Re: What is the optimum mix of hydrogen gas and helium gas for maximum lift

There is NO reason to use hydrogen in preference to helium for lifting
power; the buoyancy of hydrogen in air is 0.93 (where 1.0 is a rigid
container containing a perfect vacuum) while that of helium is 0.85. The
inflammability of hydrogen completely negates any minor lifting advantage
you might get from it.

There are good reasons that nobody uses hydrogen to lift their balloons. Helium 
(about 1/7 as dense as air) gives plenty of lift without the fire hazard. In 
fact, the only reason the Germans used hydrogen in their dirigibles is because 
they were often metal-skinned (and therefore puncture-resistant) and 
because the United States -- the chief source of helium in those days -- 
wouldn't sell them any. 

                                       Dan Berger
                                       chemist and MadSci Administrator