes about 8% less hydrogen than
>    helium to lift the same weight.
>
>
> The diffusion rate through solids for helium is about 65% of that for
> hydrogen. IOW, hydrogen 'leaks' about 35% more quickly than helium, all
> other things being equal. Shouldn't be an issue for our short flight- we
> can also add a tad more to make up the difference if we want to be really
> sure.
>
>
>
>   ------------------------------
> *From:* Ben Hallert - Vipmail <EMAIL HIDDEN>
> *To:* Rick Osgood <EMAIL HIDDEN>
> *Cc:* "EMAIL HIDDEN Maker Space" <
> EMAIL HIDDEN>
> *Sent:* Monday, January 23, 2012 9:48 AM
> *Subject:* Re: [Discuss] Near space: Gas
>
> Standard welding tank, prolly 250ft^3 I guess?  Whoops!  Forgot to ask,
> heh.
>
> - Ben
>
> On Jan 23, 2012, at 9:14 AM, Rick Osgood <EMAIL HIDDEN>
> wrote:
>
> Thanks Ben.  Do you know what size tank that is?
>
> Rick
>
> On Mon, Jan 23, 2012 at 8:45 AM, Ben Hallert - Vipmail <EMAIL HIDDEN>wrote:
>
> I called IWSI about lift gas and got done quotes:
>
> Tank rental is $5 a month
> Helium is not currently available (because of the shortage, might not get
> too much better soon)
> Hydrogen fill is $45.
>
> Regards,
>
> - Ben
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