[islandlabs] How Much Helium

John Teddy masterjediyoda
Thu Dec 24 11:11:49 EST 2009


I already have the scale.

We need a parachute, ropes, and other little things.

Plus the helium, which is the most important. I called several party places,
none of them have tanks big enough I believe. At last not the party city
places. Anyone else call? or find out about helium?

On Wed, Dec 23, 2009 at 2:39 PM, Jonathan Dahan <jedahan at gmail.com> wrote:

> 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
>>>>>>>>>>> >
>>>>>>>>>>> >
>>>>>>>>>>> _______________________________________________
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>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
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>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>
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>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
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