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Dec 07, 2005, 11:24 PM
JettPilot's Avatar
Thread OP
Question

Hydrogen Blimp


I know Hydrogen is lighter than helium, but is it significantly lighter ? How much does it cost, is it cheaper also ?
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Dec 08, 2005, 03:44 AM
rc blimp manufacturer
powerblimp's Avatar

boom


hi jett
tis is not a good idea as hydrogen is really an explosive gas!
it is too dangerous and as we use plastic envelopes PU PVC Heptax etc.. it can make static electricity and can light your ship

so it is really dangerous!!

best regards

Philipp
Dec 08, 2005, 11:55 PM
JettPilot's Avatar
Thread OP
It would make a really cool fireball I understand the problems with plastic, etc.. But what if it was a foil envalope, like those balloons they sell ??? Is hydrogen much lighter than Helium ?
Dec 09, 2005, 10:41 AM
TOMP999
Suuure, make one out of mylar. You can pick up a couple of those survival blankets (mylar) where ever camping/hunting supplies are sold. cut your shape and iron the edges together to seal it up.

I don't want to see your name show up on the Darwin Awards dude! Be careful!
TOMP
Dec 09, 2005, 12:31 PM
I'd be worried about handling hydrogen itself. Mixed with air, it'll become explosive. You'd be building a radio controlled flying bomb... that is if you don't seriously injure yourself while filling the balloon with hydrogen. Stick with helium. Safer, easier to work with, and you don't have the threat of explosion to some extent. *unless you somehow manage to punch a hole in the tank...*
Dec 09, 2005, 02:01 PM
dusty bible = dirty life
Majortomski's Avatar
Back to the first question I believe hydrogen lifts 130 percent of helium.

It always gets such a bad rap because of the Hindenburg footage, yet what you see burning on the Hindenburg is the aluminum and dope saturated fabric covering. Hydrogen burns clean, no flame.

It takes a lot of energy to initiate ignition.

The Germans operated Hydrogen filled zeps from 1900 till the Hindenburg accident; the only other losses due to hydrogen were the ones shot with incendiary rounds from the English.

BUT the big problem is building a bag that is tight enough to hold the hydrogen. The molecules are very small and a bag that holds its inflated shape with air will leak like crazy with either H or He.

Tom
Dec 09, 2005, 03:12 PM
Registered User
Ed Couch's Avatar
You might want to check the attached link on the use of helium versus hydrogen. The prime reason most countries used hydrogen instead of helium is it was considered a strategic material with only the United States having any great quantity or immediate reserve available and we would not sell to Germany at that time. The United Kingdom did receive helium for their airships during the golden years. Don't know for sure for France and Italy. Also the lift capability of hydrogen is only about 10 percent greater than that of helium. A good rule of thumb for helium is 1 oz of lift for each cubic foot of helium present. This will vary according to altitude, dewpoint etc..

Personally I will stay far away from hydrogen as a lifting gas and play with my two 13 foot and one 15 foot airships using helium. See attached link for additional information: http://en.wikipedia.org/wiki/Airship . ed
Dec 09, 2005, 04:32 PM
JettPilot's Avatar
Thread OP
30 percent would make it worth while, but 10 percent is not that much of an advantage.

I would think hydrogen would be much cheaper than Helium, which seems real expensive.

From the hindenburg footage, hydrogen just burns, there was no explosion in that footage from what I can tell.

I dont think that would earn me the Darwin award, maybe just a burnt envalope at worst.

Its not like im proposing filling a blimp with Acetylene and Oxygen
Dec 12, 2005, 04:57 PM
Registered User
As A kid I learned how to make hydrogen from Zinc nails and acid.
For fun we would fill up giant yard garbage bags and light them on fire.
Hydrogen is really safe in these smaller volumes. It burns cool and quickly. I had one blow up in my face and hardly cinged my hair.

Honestly I dont think it could burn a house down very easily let alone blow one up.

My 2cents
Scott
Dec 13, 2005, 05:05 AM
rc blimp manufacturer
powerblimp's Avatar
hi i have some friends that maks a mix 40% hydrogen 60% helium
the mix seems to be quite safe must be tested in small volume

NEVER mix hydrogen and oxigen this is an explosive mix!

also if you have a bag filled with hydrogen and small leaks it can make a gas cloud-mix all around the blimp and is quite explosive as it is mixed with oxigen.
Dec 14, 2005, 02:08 PM
if air or oxygen is inserted accidentaly into hydrogen balloon it is quite explosive but leaking hydrogen is normally lost upwards, due to its buoyancy.. if outdoors can not explode too easy.
For this reason hydrogen (and methane too) is considered safer than LPG, propane or buthane which being heavier than air, in no wind will stay close to the ground.

Fabric industry uses antistatic substances to avoid electric charging of syntethic fabrics. Not against explosions, but to avoid the uncomfortable sensation of the clothes sticking to the skin.

So hydrogen can be very explosive, it is dangerous but less than generally considered/perceived. A propane presurized bottle used by campers for cooking in a windy day can be as dangerous.

cezar
Dec 14, 2005, 05:51 PM
Perpetual Hobbiest
one word Hindenburg!
Dec 15, 2005, 08:14 AM
Quote:
Originally Posted by carlosponti
one word Hindenburg!
Well, Hindemburg contributes most to a biased perspective. Yet, even when covered in flames, hydrogen did not exploded. The hydrogen did not start the fire. Some say because its envelope material it would have burned and crashed if it had been filled with helium too. And out of 97 people (passengers + crew) there were more than 60 survivors, many of them unharmed... They found their way out through wrekage and flames. One would not expect that from the images and size of disaster.

I'm not arguing hydrogen is not more dangerous than helium, I advise nobody to use it for playing. But its dangers are probably overestimated. Or mabe not.

Unfortunately nobody has the interest to invest in running real tests to see in what situations a hydrogen blimp ignite and if there are practical methods to avoid these situations. Everybody already knows hydrogen is extremly dangerous - everybody have seen Hindemburg burning.
Dec 15, 2005, 11:44 AM
Perpetual Hobbiest
i think for most hobbiests that probably watch no precautions are more likely to endanger themselves. i just saw a post on RC universe where a guy who understands no concepts of jets wants to build his own turbine engine for his remote control car. the same concept aprises itself. a lone hobbiest with no experience or background with explosive gases ie hydrogen, oxygen, etc decides on using those dangerous materials due to easy access or cheaper price almost always ends in tragedy. hindenburg is a good image of what would happen in the case of an errand spark. as far as i know helium is an inert gas with no properties which allow it to catch fire. hydrogen is like gasoline really it doesnt explode but catches fire. hydrogen (i am mostly regurgitating high school chemistry) is volitile due to the fact that it is looking for stability within itself.
Dec 15, 2005, 03:34 PM
Marcus Franco
Guga's Avatar
I have one Approach ...

Live and let Die...

In every head there is a sentence...

I have over 3k hours of real flight time... from paragliders up to Multy Engine aircrfat, and seen ones that have much more than me... and ones that did not go over 1 or 5 or not even one hour... and died!

We have rules and comandments... it its up to each one to have goodsense...

The truth is that one day we will not have anymore Helium... and it is to expensive to produce... there is no way out... Hydrogen? or some other source

Note that the 2 projects bellow are Hybrid that means they are not lighter than air... but slightly heavier...

Take a look at this new prototype Dirigeable for military purposes...

From: http://www.aerosml.com



Or would be that the way... Hot air turbine intake and exaust outputs for controls...

Last edited by Guga; Dec 15, 2005 at 07:26 PM.


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