直升机飞行训练手册 HELICOPTER FLIGHT TRAINING MANUAL(20)

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Secondary effects of controls will also be noticed in the hover. Raising the collective will result in an increase in torque and this will cause the helicopter to yaw to the right. A yaw in the opposite direction will occur if the collective is lowered. In addition, if you are flying some piston engine helicopters, the throttle may have to be adjusted to maintain RPM as the collective is raised or lowered.
THE PEDALS
During hovering flight the anti-torque pedals are used to maintain or change the helicopter heading. In the hover, the effect of torque is more noticeable than in forward flight. Therefore, the nose of the helicopter will tend to yaw more in the hover, and this has to be countered with opposite pedal pressure. To turn left in the hover, left pedal is applied, and the reverse is true for a right turn. 
NOTE:  In a piston engine helicopter, the throttle may have to be increased slightly as left pedal is applied, and decreased as right pedal is applied.

 
Figure 8-3 Hover reference points
VISUAL CUES
In a hover any change in attitude, if not corrected, will cause the helicopter to move. You  must recognize any changes in attitude and make the necessary control corrections before the helicopter moves. Initially, it may be difficult to recognize these changes. As in upper air flying, it may be easier to first use the horizon as a reference, and then as you become more proficient focus your eyes on a reference closer to the helicopter (approximately 50 feet).
SUMMARY
The cyclic is used to control the disc attitude, and therefore the helicopter position over the ground. Height is controlled with collective, and the pedals are used to maintain directional control. In a piston-engine helicopter, the throttle may have to be adjusted as pedals or collective are moved.
NOTE:  The secret to mastering the skill of hovering a helicopter is to use very small, smooth control movements and lots of practice.
 
EXERCISE 9 - TAKEOFF AND LANDING
In this exercise you will learn how to take off to and land from the hover. It is important for reasons of safety of flight that you should be able to perform this manoeuvre accurately, as any lateral drift could cause a rolling moment if ground contact is made, possibly leading to dynamic rollover. Similarly rearward movement is undesirable, as you cannot see behind you and the tail rotor could be severely damaged should contact be made with an obstacle.
Before takeoff, the pre-take-off check should be completed, and you must look out to check the surroundings.
After every takeoff, a hover check must be completed.
Prior to landing, the area must be checked to ensure it is free of obstacles and the landing surface is suitable.
If possible make your takeoffs and landings into wind.
TAKEOFF TO THE HOVER
The first step prior to take off is to complete the pre-take off checklist. This includes a lookout to ensure the area is clear.
The effects of controls for takeoff and landing are the same as for hovering. They are used as follows:
1. The cyclic is used to maintain position over the ground during the takeoff. Before starting the takeoff, the cyclic is centralized, and then adjusted as required to ascend vertically and prevent the helicopter from drifting. Cyclic position during takeoff will vary with aircraft type, wind direction, and weight and balance. For accurate control it is important that  the cyclic inputs be very smooth and small.
2. The collective is used to lift off and climb from the ground to the normal hover height of  3 to 5 feet. The collective should be raised slowly so the other controls can be adjusted,  as the helicopter becomes “light on the skids”; this will ensure that an accurate takeoff is accomplished. The right skid will leave the ground first, so you will have to ease the  cyclic to the right to compensate for this.
3. For takeoff, the pedals are used to control the heading of the helicopter. Prior to take off the pedals are centralized. As torque is increased pedal will have to be applied to maintain heading. The amount of pedal required will vary with the wind direction and power.
　
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