What is a balloon?
A balloon is a simple aerostat that uses a fabric bag (called an envelope) that is filled with either a gas that is lighter than air, or heated air that is less dense than the air around. The lift produced by the gas or hot air is sufficient to lift a basket and its occupants.
Gas balloons, also called Charliers, use a gas that is lighter than air, usually helium or hydrogen.
Hot air balloons, also called Montgolfieres, are the aircraft that are built by Kubicek in the Czech Republic. These machines use hot air as their lifting agent.
The principle of balloon flight
When flying a gas balloon the pilot climbs by dropping sand or water ballast and descends by venting gas from the envelope. When flying a hot air balloon the pilot climbs by heating the air in the envelope by burning propane that is carried in the basket and descends by letting the air in the envelope cool.
The construction of a hot-air balloon and the essentials for flight
The balloon has three major components, an envelope to contain the hot air, a burner to heat the air in the envelope and a basket to carry the pilot, passengers, fuel, instruments and radios. A petrol powered inflation fan is used to fill the envelope with cold air before it is heated up by using the burner.
Because balloons will only drift down wind it is essential to have either a van or trailer to follow and put the balloon in once the flight is over.
A Balloon may only be flown by a licensed pilot. The minimum crew, of all but the exceptionally large balloons, is this single pilot. The number of passengers who can fly with the pilot depends on the size of the balloon envelope, the larger it is the more people the balloon can carry. The largest balloons built by Kubicek can lift the pilot and up to 20 passengers.
How safe is ballooning?
Statistically balloons are the safest of all aircraft. There are very few fatal accidents or serious injuries. Bumps and bruises are more frequent and very occasionally a limb may be broken in a bumpy landing if the wind strengthens unexpectedly. However the most dangerous part of a balloon flight is still driving in your car to the launch field!
What does a balloon flight involve?
Because a balloon can only drift with the wind it is not possible to use it as a mean of getting from one place to another. However the enormous size of the balloon envelope makes it an ideal advertising hoarding and the slow flight of a balloon allows its passengers a fantastic view of the country that it is flying over. For this reason a balloon is an excellent recreational vehicle and a wonderful advertising medium.
A balloon needs neither an airport nor a hangar; it can be carried and stored in a van and it can be flown from any clear field. The length of a balloon flight is dictated by the amount of fuel that it is carrying; most flights last between 1 and 2 hours. Because balloons are only flown in light winds a flight will normally cover 15- 20 kms.
The crew will take the balloon to a suitable take off place. This will be a clear area about the size of a tennis court and may be a meadow, a playground or a stubble field. The balloon basket will be put at the upwind end of the field and the fuel cylinders strapped into it. The burner is then mounted above the basket and then the basket is laid on its side with the burners downwind. The envelope is attached, by karabiners, to the burner frame and the envelope is then filled with cold air, blown in by the inflation fan. The pilot then heats the air in the envelope using the burner and the balloon stands up and is ready for flight. The passengers get in and the adventure can start! It is not possible to say exactly, where the balloon will land but the pilot will have looked at the weather forecast and chosen a take off site that will allow the balloon to stay clear of airfields and areas where it would be difficult to land. The wind blows in different directions at different levels so the pilot, by changing height, can choose, within limits, where the balloon will go. Most flights last about an hour so at about this time after take off the pilot will be looking for a meadow into which he can descend and land.