The Anatomy of an Airship | My Literary Quest Posted by: Jodi | January 13, 2015 The Anatomy of an Airship Lately I’ve had a huge interest in steampunk and a huge part of steampunk is airships. Today we shall learn all about the parts of an airship. It’s been a while since I’ve done a glossary post so here it is! Steampunk Airship First the three classes: Rigid: This include ships like the Hindenburg and have an internal frame that holds a series of gas-filled bags. They are usually long and bullet shaped, often greater than 360 ft. Semi-rigid: Instead of an internal frame, a semi-rigid airship uses a long metal keel that runs the length of the inside belly of the envelope. The Norge Italia is a good example and if you look closely in the picture you can see where the keel is attached to the envelope. Non-rigid: Now the most common modern airship, this class includes the blimps, like the Goodyear blimp. These are less expensive than the other two classes because of the lack of rigid internal structure in the envelope.

Rigid: The Hindenburg Non-rigid: The Goodyear Blimp Now, what all the little bits do: Gondola: The structure that holds both passengers and crew below the envelope. Usually the engines are anchored here although it’s not uncommon on rigid and semi-rigid ships for them to be placed further aft to help with balance. On rigid ships, because the gas is contained in smaller bags, the crew can also work and store equipment within the envelope itself. Engine: Powers the propulsion on the airship, which are usually large propellers on either side of the craft. Stabilizers: These are the fins that keep the ship from rolling side to side and up and down. Ballonet: Smaller balloons within the larger envelope that hold air and are used to displace the lifting gas to gain or lose altitude. Ballonet air valve: Controls intake of air into the ballonet to control altitude. Air Scoop: Used to fill the ballonets with outside air to adjust altitude. Nose Cone battens: These are the flexible but sturdy ribs that extend from the front of the the nose cone in a non-rigid airship that prevent the front of the ship from caving in on itself if there is a headwind.

Blimp: Another name for a non-rigid airship Dirigible: Another name for a rigid airship Aerostat: Another name for lighter-than-air aircraft Envelope: The main “balloon” of the airship that holds in the lifting gas. Lifting gas: Today mainly helium is used, but in earlier years hydrogen was the gas of choice. It is lighter and less expensive. It’s only drawback is the tendency to explode in the right conditions. Heated air doesn’t have enough lift for these ships, but it works for hot air balloons. Catenary Curtain: In blimps there are two of these curtains that are sewn into the envelope and then attached to the gondola with suspension cables. These help support and shape the envelope as well as hold up the gondola. Zeppelin: A name given to rigid airships after the German Count Ferdinand von Zeppelin who pioneered their use. *** How airship is made - material, manufacture, history, used, parts, History, Military airships Airship Background An airship is a large lighter-than-air gas balloon that can be navigated by using engine-driven propellers.

There are three types of airships: rigid (has an internal metal frame to maintain the envelope's shape); semi-rigid (rigid keels run the length of the envelope to maintain its shape); and non-rigid (internal pressure of the lifting gas, usually helium, maintains the envelope's shape). This essay focuses on non-rigid airships (commonly called blimps) because they are the primary type of airship in general use today. History The history of airships begins, like the history of hot air balloons, in France. After the invention of the hot air balloon in 1783, a French officer named Meusnier envisioned an airship that utilized the design of the hot air balloon, but was able to be navigated. In 1784, he designed an airship that had an elongated envelope, propellers, and a rudder, not unlike today's blimp. Although he documented his idea with extensive drawings, Meusnier's airship was never built. In 1852, another Frenchman, an engineer named Henri Giffard, built the first practical airship.

Filled with hydrogen gas, it was driven by a 3 hp steam engine weighing 350 lb (160 kg), and it flew at 6 mi/hr (9 km/hr). Even though Giffard's airship did achieve liftoff, it could not be completely controlled. The first successfully navigated airship, La France, was built in 1884 by two more Frenchman, Renard and Krebs. Propelled by a 9 hp electrically-driven airscrew, La France was under its pilots' complete control. It flew at 15 mi/hr (24 km/hr). Military airships In 1895, the first distinctly rigid airship was built by German David Schwarz. His design led to the successful development of the zeppelin, a rigid airship built by Count zeppelin. The zeppelin utilized two 15 hp engines and flew at a speed of 25 mi/hr (42 km/hr). Their development and the subsequent manufacture of 20 such vessels gave Germany an initial military advantage at the start of World War I. It was Germany's successful use of the zeppelin for military reconnaissance missions that spurred the British Royal Navy to create its own airships.

Rather than duplicating the design of the German rigid airship, the British manufactured several small non-rigid balloons. These airships were used to successfully detect German submarines and were classified as "British Class B" airships. It is quite possible this is where the term blimp originates—"Class B" plus limp or non-rigid. Passenger-carrying airships During the 1920s and 1930s, Britain, Germany, and the United States focused on developing large, rigid, passenger-carrying airships. Unlike Britain and Germany, the United States primarily used helium to give their airships lift. Found in small quantities in natural gas deposits in the United States, helium is quite expensive to make; however, it is not flammable like hydrogen. Because of the cost involved in its manufacture, the United States banned the exportation of helium to other countries, forcing Germany and Britain to rely on the more volatile hydrogen gas. Many of the large passenger-carrying airships using hydrogen instead of helium met with disaster, and because of such large losses of life, the heyday of the large passenger-carrying airship came to an abrupt end.

The first passenger-carrying non-rigid airship was invented in 1898 by Alberto Santos Dumount, a citizen of Brazil living in Paris. Under a sausage-shaped balloon with a ballonet or collapsible air bag inside, Dumount attached a propeller to his motorcycle's engine. He used both air and hydrogen, not helium, to lift the blimp. The non-rigid airship of the 1940s and 1950s After the rigid airship disasters of the 1920s and '30s, the United States as well as other countries refocused their attention on the non-rigid airship as a scientific/military tool. Aerial surveillance became the most common and successful use of the blimp. In the 1940s and '50s, blimps were used as early warning radar stations for merchant fleets along the eastern seaboard of the United States. They were also used and are still used in scientific monitoring and experiments. Although as a company it no longer makes airships, Goodyear is a name sononymous with the manufacture of blimps.

During the first half of the twentieth century, Goodyear manufactured over 300 blimps, more than any other airship manufacturer. Goodyear blimps were primarily used by the U.S. Army and Navy for aerial surveillance. Modern resurgence of the non-rigid airship Today, non-rigid airships are known more for their marketing power than for their surveillance capabilities. Blimps have been used commercially in the United States since about 1965. Advertising blimps measure about 150,000 cu ft (4,200 cu m). Since blimps can hover over one space and can be viewed over a large expanse with very little noise disturbance, they are excellent mediums for advertising at large outdoor events. The use of the night billboard on blimps has been quite an advertising fad. The sign is a matte of multicolor incandescent lamps permanently fixed to the sides of the airship envelope, and it can be programmed to spell out different messages. Originally, the signs were developed by electromechanical relay. Now they are stored on magnetic tape, developed by composing equipment on the ground, which are fed into an airborne reader.

The taped information is played back through a computer to the lamp driver circuits. The displayed messages can be seen over long distances. In the late 1980s, the use of blimps in advertising exploded. Its popularity does not seem to have let up. Raw Materials The envelope is usually made of a combination of man-made materials: Dacron, polyester, Mylar, and/or Tedlar bonded with Hytrel. The high-tech, weather-resistant plastic film is laminated to a rip-stop polyester fabric. The envelope's fabric also protects against ultraviolet light. Usually the envelope is smaller than the bladder to ensure that the envelope takes the load when the blimp is fully inflated. The bladder is made of a thin leak-resistant polyurethane plastic film. Ballonets are usually made of a fabric lighter than the envelope's because they only retain gas tightness and do not have to withstand normal main envelope pressures. Air scoops channel air to the ballonets. Blimps obtain much of their lift from lighter-than-air gases, most commonly helium, inside the envelope. Most of the metal used on the blimp is riveted aircraft aluminum. Earlier cars were fabric-covered tubing framework.

Today's gondolas are made of metal monocoque design. The nose cone is made of metal, wood, or plastic battens, laced to the envelope. Design The main body of the blimp is made up of an inner layer, the bladder, and an outer layer, the envelope. The bladder holds the helium. Because the bladder is not resistant to punctures, it is protected by the envelope. Inside the envelope are catenery curtains, which support the weight of the car by distributing the loads imposed by the airship into the fabric of the main envelope. Catenery curtains all consist of cable systems attached to the car, which terminate in the fabric curtains. The envelope's shape is maintained by regulating internal pressure of helium gas inside. Within the bladder are one or more air cells/balloons called ballonets. These are filled with air (as opposed to the rest of the bladder which is filled with helium) and are attached to the sides or bottom of the blimp. The ballonets expand and contract to compensate for changes in helium volume due to varying temperature and altitude. The pilot has direct control of the ballonets via air valves. The nose cone serves two purposes.

It provides the point of attachment for mast mooring and adds rigidity to the nose (which encounters the greatest dynamic pressure loads in flight). On the ground, the inflated blimp is secured to a stationary pole called the mooring mast. The rigid nose dish is attached to the mooring mast. The secured blimp can move freely around the mast with wind changes. There are nose lines attached to the nose dish used by the ground crew to maneuver blimp during takeoffs and landings. Airship tail surfaces come in three configurations: the cruciform (+), the X, and the inverted Y. These tails are made up of a fixed main surface and a controllable smaller surface on the aft end. These surfaces weigh only 0.9 lb per sq ft (4.4 kg per sq m). Tail fins control flight direction. They are anchored at the rear of the ship and are supported by guide wires. The elevators and rudders also help to guide the blimp's movement and are mounted to the fin's edges with hinges. The airship car, or gondola, is similar to conventional aircraft construction. The gondola contains a number of lead shot bags which are constantly adjusted based on the crew's analysis.

The gondola is attached to the blimp by either an internal load curtain or externally, by being attached to envelope sides. Inside the gondola, there a series of controls: the overhead control panel containing controls for communications, fuel, and electrical systems; throttles to regulate engine speed and propeller pitch controls to regulate angles at which propeller blades "bite" the air; fuel mixture and heat controls to regulate the degree to which fuel is mixed with air in engine; temperature controls to prevent icing; envelope pressure controls to regulate helium and ballonet air pressure; communication equipment; main instrument panel; rudder pedals to control right/left direction of blimp; elevator wheels to control up/down direction of blimp; navigational instruments; and color weather radar. The Manufacturing Process Envelope 1 The envelope is made of patterns of fabric panels. Two or three plies of cloth are impregnated with an elastomer. One of these plies is placed in a bias direction with respect to others. The pieces of the envelope can be put together in a number of ways. They can be cemented and sewn together, or heat-welded (heat-sealed). 2 The outside of the envelope is coated with aluminized paint for protection against sunlight.

The envelope will have the required shape when filled with gas. 3 The catenery curtains are attached on to the main envelope proper in a similar manner. 4 The bladder is formed from strips that are welded together. 5 The tail construction consists mostly of lightweight metal structural beams covered with doped fabric. They are held to the envelope by cables which distribute the load into fabric patches cemented or heat-welded to the envelope proper. They are not directly attached to the envelope in the manufacturing process, but put on when the blimp is inflated. Gondola 6 The frame of the gondola is made of material similar to the tail construction, covered with doped fabric. Inflation The erection of the blimp takes only a short amount of time. (The following is only one method of inflation. There are variations on this method.) 7 The envelope is spread out on the floor of the airship hangar, with a net placed over it. This net is held down by sandbags.

Gas is fed into the enveloped from tank cars each containing 200,000 cu ft (5,700 cu m) of 99.9% pure helium compressed to 2100 psi (14.5 megapascals). The net is allowed to slowly rise, with the envelope underneath it. 8 Fins, nose cone, battens, air valves, and helium valves are attached while the envelope is still near the ground. After these parts are attached, the envelope is allowed to rise high enough to permit rolling the gondola underneath it. After the gondola is attached, the net is removed and the airship is rigged for flight. Shipping 9 When transported, the uninflated fabric envelopes can be folded, shipped, and stored in a space that takes up less than 1% of its inflated volume. This feature makes the non-rigid airship more practical than a rigid one. Quality Control A blimp requires a big crew, especially on the ground. Pilots must be certified in planes or helicopters and undergo special lighter-than-air pilot training. The FAA requires a separate license to command a blimp.

As of 1995, there were only about 30 active blimp pilots in the world. Many blimps require 24-hour monitoring. The envelope and ballast are checked every hour to make sure the proper equilibrium is maintained. The Future Propulsive efficiency will be improved by using lightweight, two-stroke aviation diesel engines, gas turbines, or solar energy. New bow and stem thrusters will be developed to improve maneuverability. New lightweight plastics might change the hull design. More lightweight, high strength materials will probably be developed and inevitably improve the overall design and function of the airship. The Pentagon and the U.S. Navy have renewed interested in developing blimps for various defense, missile surveillance, radar-surveillance platforms, and reconnaissance purposes. Where to Learn More Balloon Terminology - Fly Me to the Moon Fly Me to the Moon You are here: Home / School Project Information / Balloon Terminology Balloon Terminology By Administrator Balloon Terminology All of those words and terms used by the ballooning community which might seem a little odd to an outsider. The Australian Ballooning Federation is the body in Australia that issues sport balloon pilots certificates. Aeronaut The pilot of a balloon or airship.

Aerostat A lighter-than-air craft. A hot-air balloon is an aerostat. Aerostation The science of lighter-than-air flight. AGL Above ground level Altimeter A pressure sensing device (barometer) calibrated in feet which is carried in an aircraft to tell the pilot how high the aircraft is off the ground. Balloon A generic term for an aerostat. Balloonatic Fanatic balloon enthusiasts. Many of whom eat, drink and sleep ballooning. Why else would they get up at 4:30 in the morning to stand out in the cold and do hard manual labour? Why – because they are balloonatics! Basket Also referred to as the gondola; the part of the balloon used to carry the pilot and passengers, fuel tanks, and other equipment. Constructed from wicker and light wood base, or in the case of high-altitude and long-distance craft, pressurizable materials. British Thermal Unit- BTU The quantity of heat necessary to raise the temperature of a pound (0.45Kg) of water by one degree Fahrenheit (0.56 degrees Celcius). It is approximately 1.055 kilojoules.

Burner Device used to ignite and project flammable fuel (usually propane gas) up into the envelope to heat the air in a hot-air balloon. Burners come in a variety of configurations. Carabiner A “D”, or “O” shaped locking metal clamp used to connect things together (in particular, load cables to baskets, or tie-off lines to retrieve vehicles). CASA Civil Aviation Safety Authority is the Australian government agency that regulates all non military aircraft, pilots, airports and air spaces. Certificate of Airworthiness A document which states that an aircraft is fit to fly. A balloon as to be regularly checked to make sure the fabric isn’t getting too weak, the basket isn’t unravelling etc. I Chase Also referred to as the “recovery” or more frequently “retrieve”; the process by which the aerostat is tracked during flight and retrieved afterwards by crew on the ground or in another craft (like a boat). Chase Crew The crew that chases the aerostat – more frequently known as the retrieve crew. Convergent Navigational Task – CNT A ballooning event where pilots attempt to fly from a designated distance to a single point, usually a scoring ‘X’.

Also known as Controlled Navigational Trajectory Event, or a Fly-In task. Cremation Charlie Some one who sacrifices himself during a flap inflation to stand inside the envelope and hold it up so that no valuable rip-stop gets burnt. Crown The top of the balloon envelope. Crown Line A rope which, at one end, is fastened to the top (or crown) of the balloon envelope, and at the other end, is used by a member of the crew to help stabilize the balloon during inflation and deflation. Crown Ring The ring of metal at the top of the envelope to which all the load tapes are attached. Drop Line A rope, belt or other line attached to the aerostat (usually the gondola) on one end. Normally furled or stowed during flight, it can be released by the pilot and secured by ground crewmembers who use it to maneuver the craft into or through tight landing areas. Envelope The portion of the balloon which holds the heated air (for hot-air balloons) or gas for gas balloons. Constructed of cloth such as ripstop nylon or nomex, or other light, relatively impermeable material. Fan See inflator fan. First Flight Ceremony Those who have endured it need no explanation.

Those who have not should know that its origins are cloaked in mystery and shrouded in the most sacred rites of ballooning. Suffice it to say that the ceremony involves various liquid refreshment (usually champagne). Once having successfully survived the ceremony, the Initiate has been officially inducted into the Noble Fraternity of Aeronauts. Flap Inflation Before the days of inflator fans, the only way to get cold air into the envelope prior to turning on the burner was to flap the top side of the mouth up and down. Once a small amount of air had been put inside the envelope, the pilot would periodically burn to heat the air as the mouth was flapped open. Clearly this might burn the inside of the balloon higher up, so necessitated a Cremation Charlie. Fly-in Task See basket. Hopper An aerostat where the pilot sits in a chair or harness underneather the envelope, as opposed to standing in a basket. Hesitation Waltz Competition where multiple judge declared goals are set. Inflator Fan Hot air can’t be directly put into the envelope it first has to be filled with cold air using the inflator fan. Only then can this air be heated using the burner.

Before fans, the balloon had to be flap inflated. Judge Declared Goal Competition where a single target is set and all the balloons fly from the launch site with the aim of dropping their markers as close as possible to the goal. Landowner The person, business or organization which holds the title to the property upon which the aerostat launches and/or lands. Landowner Relations Extremely important for aerostat activities, especially considering the limited control over landing location. Ideally, the pilot or chase crew should secure permission from the landowner before landing on their property. The wishes of the landowner take precedence during landing and recovery, within the limits of flight physics and safety. Landowner relations also apply to low overflights of landowner’s property. Load Tapes Reinforced vertical seams along the length of the envelope, connected by the load cables to the basket. The actual load-bearing parts of the envelope. Mouth The opening at the base of the balloon envelope through which the flames from the burner passes to heat the air inside the envelope. This is sometimes referred to as the ‘throat’… MSL Fire-resistant material that the scoop and bottom section of the envelope are made of.

Pibal A small helium filled party balloon used to show the pilot the direction and speed of the wind. This gives an idea of what direction the flight will take. Poles The stabilizing struts between the basket, the burner mount and the load cables. On some balloons the poles are actually load-bearing elements; on others they simply act as stiff or slightly flexible guides for the actual load-bearing elements and connections from envelope sensors to the instrument console. Also referred to as “burner supports”, “supports” or “flexi poles” there main job is to stop the burner knocking you on the head during landing. PIC Pilot in Command Prohibited Zone A restricted operation zone where balloon launchings and landings are prohibited by the landowner. In some cases, a minimum altitude restriction may also exist. PUT Short for ‘Pilot Under Training” or “Pilot Under Tuition”. Red Line A rope or nylon strap connected to the top of the envelope. It is used by the pilot to let some or all of the hot air inside the envelope out in order to descend or land. Red Zone The material that makes up most of envelope. Restricted Operations Zone A land area on or over which balloon operations are restricted by the landowner.

Also refered to as a prohibited zone (PZ) or a sensitive zone (SZ). Retrieve Crew See chase and chase crew. Rosiere Type of balloon that uses both gas and hot air. Sometimes called a hybrid or a temperature controlled helium balloon. These have been used for most of the ultra long distance flights since the early 1990’s. Rotation Vent A panel located about half way up the balloon which is used to orient the balloon during flight and for the landing. Two lines come from the rotation vent, one to rotate left and the other to rotate right. Scoop A specialized-shape skirt which, on American balloons, narrows to an inch or two on one side and widens to extend all the way from the top of the poles to the base of the envelope proper, forming a tilted mouth. The idea of the scoop is to provide better control of the aerostat’s orientation. Ideally, the front (or main part of the scoop) will always be kept in the direction of travel. It may also aid in keeping the envelope full. Sensitive Zone A restricted operation zone where balloon launchings and landings may be allowed by the landowner under special circumstances. In some cases, a minimum altitude restriction may also exist.

Skirt The cloth segment of the envelope below the load cable connections, frequently detachable, often made of Nomex or similar fire-resistant material. Smart Vent Is an Australian invented deflation system for balloons. It allows the pilot to release a lot of hot air from the balloon during landing and can be reset. Spotter Someone who delights in collecting balloon licence numbers, badges and anoraks. Supports Keeping a balloon tied to the ground so that it doesn’t fly away. Throat See mouth. Thumbs up The signal from a launch director that the airspace above is clear and you have permission to launch. Any digit other than the thumb means something entirely different. Uprights The metal or plastic rods that conned the envelope to the basket and hold the burner up. Vent A portion of the top or side of the envelope that can be opened briefly by the pilot to release some hot air to get the balloon to stop going up, or go down. Weather rock Any smooth stone thrown at the weatherman when he tells you it’s going to be unflyable again. ZULU Refers to the universal time zone used within the aviation community.

Also known as Grennwich Mean Time (GMT) or Universal Coordinated Time (UTC) Technical data content credited to Mr Steve Griffin The First Zeppelins: LZ-1 through LZ-4 | Airships.net The First Zeppelins The First Zeppelins: LZ-1 through LZ-4 The First Zeppelin: LZ-1 Count Ferdinand von Zeppelin began construction of his first airship, LZ-1, in June, 1898 in a floating wooden hangar on the Bodensee (Lake Constance) at Manzell (Friedrichshafen) in Southern Germany, not far from the Swiss border. The movable, floating shed allowed the ship to be positioned into the wind to enter or leave its hangar. Luftschiff Zeppelin 1 (click all photos to enlarge) The ship was completed in the winter of 1899 but von Zeppelin decided to wait until the summer of 1900 before attempting to fly his invention. The ship was inflated with hydrogen gas in June and made its maiden flight on July 2, 1900. The first flight lasted about 18 minutes and covered about 3-1/2 miles over the lake.

LZ-1 (Luftschiff Zeppelin 1) was 420 feet long, 38-1/2 feet in diameter, and contained approximately 399,000 cubic feet of hydrogen in 17 gas cells made of rubberized cotton fabric. Two metal gondolas were suspended below the ship (one forward and one aft) and each gondola housed a 4-cylinder water-cooled Daimler gasoline engine producing about 14 horsepower. Each engine was connected by long shafts to two outrigger propellers mounted on either side of the hull. Pitch was controlled by a sliding weight suspended under the hull which could be shifted fore and aft; there were no elevators for pitch control, or fins for stability.

LZ-1 in its floating shed on the Bodensee (click all photos to enlarge) The first flight of LZ-1 was the culmination of years of planning by Count Zeppelin, but as a first attempt the ship had understandable weaknesses: LZ-1 was overweight, and a severe lack of engine power and speed made it difficult to control in even slight winds; the engines themselves were unreliable, and one failed during the short maiden flight; the ship suffered from poor controllability due to its lack of horizontal or vertical stabilizing fins and control surfaces, and the sliding weight system jammed, eliminating pitch control; and most importantly, the structure itself lacked rigidity due to its weak tubular frame, which hogged during flight, with its center portion rising high above its drooping bow and stern. Attempts were made to increase the rigidity of the framework and address the other problems, and two additional flights were made, but the flights did not impress the military representatives in attendance that Zeppelin’s project deserved public funds, and Count Zeppelin was out of money. Zeppelin was forced to dismantle LZ-1.

But while LZ-1 itself was not a success, Count von Zeppelin’s basic concept — of a long rigid metal frame containing individual gas cells and covered by fabric — was sound, and formed the basis for all future zeppelin airships. LZ-2 Count Zeppelin’s second ship, LZ-2, was not built until five years later, with funds raised partly from a lottery approved as a favor by the King of Wurttemberg, and partly by the mortgage of Countess Zeppelin’s family estates. LZ-2. The stronger, more rigid frame provided by Ludwig Dürr’s triangular girders can be seen, but the ship still lacked fins for stability or control. While an improvement over LZ-1, Count Zeppelin’s second ship still did not incorporate basic design elements which would later be recognized as essential to flight stability and control, such as vertical and horizontal stabilizers and control surfaces. But LZ-2 did represent a significant technical advance due largely to engineer Ludwig Dürr ; the weak tubular girders of LZ-1 were replaced by triangular girders (visible in photo above), which provided dramatically improved rigidity and strength.

Triangular girders similar to those used on LZ-2 would be used on every subsequent zeppelin airship, and Ludwig Dürr would remain as chief engineer, designing every ship built by the Zeppelin Company after LZ-2. LZ-2 made its only flight on January 17, 1906. Zeppelin had replaced the 14 hp engines used on LZ-1 with 80 hp Daimler engines, which gave LZ-2 sufficient speed to maneuver in light winds, but engine failure forced an emergency landing during the ship’s very first flight, and it was destroyed on the ground by a storm that evening. Destruction of LZ-2 LZ-3 and LZ-4 The next two ships, LZ-3 and LZ-4, were even greater advances in technology, with huge increases in controllability, power, speed, range, and payload. Large horizontal fins and elevators finally provided greater pitch control and stability, and the ships were capable of producing aerodynamic lift.

Longer and more reliable flights became possible; in 1907, LZ-3 made a flight of 8 hours, and on July 1, 1908, LZ-4 made a flight of 12 hours over Switzerland. LZ-3 in flight Tail of LZ-3, showing horizontal stabilizers which were lacking on LZ-1 and LZ-2 (click all photos to enlarge) The record-breaking Switzerland flight of LZ-4 brought national attention to the success of Count Zeppelin and his machine, and the public began to look on the airship as a practical innovation. On July 3, 1908, King Wilhelm II of Wurttemberg and his wife, Queen Charlotte, were passengers on the fifth flight of LZ-4. The German government promised financial support for Count Zeppelin’s efforts if his ship could make an endurance flight of 24 hours, and confidant in his ship’s ability, Zeppelin agreed to the challenge. LZ-4 departed the Bodensee on August 4, 1908, for a 24-hour trial.

LZ-4 leaving its hangar on the Bodensee for the 24 hour test flight that ended at Echterdingen. LZ-4 and the “Miracle at Echterdingen” Just as it seemed that Count Zeppelin and his team had mastered the basics of airship design and operation, LZ-4 was forced to make an emergency landing in a field at the town of Echterdingen on August 5, 1908, during the 24-hour endurance flight. Pulled by a sudden storm from its temporary mooring, the ship crashed and was soon destroyed by a fiery explosion of hydrogen. Wreckage of LZ-4 at Echterdingen Wreckage of LZ-4 at Echterdingen In response to the crash, rather than lose faith in Count Zeppelin’s work, the German public rallied behind Zeppelin’s efforts; in what became known as the “Miracle at Echterdingen,” Germans contributed 6 million marks for the construction of a new airship and gave new life to the zeppelin enterprise.

Establishment of the Lufschiffbau Zeppelin The fervent financial and political support of the German public and government following the crash at Echterdingen allowed the Count to establish the Luftschiffbau Zeppelin (Zeppelin Construction Company) in September, 1908. Alfred Colsman was the Zeppelin Company’s business manager, and in 1909, journalist Hugo Eckener joined as the company’s director of public relations; within 2 years, Eckener would be an airship commander. Colsman would shortly establish DELAG , the Deutsche Luftschiffahrts-Aktiengesellschaft (German Airship Transportation Corporation Ltd) as a affiliate of the Zeppelin Company, to commercialize zeppelin travel by providing passenger service. Early zeppelin under construction at floating hangar on the Bodensee.

Early zeppelin at floating hangar on Bodensee Blimps: How They Work, Facts, and Resources | The Free Resource Blimps: How They Work, Facts, and Resources Live Search Education Blimps: How They Work, Facts, and Resources Whether they are called dirigibles, zeppelins or blimps, whether they are soft or rigid, airships all have several basic aspects in common: They are buoyed by gases that are lighter than air, propelled by internal combustion engines and may be steered with the help of rudders, propellers and pressurized air. The gases hydrogen and helium are usually used to propel airships. Helium is the more common propellant since it is easily available as a plentiful byproduct of natural gas production. Non-rigid airships, also known as blimps, are aerodynamically shaped “envelopes” made of very strong synthetic materials similar to spacesuit materials that cannot be weakened by ultraviolet light as some older materials were. The helium gas contained in this envelope maintains its shape. Pressure inside it is very low, so even if a small hole is made, the leak will not negatively affect the airship’s flying capability for hours or days.

Helium expands as the airship rises and contracts as it descends. To keep the internal pressure at a constant level despite changes in the volume of the helium gas inside it, “ballonets” are installed in the envelope. These are bags of air that can be inflated or deflated as the helium expands or contracts. “Pressure height” is achieved when the ballonets are empty. The gondola is the enclosed framework that holds the airship’s passengers and crew. Some gondolas have a camera attached to them. Two fabric curtains hang along the length of the envelope, attached to the gondola with suspension cables. Two gasoline-powered turbo-propeller airplane engines are mounted on either side of the gondola. Air scoops funnel exhaust from the engines to the ballonets, providing for an efficient way to restock the ballonets during flight. When the airship is running without the engines, electric fans can fill the ballonets. If the pilot needs to release air from the ballonets, he can do this by using one of four valves on each unit. On the tail of the airship are flight control devices such as a rudder for steering and an elevator to control the level of ascent and descent.

Inside the gondola, the pilot has instruments to control the speed, angle and direction of the craft; the fuel-to-air ratio of the engine and its temperature , to prevent icing at high altitudes; and pressure inside the envelope. The pilot also has communication devices to stay in contact with ground crews and air-traffic controllers as well as navigation equipment such as GPS or compasses. The cigar shape of the craft gives it an additional boost into the air. Taking off at a run, as an airplane does, the airship gains speed that is converted into lift when the nose of the vehicle begins to rise. The airship is reinforced with a nose-cone batten to keep the nose from caving in under air pressure. After they are in the sky , airships can hover in a particular spot like helicopters can, but without the intense power consumption, noise and vibration typical of helicopters . Since they rely on gases rather than speed to stay in the air, airships do not need much engine power to move them forward. All airships are lighter than air. In addition to blimps, there are semi-rigid airships that have a partial frame for better support and load distribution.

Rigid airships (also called zeppelins ), often associated with the military, have a full skeleton surrounding cells filled with lifting gas. The Hindenburg was one of the most famous rigid airships, and it was also a dirigible, meaning it was steerable. The word “dirigible” comes from the French for “to steer.” Share on Pinterest Inside a Blimp - How Blimps Work | HowStuffWorks How Blimps Work Nose cone battens (gray) Photo courtesy American Blimp Corporation Unlike a balloon, a blimp has a shape and structure that enable it to fly and maneuver. The following parts allow it to do this: envelope - contains the helium gas nose cone battens flight control surfaces - rudders, elevators engines gondola - holds passengers and crew This content is not compatible on this device. Move mouse over each part to view its location. Up Next We'll discuss each of these parts in the following sections. Envelope The envelope is the large bag that holds the helium gas . The envelope is generally cigar-shaped, for aerodynamic purposes, and made of a durable, airtight, lightweight fabric (polyester composites) that is much like the fabric of a space suit .

In fact, many envelopes are made by ILC Dover Corporation, the company that makes spacesuits for NASA . The envelopes can hold from 67,000 to 250,000 ft3 (1,900 to 7,093 m3) of helium, depending upon the particular blimp. The pressure inside the envelope is low, approximately 0.07 pounds per square inch (0.005 ATM). Nose Cone Battens The nose cone battens are supports that radiate from the tip of the blimp. They stiffen the front of the blimp so that it is not damaged when it is moored to the mooring mast. They also give the nose an aerodynamic shape, and prevent it from pushing in as the blimp travels forward. In addition to the battens, the mooring hooks are located in the nose of the blimp. Ballonets Ballonets are air-filled bags that are located inside the envelope. The blimp has two ballonets, one fore and one aft. The ballonets are similar to the ballast tanks of a submarine .

Because air is heavier than helium, the ballonets are deflated or inflated with air to make the blimp ascend or descend, respectively. They are also used to control the trim, or levelness, of the blimp. Catenary Curtain and Suspension Cables The two catenary curtains are located inside the envelope along the length of the blimp. They are made of fabric and sewn into the envelope, and suspension cables attach them to the gondola. The curtains help to support and shape the envelope and attach the gondola. Flight Control Surfaces The flight control surfaces are stiff, movable parts of the blimp that are mounted to the tail. They consist of the rudder and elevators. The rudder is used to steer the blimp to the starboard or port directions (yaw axis). The elevators are used to control the angle of ascent or descent (pitch axis) of the blimp. The flight control surfaces are operated by the pilot as he/she flies the blimp, and can be arranged in a "+" or "x" configuration. Engines The two engines on the blimp provide the thrust necessary to move ahead. The engines are turbo-propeller airplane engines that use gasoline fuel and are cooled by air.

The engines can generate several hundred horsepower , depending upon the particular blimp. They are located on either side of the gondola. With the engines, blimps can cruise around 30 to 70 mph (48 to 113 kph). Air Scoops The air scoops direct exhaust air from the propellers into the ballonets. This is how the pilots can fill the ballonets with air while in flight. When the engines are not running, electric fans move air into the ballonets. Air valve of a blimp Photo courtesy Goodyear Air Valves The pilots must be able to vent air from the ballonets as well as add it. This is accomplished by air valves that are located on each ballonet. There are four valves -- two fore, two aft. Helium Valve The pressure of the helium in the envelope is adjusted by changing the amount of air in the ballonets. Normally, blimp pilots do not have to add or remove helium from the envelope. However, there is a helium valve on the envelope that can be used to vent helium should the helium pressure exceed its maximum safe limit. The valve can be opened manually or automatically.

Gondola The gondola holds the passengers and crew. It is enclosed, and holds two pilots and up to 12 crew, depending upon the type of blimp (Goodyear's Eagle and Stars & Stripes each hold two pilots and six passengers). Some gondolas have specialized equipment, such as a camera, attached to them. Blimp gondola with an attached camera (round object in front) Photo courtesy American Blimp Co. Forward view inside of gondola, showing pilot seats/controls (front) and passenger seats Photo courtesy American Blimp Co.

The control panels used by the pilots include the following: Propeller controls - monitor and regulate speed (throttle), blade angle (blade pitch) and direction of the engine (forward, reverse) Fuel mixture/heat - monitor and regulate the fuel-to-air ratio of the engine and the temperature of the mix to prevent icing at higher altitudes Envelope pressure controls - monitor and regulate the helium pressure in the envelope and the air pressure in the ballonets by opening and closing the air scoops and valves Communications - maintain radio contact with ground-support team and air traffic controllers Flight surface controls - control the rudder (left/right movement) and the elevators (up/down movement) Navigation equipment - compasses , airspeed indicators, radio beacon equipment, GPS , etc. (Some blimps also have weather radar , and are instrument-rated for night-flying.) Blimp pilots are FAA-certified for lighter-than-air (LTA) craft. Goodyear's pilots undergo a comprehensive training program prior to FAA certification. In addition to piloting, Goodyear's pilots also serve as ground-support crew, including electronics technicians, mechanics, riggers and administrative personnel.

A ground crew follows the blimp wherever it goes, bringing several support vehicles, including a bus that serves as the administrative office, a tractor-trailer that serves as an electrical/mechanical shop, and a van that is the command car/utility vehicle. Night Signs Some blimps (like Goodyear) are equipped with electric lights for nighttime advertising. In the Goodyear blimp, the night signs consist of a matrix of red, green and blue light-emitting diodes (LEDs). The intensities of the LEDs can be adjusted to create various colors. The messages are programmed in with a small laptop computer that is carried aboard. Now that we have seen all of the parts of a blimp, let's look at how it flies! Blimp History tells you how, why, where and when blimps were first developed. blimps,airships,tethered balloons,zeppelins,blimp advertising,aerostats,blimp leasing and management return on investment due to the large profit margin. The gondola under the tethered balloon accommodates 30 passengers. The balloon is allowed to ascend, which typically takes five minutes.

At the top, approximately 400ft, the balloon stops and, for another few minutes passengers admire a breathtaking view to the horizon before returning to earth. For the public, the romance and appeal of ballooning is universal. The sensation is unique. A TARS ride gives the memory of a lifetime. But to the businessman, the TARS system represents an outstanding investment -- it returns an exceptionally high profit margin: So big that the full investment should easily be recovered in the first year of operation. Balloon Envelope 5750 cubic meter capacity, includes all rigging lines, gas valve, and traditional balloon net. An airship-style ballonet compensates for changing pressure resulting from temperature and altitude factors, ensuring the external size of the envelope remains constant and pressurized. The net carries the entire structural load from the envelope to the winch cable. This gives the TARS the look of a traditional gas balloon. The balloon stays inflated at all times--a low-mooring winch system secures it against winds in excess of 50 knots. Airborne it flies in winds up to 25 knots, although this may exceed the level of operational comfort.

Gondola Carries up to 30 passengers in a welded stainless-steel two-piece structure with decorative wickerwork panelling. Its circular walkway prevents passengers from bunching up, provides everyone with a clear view, and accommodates lightweight wheelchairs. An in-gondola power pack system supplies all power requirements to the balloon and its navigation lights. Winch system The essence of the winch design is mechanical simplicity to maximize safety. Central to the operation of the TARS is the custom-built electric winch. This utilizes proven components used in applications such as ski-lifts. The 22mm steel cable stored on a unique 1.5m single wrap drum holds the balloon captive and secure. Tested to 45 tons, it has a 10 to 1 safety margin. The system is self-aligning, and permits the balloon to swivel, to maintain the cable's integrity. The entire winch system fits into an ISO standard 20 foot container. Although the balloon can rise to 600 feet, normal ride height is 400 feet, balancing optimum view with a cost-effective ride duration. Power needed from a three-phase supply is only 37kw.

Should the main supply of electricity fail, an auxiliary motor with a gas-driven generator is on standby, enabling the balloon to be brought down safely. Controls TARS is operated from the gondola, linked to the winch by radio control. The operator is also in voice contact with the ground. If necessary, the balloon can be controlled by the ground operator. Advertising Platforms The Airship Simon - Airship History The Airship Simon 4. The Present and the Future 1. What is an Airship? An airship is a type of lighter-than-air aircraft with propulsion and steering systems; it is used to carry passengers and cargo. It obtains its buoyancy from the presence of a lighter-than-air gas such as hydrogen, helium, or hot air, based on archimedes' principles. The first airship was developed by the french; called a "ballon dirigible" (steerable balloon), it could be steered and also be flown against the wind, which is not possible with a simple balloon. Vehicles such as airships belong to the category of aerostats because of their ability to stand in the air. Airships and balloons are the two subcategories of aerostats.

there are three types of airships, rigid, semirigid and nonrigid. Hot air airships can be counted as a part of the nonrigid category. a) Rigid Airships (zeppelins) As its name implies, a rigid structure, traditionally an aluminum alloy, holds up the form of a rigid airship, which is also called a zeppelin, after its inventor Ferdinand Graf von Zeppelin. This structure resembles a cage that encloses a series of balloons called gas cells. these cells are tailored to fit the cylindrical space and are secured in place by a netting that transmits the lifting force of their gas to the structure. Each gas cell has two or more valves, which operate automatically to relieve pressure when the gas expands with altitude; the valves can also be operated manually so that the pilot can release gas whenever desired. Also on board is a ballast system that uses water as ballast. On the ground this ballast serves to make the airship heavier than air. When part of it is discharged, the airship ascends to a cruising altitude where the engines supply propulsion, and further ballast can be discharged to gain more altitude. As fuel is consumed, the airship becomes lighter and tends to climb.

This is countered in hydrogen-inflated airships by simply releasing gas into the atmosphere. The method is uneconomical, however, with helium-inflated airships, and they are therefore equipped with ballast generators, apparatuses that condense moisture out of the engines' exhaust gases to compensate for fuel that is consumed. But this ballast-generating equipment is expensive, complex, heavy, and difficult to maintain and is thus one of the most serious disadvantages of airships filled with the safer but more expensive helium. In general, rigid airships are only efficient when longer than 120 m because a good weight to volume ratio is only achievable for large airships. For a small airship the solid frame would be too heavy. However, the use of composite materials is changing this at this very moment with a project called the Zeppelin NT (see 4. The Present and the Future). b) Nonrigid Airships (Blimps) Nonrigid airships, also known as blimps, are the most common form nowadays. They are basically large gas balloons. In contrast to the rigid airship, the nonrigid airship has no internal structure to maintain the shape of its hull envelope.

Its shape is maintained by internal overpressure. The only solid parts are the gondola and the tail fins. Inside the gas space of the hull of modern, high-altitude blimps are two or more air diaphragms called ballonets that are kept under slight pressure, either by blowers or by air that is forced through scoops as a result of the forward motion (ram effect). The ballonets in turn exert pressure upon the gas, which fills the envelope, and this pressure in turn serves to stiffen the shape of the envelope and create a smooth flying surface. On takeoff the ballonets are almost fully inflated, but as the airship gains altitude and the gas expands, air is bled from the ballonets while a constant pressure is maintained throughout the envelope. When the gas contracts upon descent, air is pumped back into the ballonets. All the airships currently flying for publicity use are nonrigid: the Goodyear blimps, the Budweiser and the Metlife blimps, airship "Shamu" in the USA, and the Fuji blimp in Europe. c) Semirigid Airships Semirigid airships were more popular earlier this century.

Inventors sought to combine the best features of zeppelins and blimps in a semirigid type, but it met with only limited success. They usually comprised a rigid lower keel construction and a pressurized envelope above that. The rigid keel could be attached directly to the envelope or hung underneath it. The airships of the Brazilian aeronaut Alberto Santos-Dumont and of the German engineer Otto Prill were semirigid. One of the most famous representatives of the type was Italia, the airship which General Umberto Nobile used on his attempt to reach the north pole. d) Hot Air Airships Hot air airships might be counted as a fourth kind although they are part of the nonrigid class. Hot air or thermal airships derive from traditional hot air balloons. Early models were almost like balloons with an engine and tail fins added. Very soon envelopes were lengthened and the tail fins and rudders were pressurized by air from the wash of the propeller. Only newer hot air airships maintain their shape with internal overpressure in the whole envelope. Older models did not have that feature, exactly like traditional hot air balloons. 2.

The Past The history of the zeppelin started when Graf Ferdinand von Zeppelin, a young cavalry general of the German army, returned to Germany from a journey to America. He brought with him the ideas of a rigid balloon as the world had never seen it before, the zeppelin. It took years before Graf Zeppelin was able to realize his dreams. He did not get tired of trying to persuade the technical world to realize his plans of an aerostat. Finally, in the year 1899, the German emperor Wilhelm II granted Graf Zeppelin a complex near Friedrichshafen, which became the Luftschiffbau Zeppelin Ltd., where on July 3, 1900, the first zeppelin lifted off the ground. A total of 119 zeppelins were built , most of them during world war I, when 103 airships were delivered to the military, and about 40 of them were shot down while on air raids over London.

However, the most famous zeppelin was the original "Graf Zeppelin", which between 1928 and 1937 made flights to the United States, the Arctic, the Middle East, and South America; it also made one flight around the world. The last zeppelin was the "Graf Zeppelin II", which was first flown on September 14, 1938. It could carry loads of 30 tons over transoceanic distances. It was scrapped in may 1940. The british also made intermittent efforts to develop the rigid airship; They built eight during world war I and six shortly thereafter. The most noteworthy was the R-34, which in July 1919 made the first transatlantic round-trip flight. An effort to develop two airships for intercontinental air service came to grief in october 1930 when the R-101 crashed and burned in France. The R-100, which had made a successful flight to Canada earlier in the year, was subsequently scrapped. In the United States, the development of rigid airships was undertaken by the navy, and only five were operated.

The navy-built ZR-1 Shenandoah made its first flight on September 4, 1923, and was torn to pieces by a thunderstorm over southern Ohio on September 3, 1925. The ZR-2 was procured in England but crashed on August 24, 1921, before it could be delivered to the United States. The ZR-3 Los Angeles, built in Germany by Luftschiffbau Zeppelin, made its transatlantic delivery flight during October 11-15, 1924; it was flown successfully until decommissioned in 1931 and was scrapped in early 1940. The ZRS4 and ZRS5 were built by the Goodyear-Zeppelin Co. of Akron, Ohio. Their design was unique in that it provided for an internal space for five airplanes that could be launched and retrieved while the airships were in flight.

The akron first flew on September 23, 1931 and was lost in a storm over the Atlantic on April 4, 1933; The macon first flew on April 21, 1933, and crashed in the pacific on February 12, 1935. 3. The Disaster of Lakehurst Why were all the airships scrapped in 1940? - because of the Hindenburg! Crowds of onlookers had come to Lakehurst on May 6, 1937, to watch the landing of the LZ 129 Hindenburg after a long winter break. The scene was not new, for the Hindenburg had landed and started in Lakehurst, New Jersey, before. Everything seemed to be routine, especially for the spectators who did not know about an airship captain's problems with the wind, temperature, and weight. People at that time were used to airships flying over the atlantic ocean with 200,000 m3 of highly flammable hydrogen, and nobody thought of any danger; however, it was there.

While maneuvering to land at lakehurst the airship's hydrogen was ignited and the Hindenburg was destroyed by the resulting fire. 35 of the passengers and crew died, along with one member of the ground crew. Claims and speculations that the Hindenburg had been the target of sabotage have never been supported by evidence. Recent studies by a NASA engineer show that the probable cause of the disaster was a new aluminum-lacquer on the envelope which was extremely flammable. The destruction of the Hindenburg marked the end of the use of airships in world air commerce. 4. The Present and the Future Over the past few years the airship has begun to make a remarkable comeback. Many people already considered them as something belonging to the past, unsuitable for our modern times. However, the last 25 years have shown an increasing interest in nonrigid airships. In the early 1970's there were only three airships flying in the USA and now there are more than twenty in four continents, with many more on the stocks. Graf Zeppelin's dream has become reality. The modern airship is here, it is flying already. It is safe and it is commercially viable.

The future is, if carefully nurtured, now on a very solid foundation. New ships will be truly capable of transoceanic flights; after all the Graf Zeppelin flew from Tokyo to Los Angeles, non-stop, and that was in 1929. 50 years after the disaster of Lakehurst, a new zeppelin is presenting itself in Friedrichshafen, next to various other projects in the whole world. On april 23, 1997, the future arrived with the presentation of the LZ N07 Zeppelin NT (new technology) at the AERO International Flight Fair in Friedrichshafen . It is the first rigid airship since 1939, built again by the original Luftschiffbau Zeppelin Ltd., which now calls itself Friedrichshafener Zeppelin Luftschiff Ltd.. Its size is comparable to a boing 747 jumbo jet with a length of 68.4m. The frame of the new zeppelin is made up of carbon fiber compounds and aluminum alloys. Because of a new propulsion system, it is very easily maneuverable by one of the two pilots.

There are three swivel propellers of 150,000 W power each and a cross fan at the tail, used to further control the Zeppelin NT. The three swivel propellers help at takeoff and landing procedures. This reduces the ground crew to three men. the Zeppelin NT weighs only about 7000 kg and has a payload of up to 2000 kg. In the gondola, there is room for two pilots and 12 passengers. Its cruising speed is 32 m/s, with a maximum speed of 40 m/s. The unit price is 12.5 million marks (about 7.5 million $). Delivery of the first Zeppelin NT should start this year, with the first customer a Swiss company called Skyship Cruise Ltd. 14 more zeppelins have already been ordered by various companies from all over the world. AlShindagah Online Throughout history, there have been three primary types of airship construction. According to their structure, they are known as non-rigids or blimps, semirigids, and rigids. They all share four basic sections.

The first of those is the balloon, which is in the shape of a cigar. The balloon is what provides the lifting force of the airship and is filled with a lighter-than-air gas. Then there is the car, or the gondola. The car is suspended under the balloon and serves for the purpose of accommodating the passengers and cargo. All airships also have engines that drive propellers, and they have horizontal and vertical rudders for steering the airship. The first type of airship, the nonrigid, is just that - a non-rigid balloon with a car attached under it by cables. The shortcomings related to this structure have to do with the fact that when and if enough gas leaks, the balloon simply collapses. The main difference between the so-called semirigid construction and the non-rigid one is a metal frame. The frame in the semirigid extends along the balloon, thus holding it in shape and providing solid support for holding the car underneath. The rigid construction is a light structure of aluminum-alloy girders dressed in a fabric material. Instead of one big balloon, the rigid construction holds several smaller balloons, each of which can be filled with gas or emptied separately.

The rigid construction maintains the shape of the balloon regardless of whether it is full of gas or not. Conventionally, the lighter-than-air gases used in the balloons of airships are hydrogen and helium. The lightest gas, hydrogen possesses the greatest lifting power. Its disadvantage when applied to airships is that it is highly flammable. This makes it dangerous and has indeed been the reason for numerous deadly airship misfortunes. Helium, on the other hand, although not as light and not having such lifting power, is preferable for safety reasons. In fact, helium completely eliminates the flammability risk, as it does not burn. The Beginning: The First Airships In 1852, Henri Giffard of France made the first ever successful airship flight. The airship he made for this historical attempt had the modest 3 horsepower engine, which weighed some 160 kilograms. This provided enough power to ensure the large propeller attached would turn 110 times per minute. The balloon he used was a 44m long bag, which he filled with hydrogen. Giffard's first official flight was made from the Paris Hippodrome.

His average speed was about 10 km per hour and the distance he covered was some 30 km - a real achievement for the time. Twenty years later, in 1872, Paul Haenlein, an engineer from Germany, was the first to apply an internal-combustion engine to an airship. A decade after this, in 1883, Albert and Gaston Tissandier from France were the first to apply an electric motor to an airship. Not much later, further advancements saw the production of the first rigid airship. It was made in Germany in 1897 with an aluminum-sheeting hull. Ferdinand von Zeppelin In the history of airships, one name stands out - Ferdinand, Count von Zeppelin, of Germany. Zeppelin was the most accomplished pilot of rigid airships. He constructed his first airship, the LZ-1, in 1900. For its time, this was a superior construction, 128 metres long and 11.6 metres in diameter. Its aluminum frame consisted of 24 longitudinal girders, set within 16 transverse rings.

The airship was driven by two advanced 16-horsepower engines. It could reach record velocity of 32 km per hour. Zeppelin went on to making more reliable and sophisticated constructions, many of which were used in military operations throughout World War I. These airships became known as zeppelins. In the post-war years of the 1920s and 1930s, the evolution of airship design experienced new heights in Europe and America. A new long-flight record was set with a round-trip crossing in July 1919 of the Atlantic Ocean. This was a British airship - a dirigible named the R-34. In 1926, an Italian airship of semirigid construction toured successfully the North Pole. Onboard were famous explorers Roald Amundsen, Lincoln Ellsworth, and General Umberto Nobile. Soon after, in 1928 one of Zeppelin's successors, Hugo Eckener of Germany, completed the Graf Zeppelin airship. Graf Zeppelin was destined to complete 590 flights, out of which 144 were ocean crossings.

Despite these rapid achievements, airships were virtually abandoned in the late 1930s because of their cost, their slow speed compared to airplanes, and their weakness in turbulent weather conditions. Their unpopularity was also increased due to a number of frequent failures and due to the fast evolution of airplane construction in the 1930s and 1940s. The return of the Airship - the Skycat Some six decades after the aviation world saw the airship an obsolete vehicle, a revolutionary aircraft has been designed that has been declared to have ability to bring about the return of the airship. This new lighter-than-air craft has been called the SkyCat. The SkyCat is revolutionary in its capacity to bring together the benefits of lighter-than-air and those of havier-than-air craft technology. It uses helium for lifting power but the lift is aerodynamic due to its hull shape, which resembles an aircraft. Thus the SkyCat is supposedly bringing the best features of both aircraft and airship construction for its unique purposes. The result is a craft of outstanding usefulness and staying power. The SkyCat is equipped with a distinctive hover-cushion landing system, which is extended on landing and withdrawn in flight.

This unique system eliminates the need for specially prepared airport-like landing surface. In fact, the SkyCat can easily land on land, water, desert, or snow. When on land, extra stability is provided by turning the hover-cushion engines around. Thus the airship is essentially sucking down, almost forming a vacuum and is able to stay stable in place without handling equipment. The SkyCat is being developed in Cardington, UK, in three basic models. Their main difference is in the lift-size variation, the smallest with 20 tons, the middle one with 220 tons and largest one with a lift-size of 1000 tons. Apart from this, the three models are of the same construction. They are fully operable in all weather conditions open to a standard civil aircraft. According to their size, each of the models is ideal for its specific purposes. However, all the Skycats have the same benefits due to their overall identical figure. The question of speed - Skycats vs. Aircraft It is more than natural for anyone who reads this to ask himself about the speed of the SkyCats. After all, this is of crucial importance in today's fast-paced world.

If SkyCats are faster, are they to replace aircraft. The answer to this question is not a simple one, as several factors must come into consideration. To begin with, if we look at speed as an absolute measurement, then airplanes remain the faster alternative. However, this answer has a problem due to its failure to put speed into context. It certainly misses out on essential effects that act together to produce overall deployment speed. As a point in case, airplanes fly at speeds of some 1000 kilometres per hour - more than 5 times faster than the 160+ kilometers per hour at which SkyCats can fly. However, this does not mean that airplanes are capable of faster deployment speeds, because of their dependency on infrastructure and fuel. Therefore, although airplanes fly so much faster than airships, for all but the longest-distance deployments, the SkyCat actually is capable of faster deployment speeds, thus providing a competitive alternative to conventional aircraft. Benefits The 220-ton-lift SkyCat model, called the SkyShuttle, can serve as an inexpensive means of mass passenger transportation.

It can be ideal for short routes, with capacity for up to 900 passengers at a cost per passenger/km of less than half a dirham. If fitted with more spacious all-1st-Class seating, the SkyCat-220 could accommodate 420 passengers on the lower deck and will have enough space for 42 cars on the upper deck car park. The smaller, 20-ton-lift airship - the SkyCat 20 - has capacity for up to 120 passengers in economy-class seating, or 70 passengers in spacious first-class accommodation. It offers direct operating costs of less than AED3,600/hr, which comes up to about AED 36 per economy-class passenger per hour, or around AED 0.25 per passenger/km. The SkyCat will be able to land just next to a cruise liner, for instance. In addition, the SkyCat can fly passengers from the shore straight to places deep inland and maneuver adaptably from the mainland to the islands. As an added potential tourist benefit, it can hover above notable sites and hang around over awe-inspiring terrains for hours and days on end without polluting the environment.

In addition to transporting people and for fast deployment, the SkyCat can be used for other purposes such as for telecommunications and advertising. Hovering in one position at 3000 metres and set up with sophisticated transmission gear, a SkyCat 20 can be an on-demand, rapidly-deployed and very commercially viable telecommunications station for beaming out broadband, broadcast and 3G mobile wireless networks signals. When it comes to advertising potential, the SkyCat-20 can also become a low-cost large display hovering over downtown districts and offering a ground-breaking line of advertising. For extraordinary impact, the SkyCat can be fitted with two huge plasma display screens of 26m x 14m. The size will be longer than a Boeing 747. These screens can play full colour advertising video clips and even movies. They will be well visible during the day, but their impact will be unprecedented during the night. So, when will we see the first SkyCats? There is talk of a formal introduction with a grand World Tour, planned for 2005. The producers claim the SkyCat will generate an incomparable impression wherever it flies.

Indeed, plans are being made for a global scale unique launch with the SkyCats flying over 55 major international cities and over big sporting venues. Over a period of six months, the launch campaign will cover over 100,000 km. Is the SkyCat set for a dazzling future? For one, it will without a doubt transform the image of the somewhat forgotten airships. It is certainly having notable advantages over aircraft for its large payload, long range and high endurance. Its low capital and operating costs, its supposedly high safety levels, and high fuel efficiency make it even more competitive. Its potential for a broad range of functions such as tourism, disaster relief, border surveillance, and bulk transport of produce, paint a bright picture of opportunity and expectations. A century and a half after Henri Giffard's invention, the history of the airship is about to be rekindled with the arrival of a SkyCat.

Question: What is the name of the structure under a balloon or airship that holds the crew and passengers?
Answer: GONDOLA