[islandlabs] How Much Helium

Jonathan Dahan jedahan
Wed Dec 23 14:39:43 EST 2009


I got the phone, all we need is a scale now.

- Jonathan


2009/12/18 John Teddy <masterjediyoda at gmail.com>

> I talked to a guy who has experience in balloons and many launches.
>
> He said 6 meters total rope length. So that is 10 feet between
> payload/parachute, and another 10 feet between the parachute/balloon.
>
> What kind of rope are we using, and what is the mechanism we're using to
> insert helium into the balloon and close the balloon/seal it permanently?
>
> 2009/12/18 John Teddy <masterjediyoda at gmail.com>
>
>> http://ukhas.org.uk/guides:parachute_sizing_chart
>>
>>
>> 2009/12/18 John Teddy <masterjediyoda at gmail.com>
>>
>>> Also if anyone buys a parachute, email the list so no one redundantly
>>> buys one.
>>>
>>> 2009/12/18 John Teddy <masterjediyoda at gmail.com>
>>>
>>> http://www.srcf.ucam.org/~cuspaceflight/calc/<http://www.srcf.ucam.org/%7Ecuspaceflight/calc/>
>>>>
>>>> http://ukhas.org.uk/guides:balloon_data
>>>>
>>>> http://ukhas.org.uk/
>>>>
>>>>
>>>>
>>>>
>>>> 2009/12/17 John Teddy <masterjediyoda at gmail.com>
>>>>
>>>>> One we have the phone, we will put everything on a scale and measure
>>>>> the weight and we can start to whittle down to a closer degree the
>>>>> calculations.
>>>>>
>>>>> Does anyone have a scale they can bring to Wednesday's meeting?
>>>>>
>>>>>
>>>>> 2009/12/17 Burns, William <burns at cshl.edu>
>>>>>
>>>>>>  I made some assumptions... but I'm sticking w/ my 113 cubic feet
>>>>>> figure for now. (I think our requirement is half of your figure)
>>>>>> Unless the formula in the e-mail is wrong, or we start using some
>>>>>> other method/variables for estimating the helium required?
>>>>>> (what's our actual payload weight?)
>>>>>>
>>>>>> -Bill
>>>>>>
>>>>>>  ------------------------------
>>>>>> *From:* list-bounces at islandlabs.org [mailto:
>>>>>> list-bounces at islandlabs.org] *On Behalf Of *John Teddy
>>>>>> *Sent:* Thursday, December 17, 2009 5:57 PM
>>>>>> *To:* Island Labs main mailing list
>>>>>> *Subject:* Re: [islandlabs] I have an antenna for the balloon in my
>>>>>> office...
>>>>>>
>>>>>> Someone look at my figures and tell me if it makes any sense, or am I
>>>>>> way off.
>>>>>>
>>>>>> 2009/12/17 John Teddy <masterjediyoda at gmail.com>
>>>>>>
>>>>>>> Since we already spent $65, it looks like our project total cost is
>>>>>>> going to be around ~$150 at least. So roughly the same as MIT. They got some
>>>>>>> stuff gratis which we did not. Maybe if we call some engineering / tech
>>>>>>> school in the Jersey area and ask one of the professors if they want to give
>>>>>>> us helium at no cost.
>>>>>>>
>>>>>>> 2009/12/17 John Teddy <masterjediyoda at gmail.com>
>>>>>>>
>>>>>>> So if I squish Bill and my email together, we need
>>>>>>>>  *65.5 * 3.3 = 216.15*216 cubic feet of helium.
>>>>>>>>
>>>>>>>>
>>>>>>>> http://bit.ly/7Z4v6A .. I called this guy on ebay, that tank is 244
>>>>>>>> cubic feet. He said it weighs 150 pounds full. ANd he said it could be
>>>>>>>> rented for $84.99. But he is in Florida. This gives us a rough idea of
>>>>>>>> prices though. he said to rent it and use all the helium in it, is $84.99
>>>>>>>> can it can be returned after a few days or whatever.
>>>>>>>>
>>>>>>>> -John
>>>>>>>>
>>>>>>>> 2009/12/17 Burns, William <burns at cshl.edu>
>>>>>>>>
>>>>>>>>  Applying the given formula: (4/3*pi*R^3)
>>>>>>>>> Excel says: 65.5 cubic feet for a 5-ft diameter balloon.
>>>>>>>>>
>>>>>>>>> According to the Kaymont figures:
>>>>>>>>> http://www.kaymont.com/pages/sounding-balloons.cfm
>>>>>>>>>
>>>>>>>>> The launch diameter of a kaymont 350 (used by MIT) should have been
>>>>>>>>> 125 cm if their payload was 250grams.
>>>>>>>>> The launch diameter of a kaymont 800 (used by I.L.) should be 150cm
>>>>>>>>> if our payload is 250grams.
>>>>>>>>>
>>>>>>>>> Scaling-up a 5-ft balloon by the same ratio gives us a 6-ft
>>>>>>>>> balloon...
>>>>>>>>> So (ballpark) our balloon should contain 113 cubic feet of helium.
>>>>>>>>>
>>>>>>>>> Who knows what size tank might contain that much helium?
>>>>>>>>>
>>>>>>>>> -Bill
>>>>>>>>>
>>>>>>>>>  ------------------------------
>>>>>>>>> *From:* list-bounces at islandlabs.org [mailto:
>>>>>>>>> list-bounces at islandlabs.org] *On Behalf Of *John Teddy
>>>>>>>>> *Sent:* Thursday, December 17, 2009 5:04 PM
>>>>>>>>> *To:* Island Labs main mailing list
>>>>>>>>> *Subject:* Re: [islandlabs] I have an antenna for the balloon in
>>>>>>>>> my office...
>>>>>>>>>
>>>>>>>>>   I see, the person must have been mistaken. Or maybe they were
>>>>>>>>> talking about industrial tanks of larger size.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> http://www.target.com/gp/detail.html/185-8901296-2975720?ASIN=B000PGQ63O&AFID=Froogle&LNM=B000PGQ63O|Disposable_Helium_Tank&ci_src=14110944&ci_sku=B000PGQ63O&ref=tgt_adv_XSG10001<http://www.target.com/gp/detail.html/185-8901296-2975720?ASIN=B000PGQ63O&AFID=Froogle&LNM=B000PGQ63O%7CDisposable_Helium_Tank&ci_src=14110944&ci_sku=B000PGQ63O&ref=tgt_adv_XSG10001>
>>>>>>>>>
>>>>>>>>> This is a 12lb tank, and holds 15 cubic feet of helium. It only
>>>>>>>>> costs $50.
>>>>>>>>>
>>>>>>>>> I don't think 15 cubic feet of helium be nearly enough.
>>>>>>>>>
>>>>>>>>> The MIT balloon was 5 feet diameter at launch, and 20 feet at
>>>>>>>>> burst. So ours will be under 10 feet diamater at launch, and under 40 feet
>>>>>>>>> diamater at burst. My figures are off, need the sphere formula. 4/3*?*radius
>>>>>>>>> 3
>>>>>>>>>
>>>>>>>>> I don't know what the weight in the balloon (we have 800gram
>>>>>>>>> balloon, they used 350 gram right?), translates to as far as diameter and
>>>>>>>>> cubic feet of helium.
>>>>>>>>>
>>>>>>>>> From the guide:          "each cubic foot of helium can lift 28g"
>>>>>>>>> and "each pound of free lift would me 300feet per minute of ascension"
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> http://www.balloonsandhelium.net/heliumtanksforsale.html <--- they
>>>>>>>>> are way to expensive to buy. Rent or launch at a party store are the only
>>>>>>>>> options. And the weight should definitely be under 100 pounds as you said
>>>>>>>>> Mark.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> They don't actually say in the guide how much helium they use I
>>>>>>>>> believe. Does anyone see a figure on how much helium the MIT guys used? They
>>>>>>>>> use an example of "61 cubic feet of helium" to describe an example for a
>>>>>>>>> formula, but that doesn't mean that is how much they used. If we need 61
>>>>>>>>> cubic feet of helium this target tank is not nearly big enough.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> As far as the antenna goes, it was bought with a cellphone modem,
>>>>>>>>> it's designed to be used for cell phones. It's omni-directional, long, and
>>>>>>>>> quality. And it has the wire connector we need which attaches to the phone
>>>>>>>>> already I believe, so no soldering.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Thu, Dec 17, 2009 at 3:30 PM, Mark Drago <markdrago at gmail.com>wrote:
>>>>>>>>>
>>>>>>>>>> Unless the large helium tank is obscenely large, it's not 500
>>>>>>>>>> pounds.
>>>>>>>>>> I worked at a party store that rented tanks in 3 sizes (small,
>>>>>>>>>> medium,
>>>>>>>>>> large) and had a fourth size for our own uses (jumbo).  The jumbo
>>>>>>>>>> tanks were easy for one person to roll around on their edge, but
>>>>>>>>>> were
>>>>>>>>>> too heavy to really pick up and carry.  I would say they were
>>>>>>>>>> easily
>>>>>>>>>> under 100 pounds, probably closer to 60 or 70.  This is a rough
>>>>>>>>>> guess
>>>>>>>>>> as it has been 10 years since I moved one.  But I can definitely
>>>>>>>>>> say
>>>>>>>>>> they were not 500 pounds.
>>>>>>>>>>
>>>>>>>>>> Mark.
>>>>>>>>>>
>>>>>>>>>> On Thu, Dec 17, 2009 at 15:13, John Teddy <
>>>>>>>>>> masterjediyoda at gmail.com> wrote:
>>>>>>>>>> > http://i45.tinypic.com/riaop5.jpg and
>>>>>>>>>> http://i50.tinypic.com/1htb15.jpg
>>>>>>>>>> >
>>>>>>>>>> > This antenna is already rigged to connect to a usb cellular
>>>>>>>>>> modem, that is
>>>>>>>>>> > able the size of a large thumb drive. So I believe this
>>>>>>>>>> connector should
>>>>>>>>>> > work with a lot of cell phones also. When the phone comes we
>>>>>>>>>> ordered, I will
>>>>>>>>>> > bring this antenna and see if it fits.
>>>>>>>>>> >
>>>>>>>>>> > I believe the remaining parts we need are: parachute and helium
>>>>>>>>>> (and some
>>>>>>>>>> > string/rope to connect it all, and other little things which are
>>>>>>>>>> easy to
>>>>>>>>>> > get).
>>>>>>>>>> >
>>>>>>>>>> >
>>>>>>>>>> > We need to calculate how much helium we will need for the
>>>>>>>>>> baloon. As it was
>>>>>>>>>> > explained to me yesterday, the large helium tank can weigh up to
>>>>>>>>>> 500 pounds.
>>>>>>>>>> > So this is exceedingly difficult to carry around. If anyone can
>>>>>>>>>> crunch the
>>>>>>>>>> > numbers and figure out how much helium we would need, and how
>>>>>>>>>> much each size
>>>>>>>>>> > tank can hold.. that would be helpful.
>>>>>>>>>> >
>>>>>>>>>> > -John
>>>>>>>>>> >
>>>>>>>>>> > _______________________________________________
>>>>>>>>>> > List mailing list
>>>>>>>>>> > List at islandlabs.org
>>>>>>>>>> > http://freeculture.org/cgi-bin/mailman/listinfo/list
>>>>>>>>>> >
>>>>>>>>>> >
>>>>>>>>>> _______________________________________________
>>>>>>>>>> List mailing list
>>>>>>>>>> List at islandlabs.org
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>>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> _______________________________________________
>>>>>>>>> List mailing list
>>>>>>>>> List at islandlabs.org
>>>>>>>>> http://freeculture.org/cgi-bin/mailman/listinfo/list
>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>> _______________________________________________
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>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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