Steering a balloon.
We can’t change the wind…
…but we can change our altitude and we can change our launch site.
Working the winds takes knowledge and experience…
…and it is one of the great joys of the sport.
Weather Briefing –
Working the winds starts with a detailed weather briefing.
There are many, many weather websites including Blast Valve and Weather Underground where a pilot can learn wind direction and speed.
Pilots will also telephone Flight Service at 1-800-WX BRIEF (992-7433) for additional information such as turbulance warnings or temporary flight restrictions (TFRs) such as when the President comes to town.
Pibal –
A pibal, short for pilot balloon, is a helium filled toy balloon that is released before each flight.
Pibals ascend at between 250 and 300 feet per minute…
…so a pilot can estimate the direction and speed of local winds and plan the flight accordingly.
Effects of Terrain –
Air, like water, flows downhill. In Phoenix the colder air from the high country to the northeast sinks so the prevailing wind during the fall, winter, and spring are out of the east.
In Albuquerque this phenomenon is so consistant it sets up what is called the “Albuquerque Box.” The launch site for the Albuquerque International Balloon Fiesta (AIBF) is within a half mile of the Rio Grande River which flows south from the high country near Santa Fe and Taos. At launch the balloons will ride the drainage wind to the south. When they go up a couple of hundred feet they will reverse direction and fly back over the launch field. Then they can drop down and head south again.
It is quite an experience to watch the balloons work the winds during competitive events at the AIBF. The pilots, who are the best in the world, will work the winds to make three, four, or even five passes over the field as they navigate their way to the targets.
East Wall in Sunlight
The Effect of the Sun –
The sun heats the earth unevenly. The east side of a mountain will heat up more quickly in the morning than the surrounding terrain causing that air to rise. Winds in the valley will flow west to fill the vacuum.
More Effects of the Sun –
Another example is flying over brown and green fields. The sun doesn’t heat the air. It heats the ground which, in turn, transfers the heat to the air above. The ambient tempreature above a brown, unplanted field will be warmer so the relative difference between the temperature inside and outside the balloon will be less and the balloon will descent.
The opposite is true for a green, planted field. The ambient temperature is lower and the balloon will ascend.
Head on a Swivel –
Balloon pilots watch trees, smoke, and other balloons to continually
update their estimate of wind speed and direction.
Balloons Over Albuquerque
How high can a balloon fly?
Federal Aviation Regulations (FAR 91.119): Except when necessary for takeoff and landing, no person may operate an aircraft below the following minimums:
Over Congested Areas –
Over any congested area of a city, town, or settlement, or over any open air assembly of persons, an altitude of 1,000 feet above the highest obsticle with a horizontal radius of 2,000 feet of the aircraft.
Over Other Than Congested Areas –
An altitude of 500 feet above the surface, except over open water or sparcely populated areas.
Sparcely Populated Areas –
In those cases, the aircraft may not be operated closer than 500 feet to any person, vessel, vehicle, or structure.
Note –
The Federal Aviation Administration (FAA) does not specifically define congested area, other than congested area, or sparcely populated area.
Helicopters –
Helicopters may operate below the prescribed minimums FAR 91.119(d)(1).
Fudge Factor: FAR 91.119(a) –
An altitude allowing, if a power unit fails, an emergency landing without undue hazard to persons or property on the surface. Editor’s note: For a balloon that is close to the ground.
What is the maximum altitude for a balloon?
Depends on:
Ambient (outside air) Temperature –
Temperatures between 30 degrees and 60 degrees (F) are ideal for ballooning. Low fuel pressure is a problem in cold weather requiring either warming the tanks or injecting nitrogen into the tanks. High temperatures requires reducing the passenger load.
Envelope (the nylon part) Temperature –
Excessive heat inside the envelope damages the fabric. Balloon seldom fly with an envelope temperature above 250 (F).
Balloon Weight –
Sport balloons typically weigh between 600 pounds and 900 pounds. Big balloons, above 180,000 cubic feet, used by ride companies weigh well over 1,000 pounds.
Passenger Weight –
Sport balloons typically carry two or sometimes three passengers. A good rule-of-thumb is to estimate 160 pounds per person. So a pilot and two passengers would weigh in at 480 pounds.
Envelope Size –
Most sport balloons are 90,000 cubic feet or less.