| For practical purposes, hot air balloons really can't | | | | the envelope is too thin to support the weight of |
| compete with airplanes and helicopters. They're | | | | the balloon. The more air within the balloon, the |
| extremely difficult to steer, and they can only | | | | greater the buoyancy-so bigger balloons can go |
| move as quickly as the surrounding winds. But as | | | | higher than smaller ones. |
| a recreational activity, hot air ballooning can't be | | | | A pilot can cause the balloon to rise by turning on |
| beat. You're outside, feeling the wind in your hair | | | | the propane burner and heating the air within the |
| and the sun on your face, drifting serenely over | | | | envelope. To bring the balloon down, the pilot |
| the earth. If you've ever been in a hot air balloon, | | | | releases the parachute valve. That's a vent in the |
| you know it's an experience you won't soon | | | | top of the envelope that allows some of the hot |
| forget. | | | | air to escape, cooling the temperature of the |
| Hot air is less dense, and lighter, than cold air. | | | | remaining air within. This causes the balloon to sink |
| Because it's lighter, it tends to rise. If you've ever | | | | gradually. |
| taken a dive into a pool, you may have felt this | | | | There are no horizontal controls in a balloon, but |
| effect in water: the surface water is warm, but | | | | pilots can still control the horizontal movement by |
| as you move deeper, the water gets cooler. | | | | raising and lowering the altitude of the craft. |
| That's because warm water is lighter than cool | | | | Winds at different altitudes move in different |
| water and tends to rise to the top, like air. | | | | directions. If a pilot has a good working knowledge |
| The air within a hot air balloon is heated, and as it | | | | of the wind currents in the area, she can raise |
| rises, it takes the balloon-and anything attached to | | | | and lower the balloon to catch a current moving in |
| it-with it. A cubic foot of air within a balloon can lift | | | | the right direction. |
| about seven grams of weight. This isn't a lot of | | | | Still, piloting a balloon isn't an exact science. It's |
| weight, which is why the balloon has to be so big. | | | | impossible to target the precise location where |
| The balloon itself is called an "envelope." It's usually | | | | you'll land. That's why it's usually necessary for |
| made of nylon, which is the perfect fabric for hot | | | | someone on the ground to follow the balloon by |
| air balloons: it's lightweight but sturdy, and it can | | | | car to meet the balloon where it lands and |
| withstand heat without melting easily. | | | | transport the equipment. |
| Below the balloon, a burner is positioned to send a | | | | Launching and landing generally take more work |
| jet of flame upward into the envelope. The | | | | than actually flying a balloon. The inflation process |
| burner uses propane as a fuel. The fuel is stored | | | | takes only about ten or fifteen minutes, and is |
| as a highly compressed liquid in canisters attached | | | | done with a powerful fan. Once the balloon is full |
| to the burner with a fuel hose. Because it's so | | | | of air, it will still lie on the ground until the burner is |
| highly compressed, the liquid fuel flows quickly | | | | fired, heating the air in the envelope and causing it |
| through the hose to the burner when the pilot | | | | to rise. |
| turns it on. There, it's ignited by a pilot light. The | | | | A balloon descends gradually, but can still land with |
| flame heats up the surrounding metal of the | | | | a bit of a bump if the pilot isn't experienced |
| burner, which turns the fuel to gas before it gets | | | | enough to know how to bump the basket along |
| lit. This makes the flame stronger and the fuel | | | | the ground to lessen the impact. The wicker |
| usage more efficient. | | | | basket helps absorb the force of the landing. |
| If you look at a hot air balloon, you'll notice a big | | | | Wicker is lightweight and flexible, and absorbs the |
| hole in the bottom where the burner is. So why | | | | energy of landing better than a solid, less flexible |
| doesn't the hot air escape through the hole at the | | | | basket would. This way, riders aren't jarred when |
| lower end? Simple: buoyancy. Hot air is buoyant, | | | | the ride is over. |
| which means it can only rise-it can't sink and drain | | | | There's nothing like soaring over the earth in a |
| out the bottom of the balloon. As long as the air | | | | balloon. Hot air balloons are exciting, fascinating, |
| stays hot, it will continue to rise. | | | | and pure fun. If you've never taken a ride in one, |
| It won't rise forever, though. The atmosphere | | | | you're definitely missing out on an experience |
| thins as it goes up, and eventually the air within | | | | you'll never forget. |