直升機(jī)教員手冊 Helicopter Instructor’s Handbook
時間：2014-11-10 08:35來源：FAA 作者：直升機(jī)翻譯 點擊：次
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To view this page ensure that Adobe Flash Player version 9.0.124 or greater is installed. How fast the helicopter banks depends on how much lateral cyclic pressure is applied. How far the helicopter banks (the steepness of the bank) depends on how long the cyclic is displaced. After establishing the proper bank angle, return the cyclic toward the neutral position. Explain to the student that the cyclic tilts the rotor disk relative to the horizon. The amount of tilt or bank depends on how much and how long the cyclic is displaced from perpendicular to the horizon. The rotor disk always follows the cyclic. As the pilot places the cyclic in a neutral position in relation to the helicopter, the cyclic is simply maintaining the rotor disk tilt as referenced to the horizon and the helicopter follows the rotor. Returning the cyclic to the neutral position simply stops the bank (rotor tilt) from increasing or decreasing. Use the collective and throttle to maintain altitude and rpm. As the torque increases, apply more pressure to the proper antitorque pedal to maintain longitudinal trim. Depending on the degree of bank, additional forward cyclic pressure may be required to maintain airspeed. When rolling out of a turn, the cyclic is moved back to perpendicular to the horizon, which brings the rotor back to level with the horizon. Lead or lag on the rollout is necessary to complete the maneuver on the desired heading. Common Student Difficulties Attitude Visualization of the bank angle is one of the most common problems for students. The angle between the tip-path plane and the horizon should always remain stable and consistent when banking or turning the helicopter. As the bank angle is established and the perspective changes, there is a tendency to use the center of the canopy as the pitch reference. It must be emphasized that the correct pitch reference is directly in front of the student. The pitch reference point should remain stationary as the helicopter is rolled into the bank, with a helicopter appearing to pivot around the pitch reference. The correct pitch attitude is confirmed by reference to the altimeter and a level turn. If the student attempts to maintain altitude solely by reference to the altimeter, overcontrolling usually results and the student begins chasing the altitude. Leaning Away From a Turn There is a natural tendency to keep the body, or at least the head, level. When the student leans away from the turn, perspective changes, making it even more difficult to maintain the correct attitude. Failure to Clear the Area The student is frequently so occupied with the problems associated with maintaining altitude, airspeed, bank angle, etc., that the responsibility of seeing and avoiding other aircraft is neglected. Clearing the area in the direction of the turn must be included in the items the instructor calls out while talking the student through the maneuver. Stress to the student that clearing of the helicopter is continuous. Other traffic occupies the same airspace such as traffic helicopters, crop dusters, rescue, police, power-line patrols and many others. If operating near military training areas, remind the student of low level VFR and IFR routes and the increase in flight activity. Birds or anything above ground level (towers, power lines, etc.) present flight hazards as well. Rolling Out of a Turn Difficulties associated with rolling out of a turn are usually related to scan problems. The student who is preoccupied with other factors often loses track of heading. Select a prominent landmark and instruct a student to anticipate the rollout by an amount equal to about half the bank angle. Climbing and Descending Turns Climbing and descending turns are used to further develop control and coordination. They also provide the practice required for departures and landing approaches. Instructional Points As always, before making any turns, clear the helicopter in the direction of the turn, as well as above and below the helicopter. The turnand climb/descentare usually initiated simultaneously. Until the student gains proficiency, it may be easier first to establish each maneuver separately. For example, to enter a climbing/descending turn, establish the turn first then adjust the controls for the climb/descent. You may reverse the order as well, with enough practice the student will learn to simultaneously perform the required control inputs to accomplish a climbing/descending turn. Common Student Difficulties Attitude Combining turns with climbs/descents introduces new helicopter attitudes and the initial perception of these attitudes may be difficult for the student to comprehend. A thorough briefing and demonstration minimizes this problem. The first climbing/descending turns should be established by beginning the climb/descent and then rolling into the desired bank angle in order to reduce the number of simultaneous control movements required. Scan As with the previous maneuvers, the scan pattern is easily interrupted by concentrating on a specific aspect of the maneuver. During early practice of climbing/descending turns, the instructor should call out all the items that require attention, even if no correction is required. As proficiency improves, the instructor should call attention only to the items that require corrective action. Coordination Exercises Once level flight, turns, climbs, and descents have been introduced, coordination exercises should be practiced to assist a student in developing subconscious coordinated control and proficiency. A good exercise to teach compensation for power changes is to make airspeed changes while maintaining straight-and-level flight. At a safe altitude, and while maintaining a constant rpm, altitude, and heading, have the student reduce airspeed to 40 knots by simultaneously applying aft cyclic and reducing power. Now, instruct the student to accelerate to approximately 80 knots by increasing forward cyclic and power. The maneuver may be repeated, as necessary, for proficiency. During these maneuvers, allowing a stable flight for a few moments and pointing out the helicopter’s attitude at the different airspeeds will help the student become familiar with that particular helicopter’s attitudes set by the horizontal stabilizer for those airspeeds and loads. There may be an 11 percent change in the weight of some helicopters when the instructor deboards for the student’s first solo flight, and a considerable sight picture change with that much weight out of one side of the helicopter. |
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