Hot air balloon
Hot air balloons are the oldest successful human flight technology, dating back to the Montgolfier brothers' invention in Annonay, France in 1783. The first manned flight was made on November 21, 1783, in Paris by Pilâtre de Rozier and the Marquis d'Arlandes. Balloons that can be propelled through the air rather than just being carried along by the wind are known as airships.
Attractive aspects of balloon rides include the exceptional calmness and the birds-eye view. Since the balloon moves with the wind, the passengers feel absolutely no wind, unless they rise to a different alitude that contains higher speed winds that the previous altitude, during the flight. Recent balloons have been made in fantastic shapes, such as hot dogs, rocket ships, and the shapes of commercial products.
History
Balloons were the first manifestation of air power. They were used by the North for artillery observation in the American Civil War and were used for communication during the Siege of Paris in 1871. They were also used for observation of trench warfare in World War I.
Unmanned hot air balloons are mentioned in Chinese history. Chu-ko Kung-ming in the three kingdoms era used airborne lanterns for military signalling. These lanterns, known as Kung-ming lanterns nowadays, are still being flown in China, despite the risk of causing a fire upon landing.
Construction
A hot air balloon for manned flight is a fabric envelope, with an opening at the bottom called the throat, with a large basket carrying the passengers and a heater suspended just below the throat. The heater warms the air inside the balloon, making it lighter than the surrounding atmosphere, and causing the balloon and its cargo to rise.
Modern hot air balloons are usually made of synthetic fabrics (typically ripstop nylon) in order to reduce weight and increase strength. At manufacture, the material is cut in sections and sewn together along load tapes that carry the weight of the gondola or basket. The heat is supplied from a burner, a flamethrower-like device fueled by propane gas stored in pressurized tanks. The direction of flight depends on the wind, but the altitude of the balloon can be controlled either by changing the temperature of the air inside the envelope. The top of the balloon generally has a flap (often referred to as a parachute) of fabric that can be pulled open partially to release hot air in an emergency or for better control of the descent. The flap is pulled open completely to collapse the balloon after landing. In some advance hot air balloons, side vents are fitted, which when open, cause the balloon to rotate. This is a useful manoeuvre to align the basket for landing.
The lift of the balloon is determined by the temperature difference between the inside and outside air. On a hot afternoon, the balloon will not reach too great an altitude before the balloon fabric begins to deteriorate under the high temperature. Most hot air balloon launches are done in cold climate, at dawn or two/three hours before sunset. This is mainly to avoid thermals which can cause severe turbulence to a hot air balloon.
The largest manufacturer of Hot Air Balloons in the world is Cameron Balloons of Bristol, UK. Aerostar International Inc. of Sioux Falls, South Dakota is North America's largest balloon manufacturer and is a close second in world manufacturing.
Competitions
As a sport, a typical hot air balloon launch starts with unpacking the balloon from its carrying bag. A gasoline powered fan is used to blow cold air into the envelope, the cold air inflates the balloon partially to hold its shape before the burner is aimed at the center of the throat to heat up the air inside (see photo). A crew member holds on to the rope tied to the top of the balloon and slows the balloon's rise by letting the balloon drag him/her as a dead weight. Once the balloon is upright, pilot and passengers climb into the basket. When everything is ready, more heat is directed into the center of the balloon and it lifts off gradually. The rest of the crew will pack up the equipment, clean up the launch site and then follow the balloon in the retrieval transport (also known as a chase vehicle). When the balloon has landed, it is deflated and unattached from the basket uprights then packed back into its carrying bag, the burner and the basket are disconnected and it is all packed into the chase vehicle.
In competition, the pilots need to be able to read different wind directions at different altitudes. Some experienced pilots are able to take a flight in one direction, rise to a different altitude to catch wind in a returning direction. With experience, luck and the right conditions, some pilots are able to control a precision landing at the destination. On rare occasions, they may be able to return to the launch site at the end of the flight.
The dangers of the sport include excessive (vertical or horizontal) speed during landing, entangling high voltage power lines and mid-air collisions that may collapse the balloon.
In the United States, hot air balloon pilots must have an FAA license. In the UK a Private Pilots Licence issued by the CAA.
On February 27, 1999 while they were trying to circumnavigate the world in a hot air balloon, Colin Prescot and Andy Elson set a new endurance record after being in a hot air balloon for 233 hours and 55 minutes. Then on March 21st of that year, Bertrand Piccard and Brian Jones became the first to circumnavigate the Earth in a hot air balloon. On July 4, 2002, after five previous attempts, Steve Fossett became the first to achieve a round the world solo flight, while also topping his own solo endurance record.
Festivals
Throughout the year festivals are held which give a chance for balloonists to gather together and for the public to participate in the spectacle of many balloons launching at the same time. Some of the large festivals are
- Bristol International Balloon Fiesta
- Albuquerque International Balloon Fiesta
- Adam Matthews Balloon Festival (http://www.balloonglow.com)
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