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#1 broken flyer Jan 04, 2013 03:23 PM

If only I could get some helium...
 
Hey guys. So I've been working on this project of mine for awhile, 6 months or so and I am almost done with the half scale prototype. The project is a hybrid airship. It has an envelope, along with wings. Anyway... I was planning on flying this thing within a week and now it's come to a complete stop. I can't get helium anywhere... Just a few months ago I had talked to my local Praxair distribution hub through my school and we had the price figured out to 85 cents a cubic foot. Yesterday my teacher went to order the tank and they can't sell us any now. It's just not even available. I have since called every party supply store within 100 miles of me(that i know of) and none of them can get helium tanks anymore either. The only thing I can find are these little 14.9 cubic foot disposable tanks that are around $50 a piece. There's no way I can use those. For one it would take 3 tanks just to fill my little half scale(it's got a 40 cubic foot envelope), so $150 or every time to fly it. Not going to happen. And the full size one I have designed... is more like 300 cubic feet so... Hm.

Have guys been able to get helium or are you all grounded at the moment too?

#2 pyronaught Jan 04, 2013 05:54 PM

There's a global shortage of helium going on right now and many places can't get it. Just use hydrogen instead.

#3 Underthetire Jan 04, 2013 06:23 PM

Welding shops have been only selling what they have to their most loyal customers. Big shortage now for the last 6-8 months. No relief in sight I'm afraid.

#4 broken flyer Jan 04, 2013 07:23 PM

Are you guys really using hydrogen or was that a sarcastic reply? 40 cubic feet of expanded hydrogen in an electric aircraft that is prone to static and also arcs when plugging in batteries sounds like a really, really bad idea to me...

#5 Underthetire Jan 04, 2013 07:26 PM

Quote:

Originally Posted by broken flyer (Post 23714068)
Are you guys really using hydrogen or was that a sarcastic reply? 40 cubic feet of expanded hydrogen in an electric aircraft that is prone to static and also arcs when plugging in batteries sounds like a really, really bad idea to me...

Just ask the poor people on the Hindenburg.

#6 broken flyer Jan 04, 2013 07:37 PM

That's what I'm envisioning, except I'm thinking it'll blow up in my face when i go to touch it and it gets a static spark off my hand. What are you using or are you just grounded at the moment?

#7 pyronaught Jan 05, 2013 01:37 PM

Not being sarcastic. Unless hydrogen is mixed with oxygen it is not going to explode. The Hindenburg blew up because hydrogen had leaked and mixed with oxygen, then caught fire. Then the gas bags dumped all their hydrogen which immediately mixed with the air and it was a chain reaction. This is why it burned from the top down however, and why there were so many survivors since they were all at the bottom. Arcs from plugging in batteries occur outside the envelope, so how is that going to ignite anything? It is amazing how people have become such wussies in modern times. Only 100 years ago people were flying with millions of cubic feet of hydrogen above their heads and not thinking twice about it. Now you guys are cringing over the thought of a few cubic feet in an unmanned toy. You're going to have to man-up or just not fly, because helium is becoming a scarce resource.

#8 powerblimp Jan 07, 2013 09:18 AM

hydrogen filled blimp fire experiment
hydrogen filled zeppelin set to fire (0 min 57 sec)


as you can see it does not explode at all!

#9 broken flyer Jan 07, 2013 04:47 PM

I will keep this in mind. I think my drive to make this project happen is going to out weigh the danger of using hydrogen. It will just add a little more spirit of adventure to it. Thank you.

#10 pyronaught Jan 07, 2013 07:19 PM

The key is filling it with pure hydrogen and not letting it get tainted with oxygen. It's the oxygen/hydrogen combo that gets explosive. Even so, it takes a good 50/50 mixture to get a respectable boom. You could probably get one or two percent oxygen and not worry though. There is another video somewhere that shows various percentages being ignited. Everyone who has ever taken a basic college chemistry class has also done this burn test as well. The pure hydrogen just has a flame at the bottom of the test tube where it meets the air, whereas the 50/50 mixture pops with a loud chirp.

#11 Ed Couch Jan 08, 2013 01:03 PM

Gents before someone gets hurt here lets drop the whole hydrogen discussion. Its just not feasible for RC use as a lifting gas. Simply put to dang dangerous to handle. We have gone through this BS for the last six years or so and no one to my knowledge has ever flown an RC hydrogen filled vehicle on this discussion group. You damn well are not going to be let into a building to play with that and that is what you want to do. Oh its science but try to pick up some type of liability coverage for your work. You would be laughed out of the office. Helium is hard to get but its there for a while longer just keep looking. I fly everything from a 7.5 to 30 footer and I am paying about 35 percent more than last season but its still out there. If you think I'm kidding I have 7 ships operational at this time working for folks like the Dallas Cowboys, Dallas Stars, Texas Legends (2), University of Texas in Arlington and Austin plus several others and I'm yet to miss a game due to non-availability of helium. Enough said. Ed

#12 pyronaught Jan 09, 2013 09:29 AM

Ed, not everybody flies for a business and not everybody flies indoors. Hydrogen is a legitimate alternative for the outdoor hobby flier. Don't try to project your irrational fear of hydrogen onto everyone else to shut down this conversation, we have enough problems with chemical phobia and junk science spawn fears in society already.

#13 Ed Couch Jan 09, 2013 01:30 PM

Same song and dance. Show the folks some of your vehicles that you are flying with hydrogen on board. I would be interested is seeing how you do things and handle the material to make a 10 to 30 foot vehicle fly indoors or out it makes no difference. There is a old saying in my neck of the woods that says "put up or shut up". Its time to drop the subject as a waste of time before someone is seriously hurt. Check the attached from another discussion, damn it did go boom. ed

Huge Hydrogen & Oxygen Balloon Explosion (0 min 47 sec)
!

#14 powerblimp Jan 10, 2013 05:27 AM

yes for indoor it is not a good idea imagine a small leak near the blimp and this will make a perfect mix to become highly explosive.
for outdoor no problem as it is quite vented .. there is no such danger only storage can be a problem.

and bloody hell inovation is also breaking rules and thinking different as mass sheeps béééééééhééé
:-)

and the well known BOOM video was done with a perfect mix hydrogen/oxygen ratio

its like compairing a perfect mix of sulfur, saltpeter and coal = black powder with only sulfur or onyl coal nothing happens

cheers retired phil ;-)

minizepp became www.anabatic.aero



about mixing hydrogen and air be carefull as ony 4% air to 96% hydrogen gety allready explosive.

#15 Ed Couch Jan 10, 2013 09:51 AM

philip

You and I go a ways back and I agree that this as most videos on the web are a set up working under extreme conditions but all it does is show like your other video the possibility in worst case. To blow it off as not a constant risk is just wrong. The Hindenburg did not explode it burned but it did burn extremely rapidly, much of that was due to the cotton cloth covering the airframe and the nitrate dope utilized at that time for weather proofing the covering. We learn from our mistakes made by ourselves and others. Sometimes and mostly I learned from those that come before me. Whichever way Alex choses to go is fine but know the risk involved.

Congratulations on Minizepps new home. We stopped flying the bluebird a season back and its in storage now. I would love to get it back in the air sometimes soon. It was always a pleasure to fly.

ed


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