Post by e***@yahoo.comso that's not correct a rigid frame air ship is enormously heavy but adding helium within it increases it's weight as well but it still has enough buoyancy to overcome the weight of the surrounding air.
Without the helium, it has air inside it. Density of air is about 1.3kg per cubic metre (at STP). Density of helium is about 0.18kg/m3. When you put helium inside it, it replaces air, so for every m3 of helium, you reduce the weight by 1.1kg. When you put put helium into a (rigid) airship, you are removing air. It isn't adding the helium that's the important thing, it's removing the air. (Consider a hot air balloon, which works by removing air, without adding any other gas.) Adding helium _reduces_ the weight of a (rigid) airship.
The buoyancy force acting on an object of volume V immersed in a fluid of density d_fluid only depends on V and d_fluid. It's equal to V*d_fluid*g, upward, where g is the local acceleration due to gravity. Note well that, keeping V constant, adding helium does nothing to this force. Removing air from inside does nothing to this force. Only the volume and the density of the external fluid (air, in the case you are considering) matter.
The other force that you must consider is the weight of the object. That's mg, or V*d_object*g, acting downwards. So the total force is F = mg-V*d_fluid*g = V*(d_object-d_fluid)*g.
If you take a buckball, the volume V is constant. Normally, it contains vacuum. If you put helium in, it becomes heavier. This doesn't change the buoyancy (since it doesn't change volume or the density of the air outside). It increase the mass, so it increases the weight.
The more helium you cram inside, the heavier it becomes, and the net downward force increases.
Helium is not a magic anti-gravity atom.
Aristotle knew how this stuff worked, and Archimedes did the math. It isn't new. You should learn about this stuff - if not because you want to know how the world works, at least so that your schemes don't look as foolish due to being founded on elementary errors.