the amount of gas that is fed into it. The semi-rigid airship differs from the blimp by the addition of a metal bow and stern framework, connected by a keel that connects the two. The envelope's form is maintained by internal pressure in the non-rigid (blimp) and semi-rigid (in which the nose and tail sections have a metal framework connected by a rigid keel) types. The rigid type, of which the Zeppelin is the best-known example, maintains its form using an internal metal framework that protect a series of individual gas bags which can be inflated or deflated at will (Robinson, 1966).
Rigid airships were at the height of their popularity from about 1900 until 1940, although, as will be discussed later many companies around the world are beginning to utilize the design again, using space-age technology and design. The design and flight of the first successful non-rigid airship is attributed to the French inventor Henri Giffard of France (Sinclair, 1934, xiii).
This event was well-publicized and the tales of the "machine that could let man fly: captured the attention of a German Military Officer, Count Ferdinand von Zeppelin (Appendix 2). Although he admitted to having no mechanical knowledge, he was an interested student of military history and was well aware of one of the major weaknesses of warfare: the inability to achieve effective reconnoitering (Nitske, 1977). His dream was to create a machine that would let a military commander see the entire battle terrain from a birds-eye view. Being German through and through, he wanted to make his airship a colossus, bigger and better than any other country would even conceive of (Nitske, 1977).
Unfortunately, his dreams were bigger than his wallet, and the first early days of von Zeppelin's research and construction were limited. Having no mechanical ability and few funds, he turned to researching concepts of physics and finally came to a conclusion that the best desi...