ALBUQUERQUE, N.M. (KRQE) – Soon, hundreds of hot air balloons will fill the Albuquerque sky as part of the Albuquerque International Balloon Fiesta, but what goes into making a balloon fly? The answer is rooted in science.
Hot air balloons are based on a very basic scientific principle
In Albuquerque, you don’t have to go far to find the answer, as the Anderson Abruzzo International Balloon Museum and the City of Albuquerque have compiled online resources dedicated to explaining how hot air balloons work.
Both resources explain that the key to understanding the flight of hot air balloons is to look at the very basic scientific principle that states warmer air rises in cooler air. Another key fact, explained by Tom Fisher with the Anderson Abruzzo Albuquerque International Balloon Museum, is that hot air is lighter than cool air, because it has less mass per unit of volume.
When you look at hot air balloons, they are huge, not only for show, but so they can properly carry the weight of the equipment and anyone who may be riding in the basket. Fisher explained that to lift 1,000 pounds, you need about 65,000 cubic feet of hot air.
The main components of a hot air balloon
A hot air balloon is made up of 3 main parts, and each is essential to flight:
The envelope – The actual balloon, which holds the air, is made of
reinforced fabric called rip-stop nylon. The bottom, or the skirt, sits above the burner, and below that the basket. At the very top of the envelope is typically a circular piece of fabric, called the parachute valve, which can be opened and closed.
The burner – The unit that heats the air inside the envelope by using a propane flame. Some hot air balloons have multiple burners, depending on size and weight.
The basket – Where the passengers and pilot stand. The baskets are made from rattan or wicker, and each one is individually woven by hand.
Inflation, ascension and descension
To get a hot air balloon inflated, the envelope is stretched out across the ground, and the basket and burners are lying on their side at the base of the envelope.
A large fan is then used to push air into the envelope. Once the fabric starts to expand, the burners are turned on to get the heat into the envelope. When there is enough heat trapped, eventually the envelope, burners, and basket will stand upright and will be ready for ascension.
As the hot air balloon begins to rise into the sky, the direction of the flight depends on the wind, which pilots monitor. The pilot can make the balloon ascend by continuing to use the burners or descend by letting the air in the envelope cool, using the parachute valve at the very top of the balloon to let hot air out.
Once a pilot is ready to land, they will continue to descend until they reach the ground, still monitoring wind conditions and their environment surroundings to make a smooth landing. Crews on the ground will help stop and stabilize the basket, and help deflate the balloon to pack it up.
Fisher said the average duration of the flight by hot air balloon is one hour, even though technically it could fly 2-3 or more hours.
