ABC's of Ballooning
By Ruth Ludwig
NOTE: This article originally appeared in the November 1995 issue
of Flight Training magazine. It is a great overview of how balloons
fly, what it takes to become a pilot, and why balloon flight is so addicting!
It is reprinted here with permission.
We hung motionless over the lake. Vermont's fiery October foliage rolled
down the hills around us, falling into the water and its reflection
of the deep blue morning sky. A loud scream broke the silence. To the
north, a bald eagle streaked toward us, exactly at eye level. He came
to within a few yards of my passengers and me, circled us three times,
and disappeared over the ridge. Such is a morning balloon flight.
Lighter-than-air was the first aviation, and is still the choice for
many pilots more than 200 years later. You don't need an airport or
a runway. If you own a balloon, you don't need a hangar or even a tie-down
space, just a corner of your garage. Take off from your back field,
or the parking lot at the general store (with permission, of course).
Drift quietly along, experiencing little or no sensation of movement
of height. Land on a freshly cut hayfield, or the softball diamond before
the players even get out of bed.
How do balloons work?
Balloons are aircraft, regulated under the same Federal Aviation Regulations
as every other category. Balloons are aerostats, that is, static within
the air. Once a balloon is buoyant, it moves with the air mass in which
it floats, no faster, no slower, no different direction. The pilot has
altitudinal control, and can alter the balloon's course by finding an
air mass going in a slightly different direction.
 A
balloon has an envelope, basket, and sometimes a burner and fuel system.
The envelope is the fabric part of the balloon, the bag that holds the
lifting gas. The basket (traditionally wicker) is the passenger compartment.
In a hot air balloon, a burner hangs between the envelope and the basket.
It burns liquefied propane gas (lpg) to make an intensely hot and long
flame, capable of heating a large volume of air very quickly.
The FAI identifies three classes of balloon: gas, hot air, and roziere
(combination gas/hot air). A gas balloon's envelope contains a gas such
as helium, hydrogen, or, in recent years, ammonia. To ascend, the pilot
releases ballast (usually sand or water), and to descend valves out
some gas. While gas ballooning is a beautiful, silent way to travel,
it requires many hours and crew people to fill the balloon and is tremendously
expensive because of the cost of the gas ($1,000 to $3,500 for one flight's
helium).
Hot air balloons use plain old air as the lifting gas. By heating the
air inside the balloon, the pilot makes that air less dense (lighter)
than the outside air, and the balloon rises. As the internal air cools,
the balloon becomes heavier, and descends if the pilot doesn't add more
heat. Fuel for a hot air balloon flight may cost $10 to $50.
Combination gas/hot air balloons, called rozieres, use a small burner
to heat air inside a cone-shaped space surrounding a gas balloon cell.
The warm air heats and expands the gas, adding more lift.
In this article, we'll be look at hot air ballooning, since that's
where nearly all balloon pilots begin their training.
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