[islandlabs] How Much Helium

John Teddy masterjediyoda
Fri Dec 18 17:46:32 EST 2009


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*?*radius3
>>>>>>
>>>>>> 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
>>>>>>> >
>>>>>>> > _______________________________________________
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>>>>>>> >
>>>>>>> >
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>>>>>>
>>>>>>
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>>>>>
>>>>
>>>
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