Bruce Blake would make the point in December 2001 Page25 Airship No 134 that non-rigid airship envelopes are monocoque, primary structures. He also makes the point such envelopes are capable of catastrophic failure (we know many examples). This paper would suggest that though only non-rigid is practical for heavy lift airships a Hybrid Rigid / Non Rigid must be considered in the first instant. This would allow the non-rigid heavy lift airship to be developed in the Prototype State over a time scale perhaps equal to that of the Harrier Jump Jet.
ADG Webb on page 29 Airship No 134 would further suggest that helium is difficult to extract and in short supply. He further makes the point natural gas in Dexter Kansas refused to burn when helium was present. Will a mixture of helium and hydrogen save helium stocks. Are scientists able to produce hydrogen such that it will retain the same characteristics however it will refuse to burn?