Airships - What's a Dirigible?

Blimps and zeppelins are both dirigibles. But blimps have soft bodies, while zeppelins have rigid bodies. The hindenburg had a frame made of duralumen, which sounds a little like something from startreck but is really a hardened alloy of aluminum. Ominously, some of the dura n that went into the hendenburg had been salvaged from the 19 30 crash of the british airship r one o one. So you had materials re cycled from one doomed airship going into the structure of another doomed airship.