[thechao]

I tried to convince a group that:

1. Hot air balloons get their lift from hot air; and,

2. Dirigibles can get their lift from hydrogen; thus,

3. Hot hydrogen dirigible?

Blah blah blah ... exploding dirigibles ... blah blah blah. The lifting efficiency is outrageous.

[Gravityloss]

Even if you used weightless atoms to fill your balloon, the lift is only the weight of the air it displaces. So you don't really get much better since hydrogen already weighs so little.

Air is about 30 grams per mole and hydrogen is two grams per mole. So going entirely weightless you could go from 28 grams of lift per mole to 30 grams of lift per mole, a 7% increase.

[thechao]

But 100% more firing a flamethrower into your hydrogen filled envelope while looking your customers in the eye.

[scoopertrooper]

Just crazy enough to work. Hydrogen doesn't autoignite till 500 degrees celsius, while your average hot air balloon only heats gas to 100 degrees.

You'd want to be damn sure about the reliability of your thermocontroller though.

[b112]

I think the fuels, and components to heat without flame, might reduce the benefit a lot.

I have often wondered about super strong materials, a sphere with vacuum inside.