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AIRSHIP FAQ:

airship (air-ship)

Definition :- aircraft consisting of a cigar-shaped balloon that carries a propulsion system (propellers), a steering mechanism, and accommodations for passengers, crew, and cargo. The balloon section is filled with a lighter-than-air gas-either helium, which is non-flammable, or hydrogen-to give the airship its lift. The balloon maintains its form by the internal gas pressure in the nonrigid (blimp) and semirigid types of airships; the latter in addition has a rigid keel. The rigid type maintains its form by having a metal framework that holds its shape regardless of the internal gas pressure; inside the hull are a number of small gas-filled balloons. The first successful power-driven airship was built by the French inventor Henri Giffard in 1852. Count Ferdinand von ZEPPELIN of Germany invented the first rigid airship, which was completed in 1900. The German airship Hindenburg burned at its mooring mast at Lakehurst, N.J., in 1937. No rigid airship survived World War II. Modern blimps are used in antisubmarine warfare, television photography, and advertising.

Q: What Kinds of Airships are there?

A: There are three main categories of airships, Rigid, Semi-Rigid, Non-Rigid.

Rigid Airships
As their name implies, rigid airships have an internal frame. The rigid structure, traditionally an aluminium alloy, or duralium creates the form of the airship. The design was also to create a more aerodynamic shape. In general rigid airships are only efficient when longer than 120 Meters (360ft.) Because a good weight to volume ratio is (or was) only achievable for large airships. For a small airship the solid frame would have been too heavy. The R101 and R100 departed from traditional lines of following Zeppelin airships, in that they were far more aerodynamic than the standard Zeppelin pencil type shape.

Semi-rigid Airships
Semi-rigid airships were more popular earlier this century. They usually comprise a rigid lower keel construction and a pressurised envelope above that. The rigid keel can be attached directly to the envelope or hung underneath it. The airships of Brazilian aeronaut Alberto Santos-Dumont were semi-rigids. The most famous representatives of the type were the Norge and the Italia, the airships which General Umberto Nobile used on his attempt to reach the North Pole. The British purchased one ship from the Italians - the SR1.

Non-rigid Airships or Blimps
Non-rigid airships, also known as Blimps, are the most common form nowadays. They are basically large gas balloons. Their shape is maintained by their internal gas pressure. The only solid parts are the passenger gondola slung beneath the ship, and the tail fins. All the airships currently flying for publicity use are of that type; the Goodyear Airships, The Lightship Airships seen as the Budweiser and the Metlife Blimps in the USA, and the Fuji Blimp in Europe. Many of these ships are always remembered and referred to as their advertising which they carry, and not the manufacturer.

Q: Where does the term "Blimp" come from?

A: The popular story is that during World War II, a military general visited one of the many airship stations operated by the U.S. Navy. Trying to find out what material an airship was made from, he tapped his finger against the fully pressurised envelope of a non-rigid Navy airship. The general described the sound he heard, "blimp," and blimps have been called blimps ever since. However the contrary story is that the "Airships or Balloons" were classed a "B" category and non rigid, hence "limp". So they were "B"Limp class.

Q: How fo airships actually Fly?

A: Why airships fly is explained by the Principle of Archimedes: "Bodies submerged into a fluid receive from it a lifting force which is equal to the mass of the displaced fluid." (This is the same principle that explains why boats float on water.) The airship is filled with a lifting gas (Hydrogen, Helium, hot air or natural gas). The air in which the airship finds itself has a higher specific weight than the lifting gas. The envelope filled with the light gas generates a lift that is equal to the weight of the displaced air. Like a (light) cork floating in (heavier) water, a helium or hydrogen filled balloon floats in the heavier air.

Q: What is the Lift of Helium ?

A: As a rule of thumb, 1 cubic meter of hydrogen lifts 1.1 kilogram, 1 m3 of helium lifts 1 kg. These figures are on the safe side and allow for variations in altitude, temperature, humidity and also purity of the helium.


Q: Can I get a ride on an Airship at Cardington ?

A: The answer at present is unfortunately usually NO. Despite all the modern technology used in today's airships they are cost effective only for advertising and aerial photography purposes. In relatively small airships, passenger transportation is not profitable enough unless it is combined with an advertising mission. In the past, the small number of airship rides which is available has been given to executives and clients of the advertisers/sponsors of the blimps. Airship Industries in the UK ran a successful Passenger scheduled service over London during 1982- 1990.

Q: I want to build an airship. Where do I start?

A: Airships need to be "housed" and therefore you need to design an airship which can fit in to and get out of the building in which you are going to build it in. The recognisable airship sheds of Cardington, Lakehurst and now Brandt in Germany are some the largest buildings ever constructed to house the massive ships. Remember : the size of the airship is dependent on the size of the building you built it in !.

Q: Where can I find More Information?

A: If you check out the research centre on Airshipsonline.com, then this should help answer your queries. The Links page to other sites should give you a huge selection of other websites on the net which can help.

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