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During a turn, instrument indications are as follows:
TURN AND BANK INDICATOR. The needle will deflect in the direction of the turn and will indicate the rate at which the helicopter is turning. In a co-ordinated turn the ball will be centred in its curved glass tube. If the ball is off-centre to the inside of the turn, the helicopter is slipping into the centre of the turn. If the ball is off-centre to the outside of the turn, the helicopter is skidding out from the turn.
ATTITUDE INDICATOR. The horizon bar will remain parallel to the real horizon, and the miniature aircraft in relation to the horizon bar will bank in the same direction as the helicopter. This instrument indicates the angle of bank and the attitude of the helicopter in the pitching plane. The nose of the miniature aircraft in relation to its artificial horizon corresponds to the pitch attitude of the nose of the helicopter in relation to the real horizon.
HEADING INDICATOR. Immediately as a turn begins, this instrument begins rotating to indicate the successive new headings of the helicopter during the turn. When the turn stops, it stops. To decrease the numerical values on the face of the instrument turn left; to increase values turn right. A memory aid is “left for less”.
AIRSPEED INDICATOR. The instrument that does not perceptibly react until well into a co-ordinated turn is the airspeed indicator. Since the load factor increases as a result of the turn, additional lift must be obtained by tilting the rotor to the rear. In a gentle turn the decrease is barely noticeable, even in a well-executed medium turn the airspeed may be only slightly lower. If the nose is allowed to pitch up too high there will be a decrease in airspeed; conversely, if the nose is allowed to pitch down too low, the airspeed indicator will rapidly indicate an increase in speed.
ALTIMETER. In a co-ordinated level turn, the altimeter needle would remain stationary at the selected altitude. If the nose is held too high, there will be an increase in altitude. If the nose is allowed to drop too low, a decrease in altitude will be indicated.
EXERCISE 7 - AUTOROTATIONS 1 (UPPER AIR)
An autorotation may be defined as the condition of flight where the rotor is driven by aerodynamic forces, with no power being delivered by the engine. Autorotational flight is a basic and essential emergency procedure at which every helicopter pilot must be proficient. Although modern helicopter engines and other major components are extremely reliable, pilots will ensure that they are capable of flying the helicopter under other than normal situations, including engine failure. During autorotation the helicopter is still flying despite the fact that the engine is not delivering motive power to the rotors. It remains fully manoeuvrable albeit in descending flight. Remember also that the airflow is now upward through the disc rather than downward as in powered flight. Prior to conducting this exercise, your instructor will review with you the manufacturer’s recommended airspeeds and rotor RPM for minimum rate of descent in autorotation. These speeds can be found in the aircraft flight manual.
This exercise will be your introduction to autorotations. In it you will be concentrating on the entry procedure, establishing a descent at the airspeed for the minimum rate of descent, and how to conduct an overshoot to the climb from the autorotational descent.
CHECKS
Good airmanship requires that, prior to carrying out autorotational descents, you must perform “pre-entry” checks, to include:
1. pre-landing check. It is important to ensure that all engine instrument indications are normal since you will be retarding the throttle to idle. Check you are still strapped in and there are no loose articles in the cabin;
2. look out. Confirm that the immediate vicinity is clear of other aircraft and pay particular attention to your descent path ahead and below;
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直升机飞行训练手册 HELICOPTER FLIGHT TRAINING MANUAL(17)
