How Does a Hot Air Balloon Work?


A Hot Air Balloon is essentially made up of three parts:

  • The Envelope –The fabric that holds the air
  • The Basket – Where the pilot and passengers stand
  • The Burner –  Heats up the envelope (propane or LPG is used)

Balloon diagram
A Pilot, Crew Chief and Crew are needed to get the balloon up in the air. Once all the safety checks are done, the envelope is filled with cold air using a fan.  Once there is enough air  in the envelope the pilot then adds heat, from the burners, which then stands the balloon up. Once standing the pilot then continues to heat up the envelope until buoyant and the balloon will soon leave the ground. The pilot must keep firing the burner at regular intervals throughout the flight to ensure that the balloon continues to be stable. Naturally, the hot air will not escape from the hole at the very bottom of the envelope as firstly, hot air rises and secondly, the buoyancy keeps it moving up.

The controls for piloting a balloon are relatively simple….

1 – To move the balloon upwards – the pilot puts more heat in the envelope, more heat the higher the balloon goes.

2 – To move the balloon downwards – the ‘Parachute Valve’ at the very top of the balloon is what is used to bring the balloon down towards the ground. It is essentially a circle of fabric cut out of the top of the envelope which is controlled by a long cord which runs down through the middle of the envelope to the basket. If the pilot wants to bring the balloon down he simply pulls on the cord which will open the valve, letting hot air escape, decreasing the inner air temperature. This cooling of air causes the balloon to slow its ascent.


How does a balloon go from one destination to another?

The pilot can manoeuvre horizontally by changing the vertical position of the balloon because the wind blows in different directions at different altitudes. If the pilot wants to move in a particular direction they simply ascend and descend to the appropriate level and ride with the wind.