Descents
To start a descent from level flight, skip one burn, and
then go back to the level-flight regimen to hold the
descent at a constant rate.
To check winds below, look for the calm side of a
pond, ripples on water, a flag, smoke, or movement
of tall grass. You could also drop some tissue rolled
into a small ball. The procedure for detecting wind
speed and direction in a descent is similar to that of
an ascent; a slow descent of 100 to 200 FPM allows
you to make certain subtle changes.
A rapid descent in a balloon is a relative term, and is
not defined. A 700 FPM descent started at 3,000
feet AGL is not necessarily rapid. A 700 FPM descent
started at 300 feet AGL is rapid and may be critical.
Rapid descents should be made with adequate ground
clearance and distance from obstacles.
You can learn the classic balloon flare by matching
the VSI to the altimeter, i.e., descend 500 FPM from
500 feet AGL, 400 FPM from 400 feet AGL, etc.
Below 200 feet do not use instruments; look below
for obstacles, especially powerlines.
Hot air balloons are equipped with a vent (which may
be called maneuvering vent or valve). When
opened, the vent releases hot air from the envelope
and draws cooler air in at the mouth, thus reducing
the overall temperature, allowing the balloon to
descend.
Learn to calibrate the use of the vent, as well as the
burners. Know how much air is being released so as
to know what effect to expect. For predictability, time
the vent openings, and open the vent precisely.
Parachute vent balloons usually have a manufacturer's
limitation on how long the vent may be open. Side
vents may be used more liberally because the air being
exhausted from the envelope is much cooler than air
vented from a parachute top. A side vent opening of
5 seconds may be the equivalent of only 1 second of
top vent. Use the vent sparingly; it should not be used
instead of patience. Avoid using the vent to descend;
use of the vent is wasteful and disruptive.
The only direct control of the balloon the pilot has is
vertical motion. You can make the balloon go up by
adding heat. You can make it come down by venting
or not adding heat. For horizontal or lateral motion,
you must rely on wind, which may or may not be
going in the direction you wish to go. A good pilot
learns to control vertical motion precisely and variably
to provide maximum lateral choice.
MANEUVERING
The art of controlling the horizontal direction of a free
balloon is the highest demonstration of ballooning skill.
The balloon is officially a non-steerable aircraft.
Despite the fact that balloons are non-dirigible, some
pilots seem to be able to steer their balloons better
than others.
There are broad physical laws that should be
understood to help maneuver a balloon horizontally.
For example, cold air flows downhill, hot air flows
uphill, and in the Northern Hemisphere, as altitude is
gained, wind is deflected to the right, or clockwise
due to Coriolis force.
Being knowledgeable of the wind at various altitudes,
both before launch and during flight, is the key factor
for maneuvering. The following describes some ways
you can determine wind conditions.
WINDS ABOVE Pibal
Pibal is short for pilot balloon. Many balloon pilots
believe that pibals are a must for determining local
wind conditions. To deploy your own pibals, all you
need is a bottle of helium and a bag of toy balloons.
A 9-inch, dark-colored toy balloon filled with helium
will climb at a faster rate than a normal balloon climbout
and can be visible for over 1,000 feet AGL, even
before official sunrise.
One method is to send up two or three pibals at 10 to
15 second intervals to fly at different altitudes. You
can get them to climb at different rates and fly at
different altitudes by diluting the helium with air. To
do this, fill the balloon partially with helium and add
some air by blowing with the mouth.
A 9-inch toy balloon filled to 7 inches with helium and
topped off to 9 inches with a good puff of breath may
show winds at different altitudes. The second balloon
released will confirm the changes in direction made
by the first balloon or show a completely different
flightpath confirming variable or changing winds.
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