Hot air balloons consist - in simple terms - of an envelope, a basket and a lifting gas. The envelope is the part that resembles a balloon, giving these aircraft their name. The basket or gondola hangs below and carries the passengers or cargo. The lifting gas is the contents of the envelope which, being lighter than air, makes the whole thing buoyant. As the name suggests, hot air can make a balloon fly, though it’s not the only option.


Balloons of all shapes and sizes


ALL SHAPES AND SIZES



  • Round: When you picture a hot air balloon, you probably picture something round. That’s no surprise, as round envelopes are the most common - especially when it comes to leisure and recreational flight. Round balloons range in size from “hoppers,” so small that they can only carry one person who is attached by a harness in place of a basket, to large balloons with a volume of 600,00 cubic feet that are capable of carrying loads of over a ton.
  • Teardrop: As the name suggests, these are balloons with a more elongated envelope, vertically speaking. They are better suited to long-distance travel and can reach altitudes of two miles. That’s only about a third of the height that a commercial aeroplane flies at, but it’s still enough to make looking down a stomach-lurching experience.
  • Elliptical: These are racing balloons, capable of gaining more speed from air currents. The pay-off is that they’re less stable than their round cousins, so they’re not a common sight in the skies.
  • Novelty: An envelope of any shape, provided it has a large enough volume and a somewhat central tipping point, can be used to lift a basket into the air. Cue innovative and imaginative designs. If you’re ever lucky enough to be in Southwest England during the Bristol International Balloon Fiesta, you might see envelopes in the shape of Spongebob Squarepant, the Minions, Darth Vader and more!*

Novelty balloon at a balloning fest


LIGHTER-THAN-AIR TECH



  • Hot air: The simplest, most common and oldest form of lifting gas is just air, heated by a burner to be less dense than the air outside the envelope. Literal hot air balloons are also known as Montgolfier balloons, named after Montgolfier brothers who invented them in 1784.
  • Gas: It’s also possible to use a gas that’s lighter than air to make a balloon fly. Hydrogen proved to be an unreliable lifting gas as it’s flammable, so helium is the most common choice.
  • Hybrid: You could argue that a balloon using gas isn’t a hot air balloon at all. That’s not the case with hybrid balloons, whose envelopes contain both helium and heated air in separate compartments. The helium provides extra buoyancy, which can be made even more buoyant when the temperature of the whole envelope is raised by heating air with the burner. Hybrid or Rozière balloons, named after inventor Jean-François Pilâtre de Rozier, hold the records for the longest and highest flights.

Heating the air at launch



DIFFERENT STYLES OF BASKET



  • Standard: The typical hot air balloon basket or gondola is made of wicker and has enough space for 3-5 people. If you’re planning to take a hot air balloon flight, remember that that number includes the pilot! The burner sits between the basket and the envelope and is controlled by the pilot.
  • Intimate: Some baskets are designed for couples. Imagine an exclusive flight with your sweetheart, high above the ground. What could be better? How about adding a champagne toast into the equation? This is a service which is offered by many hot air balloon operators. Again, remember that, unless you’re licensed to fly, there will be a pilot present!
  • Large: Most sightseeing balloon rides nowadays take place in large baskets that hold a dozen people or more. They often come with seating, which is arranged in such a way as to make sure that everyone can enjoy the views.
  • Glass: When it comes to aerial sightseeing, there’s nothing like a glass-bottomed hot air balloon. Totally safe and very impressive, these models raise the sensation of flying to new levels.