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heading, the groundspeed becomes less and the rate of
departure from the road decreases. The wind correction
angle will be at the maximum when the powered
parachute is headed directly crosswind.
After turning 90°, the powered parachute’s heading
becomes more and more an upwind heading,
the groundspeed will decrease, and the rate of closure
with the road will become slower. If a constant
steeper bank were maintained, the powered parachute
would turn too quickly for the slower rate of closure,
and would be headed perpendicular to the road prematurely.
Because of the decreasing groundspeed and
rate of closure while approaching the upwind heading,
it will be necessary to gradually shallow the bank
during the remaining 90° of the semicircle, so that the
Figure 9-5. S-turns.
9-8
wind correction angle is removed completely and the
wing becomes level as the 180° turn is completed at
the moment the road is reached.
At the instant the road is being crossed again, a turn
in the opposite direction should be started. Since the
powered parachute is still flying into the headwind,
the groundspeed is relatively slow. Therefore, the turn
will have to be started with a shallow bank so as to
avoid an excessive rate of turn that would establish
the maximum wind correction angle too soon. The
degree of bank should be that which is necessary to
attain the proper wind correction angle so the ground
track describes an arc the same size as the one established
on the downwind side.
Since the powered parachute is turning from an upwind
to a downwind heading, the groundspeed will
increase and after turning 90°, the rate of closure
with the road will increase rapidly. Consequently, the
angle of bank and rate of turn must be progressively
increased so that the powered parachute will have
turned 180° at the time it reaches the road. Again, the
rollout must be timed so the powered parachute is in
straight-and-level flight directly over and perpendicular
to the road.
Throughout the maneuver a constant altitude should
be maintained, and the bank should be changing constantly
to affect a true semicircular ground track.
Often there is a tendency to increase the bank too
rapidly during the initial part of the turn on the upwind
side, which will prevent the completion of the
180° turn before re-crossing the road. This is apparent
when the turn is not completed in time for the powered
parachute to cross the road at a perpendicular
angle. To avoid this error, the pilot must visualize the
desired half circle ground track, and increase the bank
during the early part of this turn. During the latter part
of the turn, when approaching the road, the pilot must
judge the closure rate properly and increase the bank
accordingly, so as to cross the road perpendicular to it
just as the rollout is completed.
Common errors in the performance of S-turns across
a road are:
• Failure to adequately clear the area.
• Gaining or losing altitude.
• Inability to visualize the half circle ground
track.
• Poor timing in beginning and recovering from
turns.
• Faulty correction for drift.
• Inadequate visual lookout for other aircraft.
Turns Around a Point
As a training maneuver turns around a point is a logical
extension of the principles involved in the performance
of S-turns across a road. Its purposes as a
training maneuver are:
• To further perfect turning technique.
• To perfect the ability to subconsciously control
the powered parachute while dividing attention
between the flightpath and ground references.
• To teach the student that the radius of a turn is a
distance which is affected by the degree of bank
used when turning with relation to a definite
object.
• To develop a keen perception of altitude.
• To perfect the ability to correct for wind drift
while in turns.
In turns around a point, the powered parachute is
flown in a complete circle of uniform radii or distance
from a prominent ground reference point while maintaining
a constant altitude; do not go lower than 200
feet.
The factors and principles of drift correction that are
involved in S-turns are also applicable in this maneuver.
As in other ground track maneuvers, a constant
radius around a point will, if any wind exists, require
a constantly changing angle of bank and wind correction
angles. The closer the powered parachute is to a
direct downwind heading where the groundspeed is
greatest, the steeper the bank and the faster the rate
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Powered Parachute Flying Handbook动力伞飞行手册(75)
