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The distance from the field boundary should be
the same as from the other sides of the field.
Usually, drift should not be encountered on the upwind
or the downwind leg, but it may be difficult to
find a situation where the wind is blowing exactly
parallel to the field boundaries. This would make it
necessary to use a slight wind correction angle on all
the legs. It is important to anticipate the turns to correct
for groundspeed, drift, and turning radius. When
the wind is behind the powered parachute, the turn
must be faster and steeper; when it is ahead of the
powered parachute, the turn must be slower and shallower.
These same techniques apply while flying in
airport traffic patterns.
Common errors in the performance of rectangular
courses are:
• Failure to adequately clear the area.
• Failure to establish proper altitude prior to
entry. (Typically, entering the maneuver while
descending.)
• Failure to establish appropriate wind correction
angle resulting in drift.
• Gaining or losing altitude.
• Abrupt control usage.
• Inability to adequately divide attention between
powered parachute control, maintaining ground
track, and maintaining altitude.
• Improper timing in beginning and recovering
from turns.
• Inadequate visual lookout for other aircraft.
S-Turns Across a Road
An S-turn across a road is a practice maneuver in
which the powered parachute’s ground track describes
semicircles of equal radii on each side of a
selected straight line on the ground. [Figure 9-5] The
straight line may be a road, fence, railroad, or section
line that lies perpendicular to the wind, and should
be of sufficient length for making a series of turns. A
constant altitude should be maintained throughout the
maneuver; do not go lower than 200 feet.
S-turns across a road present one of the most elementary
problems in the practical application of the turn
and in the correction for wind drift in turns. The application
of this maneuver is considerably less advanced
in some respects than the rectangular course. However
it is taught after the student has been introduced
to the rectangular course in order that he or she may
have a knowledge of the correction for wind drift in
straight flight along a reference line, before attempting
to correct for drift by applying a turn.
The objectives of S-turns across a road are to develop
the ability to compensate for drift during turns, orient
the flightpath with ground references, follow an assigned
ground track, arrive at specified points on assigned
headings, and divide the pilot’s attention. The
maneuver consists of crossing the road at a 90° angle
and immediately beginning a series of 180° turns of
uniform radius in opposite directions, re-crossing the
road at a 90° angle just as each 180° turn is completed.
9-7
To accomplish a constant radius ground track requires
a changing rate of turn and angle of bank to establish
the wind correction angle. Both will increase or decrease
as groundspeed increases or decreases.
The bank must be steepest when beginning the turn on
the downwind side of the road and must be shallowed
gradually as the turn progresses from a downwind
heading to an upwind heading. On the upwind side,
the turn should be started with a relatively shallow
bank and then gradually steepened as the powered
parachute turns from an upwind heading to a downwind
heading. In this maneuver, the powered parachute
should be rolled from one bank directly into the
opposite just as the reference line on the ground is
crossed.
Before starting the maneuver, a straight ground reference
line or road that lies 90° to the direction of
the wind should be selected, then the area should be
checked to ensure that no obstructions or other aircraft
are in the immediate vicinity. The road should be
approached from the upwind side, at the selected altitude
on a downwind heading. When directly over the
road, start the first turn immediately. With the powered
parachute headed downwind, the groundspeed is
greatest and the rate of departure from the road will
be rapid; so the roll into the bank must be fairly rapid
to attain the proper wind correction angle. This prevents
the powered parachute from flying too far from
the road and from establishing a ground track of excessive
radius. During the latter portion of the first
90° of turn when the powered parachute’s heading is
changing from a downwind heading to a crosswind
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Powered Parachute Flying Handbook动力伞飞行手册(74)
