how much helium gas is needed for 12 feet helium balloon

[Dr.V.Balaji]

Dear all,

I am a marine ecologist from an environmental NGO www.omcar.org,
India. I was inspired by grassrootmapping and unerbahn (Mr.J.Warren),
so now preparing for a grassroot aerial mapping project in our area.

I would like to know that how much cum of helium is needed to fill 12
feet sky balloon (sphere).

thanks a lot

balaji

[Jeffrey Warren]

Hi, Dr. Blaji -

Please tell us more about your project!

A 12 foot diameter, spherical balloon is 900 cubic feet or 25.6 cubic meters.

It could lift an awful lot of weight... i'd estimate 6-7 kg. Do you really need one that big?

And the usual large helium tanks, which cost ~$250 each in the US, are about 250 cubic feet - so that would make around $900 for all that helium, and that's only in the US, where it's pretty cheap.

What are you trying to lift?

Best,

Jeff

[V.Balaji,OMCAR Foundation]

Dear Mr. Jeffrey Warren,

Thank you for your email.  Our project probably start in january 2011.  The aim of this project is to create participatory grassroot aerial maps using villagers of our region.  

I will share the project activities with this group frequently.  

Could you suggest me a right size of the balloon?  A 12 foot balloon cost about 224 US dollars, the dealers said it will take around 7 cylinders (each with 7 cubic meter of helium) that cost around 1000 us dollars.  Such an expensive material for us!

I need to know the exact size of balloon that can lift the camera+the weight of the connecting rope of 1000m.  Please let me to know.

yours sincerely

V.Balaji

--
Dr. V.Balaji., M.Sc., M.Phil., Ph.D.,
Director
OMCAR FOUNDATION
69, Vendakottai Road
Valavanpuram
Pattukkottai(post)
Tamil Nadu
INDIA - 614601
Mobile: 9360548117
Phone: +914372236117
www.omcar.org

[Mathew Lippincott]

I think Jeffrey is right on payload weight. 12 feet is big! I would suggest a smaller balloon, maybe an emergency blanket balloon, like in the grassroots mapping guide.
1000 cubic feet of helium has approximately 64lbs of lift.  At 905 cu ft, an ideal 12 foot balloon has a total lift of 57lbs.

it says here 57.97, under 12ft balloon:
this is a great balloon lift look up chart.
http://www.chem.hawaii.edu/uham/lift.html

[Gary Mortimer]

That size of balloon is way too big, you will also have issues controlling it or rather restraining it at 3000' .You might also look up super heating, certainly something you would have to consider.

[Jeffrey Warren]

Well, it seems like you want to lift just a camera, that is, the same amount as most of us are trying to lift. I've found that a 5-foot sphere is approx right for lifting a 200g camera plus the string.

Thanks for the tables, Mathew - i always seem to calculate lift incorrectly, which i suppose is because i usually do it 'by feel' - i.e. i fill until it's pulling hard enough. My friend Josh always asks me if I've done any Math when we're about to do a flight.

Dr. Balaji - for cheap materials, you should take a look at this page: http://wiki.grassrootsmapping.org/show/BalloonMaterialsList

It lists, for example, the metallized mylar blankets which you can buy for $0.50 each, which can be folded and taped shut into pretty large balloons. I think you should then need only a single 7 cubic meter tank of helium --- and depending on how big you make your balloon, i think you may be able to fill the balloon 2-3 times before running out. (Mathew, please catch any errors, but i think that's right!)

It sounds like a very exciting project, and I'm eager to hear more.

Jeff

[dean jordan]

http://www.chem.hawaii.edu/uham/lift.html

dean jordan

www.nabx.net

www.jordanairkites.com

aoxomoxoa

[V.Balaji,OMCAR Foundation]

Dear all,

Excellent feedbacks.  Thank you all sharing your time and knowledge.  I just sent the proposal to our government for financial support for this project.  the aim of the project is to create low cost high resolution aerial images using balloon aerial photographic technique.  

Then we will use this map as a raster image to create thematic maps of land ownership, encroachments, shrimpfarms, coastal forestry. This baseline maps will be used for desilting the flood drainage canal systems and planting trees in selected coastal areas by the participatory decision making.

Its just an idea that I developed recently, I know it will take long time...and I will update.

yours sincerely

V.Balaji