Helium is hard to find in our area and we are considering switching to hydrogen for our upcoming launch. Any tips on switching to hydrogen for our HAB launch? I am guessing our main concern is keeping it from exploding. But information about type of balloon (same as helium), calculations, filling precautions, etc. would also be appreciated.Spencer
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Personally:
* I would not be filling using H2 indoors - too many sources
of ignition (light switches...) and dire consequences if ignited.
* Ensure the balloon cannot rub against anything and generate
static (e,g, canvas tent) - there have been incidents of balloon
ignition.
* Have Some form of visible "Highly Flamable" warning on the
balloon if it comes partly filled (as they sometimes do) .
* I can't see the need for flashback Arrestors (as suggested by ARHAB) - you have no plans to ignite the gas.
Steve G8KHW
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I remember reading about that several years ago - what I read wasn't very conclusive. The hydrogen inside the tube and balloon becomes rapidly near 100% concentration (after mixing with any any trapped air) - so there would not be an ignition even if an internal discharge were to occur. Maybe there is a chance as the balloon is detached from the fill tube. Personally I haven't seen any indication of static in/on fill tubes or balloons, I haven't heard of any instances of ignition from this cause (where as I have been for a balloon rubbing on a canvas tent).
The domestic gas companions seem quite happy to pump flammable gas round in plastic pipes - although probably not at the velocities of a HAB fill.
Steve
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