About Ballooning

How

Hot Air Balloons Work

On the 19th of September 1783, Pilatre de Rozier, a scientist, launched the first hot air balloon called ‘Aerostat Reveillon’. The passengers were a sheep, a duck and a rooster and the balloon stayed in the air for a grand total of 15 minutes before crashing back to the ground. The first manned attempt came about 2 months later on the 21st of November, with a balloon made by 2 French brothers, Joseph and Etienne Montgolfier. The balloon was launched from the center of Paris and flew for a period of 20 minutes. The birth of hot air ballooning!

Recently, balloon envelopes have been made in all kinds of shapes, such as hot dogs, rocket ships, and the shapes of commercial products. Hot air balloons work with buoyancy. You’ve heard people say “hot air rises,” right? Well, the air inside the balloon is heated up by the propane, and lifts the balloon off the ground because the air inside the envelope is hotter than the air outside of the balloon. It can be a little tricky to steer, as you can mostly only really control the balloon going up and down, but can raise and lower the balloon in a way that catches small wind currents as a way of ‘steering.’

THE PARTS OF A HOT AIR BALLOON

A hot air balloon consists of a bag called the envelope that is capable of containing heated air. Suspended beneath is a gondola or wicker basket (in some long-distance or high-altitude balloons, a capsule), which carries passengers and (usually) a source of heat, in most cases an open flame that runs on propane. The heated air inside the envelope makes it buoyant since it has a lower density than the relatively cold air outside the envelope. The deflation port at the top of the envelope allows hot air to escape at a controlled rate, slowing the rise of the balloon or allowing descent.

As with all aircraft, hot air balloons cannot fly beyond the atmosphere. Unlike gas balloons, the envelope does not have to be sealed at the bottom since the air near the bottom of the envelope is at the same pressure as the surrounding air. In today’s sport balloons, the envelope is generally made from nylon fabric and the mouth of the balloon (closest to the burner flame) is made from fire resistant material, such as Nomex.

Refer to the diagram at the left for more details.

Hot Air Balooning FAQS

How do balloons fly?

Warmer air rises in cooler air. Heating the air in the balloon with the use of fire causes the balloon to rise. The air must be reheated by firing the burner to keep the balloon in flight.

How do you steer a balloon?

The short answer is that you don’t! However it isn’t as uncontrolled as it seems. Prior to flying, the pilot releases a small helium balloon (called a “pie ball”) to get the direction of the winds aloft. Once the hot air balloon is air borne, the pilot can move the balloon up and down to utilize the varying directions of wind to change course.

What are balloons made of?

The big fabric part, called the envelope, is made of nylon. The lower portions around the opening are made from a fire resistant material like Nomex. The baskets are made of wicker since it is strong, lightweight and flexible enough to hold up under the stress of repeated landings.

What fuel do hot air balloons use?

Propane is the most common fuel. The fuel is carried in aluminum or stainless steel tanks that fit inside the basket. Average fuel consumption is about 15 gallons per hour for an average sport size balloon.

How long do balloon flights last?

The length of the flight depends on the wind speed, direction of flight and the availability of landing sites. ALL balloon flights are completely dependent on weather conditions.

When is the best time to fly?

Temperature plays a role in the ability for a balloon to fly. High temperatures greatly reduce the amount of weight a balloon can lift. Colder temperatures are better for the balloon’s performance… the colder the better! So, typically early mornings are the best time to fly.