Mixed gas airships?

Insider

Banned
I lately read about zeppelins and ASW blimps in the I WW and I wonder: Hydrogen is cheap, but requires a lot of safety precautions because of tendency blow up when mixed with air. Helium is expensive and a little less effective, but more safe in use (just toxic, not explosive). Why not take a bit of either and mix? The mixture should displace enough oxygen in air in case of breach (to prevent fire and explosion) and be cheaper than using unadulterated Helium. Perhaps as a postwar modification to cure Hindenburg and R100 problems?

Would that be effective?

I am not aiming at creating POD decisive enough to create world were heavier then air transport is outsted in favour of lighter then air, but perhaps popular enough to keep them in service after II WW as ASW and early warning craft?
 
The plans for HINDENBURG were to do just that, sort of. The designers really wanted helium, but it was astronomically expensive unless you were the US Navy, and the Americans weren't selling. So, they were going to build a gas cell inside a gas cell. The inner cell would be the bulk of the volume, nice cheap hydrogen that you could vent if you needed to without worrying too much. The outer cell would only be a metre or two deep, relatively little volume, but filled with fireproof helium. That way, the helium keeps oxygen and sparks from the hydrogen. More of a weightless firewall than lift gas, really.

The idea was dropped because the weight added by the second set of bags and more complicated plumbing, together with the cost of helium and its' reduced buoyancy, made it pointless. After all, what's the worst that can happen to a gigantic self-propelled bag of flammable gas?
 

Driftless

Donor
The level of technical sophistication for the double envelope sounds more feasible with modern synthetic materials than the old school gas bags.
 
This seems unlikely to help, to me. In a typical airship explosion, the issue (at least at first) is getting enough oxygen in; mixing the hydrogen with helium will reduce the amount of available hydrogen, but that's not typically the problem.
 
The Graf Zepplin used a gas like propane for fuel, that way would not have to carry as much ballast.
 

hammo1j

Donor
The level of technical sophistication for the double envelope sounds more feasible with modern synthetic materials than the old school gas bags.

I'm wondering if there has been any attempt to use modern materials with hydrogen. Possibly for drone cargo airships.
 
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