How the Balloon Works
Here we shall explain how the balloon works, including what
makes it rise and fall and how a pilot is able to maneuver it in flight.
Hot air balloons are an ingenious application of basic scientific principles.
Warmer air rises in cooler air. This is because hot air is lighter than
cool air as it has less mass per unit of volume. Mass can be defined
by the measure of how much matter something contains. The actual balloon
(called an envelope) 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 1000 pounds worth of weight you would need almost
65,000 cubic feet of heated air! To help keep the balloon in the air
and rising, hot air needs to be propelled upwards into the envelope
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
Using propane gas the burner heats up the air in the envelope to move the balloon
off the ground and into the air. The pilot must keep firing the burner
at regular intervals throughout the flight to ensure that the balloon
continues to be stable. Little hot air escapes from the hole at the
very bottom of the envelope as hot air rises.
The controls for piloting a balloon are actually extremely simple....
1 - To move the balloon upwards - the pilot fires the
flame up into the envelope. 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 chord 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 chord which will
open the valve, letting hot air escape, decreasing the inner air temperature.
Well, how does the balloon move from place to place? The answer is very
simple, the pilot can maneuver 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.
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