Did you know that hot air balloons are beautiful and mesmerizing? They are also quite interesting because there isn’t much to them, and yet they can fly at high altitudes! What’s the science behind a hot-air balloon? What are they made of? How long can a hot-air balloon stay in the air? How do hot-air balloons fly horizontally? Can you go too high in a hot-air balloon? We’re going to look into each of these burning questions and answer each of them to the best of our ability.
Hot-air balloons work on the principles of buoyancy and the lightness of hot air. The air within the balloon is heated, so it rises. When it rises, the air exerts an upward force against the roof of the balloon. This force pushes the balloon upward and generates lift.
Did you know that a hot-air balloon is a lighter-than-air aircraft that has been around for centuries? This seems like a long time for something that can fly. Hot-air balloons were the first successful human-carrying flight! In 1783, the Montgolfier brothers designed the first untethered balloon. They piloted this balloon with Jean-Francois Pilatre de Rozier and Francois Laurent d’Arlandes on November 21st, in Paris, France.
Hot air balloons didn’t reach North America for another decade! In1793 Jean-Pierre Blanchard launched a hot-air balloon from the Walnut Street Jail, in Philadelphia, Pennsylvania. He flew to the Clement Oak in Deptford, New Jersey. Witnesses included George Washington, John Adams, Thomas Jefferson, James Madison, and James Monroe. Now that we know a little about their history, we can take a deeper look at them!
Did you know there are three different hot-air balloons? There are balloons called Montgolfier that use fire to heat the air inside. Then there are hybrid balloons. These still use hot air but have a compartment of helium or hydrogen gas. The third is a pure gas balloon, in which we can only change the altitude by venting the gas. It is these balloons that are mostly used by record breakers because they require less fuel.
The Science Behind the Hot-Air Balloon
Did you know there are scientific explanations for everything? Well, we can tell you that hot-air balloons are no different! The science behind a hot-air balloon is very basic. Heated air has more density than cool air. That means the molecules bounce around energetically and create more space between them, thus pushing the hot air upwards.
Hot air is much lighter than cold air. Look at it this way, a cubic foot of air equals about twenty-eight grams, but when heated at 100 degrees F, that mass shrinks. Now the same cubic foot of air weighs only twenty-one grams, having lost seven grams. Therefore, a hot-air balloon is so massive. They have to accommodate all that air. We also need a tremendous amount of hot air to lift a balloon of that size.
Most hot-air balloons hold 77,000 cubic feet of air, but some can hold up to 600,000 cubic feet!
For the hot-air balloon to rise, we need to heat the air. We do this process by using a burner that is located under the open balloon envelope. When the air cools, the pilot needs to reheat the air by firing the burner. This burner usually runs on propane.
Once the air is hot, it can’t escape the hole at the bottom of the envelope because buoyancy keeps the air on the move. The pilot controls the ascent by pulling a cord attached to the parachute valve. By doing this, he forces the hot air to escape the envelope, thus decreasing the inner temperature. This is how the balloon slows, and if they keep the valve open long enough, the hot-air balloon will sink.
This is how a hot-air balloon works, heat makes the balloon rise, and venting makes the balloon sink. There isn’t much to it, and it’s pretty straightforward. It’s just two simple steps, and that’s the basis of how a hot-air balloon runs. Yet, what are they made of? How long can a hot-air balloon stay in the air?
How do hot-air balloons fly horizontally? Can you go too high in a hot-air balloon? We’ll get to the rest of these questions in just a minute, but right now, we want to focus on what it’s made of. What materials can enable an object such as this to fly, and is there anything special about these materials?
What Are Hot Air Balloons Made Of?
Did you know, there are three essential parts of a hot-air balloon that make up the whole. There’s the burner, the crucial piece that is used to heat the air required to fly the balloon. Then you have the balloon envelope. This is the bulb-shaped balloon that takes up most of the structure. Finally, you have the gondola or wicker basket that holds the passengers and fuel tanks.
The bulk of the balloon is the envelope. This holds the air required to fly. They constructed this of very large nylon gores, that is reinforced by sewn-in webbing. The gores, which are gigantic, run from the base of the balloon envelope to the top, otherwise known as the crown.
They made this area of smaller panels. Using nylon is crucial because nylon is lightweight and sturdy at the same time. It also holds a high melting temperature, which comes in handy when you heat air. The skirt which attaches to the base of the envelope is nearest to the burner. They also coated it in a special heat-resistant material.
The burner is the engine. They connect this to a metal frame that’s attached above the gondola and below the envelope. The burner mixes the propane with oxygen and burns it. A valve pulled by the pilot controls the burner. This valve fires the burner into the envelope and heats the air.
The gondola is located just below the burner. These come in many shapes and sizes, but the walls are an average height of three feet. These are high enough to feel secure but low enough to see over. Gondolas come in two types; open and T partition.
An open gondola is when the pilot, fuel tanks, and the passengers occupy the same space. The T partition divides the space off into two compartments. This separates the pilot and tanks from the passengers. T partitions have struts, and they are a stronger structure than an open gondola. This is because the T partition makes the balloon more balanced.
Gondolas are the most complicated structure because of the abuse we put them through. They are constantly on the move, shift from place to place, and sway due to weather conditions. Then, whenever a balloon lands, it hits hard on the gondola’s floor. This means that both in the air and on the ground, the gondola sees a tremendous force. Because of this, it needs to be robust and able to distribute shock. Therefore, even after two centuries, we are still using wicker for the gondola.
Did you know wicker is a resilient material? It is lightweight, yet sturdy and flexible. It absorbs shock and doesn’t shatter because of hard landings or freezing temperatures. Wicker is best for impact absorbency, strength, is easy to repair, and resists entanglement in power lines and branches.
They make gondolas of a tight vertical weave around a stainless steel frame. They usually pad the inside of the gondola with leather or suede. While they usually coat the outside with urethane, protecting it from rot because of dampness.
Aside from this, there are also various instruments that modern-day pilots must have in his balloon. One that measures altitude, a radio, and a GPS. The GPS is to navigate and monitor the speed and direction of the balloon.
How long can a hot-air balloon stay in the air? How Do hot air balloons fly horizontally? Can you fly too high in a hot-air balloon? We’ll get to these other questions in a minute, but first, we’ll look into how long can a hot-air balloon stay in the air.
How Long Can a Hot-Air Balloon Stay in the Air?
Did you know hot-air balloons usually stay in the air as long as they keep the air hot? Balloons also have limited fuel. Therefore, the average hot-air balloon ride usually lasts about two hours. However, there have been moments that hot air balloons have stayed in the air for longer periods.
The longest a hot-air balloon has stayed in the air was twenty days. In 1999, Bertrand Piccard and Briton Brian Jones traveled the entire world in just twenty days. The trip from Switzerland to a desert near Cairo was the first-ever non-stop trip around the entire world by a hot-air balloon.
This was pretty impressive, but then there was Steve Fossett. He was the first person ever to fly around the world, in a hot-air balloon alone. In a balloon called the Spirit Freedom, powered on both hot air and helium. It had an envelope of a hundred and forty feet tall and sixty feet wide.
He specially designed the balloon with an auto-pilot system so he could sleep. Steve flew from Australia to Australia in just fourteen days! Yet these hot-air balloons are not passenger balloons and are specially designed for extreme goals. It is unlikely that a passenger balloon would go much longer than two hours.
But how does a hot-air balloon fly horizontally? Can you go too high in a hot-air balloon? Let’s take a look at this more in-depth.
How Do Hot-Air Balloons Fly Horizontally?
Did you know in a hot-air balloon, there is no actual steering mechanism or propulsion? The balloon goes up; it goes down and, with any luck, it rides the wind. What do we mean by that? It’s simple, hot-air balloons use the speed and direction of the wind to travel. That’s right, pilots can influence their direction by changing altitudes.
They will ascend or descend to the appropriate level. Since wind speed increases higher in the atmosphere, pilots can control horizontal speed by changing altitude. This is possible because, at these altitudes, the wind speed and direction are very different. The pilot would have to place the balloon at different altitudes at certain times while in flight to change the direction – but they can do it.
After all, with hot-air balloons, the operation is controlling the temperature and volume of the hot-air balloon. The pilot usually does this, who opens the parachute valve, which allows the ability of descent. By valving off all that excess heat, you, therefore, make the balloon heavier for landing.
Can you go too high in a hot-air balloon? That depends on what you’d class as too high.
Can You Go Too High in a Hot-Air Balloon?
Did you know a hot-air balloon normally only flies between 1000 and 3000 feet off the ground? To put that into perspective for you, most small planes fly between 2000 and 10,000 feet. So, that’s not all that high. However, some specially designed hot-air balloons have reached much higher heights.
On November 26th, 2005, Vijaypat Singhania from Bombay, India, wanted to break the record for the highest hot-air balloon flight. He took off in a specially designed balloon, called Envelope. It was a hundred and sixty feet high. One of the most prominent hot-air balloon developers and producers designed Envelope, Don Cameron. The Envelope reached an altitude of 69,850 feet and landed safely 150 miles from Bombay.
On February 2nd, 1966, Nicholas Piantanida had reached 123,500 feet in his Project Strato-Jump II balloon. He should have jumped with a parachute and free fall, but that fell through. He ended up returning to earth in the basket, and surprisingly, he survived reentry.
Then there was Felix Baumgartner, who on October 14th, 2012 took a balloon flight that started around Roswell, New Mexico. He reached 127,851 feet and parachuted from that height to get back to earth. He wasn’t the only one to jump from these heights. Only two years later, Alan Eustace, who is a senior VP of Google, reached 135, 906 feet in a helium balloon. Then he returned to earth with a parachute jump. Yet, not every mission in a hot-air balloon was a happy one.
On November 4th, 1927, Captain Hawthorne C. Grey had reached 43,380 feet. But his oxygen ran out, and he suffocated. While on January 30th, 1934, USSR balloon, Osoaviakhim-1 had reached 72,000 feet. The three-member crew was tragically killed when the balloon broke up during the descent.
You’ve got to remember that propane-fueled hot-air balloons will not fly very high. There have been hydrogen and helium-powered hot air balloons known to have flown much higher. One of the highest manned flights was Alan Eustace’s 135,906 feet. Some unmanned hot-air balloons have made it to 173,900 feet. This is only possible because of a greater buoyancy and lift that is created with lighter gases, like hydrogen and helium. You can create even more buoyancy and lift by heating the helium to reduce its density.
Height equals danger with hot-air balloons. Think about it for a minute. There are several things to make it dangerous. A hot-air balloon can only rise until the atmosphere has the same weight as the balloon. Even if that wasn’t the case, with the thin air you could pass out, the fuel could combust, or you could run out of fuel. Therefore, it is impractical that a hot-air balloon goes too high.
Many people are afraid of hot air balloons because they are afraid of heights. After all, in a hot-air balloon, you’re exposed. For a person afraid of heights, being 3000 feet in the air in a wicker basket would not be very fun, would it? However, hot-air balloons aren’t as bad as you think they might be. Hot-air balloons are the safest form of air travel, and balloon accidents are uncommon.
This is because balloons only fly in pleasant weather and slow winds. Most commercial hot-air balloons fly within two hours of sunrise and two hours of sunset. This is when the winds are at their calmest and most consistent. There are only three types of landings with hot air balloons. These landings are stand-up, tip-over, and emergency landing. 99.9% of balloon landings are stand-up or tip-over, both of which are 100% safe and very much normal.
Conclusion
Now that we’ve learned a little more about hot air-balloons and answered those questions, we can feel more comfortable. Hot-air balloons are scary to some people, but they don’t have to be. After all, most commercial hot-air balloons only go up between 1000 and 3000 feet. Sure, that’s high and for someone afraid of heights, it’s nightmarish. However, if you are going to conquer your fear of heights, the best and safest way is to start with a hot-air balloon.
