曝光台 注意防骗
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During the launch phase of a flight, building/landowner relations is an easy task. The pilot should select launch sites that avoid flight paths and landings around sensitive areas, such as livestock, expensive crops, nature preserves, etc. Once a launch site is selected, the pilot should make an effort to identify the property as public or private. Generally, school fields and local parks may be used without further inquiry unless there have been previous problems with balloons. In such a case it would be appropriate to check with the local authorities for the use of these facilities.
Private property, however, is another issue. A balloon pilot and crew should never assume the right to use a private location to launch or recover a balloon. To do so exhibits a degree of arrogance that has no place in ballooning and subjects everyone participating to trespass laws. The landowner usually lives on the property and has paid for that right. In the event that no one is immediately available, the pilot should either select another launch site or perhaps inquire of neighbors who may be able to inform you of the landowner’s location. Finding the landowner and obtaining permission to use a particular field may be one of the most important tasks of the launch process for the crew chief, if one is assigned. Undoubtedly, the one time the pilot does not have appropriate authorization for use of a launch site and uses another’s property, someone will be watching and problems later ensue.
The positive side of this is that most landowners welcome the balloon pilot and his crew, want to learn a little about balloons, and gladly allow the use of their property for the launch. Many see this as an opportunity and actively participate in the process. Others may grant permission, but stand back from the activity. Whichever type of landowner is encountered, they usually respond positively to a pilot and crew that respect rights and protects landowner interests.
Chapter Summary
It is frequently said that every pilot sets up equipment and prepares for flight in a different manner. The purpose of this chapter is not to emphasize those differences, but rather to illustrate the underlying similarities and procedures that every balloon pilot must follow to safety begin a flight.
6-18
7-1
Introduction
This chapter discusses various aspects of inflight maneuvers. It covers the standard burn, level flight, ascents and descents, maneuvering and lateral control, and contour flying. This chapter also includes information on chase crew management, landowner relations, and tethering.
Inflight
Maneuvers
Chapter 7
7-2Burner Ratings
During any discussions of burner output, talk usually turns to the issue of “burner ratings”; that is, the amount of heat actually produced by a specific burner. Invariably, the talk turns into a “my burner is better than yours” type of exchange. In reality, there is virtually no difference between the burners produced by the major manufacturers and their respective output.
A pilot needs to understand the concept of British Thermal Units, or BTU, as a measurement of output. A BTU is defined as the quantity of heat required to raise the temperature of one pound of water by one degree Fahrenheit. While not particularly relevant to heating air, this has come to be a generally accepted form of measure for burner output. Of the four major manufacturers, three rate their burners at 18 to 19 million BTU output; the fourth at 43.9 million (with the caveat that that is produced at a supply line pressure of 200 PSI, well above the pressures that most balloonists use). A pilot needs to be aware that BTU output in a balloon burner equates to the amount of propane that is burned in an hour; BTU output is usually computed on this basis. Referring to the Propane Primer in Chapter 2, propane has a nominal value of 91,600 BTU per gallon under ideal circumstances. A simple mathematical calculation indicates that the average burner (a 18.5 million BTU rating) consumes approximately 202 gallons of fuel per hour. (18.5 million BTU divided by 91,600 BTU per gallon of propane = 201.96 gallons of fuel)
However, balloon burners are not used for an hour at a time; instead, they are used for very short periods of time, as discussed on page 7-2. If the numbers above are recalculated, it can be said that the standard burn of four seconds, as described in this section, puts approximately 5,139 BTU of heat into the balloon’s envelope. Remember, this is a theoretical statement of heat available, as no burner is 100 percent efficient.
There are numerous factors involved in burner design, such as volume backpressures, restrictions in the internal plumbing design, and more, all of which contribute to the final output rating. It is helpful to remember that the mathematics of burner design reveals the fact that output is a linear equation, when compared to pressure input; there is a direct correlation between the fuel line pressure and the burner’s output. This is not the case with the noise output of the burner, as the noise output increases exponentially as the pressure is increased. Reduction of burner noise represents the next hurdle in burner design; perhaps someday it will be possible to enjoy an almost silent balloon flight.
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Balloon Flying Handbook(84)
