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How Do You Control The Height Of A Hot Air Balloon?

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In this post, we’ll look at what causes these balloons to rise into the air, as well as how the design of the balloon allows the pilot to manage height and vertical speed of a hot air balloon flight

The stunning simplicity of these early passenger-carrying balloons will wow you.   

Warmer air rises in cooler air, hence hot air balloons are based on this simple scientific fact.

How Do You Control The Height Of A Hot Air Balloon?

Because it contains less mass per unit of volume, heated air is lighter than cool air.

Air weighs around 28 grams per cubic foot (about an ounce). It weights around 7 grams less if you heat it by 100 degrees Fahrenheit.

As a result, a hot air balloon can lift around 7 grams per cubic foot of air.

That’s why hot air balloons are so massive: it takes around 65,000 cubic feet of hot air to hoist 1,000 pounds.    We’ll look at the different components of hot air balloons in the next section to see how they heat the air. 

Hitting The Heights

An air balloon pilots flight hinges on a mechanism to reheat the air to keep the balloon soaring. A burner is positioned beneath an open balloon envelope in hot air balloons to accomplish this.

The hot air balloon pilot pilot can reheat the air in the balloon as it cools by firing the burner. 

Hot air balloons heat the air by burning propane, the same gas that is used in outdoor barbecues.  

The propane is kept in lightweight cylinders in the balloon basket in compressed liquid form.

The intake hose extends all the way to the bottom of the cylinder, allowing the liquid to be drawn out.

The propane flows fast via the hoses to the heating coil because it is heavily pressurized in the cylinders.

The heating coil is nothing more than a coil of steel tubing wrapped around the burner.

When the balloonist turns on the burner, propane is released as a liquid and lit by a pilot light. 

The flame heats the metal in the tube around it as it burns. When the tubing heats up, the propane running through it heats up as well. Before it is lit, this converts the propane from a liquid to a gas.

This gas produces a more intense flame with lower fuel usage. 

The envelope of most modern hot air balloons is made of long nylon gores strengthened with sewn-in webbing.

The gores are made up of a number of tiny panels that go from the base of the envelope to the crown.   Because nylon is lightweight but also quite robust and has a high melting point, it works well in balloons.

To prevent the flame from igniting the balloon, the skirt, the nylon at the bottom of the envelope, is treated with a special fire-resistant material. 

Because buoyancy keeps the hot air flowing up, it won’t escape from the opening at the bottom of the envelope. The balloon will continue to climb if the pilot keeps firing the fuel jets. Buoyancy is essential for balloon navigation and direction of balloon.

However, there is a maximum altitude because the air gets so thin that the buoyant force is insufficient to lift the balloon.

Because the buoyant force is proportional to the weight of air displaced by the balloon, a larger balloon envelope has a higher upper altitude limit than a smaller balloon. 

Controlling The Height

It takes skill to pilot a balloon, but how the hot air balloon works and the controls are actually quite basic. The pilot moves a switch that opens the propane valve to hoist the balloon.

So starts the balloon pilots flight plan and flight by air balloon.

This lever operates similarly to the knobs on a gas grill or stove: as you crank it, the gas flow increases, increasing the size of the flame.

How Do You Control The Height Of A Hot Air Balloon?

By shooting a larger flame to heat the air more quickly, the pilot can enhance the vertical speed. 

A control that opens a second propane valve is also seen on many hot air balloons. This valve directs propane to a line that runs around the heating coils, bypassing them.

This allows the pilot to burn liquid propane rather than propane gas. Liquid propane generates a less efficient, weaker flame than gas, but it is more quieter.

This second valve is frequently used by experienced balloon pilots over livestock farms to avoid scaring the animals. 

A string is also used to open the parachute valve at the top of the envelope in hot air balloons.

When the pilot pulls the connecting cable, a little amount of hot air escapes from the envelope, lowering the temperature inside. As a result, the balloon’s rise is slowed.

The balloon will sink if the pilot keeps the valve open long enough. 

These are the sole controls: heat to raise the balloon and venting to lower it.

This presents an intriguing question: how do pilots carry hot air balloons from one location to another if they can only move them up and down?

Because wind flows in different directions at different altitudes, pilots can move horizontally by adjusting their vertical position.

A pilot rides with the wind and ascends and falls to the proper level to move in a specific direction. Pilots can also regulate horizontal speed by altering altitude since wind speed rises as you fly higher in the atmosphere. 

Even the most skilled pilot, however, does not have perfect control over the balloon’s trajectory or balloon flight time.

Wind conditions usually limit the pilot’s options. As a result, a hot air balloon cannot be piloted along a precise path.

The Direction of Flight

Hot air balloons are popular since they are one of the few ways to fly without the use of an engine. Traveling high in the air is amazing, but controlling your balloon to fly in a specific direction can be difficult.

To stay aloft, the hottest air balloon must keep a consistent altitude and be able to maneuver around obstructions. Hot air balloon designers have devised unique propellers that can rotate in different directions to achieve these functions. 

But it’s extremely unlikely that you’ll be able to return the balloon to its original location.

Unlike flying an airplane, navigating a hot air balloon is mainly improvised on the fly.

How Do You Control The Height Of A Hot Air Balloon?

As a result, some members of a hot air balloon crew must remain on the ground and drive behind the balloon to follow the balloon into land

They can then arrive to pick up the passengers and the equipment of the balloon.

This ends the flight by air balloon

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