Concept
Aerostat
Related concepts (14)
Lifting gas
A lifting gas or lighter-than-air gas is a gas that has a density lower than normal atmospheric gases and rises above them as a result. It is required for aerostats to create buoyancy, particularly in lighter-than-air aircraft, which include free balloons, moored balloons, and airships. Only certain lighter than air gases are suitable as lifting gases. Dry air has a density of about 1.29 g/L (gram per liter) at standard conditions for temperature and pressure (STP) and an average molecular mass of 28.
Barrage balloon
A barrage balloon is a type of airborne barrage, a large uncrewed tethered balloon used to defend ground targets against aircraft attack, by raising aloft steel cables which pose to hostile aircraft a severe risk of collision, making the attacker's approach difficult and hazardous. Early barrage balloons were often spherical. The kite balloon, having a shape and cable bridling which stabilises the balloon and reduces drag, could be operated at higher wind speeds than could a spherical balloon.
Airship
An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air. In early dirigibles, the lifting gas used was hydrogen, due to its high lifting capacity and ready availability. Helium gas has almost the same lifting capacity and is not flammable, unlike hydrogen, but is rare and relatively expensive.
Balloon (aeronautics)
In aeronautics, a balloon is an unpowered aerostat, which remains aloft or floats due to its buoyancy. A balloon may be free, moving with the wind, or tethered to a fixed point. It is distinct from an airship, which is a powered aerostat that can propel itself through the air in a controlled manner. Many balloons have a basket, gondola, or capsule suspended beneath the main envelope for carrying people or equipment (including cameras and telescopes, and flight-control mechanisms).
Tethered balloon
A tethered, moored or captive balloon is a balloon that is restrained by one or more tethers attached to the ground and so it cannot float freely. The base of the tether is wound around the drum of a winch, which may be fixed or mounted on a vehicle, and is used to raise and lower the balloon. A balloon is a form of aerostat, along with the powered free-flying airship, although the American GAO has used the term "aerostat" to describe a tethered balloon in contrast to the powered airship.
Hot air balloon
A hot air balloon is a lighter-than-air aircraft consisting of a bag, called an envelope, which contains heated air. Suspended beneath is a gondola or wicker basket (in some long-distance or high-altitude balloons, a capsule), which carries passengers and a source of heat, in most cases an open flame caused by burning liquid propane. The heated air inside the envelope makes it buoyant, since it has a lower density than the colder air outside the envelope. As with all aircraft, hot air balloons cannot fly beyond the atmosphere.
Rigid airship
A rigid airship is a type of airship (or dirigible) in which the envelope is supported by an internal framework rather than by being kept in shape by the pressure of the lifting gas within the envelope, as in blimps (also called pressure airships) and semi-rigid airships. Rigid airships are often commonly called Zeppelins, though this technically refers only to airships built by the Luftschiffbau Zeppelin company. In 1900, Count Ferdinand von Zeppelin successfully performed the maiden flight of his first airship; further models quickly followed.
Observation balloon
An observation balloon is a type of balloon that is employed as an aerial platform for gathering intelligence and spotting artillery. The use of observation balloons began during the French Revolutionary Wars, reaching their zenith during World War I, and they continue in limited use today. Synonyms include espionage balloon, reconnaissance balloon, spy balloon, and surveillance balloon. Historically, observation balloons were filled with hydrogen.
Circumnavigation
Circumnavigation is the complete navigation around an entire island, continent, or astronomical body (e.g. a planet or moon). This article focuses on the circumnavigation of Earth. The first circumnavigation of the Earth was the Magellan Expedition, which sailed from Sanlucar de Barrameda, Spain in 1519 and returned in 1522, after crossing the Atlantic, Pacific, and Indian oceans. Since the rise of commercial aviation in the late 20th century, circumnavigating Earth is straightforward, usually taking days instead of years.
Buoyancy compensator (aviation)
The static buoyancy of airships in flight is not constant. It is therefore necessary to control the altitude of an airship by controlling its buoyancy: buoyancy compensation. Changes in air temperature (and thus the density of air) Changes in lifting gas temperature (for example, the heating of the hull by the sun). Accumulation of additional ballast (for example, precipitation or icing on the envelope) Changes in ballast (for example, during a flight maneuver or the dropping of ballast) Changes in weight of fuel on board, due to fuel consumption.