stakddek,
the hydrogen found in nature is often not comprised of an individual atom. It's primarily found as H2 a diatomic (two atom) compound. At this point it's a molecule, because it's a combination of two atoms. Hydrogen has one valence electron, it wants to gain another electron to fill its 1s energy level. Energy level 1 can only hold two electrons in the 1s orbital, so gaining another electron fills it. Thus, the H molecule takes up more area then the He atom making it harder to permeate the gas cell, making H easier to contain then He.
The lifting power of H is only about 7%> than He. It would probably be a public safety issue with the FAA, imagine a bag full of hydrogen floating above a city. Safer to gently heat the He as time goes on to make up for the He loss, this heat would increase the He volume.
As far as tilting the air ship towards the sun, for more direct sunlight, yes they could possibly do it, but then the aerodynamics would be messed up as far as keeping it in its station keeping area. They could do this by moving the He to starboard or portside, they can and will move it fore an aft for ascent, decent. But moving it around too much will and of itself generate loss.
Looking at the rendition of it, the thin film goes a few degrees below the center line, capturing the first rays of the early morning sun, or the last rays of the day. bors~
AI
