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Old May 04, 2013, 10:54 PM
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Rigid airship feasibility

Is it feasible to make a structure out of balsa sticks or carbon fiber rods, cover it with monokote and then fill it with a number of gas bags? basically and airship...

Would this be too heavy? I want it to be reasonably large, with enough lift to hold a gopro, twin edfs and maybe some fpv equipment.... would it make a difference if i decided to use hydrogen instead of helium?...(please no comments on the flammability debate)

Feasible?
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Old May 04, 2013, 11:47 PM
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Originally Posted by bshey View Post
Is it feasible to make a structure out of balsa sticks or carbon fiber rods, cover it with monokote and then fill it with a number of gas bags? basically and airship...

Would this be too heavy? I want it to be reasonably large, with enough lift to hold a gopro, twin edfs and maybe some fpv equipment.... would it make a difference if i decided to use hydrogen instead of helium?...(please no comments on the flammability debate)

Feasible?
Yes carbon fiber rods are perfect for airship structures. Yes, your method of building should work. Yes its going to have to be pretty big and have a decent number of lifting bags. Hydrogen is more greener to use and cheaper to buy. You can make your own hydrogen so that's a lot of money you can save their by using hydrogen instead of helium. As you probably know helium is expensive and buying a tank can burn a whole in your wallet big time.
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Old May 04, 2013, 11:53 PM
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Yes carbon fiber rods are perfect for airship structures. Yes, your method of building should work. Yes its going to have to be pretty big and have a decent number of lifting bags. Hydrogen is more greener to use and cheaper to buy. You can make your own hydrogen so that's a lot of money you can save their by using hydrogen instead of helium. As you probably know helium is expensive and buying a tank can burn a whole in your wallet big time.
Ok. How big would this blimp need to be to lift what i want to put on it?
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Old May 05, 2013, 12:06 AM
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Ok. How big would this blimp need to be to lift what i want to put on it?
Well you'll have to weigh these items and play with different helium or hydrogen amounts to see how much they will lift. But you also have to think about how much the material weighs. It pretty much all depends on how much equipment you plan on putting on your blimp. I would say at least 10ft+ in length. More in the plus range if you add all the equipment.
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Old May 05, 2013, 12:31 AM
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Well you'll have to weigh these items and play with different helium or hydrogen amounts to see how much they will lift. But you also have to think about how much the material weighs. It pretty much all depends on how much equipment you plan on putting on your blimp. I would say at least 10ft+ in length. More in the plus range if you add all the equipment.
any idea of the diameter?
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Old May 05, 2013, 12:50 AM
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any idea of the diameter?
Maybe 6ft to 8ft. Ill do some research on how much lift you need and the exact size of it. I have a calculation tool that tells you how much hydrogen or helium per cubic meter that the the blimp will need to lift the objects. I just need the weights of the items...

Do you have a gondola? This would also play a big role in the weight of the blimp.
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Old May 05, 2013, 08:19 PM
John C.
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You might do better making a semi-rigid, such as the Norge, the first airship to reach the North Pole (http://en.wikipedia.org/wiki/Norge_%28airship%29); you will be dealing with a lot of structural weight using ballonets inside a rigid skin like a full-size zeppelin. http://www.popsci.com/diy/article/20...l-1935-airship is an article about someone who built a 20-foot model of the U.S.S. Macon; it does not say whether he used ballonets inside the skin, or used the skin as the gas bag. Airships have the advantage that the Square/Cube Law works for you as your model gets bigger; I have been having trouble making LTA models that are as small as possible...
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Old May 05, 2013, 08:41 PM
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1000 cubic feet of Hydrogen will lift ~75 lbs at a standard temperature whereas Helium will lift ~69 lbs. Hydrogen is VERY flammable! Remeber the Hindenburg! (or was that the Maine?) Helium is inert. I've contemplated a Zeppelin of ~20 feet length made with carbon fiber or, preferrably, Kevlar. Modern batteries make it feasible. As a pure 'work horse' as you've planned a blimp would be better.
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Old May 09, 2013, 02:02 AM
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1000 cubic feet of Hydrogen will lift ~75 lbs at a standard temperature whereas Helium will lift ~69 lbs. Hydrogen is VERY flammable! Remeber the Hindenburg! (or was that the Maine?) Helium is inert. I've contemplated a Zeppelin of ~20 feet length made with carbon fiber or, preferrably, Kevlar. Modern batteries make it feasible. As a pure 'work horse' as you've planned a blimp would be better.
the reason hydrogen lifts more than helium is because it's lighter. hydrogen has an atomic mass of 1.01 where as helium has an atomic mass of 4.00. the fact that helium is inert (the atom has a full outer shell of electrons so it dosn't need to react with anything to become stable) makes it a winner for me. I want to make a model of the USS Macon with the trapeze system for launching and retreaving the sparrowhawk fighters. the zepplin is roughly 35 times the legnth of the fighters so if i made a 200mm long sparrow hawk my zepplin would have to be near to 18 meters long to be in scale! better to fill it with helium so there is less chance of your hard work going up in smoke (even though it would look cool falling from the sky burning)
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Old Jun 06, 2013, 03:46 PM
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the reason hydrogen lifts more than helium is because it's lighter. hydrogen has an atomic mass of 1.01 where as helium has an atomic mass of 4.00.
Not quite... Hydrogen does not naturally appear as single-atomic form, but binds with its neighbour to achieve "octet" at the outer orbit (the two hydrogen atoms share their outer electrons so they have practically two) and thus forming a hydrogen molecule. The molecular mass is thus 2,02. Practically hydrogen offers about 7-8% better lift. It has also been discussed that hydrogen isn't as dangerous as usually thought. Just not worth the extra hassle, if helium is available.
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