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Ballonets
A ballonet is an inflatable bag inside the outer Aerostat, envelope of an airship which, when inflated, reduces the volume available for the lifting gas, making it more dense. Because air is also denser than the lifting gas, inflating the ballonet reduces the overall lift, while deflating it increases lift. In this way, the ballonet can be used to adjust the lift as required. Ballonets may typically be used in non-rigid airship, non-rigid or semi-rigid airship, semi-rigid airships, commonly with multiple ballonets located both Bow (ship), fore and Stern, aft to maintain balance and to control the Flight dynamics (aircraft), pitch of the airship. The image illustrates the principle of a balloon within a balloon. The outer balloon represents the airship's outer envelope or gasbag, while the red inner balloon represents the ballonet. In an airship the ballonet would be much smaller relative to the size of the gasbag; for example, in the French airship Lebaudy Patrie the volume of th ...
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Airship
An airship, dirigible balloon or dirigible is a type of aerostat (lighter-than-air) aircraft that can navigate through the air flying powered aircraft, under its own power. Aerostats use buoyancy from a lifting gas that is less dense than the surrounding air to achieve the lift (physics), lift needed to stay airborne. In early dirigibles, the lifting gas used was hydrogen gas, hydrogen, due to its high lifting capacity and ready availability, but the inherent flammability led to several fatal accidents that rendered hydrogen airships obsolete. The alternative lifting gas, helium gas is not flammable, but is rare and relatively expensive. Significant amounts were first discovered in the United States and for a while helium was only available for airship usage in North America. Most airships built since the 1960s have used helium, though some have used thermal airship, hot air. The envelope of an airship may form the gasbag, or it may contain a number of gas-filled cells. An air ...
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Airships
An airship, dirigible balloon or dirigible is a type of aerostat (lighter-than-air) aircraft that can navigate through the air flying under its own power. Aerostats use buoyancy from a lifting gas that is less dense than the surrounding air to achieve the lift needed to stay airborne. In early dirigibles, the lifting gas used was hydrogen, due to its high lifting capacity and ready availability, but the inherent flammability led to several fatal accidents that rendered hydrogen airships obsolete. The alternative lifting gas, helium gas is not flammable, but is rare and relatively expensive. Significant amounts were first discovered in the United States and for a while helium was only available for airship usage in North America. Most airships built since the 1960s have used helium, though some have used hot air. The envelope of an airship may form the gasbag, or it may contain a number of gas-filled cells. An airship also has engines, crew, and optionally also payload acc ...
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Non-rigid Airship
A non-rigid airship, commonly called a blimp ( /blɪmp/), is an airship (dirigible) without an internal structural framework or a keel. Unlike semi-rigid and rigid airships (e.g. Zeppelins), blimps rely on the pressure of their lifting gas (usually helium, rather than flammable hydrogen) and the strength of the envelope to maintain their shape. Blimps are known for their use in advertising, surveillance, and observation due to their maneuverability, slow speeds and steady flight capabilities. Principle Since blimps keep their shape with internal overpressure, typically the only solid parts are the passenger car (gondola) and the tail fins. A non-rigid airship that uses heated air instead of a light gas (such as helium) as a lifting medium is called a hot-air airship (sometimes there are battens near the bow, which assist with higher forces there from a mooring attachment or from the greater aerodynamic pressures there). Volume changes of the lifting gas due to temperature ...
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Ballonet Analogue
A ballonet is an inflatable bag inside the outer envelope of an airship which, when inflated, reduces the volume available for the lifting gas, making it more dense. Because air is also denser than the lifting gas, inflating the ballonet reduces the overall lift, while deflating it increases lift. In this way, the ballonet can be used to adjust the lift as required. Ballonets may typically be used in non-rigid or semi-rigid airships, commonly with multiple ballonets located both fore and aft to maintain balance and to control the pitch of the airship. The image illustrates the principle of a balloon within a balloon. The outer balloon represents the airship's outer envelope or gasbag, while the red inner balloon represents the ballonet. In an airship the ballonet would be much smaller relative to the size of the gasbag; for example, in the French airship Lebaudy Patrie the volume of the ballonet was approximately one-fifth that of the envelope. History The ballonet was fi ...
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Semi-rigid Airship
A semi-rigid airship is an airship which has a stiff keel or truss supporting the main envelope along its length. The keel may be partially flexible or articulated and may be located inside or outside the main envelope. The outer shape of the airship is maintained by gas pressure, as with the non-rigid "blimp". Semi-rigid dirigibles were built in significant quantity from the late 19th century but in the late 1930s they fell out of favour along with rigid airships. No more were constructed until the semi-rigid design was revived by the Zeppelin NT in 1997. Semi-rigid construction is lighter-weight than the outer framework of a rigid airship, while it allows greater loading than a non-rigid type. Principle More or less integrally attached to the hull are the gondola, engines and sometimes the empennage (tail). The framework has the task of distributing the suspension loads of these attachments and the lifting gas loads evenly throughout the whole hull's surface and may als ...
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Robert Brothers
Les Frères Robert were two French brothers. Anne-Jean Robert (1758–1820) and Nicolas-Louis Robert (1760–1828) were the engineers who built the world's first hydrogen balloon for professor Jacques Charles, which flew from central Paris on 27 August 1783. They went on to build the world's first manned hydrogen balloon, and on 1 December 1783 Nicolas-Louis accompanied Jacques Charles on a 2-hour, 5-minute flight. Their barometer and thermometer made it the first balloon flight to provide meteorological measurements of the atmosphere above the Earth's surface. The brothers subsequently experimented with an elongated elliptical shape for the hydrogen envelope in a balloon they attempted to power and steer by means of oars and umbrellas. In September 1784 the brothers flew 186 km from Paris to Beuvry, the world's first flight of more than 100 km. Career Background The Robert brothers were skilled engineers with a workshop at the ''Place des Victoires'' in Paris, w ...
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Linear Actuator
A linear actuator is an actuator that creates linear motion (i.e., in a straight line), in contrast to the circular motion of a conventional electric motor. Linear actuators are used in machine tools and industrial machinery, in computer peripherals such as disk drives and printers, in valves and Damper (flow), dampers, and in many other places where linear motion is required. Hydraulics, Hydraulic or Pneumatics, pneumatic cylinders inherently produce linear motion. Many other mechanisms are used to generate linear motion from a rotating motor. Types Mechanical actuators Machine, Mechanical linear actuators typically operate by conversion of rotary motion into linear motion. Conversion is commonly made via a few simple types of mechanism: * Screw (simple machine), Screw: leadscrew, screw jack, ball screw and roller screw actuators all operate on the principle of the simple machine known as the screw. By rotating the actuator's nut, the screw shaft moves in a line. * Whe ...
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Butterfly Valve
A butterfly valve is a valve that isolates or regulates the flow of a fluid. The closing mechanism is a disk that rotates. Principle of operation Operation is similar to that of a ball valve, which allows for quick shut off. Butterfly valves are generally favored because they cost less than other valve designs, and are lighter weight so they need less support. The disc is positioned in the center of the pipe. A rod passes through the disc to an actuator on the outside of the valve. Rotating the actuator turns the disc either parallel or perpendicular to the flow. Unlike a ball valve, the disc is always present within the flow, so it induces a pressure drop, even when open. A butterfly valve is from a family of valves called quarter-turn valves. In operation, the valve is fully open or closed when the disc is rotated a quarter turn. The "butterfly" is a metal disc mounted on a rod. When the valve is closed, the disc is turned so that it completely blocks off the passageway. Wh ...
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Louis Philippe II, Duke Of Orléans
Louis Philippe II, Duke of Orléans (Louis Philippe Joseph; 13 April 17476 November 1793), was a French Prince of the Blood who supported the French Revolution. Louis Philippe II was born at the to Louis Philippe I, Duke of Orléans, Louis Philippe I, Duke of Chartres, and his wife, Louise Henriette de Bourbon, Louise Henriette de Bourbon-Conti. He was titled Duke of Montpensier at birth. When his grandfather Louis, Duke of Orléans (1703–1752), Louis, Duke of Orléans, died in 1752, his father became the new Duke of Orléans and Louis Philippe II became Duke of Chartres. When his father died in 1785, he became Duke of Orléans and First Prince of the Blood. He was styled as Serene Highness (). In 1792, during the French Revolution, Revolution, Louis Philippe changed his name to . He was a cousin of King Louis XVI and one of the wealthiest men in France. He actively supported the Revolution of 1789, and was a strong advocate for the elimination of the present absolute monarch ...
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Meudon
Meudon () is a French Communes of France, commune located in the Hauts-de-Seine Departments of France, department in the Île-de-France Regions of France, region, on the left bank of the Seine. It is located from the Kilometre Zero, center of Paris. The city is known for many historic monuments. Geography The town of Meudon is built on the hills and valleys of the Seine. The forest of Meudon lies for the most part to the west of the town. The north-west part of Meudon, overlooking the Seine, is known as ''Bellevue'' ("beautiful view"). The neighboring communes are: Sèvres (North-west), Boulogne-Billancourt (North); Issy-les-Moulineaux (northeast), Clamart (east and southeast), Vélizy (south and southwest) and Chaville (west). The town includes several districts: Meudon-sur-Seine, Val Fleury, Meudon-Centre, Bellevue and Meudon-la-Forêt. History At Meudon, the argile plastique clay was extensively mined in the 19th century. The first fossil of the European diatryma ' ...
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Saint-Cloud
Saint-Cloud () is a French commune in the western suburbs of Paris, France, from the centre of Paris. Like other communes of Hauts-de-Seine such as Marnes-la-Coquette, Neuilly-sur-Seine and Vaucresson, Saint-Cloud is one of France's wealthiest towns, with the second-highest average household income of communities with 10,000 to 50,000 households. Saint-Cloud is home to the International Bureau of Weights and Measures (BIPM), located in the Parc de Saint-Cloud's Pavillon de Breteuil. History The town is named after Clodoald, grandson of Clovis, who is supposed to have sought refuge in a hamlet on the Seine near Paris, then named Novigentum, like many other newly founded mercantile settlements outside the traditional towns. After he was canonized, the village where his tomb was located took the name of Sanctus Clodoaldus. A park contains the ruins of the Château de Saint-Cloud, built in 1572 and destroyed by fire in 1870 during the Franco-Prussian War. The château wa ...
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Jean Baptiste Meusnier
Jean Baptiste Marie Charles Meusnier de la Place (Tours, 19 June 1754 — le Pont de Cassel, near Mainz, 13 June 1793) was a French mathematician, engineer and Revolutionary general. He is best known for Meusnier's theorem on the curvature of surfaces, which he formulated while he was at the École Royale du Génie (Royal School of Engineering). He also discovered the helicoid. He worked with Lavoisier on the decomposition of water and the evolution of hydrogen. Dirigible balloon Meusnier is sometimes portrayed as the inventor of the dirigible, because of an uncompleted project he conceived in 1784, not long after the first balloon flights of the Montgolfiers, and presented to the French Academy of Sciences. This concerned an elliptical balloon (''ballonet'') 84 metres long, with a capacity of 1,700 cubic metres, powered by three propellers driven by 80 men. The basket, in the form of a boat, was suspended from the canopy on a system of three ropes. Jacques Charles and '' ...
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