|
|
|
 |
|
|
|
This section will focus on all airships that are not classified as rigid. Non-rigid airships include: Blimps (Non-rigid Airships)
|
Non-rigid airships are often called blimps. The word blimp came from the sound that the envelope of the airship makes when you tap it with your finger. Blimps depend on the higher pressure of their buoyant gasses to retain their shapes. The only rigid components are the engines, fins, and the gondola or car that hangs from the blimp’s belly. They are usually filled with the Nobel Gas Helium. Blimps were used in several wars including the First and Second World Wars but are scarcely used in modern times, except for advertising and filming purposes. They are ideal for those purposes because of their eye-catching profile and their ability to remain in one patch of air for long periods of time.
Blimps are also used for research purposes where they can remain stationary for hours, allowing data to be gathered from above. Blimps were often used by militaries before they were replaced by conventional aircraft. Blimps were in wide use by the US Navy before and after World War II. Militaries around the globe are considering taking advantage of the unique properties of non-rigid airships once more.
|
Hybrid airships have a take off weight greater than the lift provided by the buoyant gasses that are trapped inside of them. This excess weight requires extra lift to come from somewhere. That somewhere is from the design of the airship itself and its engines. Hybrid airships have unique designs that produce lift in the same way as a conventional aircraft, through the use of airfoil. Several hybrid airships are on the drawing boards for civilian and military use.
|
Semi-rigid airships are similar to blimps in that they have no internal frame to support their envelopes. They do have, however, rigid objects on them that give them some backbone. A stiff keel runs along the length of the airship for distributing weight and attaching fins and engines.
|
Metal-clad airships are designated as any airship that uses a thin metallic envelope instead of the cloth  and rubber the trap the buoyant gasses of other airships. Only two metal-clads have been built: the ZMC 2 and Schwarz's aluminum ship of 1897.
David Schwarz was the Hungarian inventor whose work helped out Count Zeppelin in building rigid airships. Schwarz built an airship that was supported by an internal frame that was covered by an aluminum envelope. The airship crashed and was not successful. Schwarz died shortly after the flight, due to a heart attack that was attributed to a call from the German Army with informed him that his invention had been accepted. The ZMC 2 was built as a scale-model for the U.S. Navy. It was teardrop shaped with eight fins for stabilization and flight control. The ZMC-2’s skin was made out of a thin sheet of an aluminum alloy. It flew for ten years until, in 1941, it was dismantled for scrap metal. It was considered to be successful, but the company that manufactured it was hit hard by the Great Depression and there was no interest in building a larger airship. The ZMC-2 had a volume of 200,000 cubic feet (5667 cubic meters), was 150 feet (45.4 meters) long and 50 feet (16.2 meters) wide, had a top speed of 70 mph (112 km\h), and a range of 675 miles (1087 km). |