Aerostats were the first airplanes that allowed people to see the world from above. Learn what aerostats are with a focus on balloons, the different types of balloons, and their uses.

In a broader sense, a balloon is a hollow airplane made of lightweight material, filled with lighter air, which allows it to gain flight and float in the air. A controlled balloon (with an engine) is called an airship or dirigible.

However, the term blimp is also used in a narrower sense, which refers to a statically tethered balloon. Since we have already discussed blimps, balloons are what most of the information here will be about.

A principle that defies gravity
Archimedes’ principle applies not only to liquids, but also to gases. In principle, every physical body in air or gas loses as much weight as the air or gas that is pushed out.

Archimedes’ principle states that: “The upward buoyant force acting on a body submerged in a liquid, fully or partially submerged, is equal to the weight of the liquid which the body displaces and acts upward in the center of mass of the displaced liquid.”

Bodies that are proportionally light to their volume achieve lift. So, for example, a body with a volume of 1 m3 will increase the lift by 12.93 N (a body weighing 1.293 kg with a volume of 1 m3 will float in air) because it is the force of displaced air. If the weight of this body is less than the lift, the body will gain height. At higher altitudes, the elevator is much weaker because the air is thinner.

What is a balloon?
A balloon is a hollow airplane made of a light material, which has no means of propulsion (or sometimes equipped with an auxiliary engine) and with limited steering capabilities (a controlled balloon with an engine is called a dirigible or airship).

It is filled with LTA gas, which allows it to fly in the Earth’s atmosphere. The gas is filled inside a fabric shell to which a basket, nacelle, or capsule is attached. The basket acts as a housing unit for people and equipment. Balloons can be in three states:

Balloon
Hot air expands, so heated air in a certain volume of space contains less air. The air becomes lighter, and if the balloon is lighter than the force acting upward, it will rise. However, it will only stay in the air as long as it has fuel to keep the air heated.

The first hot air balloons used solid fuel instead of heat instead of the hydrogen used in the next balloons, which proved to be more practical and pretty much ended the balloon phase.

After World War II, the breakthrough of bottled gas burners revived the use of the balloon for sports and recreation.

The height of the balloon is adjusted by turning the burner on or off as needed. In this way the air is heated or cooled, and acts accordingly.

Gas Balloon.
When a lighter air is filled inside a compartment made of a thin material, it is allowed to rise. This is the most common type of balloon.

You’ve probably seen a bunch of gas balloons tied to a rock, or something at a carnival, or a child crying because a balloon came out of his hand and is now drifting toward the sky….

Gas balloons could fly at higher altitudes and cover greater distances than balloons. However, they were more dangerous because they contained flammable hydrogen or coal gas. Today, most gas balloons use helium.

Rozier Balloon.
The Rozier balloon has a chamber filled with uncontaminated LTA gas and for heated gas (the same as a balloon balloon). This combination of compartments allows for easier altitude control and more air time. This balloon is commonly used for record flights.