Because the molecules that make it up move further apart and take up more space. As a result, it becomes less dense than the cold air outside. According to Archimedes' principle, this difference in density creates an upward force, allowing the hot air balloon to rise smoothly while maintaining its buoyancy.
The lift force always depends on the total weight: passengers, basket, envelope, burner and propane cylinders.
A hot air balloon carrying around eight passengers usually weighs approximately 1,500 kg at take-off. The air inside reaches approximately between 90°C and 120°C, generating enough lift.
A hot air balloon combines three systems that work together: the envelope, the burner and the basket.
The envelope is a huge polyester or nylon bag made up of panels reinforced with load tapes, attached with safety carabiners to steel cables that are fastened to the steel frame supporting the burner. Its volume is usually between 2,000 and 10,000 m³.
The area closest to the burner includes a fire-resistant fabric that can withstand the direct heat of the flame. It is called Nomex and is the most commonly used, although others also exist.
The burner works by burning propane gas, producing between 2 and 10 million BTU per hour and generating a flame that heats the air inside the envelope.
Hot air is the balloon's only means of vertical control. The pilot uses the burner intermittently to control the balloon's stability, ascent or descent. The burner is attached to a steel base that becomes the central connection point of the balloon, where the steel cables extending from the envelope and the basket also converge, providing a very secure yet flexible attachment.
The basket is usually made of wicker because of its flexibility. Steel cables run through and around it, ending fastened to the steel structure that supports the burner. Depending on the model, it can carry from 2 passengers up to 32 passengers in the largest models currently available.
It also includes safety elements: handles, seat belts, separate compartments for passengers and propane cylinders secured in the compartment reserved for the pilot.
The pilot controls altitude with precision, using changes in wind direction at different heights to establish the desired route.
For ascent, the pilot turns on the burner. By heating the air inside, buoyancy increases and the balloon rises.
For descent, depending on the temperature inside the envelope, it may be enough to wait a few minutes for the air to cool and cause a gentle descent. Alternatively, it may be necessary to release a certain amount of air by pulling the rope that slightly opens a vent located in the upper area of the envelope.
In both cases, the aim is to cool the air inside the envelope in order to lose altitude.
The pilot looks for favourable air currents at different heights so that the balloon follows the wind. A hot air balloon has no rudder and no lateral propulsion. Before take-off, we carry out a detailed weather assessment to choose the best route.
It is an experience enjoyed with all five senses.
Inflation takes between 15 and 20 minutes. The envelope is spread out on the ground and, slowly, the air begins to lift it. Before take-off, we use this time to carry out the necessary checks and give you safety instructions.
You will float without engine noise or turbulence, enjoying the panoramic views in complete peace and quiet. You will experience a surprising sense of calm, perfect for creating an unforgettable moment on a romantic balloon flight or any special occasion.
During the descent, the pilot will give instructions to the ground team so they are ready to receive the balloon and passengers after landing.
The descent usually takes place at a very gentle vertical speed and, depending on the horizontal wind, the basket may come to a stop with 2 or 3 slight bounces, or it may drag along the ground for a few metres before enough air has been released from the envelope and it comes to a complete stop.
In no case does this pose a danger to passengers, who receive simple and clear instructions on the safety position during the landing phase.
At Globus Kon-Tiki, we offer flights in more than 16 areas of Catalonia. We fly from Montserrat to the Ebro Delta. We also offer flights over the Pyrenees and the Costa Brava.
Now that you know how a hot air balloon works, all that is left is to experience it for yourself, safely and with our team by your side. You will love floating over Catalonia at sunrise!
