曝光臺 注意防騙 網曝天貓店富美金盛家居專營店坑蒙拐騙欺詐消費者

increase the power approximately 100 to 150 feet
prior to reaching the desired altitude. The power setting
should be that which is necessary to maintain the
desired airspeed in level flight. Hold the vertical speed
constant until approximately 50 feet above the desired
altitude. At this point, the altimeter becomes primary
for pitch, and the airspeed indicator becomes primary
for power. The leveloff from a constant rate descent
should be accomplished in the same manner as the leveloff
from a constant airspeed descent.
COMMON ERRORS DURING STRAIGHT CLIMBS
AND DESCENTS
1. Failure to maintain heading.
2. Improper use of power.
3. Poor control of pitch attitude.
4. Failure to maintain proper pedal trim.
5. Failure to level off on desired altitude.
TURNS
When making turns by reference to the flight instruments,
they should be made at a definite rate. Turns
described in this chapter are those that do not exceed a
standard rate of 3° per second as indicated on the turnand-
slip indicator. True airspeed determines the angle
of bank necessary to maintain a standard rate turn. A
rule of thumb to determine the approximate angle of
bank required for a standard rate turn is to divide your
airspeed by 10 and add one-half the result. For example,
at 60 knots, approximately 9° of bank is required
(60 ÷ 10 = 6 + 3 = 9); at 80 knots, approximately 12° of
bank is needed for a standard rate turn.
To enter a turn, apply lateral cyclic in the direction of the
desired turn. The entry should be accomplished
smoothly, using the attitude indicator to establish the
approximate bank angle. When the turn indicator indicates
a standard rate turn, it becomes primary for bank.
The attitude indicator now becomes a supporting instrument.
During level turns, the altimeter is primary for
pitch, and the airspeed indicator is primary for power.
Primary and supporting instruments for a stabilized standard
rate turn are illustrated in figure 12-20. If an
Figure 12-20. Flight instrument indications for a standard rate turn to the left.
40
50 60 70
80
90
100
110
0 120
10
20
30
TORQUE
PERCENT
Primary Bank Initially
 

Supporting Pitch
Primary Power Primary Pitch
Primary Bank as
 Supporting Pitch
Turn is Established
Supporting

Power

 

12-16
increase in power is required to maintain airspeed, slight
forward cyclic pressure may be required since the helicopter
tends to pitch up as collective pitch angle is
increased. Apply pedal trim, as required, to keep the ball
centered.
To recover to straight-and-level flight, apply cyclic in
the direction opposite the turn. The rate of roll-out
should be the same as the rate used when rolling into
the turn. As you initiate the turn recover, the attitude
indicator becomes primary for bank. When the helicopter
is approximately level, the heading indicator
becomes primary for bank as in straight-and-level
flight. Cross-check the airspeed indicator and ball
closely to maintain the desired airspeed and pedal trim.
TURNS TO A PREDETERMINED HEADING
Ahelicopter turns as long as its lateral axis is tilted; therefore,
the recovery must start before the desired heading is
reached. The amount of lead varies with the rate of turn
and your piloting technique.
As a guide, when making a 3° per second rate of turn,
use a lead of one-half the bank angle. For example, if
you are using a 12° bank angle, use half of that, or 6°,
as the lead point prior to your desired heading. Use this
lead until you are able to determine the exact amount
required by your particular technique. The bank angle
should never exceed the number of degrees to be
turned. As in any standard rate turn, the rate of recovery
should be the same as the rate for entry. During
turns to predetermined headings, cross-check the primary
and supporting pitch, bank, and power instruments
closely.
TIMED TURNS
A timed turn is a turn in which the clock and turn-andslip
indicator are used to change heading a definite
number of degrees in a given time. For example, using
a standard rate turn, a helicopter turns 45° in 15 seconds.
Using a half-standard rate turn, the helicopter
turns 45° in 30 seconds. Timed turns can be used if
your heading indicator becomes inoperative.
Prior to performing timed turns, the turn coordinator
should be calibrated to determine the accuracy of its
indications. To do this, establish a standard rate turn by
　
中國航空網 www.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：ROTORCRAFT FLYING HANDBOOK2(27)