>From Stephen A. Lawrence ...
> Hydrogen has more lift, it's cheaper, and it's easier to contain > (molecule's roughly twice as big, doesn't slip through the pores so > quickly). Helium's a very poor second choice, except for the > flammability issue. > > OTOH hydrogen is explosive in certain circumstances, so you might be > suspected of terrorist activities if it got around that you were making > large amounts of it. > I cast my lot with those who tend to think the main reason helium is being chosen in this intriguing design is due to an overly skewed perception of the dangers that hydrogen pose. The Hindenburg disaster still haunts our minds, and the irony is that hydrogen's flammability issue was the least of the problems that actually caused so much death and destruction when the airship finally crashed to the ground. Unfortunately, hydrogen continues to be unfairly blamed as the reason for so much death and destruction. I believe a recent NOVA TV program installment showed convincing evidence to back up the theory that the highly flammable skin properties of the Hindenburg's fuselage, as well as diesel fuel, were the actual causes for so much death and destruction. Film of the Hindenburg disaster show hydrogen combusting with the surrounding air as an orange ball that quickly goes upwards and AWAY from the air ship. Meanwhile, the film footage clearly shows the highly flammable skin of the airship catching fire and spreading like wildfire throughout the entire skeletal structure as it crashes to the ground. This is followed by explosions from on-board diesel fuel rupturing. Nova was fortunate enough to have obtained a small sample of original skin from the airship. They analyzed its properties. If memory serves me correctly, they finally set part of the skin on fire. It burned as if it was the equivalent of a solid fuel propellant. Had helium been substituted I suspect the Hindenburg would still have caught fire and crashed to the ground. There still would have been a major disaster with probably many lives lost. Hydrogen, however, would not have been blamed for the cause. The most likely cause was due to an unfortunate (and very common) static charge buildup that would likely have ignited the airship's flammable skin. I realize there still exist conspiratorial theories suggesting actual sabotage had been involved, but Occam's razor suggests (a least to me) that Mother Nature was the most likely guilty party. This prejudice, unfortunately, is probably adding unnecessarily to the costs to the intriguing rotary generator. I would therefore agree with those who suggest hydrogen is likely to be a better alternative than more expensive helium. I think the benefits would far outweigh the dangers. It seems to me that if lightening were to strike the rotary design while in operation and fatally rip the fabric apart the structure would crash to the ground regardless of whether it had been filled with helium or hydrogen. Regards, Steven Vincent Johnson www.OrionWorks.com
