How Do Hot Air Balloons Work? Read Here!

Hot air ballooning  is one of the oldest forms of travel, and perhaps the earliest form of aviation in human history. With literally thousands of years worth of history behind it, with new developments and advancements still being made, it’s only natural that the contemporary hot air balloon ride interest you.

Despite this, the fundamental functionality of a hot air balloon has changed very little. A form of “lighter than air” travel using basic scientific principles in order to elevate and cover large distance. From gas balloons in the early 20th century, to modern liquid propane.

How do hot air balloons work? Through convection, heated air is created using a propane burner. Heated air has a lower density, meaning the air molecules are lighter than the cooler air molecules outside the balloon. Being lighter, the hot air rises, bringing the rest of the balloon with them.

While a very basic understanding, humans haven’t always had access to propane, nor nylon, nor ignition burners. So how did we get here? I’m sure many of you reading will know of other “lighter than air” gases such as hydrogen and helium that are used for flight, so perhaps you’re curious why propane is used as an alternative. 

The Basics

Passenger-carrying balloons can greatly vary in size. From 77,000 cubic feet to the largest balloon which can reach 600,000, these sizes explain how many cubic feet of air the balloon, or envelope to use the technical term, can contain. The ‘600’ is perhaps the biggest passenger balloon available. 

The contemporary balloon material is nylon, which provides a sturdy and strong material resistance to wear and tear, and the balloon shape is often an inverted tear drop. When balloons are used for advertising, they may be fitted with a special shape by the client. 

A burner for the liquid propane and tanks with oxygen allow for easy ignition, controlling the altitude of the balloon with the heated air process mentioned above, by turning the propane valve. Inside the hot air balloon envelope, a process called convection keeps the heat energy flowing inside, essentially powering the balloon for the duration of a passenger flight.

A cubic foot of air weighs roughly 28 grams, and heating it to 100 degrees Fahrenheit will result in the same cubic foot weighing 21 grams instead. A whole 7 grams less. This would mean that each cubic foot of air contained in the hot air balloon could lift 7 grams. With larger balloon sizes containing hundreds of thousands of cubic feet, it become very clear how impressive of a system ballooning really is.

Some models also include a whisper burner, a secondary ignition source used by balloon pilots that burn the liquid propane fuel slower, allowing it to be more quiet. These are less effective than the regular burner, but are often used when travelling over residential areas, or grazing livestock. 

However, it’s important to mention that air balloons come with maximum loading capacities, which should be strictly followed. Although the envelope is connected to the basket via strong metal cables, any excess exertion on the metal frame can be problematic for the balloon. Safety guides exist for the prevention of ht air balloon accidents for a reason. 

How Does it Land?

In a modern nylon or canvas balloon, a larger balloon envelope is usually equipped with a vent at the top. A pilot can open this vent to begin a descent, by letting the hot air escape from it. Waiting for the hot air to naturally escape or cool can take longer periods of time, so the vent speeds up this process and can bring a balloon into land.

When actually landing a balloon basket, the pilot and passengers assume the seated landing position. This involves bending at the knees, turning your back on the direction of travel, and holding ropes provided for support. Hot air balloon landings are notoriously bumpy, so this position helps avoid unwanted falls and injury. 

Once the balloon basket is on the ground again, your air balloon flight is over. You should meet ground staff, who may have arrived in a ground crew vehicle. This will be the chase crew in charge of collecting your party and the balloon, so you aren’t lost in the middle of nowhere. A ground tarp may be used to prevent wear and tear on the balloon.

The Materials

Light nylon is now the most common material in the manufactory of air balloon envelopes. Fashioned into nylon gores, or panels, these balloon designs can withstand significant wear and tear. Whether that be from animal, getting tangled, or even just weathering. 

Nylon is a far better alternative than simple canvas and rubber, materials used in the 18th century. These materials were easy to break in comparison to modern nylon, and hot air balloons have seen significant improvement since the introduction of nylon into the design. Pushing for better designs allows balloon aviation to continue to test limits and boundaries, setting records on the way.

Modern balloon baskets are one of the most innovative parts of the entire balloon. The wicker basket is reinforced with a steel frame, preventing easy breakages. However, the wicker material still remains with some flexibility, easing the force of a rough landing and absorbing some of the shock.

The surfaces inside the basket are also covered in smooth leather, allowing for better grip for pilots and passengers during actual balloon flight. A balloon basket is also synonymous with the wonders of ballooning, a picturesque centre piece for the romantic idea of a hot air balloon ride. 

Finally, specially-fitted heat shields are becoming an increasingly common feature on air balloons. Designed to be place near the burner, the passenger will have a more comfortable and enjoyable experience as the shield prevents some of the burner’s heat from reaching the customer.

The History

Early ballooning designs were much less sleekly designed than their modern counterparts. Materials were poorer, but the pilots were just as brave. Spherical balloons were first designed before the development of the well known tear drop we all love today. 

These were also included in many designs of the 1960s, by a man called Ed Yost. Despite this, he still went on to develop the contemporary light bulb shaped envelope most balloons use. Earlier than that though, a popular balloon type was the smoke balloon.

The smoke balloon was little more than a carnival attraction in the early 20th century. Not attached to any heat source, smoke and heat would simply raise an envelope and then let it sink back to the Earth. A far cry from modern balloon aviation and travel, and nothing like the Virgin balloon baskets you’d expect billionaire companies to produce.

Gas balloons came into fashion during the 20th century, replacing the hot air balloon quickly. Gas, especially the hydrogen balloon, became fashionable quickly. This is because the gas balloon dirigible designs could be steered. They also boasted longer flight times, and were less affected by wind conditions, becoming a favourited pilot balloon.

More recently, the hybrid balloon was developed. Using a mix of common propane, and another gas such as helium or hydrogen, allows for longer flight times and relatively carbon neutral travel. 

Advanced Balloon Science

Liquid propane is used as fuel for most commercial balloons, but you may be more used to seeing propane in gas form. A common heat source for outdoor cooking, propane tanks mixed with oxygen on balloons are kept highly pressurised. This high pressure is what prevents the liquid from becoming a gas, as propane is naturally an odourless gas at room temperature. 

Other technical equipment can be found on professional balloons. Expert pilots can take complete control with a simple turn of their propane valve, with equipment to help them keep track of wind movement. Wind conditions affect balloon travel greatly, so strong winds on a hot air balloon can be detrimental to an otherwise controlled travel. 

Keeping track of the wind speed and wind current can help a pilot navigate unexpected weather events, and mitigate the way in which the wind blows the balloon off course. This is why it’s always essential to have a fully trained pilot on board your hot air balloon trip, with hours of ballooning experience.

With the ongoing Billionaire Space Race, it has also become a trend among the ultra wealthy billionaires to construct high-tech balloons designed for around the world journeys. These new hot air balloon designs look to improve upon existing design philosophies, but some seek to radically change the fundamentals of a hot air balloon. 

Have you ever wondered why hot air balloons don’t suddenly burst in the air? You would be correct in thinking that air pressure would apply force to the balloon constantly. However, an inflated balloon filled with air exerts just as much pressure outwards as the pressure being applied from outside.

This equal application of force reaches a net zero, meaning that air pressure will never cause your hot air balloon to suddenly explode, a common nightmare for unexperienced ballooners. In fact, compared to other flying craft, air balloons are easily among the safest.

Steering and Altitude

Without an engine or motor, which would add unnecessary weight, hot air balloon steering can’t be done in the normal sense. Traditionally, without a motor, the burner lets a pilot control altitude to steer during a flight. Different altitude levels result in different wind speeds.

Experienced pilots developed their skills over time, allowing for some expert hot air balloon piloting over extended periods. Professionals can adjust altitude by mere centimetres for the right steering with their incredible anticipation skills, which is why it’s important to train and practise before jumping into the deep end.

Balloon pilots must be certified with the relevant aviation authority, and be able to perform and understand the necessary safety precautions. Pilots have a great deal of control over the altitude of their air balloon, and can dictate their exact direction of travel if done correctly. 

Basic Safety

 Balloon passengers should always be aware of basic safety procedures before boarding a balloon. The very literal first step is getting into your balloon basket. Most designs come with foot holes, allowing a passenger to easily climb inside for their trip.

Although the basket is lined with a steel frame, it is important to attach any safety equipment provided. Parachutes, harnesses, seatbelts, all designed to prevent you accidentally falling over the side of the balloon in an accident. 

Although more common among sport balloons, motors and high-powered fans can pose a serious hazard if in operation. You should take care to always be aware of such equipment, and avoid interacting with it unless you’re safely on the ground and it has been switched off. 

This also applies to touching the burner. You may think your magical balloon ride experience is nothing more than a balloon with air, but dangerous equipment should only be handled by professionals. Always make sure to listen to your pilot and other hot air balloon crew when they give you safety instructions.

Other Ballooning

At a balloon port, you can see air balloons being put to all kinds of use. For sport enthusiasts, balloon races can be some of the most exciting entertainment for both a participator and spectator. Gas balloons compete in the world famous Gordon Bennett Cup each year.

If races aren’t for you, balloon tours are excellent year round subject to wind conditions. If you are able to get in the air with nice wind, then you’re in for the time of your life. Festivals and one-off flights are also commonly available, for individuals, and groups of varying sizes.

There are even balloons for advertising purposes. Famous brands can reach a wide audience from on high, literally. When well positioned, a stationary balloon can be seen by thousands, or perhaps you’d like a balloon to fly over the city much like a blimp.