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时间:2010-05-09 10:21来源:蓝天飞行翻译 作者:admin
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9-7
increase. Also, at the 45° point, the pitch attitude
should start to decrease slowly toward the horizon and
the 90° reference point. Since the airspeed is still
decreasing, right-rudder pressure will have to be
applied to counteract torque.
As the airplane’s nose is being lowered toward the 90°
reference point, the bank should continue to increase.
Due to the decreasing airspeed, a slight amount of
opposite aileron pressure may be required to prevent
the bank from becoming too steep. When the airplane
completes 90° of the turn, the bank should be at the
maximum angle (approximately 30°), the airspeed
should be at its minimum (5 to 10 knots above stall
speed), and the airplane pitch attitude should be
passing through level flight. It is at this time that an
imaginary line, extending from the pilot’s eye and
parallel to the longitudinal axis of the airplane, passes
through the 90° reference point.
Lazy eights normally should be performed with no
more than approximately a 30° bank. Steeper banks
may be used, but control touch and technique must be
developed to a much higher degree than when the
maneuver is performed with a shallower bank.
The pilot should not hesitate at this point but should
continue to fly the airplane into a descending turn so
that the airplane’s nose describes the same size loop
below the horizon as it did above. As the pilot’s
reference line passes through the 90° point, the bank
should be decreased gradually, and the airplane’s nose
allowed to continue lowering. When the airplane has
turned 135°, the nose should be in its lowest pitch
attitude. The airspeed will be increasing during this
descending turn, so it will be necessary to gradually
relax rudder and aileron pressure and to
simultaneously raise the nose and roll the wings level.
As this is being accomplished, the pilot should note the
amount of turn remaining and adjust the rate of rollout
and pitch change so that the wings become level and
the original airspeed is attained in level flight just as
the 180° point is reached. Upon returning to the
starting altitude and the 180° point, a climbing turn
should be started immediately in the opposite direction
toward the selected reference points to complete the
second half of the eight in the same manner as the first
half. [Figure 9-5]
Due to the decreasing airspeed, considerable rightrudder
pressure is gradually applied to counteract
torque at the top of the eight in both the right and left
turns. The pressure will be greatest at the point of
lowest airspeed.
More right-rudder pressure will be needed during the
climbing turn to the right than in the turn to the left
because more torque correction is needed to prevent
yaw from decreasing the rate of turn. In the left
climbing turn, the torque will tend to contribute to the
90° POINT
1. BANK APPROX 30°
2. MINIMUM SPEED
3. MAXIMUM ALTITUDE
4. LEVEL PITCH ATTITUDE
135° POINT
1. MAX. PITCH-DOWN
2. BANK 15°(APPROX.)
45° POINT
1. MAX. PITCH-UP
ATTITUDE
2. BANK 15°
(APPROX.)
ENTRY:
1. LEVEL FLIGHT
2. MANEUVERING OR CRUISE
SPEED WHICHEVER IS LESS
OR MANUFACTURER'S
RECOMMENDED SPEED.
180° POINT
1. LEVEL FLIGHT
2. ENTRY AIRSPEED
3. ALTITUDE SAME AS
ENTRY ALTITUDE
Figure 9-5. Lazy eight.
Ch 09.qxd 5/7/04 8:14 AM Page 9-7
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9-8
turn; consequently, less rudder pressure is needed. It
will be noted that the controls are slightly crossed in
the right climbing turn because of the need for left
aileron pressure to prevent overbanking and right
rudder to overcome torque.
The correct power setting for the lazy eight is that
which will maintain the altitude for the maximum and
minimum airspeeds used during the climbs and
descents of the eight. Obviously, if excess power were
used, the airplane would have gained altitude when the
maneuver is completed; if insufficient power were
used, altitude would have been lost.
Common errors in the performance of lazy eights are:
• Failure to adequately clear the area.
• Using the nose, or top of engine cowl, instead of
the true longitudinal axis, resulting in
unsymmetrical loops.
• Watching the airplane instead of the
reference points.
• Inadequate planning, resulting in the peaks of the
loops both above and below the horizon not
coming in the proper place.
 
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