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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 PDF Create! 5 Trial www.nuance.com 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. www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：AIRPLANE FLYING HANDBOOK 飞机飞行手册下
