How it works
Balloons are able to rise into the air on the simple principal that warm air rises. The warm air in the balloon is lighter than the cooler air around it and it has less mass per unit of volume. The actual balloon (which we refer to as the 'envelope' in the business) has to be so large as it takes such a large amount of heated air to lift it off the ground. For example, to lift 450kg worth of weight you would need almost 65,000 cubic feet of heated air! To help keep the balloon in flight the air in the balloon must be continually heated using the burner (see separate section on burners for more information.)
Hot Air Balloons are made up of 3 main parts:
- The Envelope
The actual fabric balloon which holds the air
- The Burner
The unit which propels the heat up inside the envelope
- The Basket
Where the passengers and pilot stand
The burner uses propane gas to heat up the air in the envelope to get the balloon off the ground and into the air. The pilot must regularly fire the burner(s) to maintain a stable flight. As hot air rises very little air is lost through the hole in the bottom of the envelope.
The controls for piloting a balloon are simple....
1 - To move the balloon upwards - the pilot opens up the propane valve which lets the propane flow to the burner which in turn fires the flame up into the envelope. Works in much the same way as a gas grill, the longer you open the valve, the more heat, the faster the balloon rises.
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. A gentle decent can also be initiated by burning less often as the balloon gradually cools due to heat loss from the warm surface of the balloon.
3 - How you steer a hot air balloon - To navigate to the destination the pilot must catch a wind going in the right direction. 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. This is however limited to the variation in wind direction on the day which may only be 10 degrees and is rarely consistent through the flight period.
4 - The ideal wind speed for hot air balloon flights - To provide the best conditions for a safe balloon flight landing the maximum surface wind speed on the day of the balloon ride must not exceed 10 miles an hour. Overnight winds on the surface ease down due to the cooling of the earth due to a process called "de-coupling". So soon after dawn, the wind on the ground may only be a few miles an hour, but within 2 hours of sunrise the suns heat will mix up the cold layer of air on the ground and increase the wind to 10 miles an hour or more. So this is why the best time of the day for a hot air balloon ride is without doubt early morning. The same process happens in reverse at the end of the day so evening flights with the surface wind decreasing as dusk approaches are the other time of the day that hot air balloons can fly. The exception to this is equatorial regions of the world where dusk occurs very quickly and there is to little time from the suns energy reducing to sunset occurring. In these areas only morning balloon flights are made. See our balloon weather page for more information about what is good weather for ballooning and balloon rides.
