HOT AIR BALLOONING | THE COMPLETE GUIDE
How Do Hot Air Balloons Work?
Hot air balloons rely on a simple principle of physics to achieve their buoyancy and lift. This page will walk you through how hot air balloons are inflated, launched, flown, landed and retrieved in a typical flight.
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The Basics
The key components of a hot air balloon include the envelope, the burner, and the basket. The envelope is the large, colourful fabric that gives the balloon its distinctive appearance. Typically made of nylon or polyester, the envelope is filled with hot air to generate lift. The burner, fueled by propane, is responsible for heating the air inside the envelope. The basket serves as the passenger compartment and is attached to the envelope via strong cables. Hot air balloons cannot steer. They are moved along by winds, which the pilot has assessed. Using alitermeters and GPS/maps, the pilot assesses their location, fuel remaining, and landing options to ensure a safe flight and landing.
What Happens On a Hot Balloon Flight?
The rest of this page will walk you through the rigging, launching, flying navigating and safe landing of a typical hot air balloon flight.
The Rigging
The process begins with the rigging of the basket. The propane tanks are filled, and placed in their dedicated, secure places within the basket, and fastened tight with straps. The pilot (or occasionally, experienced crew) will connect the propane tank via thick hoses to the burner frame, which is held above the basket by strong poles. The pilot will then check all of the connections between the propane tanks, hoses, and the burner frame, ensuring all is secure.
The pilot will also conduct a test of the burners at this stage, to ensure that the gas is flowing to the burners effectively, and that there are no leaks.
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When satisfied, the pilot will then also fasten flying instruments. Traditionally, this would include maps, a compass, a stopwatch and an altimeter. In more modern times, many pilots rely on digital devices for measurements of height above sea level and map-bearings.
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The basket and burner frame together are then laid or tipped gently onto the ground so that they lie horizontally.
The envelope is laid out in front of the burner frame, in the direction of the wind which indicates the direction that the balloon will take off in.
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The crew, and the pilot connect the envelope to the burner frame. The pilot conducts their secondary checks again on all of these connections to ensure no wires are twisted and putting unnecessary strain on the connections.
Cold Inflation
Next, an industrial fan is started up to the side of the basket and burner frame, with crew members holding the mouth of the envelope open to allow in the air.
As the envelope begins to fill and take shape with the cold air, the pilot will often walk around the full external area of the balloon to inspect and check for any signs of stress or issues with the envelope fabric. They will often walk inside the mouth of the still inflating envelope to inspect the balloon from within.
Hot Inflation
Once the envelope is inflated to a sufficient degree (typically 50-65% of its total inflated volume) and the pilot has given warning to the crew to prepare, the burner is ignited and blasts heat into the mouth of the envelope, heating the air inside.
Propane is combusted in the burner, producing a very hot flame which heats the air within the envelope. Hot air is lighter than cold air, so as the temperature inside the envelope increases, the air becomes less dense, causing it to rise.
As the air inside the envelope becomes hotter, it creates a pressure differential between the inside and outside of the balloon. This pressure difference generates lift, propelling the balloon upward. The hot air inside the envelope draws more air from outside within, filling the rest of the envelope and expanding it to its full volume.
The hotter the air inside the envelope, the greater the lift produced. The pilot carefully controls the amount of heat being sent into the envelope, and so, the speed at which the envelope expands and rises, bringing the burner and frame and basket gently upright as the envelope rises into the air.
Taking Off
The pilot will then assess the relative buoyancy of the hot air balloon. At this point, while still tethered safely to the ground, any passengers or crew who are due to fly in the balloon will be invited into the basket. All the while, the pilot periodically adds more heat to the envelope. As the weight of the basket increases, more lift, via greater heat within the envelope relative to the temperature of the air outside, is needed to maintain the level of buoyancy.
When all the final checks are completed, and the safely briefing given to all passengers and crew within the basket, the pilot will declare that the balloon is ready to take off, and release the tether, and increase the buoyancy of the balloon via the burners simultaneously, allowing the balloon to rise into the air.
Flying
Balloonists can control the altitude of the balloon by adjusting the intensity and frequency of the use of the burner. The more often, and for longer bursts that they use the burner, the hotter the air inside the envelope is relative to the air outside the envelope, and the balloon will ascend. To descend, they can allow the air inside the envelope to cool gradually.
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The flight of a hot air balloon is also influenced by wind patterns. While the balloon itself is carried along with the wind, skilled pilots can navigate to different altitudes where winds may be blowing in different directions. This allows for a degree of control over the balloon's direction.
Navigating
Hot air balloon pilots navigate through a combination of altitude control and utilizing different wind currents at various altitudes. While they lack the precise directional control seen in other aircraft, skilled balloonists can make strategic use of wind patterns to guide their journey. Hence the global hot air ballooning competitions allowing the most skillful pilots to compete in a variety tasks and races testing accuracy and navigational skills.
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To navigate vertically, pilots control the balloon's altitude by adjusting the intensity of the burner. By heating the air inside the envelope, the balloon ascends, and by allowing the air to cool, it descends. Pilots often ascend or descend to different altitudes to catch winds blowing in different directions. This technique, known as "box the wind," enables them to navigate within a limited range.
Horizontal navigation is less direct in a hot air balloon. Pilots cannot steer like in traditional aircraft. Instead, they rely on understanding wind patterns at various altitudes. Comprehensive analysis of the weather is the responsibility of the pilot before embarking on any flight.
This meteorological information will give the pilot an indication of the overall direction of the prevailing wind, and there the overall direction of travel of the aircraft, and likely speed - therefore giving an indication of the distance they are likely to travel within a given amount of time airborne. Within this overall direction the pilot can adjust by ascending or descending, using winds blowing in slightly different directions at different heights.
Despite the lack of perfectly precise directional control, hot air balloon navigation offers a unique and serene experience, allowing pilots to go with the flow of the wind and enjoy the picturesque landscapes below. Balloonists often rely on their experience, maps, weather forecasts, and a keen understanding of atmospheric conditions to navigate their way through the skies.
Landing
The pilot will begin to consider ending the flight and landing the balloon while considering some of these factors:
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Weather
Even if the weather and the meteorological forecast were favourable at the beginning of the flight, this may change. If the pilot feels that conditions are no longer appropriate to continue the flight (ie. increasing wind, or rain), they may decide to end the flight.
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Light conditions
All flights require clear daylight to allow the pilot to navigate take off and landing safely. Usually the flight is planned to take place either first thing in the morning, where there is no risk that the light will disappear, or the flight has been planned for the evening with plenty of time before the light will fade and the sun will set. If the weather conditions change such that the light begins to fade earlier than expected, the pilot may decide to land earlier than anticipated.
Fuel
The primary factor is fuel provision. Different sized balloons carry different volumes of fuel (propane), however on average the fuel provision allows for 1 - 2 hours of flight time for most hot air balloons. Pilots monitor the level of fuel the balloon is carrying attentively throughout the flight. At the point where 70-75% of fuel has been consumed, typically around the 1 hour mark, the pilot will look to land. Leaving enough fuel in reserve in case there are issues finding an appropriate landing spot.
Landscape and landing options
After an appropriate amount of flight time - however long the pilot has wanted to spend in the air, assuming the factors above have allowed it - the pilot will begin to look both to the ground, and on maps, for appropriate places to land. Most often, this will be empty fields in farms (away from livestock, or crops which can be damaged) or public land eg. parks (away from roaming people and children), or domestic land. Pilots carry maps which indicate areas which are not appropriate to land in, allowing them to choose the safest and most appropriate place to land the balloon.
And now, to land.
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Having decided on the upcoming prime landing location, the pilot will brief the passengers in the basket on how to position themselves for a safe landing. The pilot will then begin to allow the envelope to gently cool, reducing the use of the burner slightly. Carefully controlling the heat within the envelope is key to ensure a gentle descent. The pilot must keep a degree of lift easily accesible in the envelope during the descent so that the balloon can ascend if there is an issue with the landing.
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The pilot and passengers brace (bending their knees and holding on tight to saftey ropes) as the basket reaches the ground. Depending on the wind speed / speed of descent, the basket may bounce silghtly, or drag along the ground for a few metres before coming to a stop. The pilot will pull the parachute valve cord whilch pulls the detactable parachute down from within the envelope, allowing the hot air to escape out of the top of the envelope, deflating it.
Getting Back (the 'Retrieve')
Ever since the hot air balloon took off from its launch location, it has been doggedly followed by the crew. The chief crew member will have overseen the packing up of the remainder of the balloon equipment (envelope bag, fan etc) into the balloon’s trailer, and then set off with radios, maps and phones, to follow the balloon. Some crews enjoy the challenge of keeping up with the balloon in their vision and navigating roads carefully to stay in slow pursuit of the balloon throughout its flights. Occasionally this is not possible to do safely due to the nature of the roads, of the speed the balloon is flying at.
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This is why the pilot and crew both carry radios and other contact equipment. Once the pilot has landed, they can confirm their location to the crew via map coordinates, or by digitally sharing their location.
The crew find their way to the landed balloon, and find a point of access to the landing site. The pilot by this point will have aimed to locate the landowner where they have landed, to ask permission to allow the crew vehicle into the field to assist in packing up the balloon.
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Pilots often carry a traditional ‘thank you’ for the landowners, particularly farmers, in the form of a bottle of whiskey or wine, to show gratitude for allowing the balloon to land, and allowing the crew onto the premises to retrieve the balloon and the pilot and passengers.
The Hot Air Balloon Encyclopedia
Experience the thrilling freedom of Hot Air Ballooning, offering a unique perspective on the world from higher altitudes. Amidst the serene landscape, find relaxation and awe, making it an exciting journey to explore nature's beauty and savor magical moments. Look no further for an adventurous escape!