Non-Rigid, Semi-Rigid, and Rigid

[WillowPtarmigan]

What are the advantages and disadvantage of non-rigid, semi-rigid, and rigid airships?

[sky captain]

good question. non-rigid airships (blimps) have ballonets, or air bags inside the outer envelope, which is the external part of the blimp. the air bags expanded or contracted to compensate for gas changes. Blimps had no framework, so they often collapsed when there is too much stress on the gas bags. Designers added a fixed keel on the bottom of the outer envelope. These were called semi-rigid airships. Rigid airships had an internal framework made of either steel or aluminum, that gave them their shape. it's basically a fuselage for an airship. The internal framework supported the outer envelope and kept the gas bags in place as well. the internal framework and the keel on a rigid airship was strong enough to carry passengers and cargo. they all have their advantages and disadvantages, because they all served different purposes.