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will have no usable reference points to start and complete
the turns. The closer the track of the powered
parachute is to the field boundaries, the steeper the
Figure 9-3. Effect of wind during turns.
9-5
gresses, the bank angle is reduced gradually because
the tailwind component is diminishing, resulting in
a decreasing groundspeed. During and after the turn
onto this leg (the equivalent of the base leg in a traffic
pattern), the wind will tend to drift the powered parachute
away from the field boundary. To compensate
for the drift, the amount of turn will be more than
90°.
The rollout from this turn must be such that as the
wing becomes level, the powered parachute is turned
slightly toward the field and into the wind to correct
for drift. The powered parachute should again be
the same distance from the field boundary and at the
same altitude, as on other legs. The base leg should be
continued until the upwind leg boundary is being approached.
Once more the pilot should anticipate drift
and turning radius. Since drift correction was held on
the base leg, it is necessary to turn less than 90° to
align the powered parachute parallel to the upwind leg
boundary. This turn should be started with a medium
bank angle with a gradual reduction to a shallow bank
bank necessary at the turning points. Also, the pilot
should be able to see the edges of the selected field
while seated in a normal position and looking out the
side of the powered parachute during either a lefthand
or right-hand course. The distance of the ground
track from the edges of the field should be the same
regardless of whether the course is flown to the left or
right. All turns should be started when the powered
parachute is abeam the corner of the field boundaries
headed downwind where ground reference maneuvers
are typically started. These should be the determining
factors in establishing the distance from the boundaries
for performing the maneuver.
Although the rectangular course may be entered from
any direction, this discussion assumes entry on a
downwind.
On the downwind leg, the wind is a tailwind and results
in an increased groundspeed. Consequently, the
turn onto the next leg is entered with a fairly fast rate
of turn and a higher (medium) bank. As the turn pro-
Figure 9-4. Rectangular course.
9-6
as the turn progresses. The rollout should be timed
to assure paralleling the boundary of the field as the
canopy becomes level.
While the powered parachute is on the upwind leg, the
next field boundary should be observed as it is being
approached, to plan the turn onto the crosswind leg.
Since the wind is a headwind on this leg, it is reducing
the powered parachute’s groundspeed and during the
turn onto the crosswind leg will try to drift the powered
parachute toward the field. For this reason, the
roll-in to the turn must be slow and the bank relatively
shallow to counteract this effect. As the turn progresses,
the headwind component decreases, allowing
the groundspeed to increase. Consequently, the bank
angle and rate of turn are increased gradually to assure
that upon completion of the turn the crosswind
ground track will continue the same distance from the
edge of the field. Completion of the turn with the wing
level should be accomplished at a point aligned with
the upwind corner of the field.
Simultaneously, as the wing is rolled level, the proper
drift correction is established with the powered parachute
turned into the wind. This requires that the turn
be less than a 90° change in heading. If the turn has
been made properly, the powered parachute should
be the same distance from the field boundary and
at the same altitude, as on other legs. While on the
crosswind leg, the wind correction angle should be
adjusted as necessary to maintain a uniform distance
from the field boundary.
As the next field boundary is being approached, the
pilot should plan the turn onto the downwind leg.
Since a wind correction angle is being held into the
wind and away from the field while on the crosswind
leg, this next turn will require a turn of more than 90°.
Since the crosswind will become a tailwind, causing
the groundspeed to increase during this turn, the
bank initially should be medium and progressively
increased as the turn proceeds. To complete the turn,
the rollout must be timed so that the wing becomes
level at a point aligned with the crosswind corner of
the field just as the longitudinal axis of the powered
parachute again becomes parallel to the field boundary.
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Powered Parachute Flying Handbook动力伞飞行手册(73)
