Moored balloon
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A moored balloon is an inflated fabric structure, often shaped like an airship and usually filled with helium that is restrained by a cable attached to the ground or a vehicle. Moored balloons differ from airships and free balloons in that airships and free balloons are both free flying.
Moored balloons are sometimes called aerostats. However the term aerostat can also be used to refer to all lighter than air aircraft. In this broader sense, moored balloons are a type of aerostat.
Moored balloons come in three forms:
- 1) Traditional sausage shaped (i.e. blimp shaped) with fins to stabilise them, but relying upon helium alone for lift:
- 2) Simple round balloons relying on helium alone, but without stabilisation, which sometimes are used to make passengers fly, or support advertisement, like the aerophile balloons;
- 3) Helikites, that utilise both helium and wind, if it is available.
A Helikite has a kite attached directly to its oblate-spheroid balloon to stabilise it and to create a single aerodynamic structure for wind lift. Helikites can fly in higher winds than other types of aerostat and to greater altitude.
[edit] Applications
Designed by Albert CAQUOT, french engineer, in 1914, the barrage balloons of World War I and World War II were examples of moored balloons. Today, moored balloons are used for lifting: cameras; radio antennas; electro-optical sensors; radio-relay equipment and advertising banners - often for long durations. Moored balloons are also used for position marking and bird control work.
During the 1990 Invasion of Kuwait, the first indication of the Iraqi ground advance was from a radar-equipped moored balloon that detected Iraqi armor and air assets moving south.[1] Surveillance moored balloon have been used in the 2004 American occupation of Iraq. Utilizing a high-tech optics system to detect and observe enemies from miles away and have been used accompanying foot patrols in Baghdad.
The USGS uses moored balloons to carry equipment to places where conventional aircraft cannot go, such as above an erupting volcano. Moored balloon are ideal as they can easily remain more or less in one place; are less likely to be damaged by volcanic ash; and are less expensive to operate than a helicopter.
The Drug Enforcement Administration has contracted with Lockheed Martin to operate a series of radar-equipped moored balloons to detect low-flying aircraft attempting to enter the United States. A total of twelve moored balloons are positioned approximately 350 miles apart, from California to Florida to Puerto Rico, providing unbroken radar coverage along the entire southern border of the US.[2]
Worldwide Aeros Corp. manufactures a family of moored balloons systems for variety of uses. Aerophile SA.is the world leader of big tethered gas balloon with passengers. They have made more than 1 280 000 passengers flown since 1993 with this concept.
Moored balloons can be used as temporary transmitters, instead of a radio mast: either by using the mooring rope, which holds the balloon, as the antenna; or by carrying antennas on the balloon, fed by a radio frequency cable contained inside the mooring rope. The advantage of moored balloons is that large antenna heights are easily realizable. A use of an antenna carried by a captured balloon took place for GQV-transmitter in 2003.
Moored balloons are sometimes used for advertisement, either by lifting up advertisement signs, or by using a balloon with advertisement on it. Often both methods are combined. It is not uncommon to use specially designed balloons. By suspending a light source within the envelope, the balloon can be made to glow at night, drawing attention to its message. The big tethered gas balloons can also lift up 30 passengers at 1 000 feet [3].
[edit] See also
