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drift correction is maintained.
SHORT-FIELD TAKEOFF
Wing flaps should be lowered prior to takeoff if
recommended by the manufacturer. Takeoff power
should be applied smoothly and continuously, (there
should be no hesitation) to accelerate the airplane as
rapidly as possible. As the takeoff roll progresses, the
airplane’s pitch attitude and angle of attack should be
adjusted to that which results in the minimum amount
of drag and the quickest acceleration. The tail should
be allowed to rise off the ground slightly, then held in
this tail-low flight attitude until the proper lift-off or
rotation airspeed is attained. For the steepest climb-out
and best obstacle clearance, the airplane should be
allowed to roll with its full weight on the main wheels
and accelerated to the lift-off speed.
Ch 13.qxd 5/7/04 10:04 AM Page 13-3
13-4
SOFT-FIELD TAKEOFF
Wing flaps may be lowered prior to starting the takeoff
(if recommended by the manufacturer) to provide
additional lift and transfer the airplane’s weight from
the wheels to the wings as early as possible. The
airplane should be taxied onto the takeoff surface
without stopping on a soft surface. Stopping on a soft
surface, such as mud or snow, might bog the
airplane down. The airplane should be kept in
continuous motion with sufficient power while lining
up for the takeoff roll.
As the airplane is aligned with the proposed takeoff
path, takeoff power is applied smoothly and as rapidly
as the powerplant will accept it without faltering. The
tail should be kept low to maintain the inherent
positive angle of attack and to avoid any tendency of
the airplane to nose over as a result of soft spots, tall
grass, or deep snow.
When the airplane is held at a nose-high attitude
throughout the takeoff run, the wings will, as speed
increases and lift develops, progressively relieve the
wheels of more and more of the airplane’s weight,
thereby minimizing the drag caused by surface
irregularities or adhesion. If this attitude is accurately
maintained, the airplane will virtually fly itself off the
ground. The airplane should be allowed to accelerate
to climb speed in ground effect.
TOUCHDOWN
The touchdown is the gentle settling of the airplane
onto the landing surface. The roundout and touchdown
should be made with the engine idling, and the airplane
at minimum controllable airspeed, so that the airplane
will touch down at approximately stalling speed. As
the airplane settles, the proper landing attitude must be
attained by applying whatever back-elevator pressure
is necessary. The roundout and touchdown should be
timed so that the wheels of the main landing gear and
tailwheel touch down simultaneously (three-point
landing). This requires proper timing, technique, and
judgment of distance and altitude. [Figure 13-1]
When the wheels make contact with the ground, the
elevator control should be carefully eased fully back
to hold the tail down and to keep the tailwheel on the
ground. This provides more positive directional
control of the airplane equipped with a steerable
tailwheel, and prevents any tendency for the airplane
to nose over. If the tailwheel is not on the ground,
easing back on the elevator control may cause the
airplane to become airborne again because the change
in attitude will increase the angle of attack and
produce enough lift for the airplane to fly.
It is extremely important that the touchdown occur
with the airplane’s longitudinal axis exactly parallel to
the direction the airplane is moving along the runway.
Failure to accomplish this not only imposes severe
side loads on the landing gear, but imparts
groundlooping (swerving) tendencies. To avoid these
side stresses or a ground loop, the pilot must never
allow the airplane to touch down while in a crab or
while drifting.
AFTER-LANDING ROLL
The landing process must never be considered
complete until the airplane decelerates to the normal
taxi speed during the landing roll or has been brought
to a complete stop when clear of the landing area. The
pilot must be alert for directional control difficulties
immediately upon and after touchdown due to the
ground friction on the wheels. The friction creates a
pivot point on which a moment arm can act. This is
because the CG is behind the main wheels.
[Figure 13-2]
Any difference between the direction the airplane is
traveling and the direction it is headed will produce a
moment about the pivot point of the wheels, and the
airplane will tend to swerve. Loss of directional
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AIRPLANE FLYING HANDBOOK 飞机飞行手册下(56)
