Movement
Helicopter
Side Movement
Figure 9-9. During a slip, the rotor disc is tilted into the wind.
Wind
Movement
Helicopter Ground
Helicopter
Track
Heading
Figure 9-10. To compensate for wind drift at altitude, crab the
helicopter into the wind.
9-12
STRAIGHT-AND-LEVEL FLIGHT
Straight-and-level flight is flight in which a constant
altitude and heading are maintained. The attitude of the
helicopter determines the airspeed and is controlled by
the cyclic. Altitude is primarily controlled by use of the
collective.
TECHNIQUE
To maintain forward flight, the rotor tip-path plane must
be tilted forward to obtain the necessary horizontal
thrust component from the main rotor. This generally
results in a nose-low attitude. The lower the nose, the
greater the power required to maintain altitude, and the
higher the resulting airspeed. Conversely, the greater
the power used, the lower the nose must be to maintain
altitude. [Figure 9-11]
When in straight-and-level flight, any increase in the
collective, while holding airspeed constant, causes the
helicopter to climb. A decrease in the collective, while
holding airspeed constant, causes the helicopter to
descend. A change in the collective requires a coordinated
change of the throttle to maintain a constant
r.p.m. Additionally, the antitorque pedals need to be
adjusted to maintain heading and to keep the helicopter
in longitudinal trim.
To increase airspeed in straight-and-level flight, apply
forward pressure on the cyclic and raise the collective
as necessary to maintain altitude. To decrease airspeed,
apply rearward pressure on the cyclic and lower the
collective, as necessary, to maintain altitude.
Although the cyclic is sensitive, there is a slight delay
in control reaction, and it will be necessary to anticipate
actual movement of the helicopter. When making
cyclic inputs to control the altitude or airspeed of a helicopter,
take care not to overcontrol. If the nose of the
helicopter rises above the level-flight attitude, apply
forward pressure to the cyclic to bring the nose down.
If this correction is held too long, the nose drops too
low. Since the helicopter continues to change attitude
momentarily after the controls reach neutral, return the
cyclic to neutral slightly before the desired attitude is
reached. This principal holds true for any cyclic input.
Since helicopters are inherently unstable, if a gust or
turbulence causes the nose to drop, the nose tends to
continue to drop instead of returning to a straight-andlevel
attitude as would a fixed-wing aircraft.
Therefore, you must remain alert and FLY the helicopter
at all times.
COMMON ERRORS
1. Failure to properly trim the helicopter, tending to
hold antitorque pedal pressure and opposite
cyclic. This is commonly called cross-controlling.
2. Failure to maintain desired airspeed.
3. Failure to hold proper control position to maintain
desired ground track.
TURNS
A turn is a maneuver used to change the heading of the
helicopter. The aerodynamics of a turn were previously
discussed in Chapter 3—Aerodynamics of Flight.
TECHNIQUE
Before beginning any turn, the area in the direction of
the turn must be cleared not only at the helicopter’s altitude,
but also above and below. To enter a turn from
straight-and-level flight, apply sideward pressure on
the cyclic in the direction the turn is to be made. This is
the only control movement needed to start the turn. Do
not use the pedals to assist the turn. Use the pedals only
to compensate for torque to keep the helicopter in longitudinal
trim. [Figure 9-12]
How fast the helicopter banks depends on how much
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