How Hot Air Balloons Work
Hot air balloons are one of the oldest flying machines ever invented, and they work on a very simple principle: hot air rises.
For practical purposes, hot air balloons really cant compete with airplanes and helicopters. Theyre extremely difficult to steer, and they can only move as quickly as the surrounding winds. But as a recreational activity, hot air ballooning cant be beat. Youre outside, feeling the wind in your hair and the sun on your face, drifting serenely over the earth. If youve ever been in a hot air balloon, you know its an experience you wont soon forget.
Hot air is less dense, and lighter, than cold air. Because its lighter, it tends to rise. If youve ever taken a dive into a pool, you may have felt this effect in water: the surface water is warm, but as you move deeper, the water gets cooler. Thats because warm water is lighter than cool water and tends to rise to the top, like air.
The air within a hot air balloon is heated, and as it rises, it takes the balloonand anything attached to itwith it. A cubic foot of air within a balloon can lift about seven grams of weight. This isnt a lot of weight, which is why the balloon has to be so big.
The balloon itself is called an envelope. Its usually made of nylon, which is the perfect fabric for hot air balloons: its lightweight but sturdy, and it can withstand heat without melting easily.
Below the balloon, a burner is positioned to send a jet of flame upward into the envelope. The burner uses propane as a fuel. The fuel is stored as a highly compressed liquid in canisters attached to the burner with a fuel hose. Because its so highly compressed, the liquid fuel flows quickly through the hose to the burner when the pilot turns it on. There, its ignited by a pilot light. The flame heats up the surrounding metal of the burner, which turns the fuel to gas before it gets lit. This makes the flame stronger and the fuel usage more efficient.
If you look at a hot air balloon, youll notice a big hole in the bottom where the burner is. So why doesnt the hot air escape through the hole at the lower end? Simple: buoyancy. Hot air is buoyant, which means it can only riseit cant sink and drain out the bottom of the balloon. As long as the air stays hot, it will continue to rise.
It wont rise forever, though. The atmosphere thins as it goes up, and eventually the air within the envelope is too thin to support the weight of the balloon. The more air within the balloon, the greater the buoyancyso bigger balloons can go higher than smaller ones.
A pilot can cause the balloon to rise by turning on the propane burner and heating the air within the envelope. To bring the balloon down, the pilot releases the parachute valve. Thats a vent in the top of the envelope that allows some of the hot air to escape, cooling the temperature of the remaining air within. This causes the balloon to sink gradually.
There are no horizontal controls in a balloon, but pilots can still control the horizontal movement by raising and lowering the altitude of the craft. Winds at different altitudes move in different directions. If a pilot has a good working knowledge of the wind currents in the area, she can raise and lower the balloon to catch a current moving in the right direction.
Still, piloting a balloon isnt an exact science. Its impossible to target the precise location where youll land. Thats why its usually necessary for someone on the ground to follow the balloon by car to meet the balloon where it lands and transport the equipment.
Launching and landing generally take more work than actually flying a balloon. The inflation process takes only about ten or fifteen minutes, and is done with a powerful fan. Once the balloon is full of air, it will still lie on the ground until the burner is fired, heating the air in the envelope and causing it to rise.
A balloon descends gradually, but can still land with a bit of a bump if the pilot isnt experienced enough to know how to bump the basket along the ground to lessen the impact. The wicker basket helps absorb the force of the landing. Wicker is lightweight and flexible, and absorbs the energy of landing better than a solid, less flexible basket would. This way, riders arent jarred when the ride is over.
Theres nothing like soaring over the earth in a balloon. Hot air balloons are exciting, fascinating, and pure fun. If youve never taken a ride in one, youre definitely missing out on an experience youll never forget.
By: Janette Vince
Article Directory: http://www.articledashboard.com
J.Vince is director of www.thanksdarling.com supplier of experience days out and gifts. For a range of flying experiences including hot air balloon flights visit www.thanksdarling.com/categories/balloon-flights.htm
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