Not sure how to use a neutrally buoyant fuel for a vehicle like this. at 1 kg/m^3, like air, your fuel is 10% of the volume of your vehicle, which displaces lif

Not sure how to use a neutrally buoyant fuel for a vehicle like this. at 1 kg/m^3, like air, your fuel is 10% of the volume of your vehicle, which displaces lifting gas and increases structure (which requires more lifting gas).