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unnecessarily.
• Inadequate rotation resulting in excessive speed after
lift-off.
• Inability to attain/maintain best VX airspeed.
• Fixation on the airspeed indicator during initial
climb.
Soft/Rough Field Takeoff and Climb
Takeoffs and climbs from soft fi elds require the use of
operational techniques for getting the WSC aircraft airborne
as quickly as possible to eliminate the drag caused by tall
grass, soft sand, mud, and snow, and may or may not require
climbing over an obstacle. The technique makes judicious
use of ground effect and requires a feel for the WSC aircraft
and fi ne control touch. These same techniques are also useful
on a rough fi eld where it is advisable to get the aircraft off
the ground as soon as possible to avoid damaging the landing
gear.
Soft surfaces or long, wet grass usually reduce the aircraft’s
acceleration during the takeoff roll so much that adequate
takeoff speed might not be attained if normal takeoff
techniques were employed.
It should be emphasized that the WSC aircraft is different
from most aircraft. The high wing creates a high center of
gravity in which the front wheel can bog down in soft fi elds
and fl ip the WSC aircraft forward. The propeller in the
back pushing down on the front wheel also contributes to
this unique situation. This is a limitation for WSC aircraft
that should not be ignored. WSC aircraft that land in soft
fi elds or sand may not be able to take off. There is a wide
variation of manufacturer designs with the least preferable
being a skinny, high pressure, highly loaded front tire. WSC
aircraft with large wide tires that can be operated at low
pressure are designed for operation in soft and rough fi elds.
[Figures 7-11 through 7-13]
Correct takeoff procedure for soft fi elds and rough fi elds is
quite different from that appropriate for short fi elds with fi rm,
smooth surfaces. To minimize the hazards associated with
takeoffs from soft or rough fi elds, support of the aircraft’s
weight must be transferred as rapidly as possible from the
wheels to the wings as the takeoff roll proceeds. Establishing
and maintaining a relatively high angle of attack with a nosehigh
pitch attitude as early as possible achieves this.
7-11
Figure 7-12. Example of a WSC aircraft designed with a wide low-pressure front wheel for soft field operation.
Figure 7-13. Grass fields are commonly used for WSC operations but require a longer time to accelerate to takeoff speed.
7-12
Figure 7-14. Rough and soft field takeoff.
ACCELERATE WITH NOSE UP ACCELERATE IN GROUND EFFECT CLIMB AT VY
Rotate and lift off
as soon as possible
Stopping on a soft surface, such as mud, snow or sand,
might bog the aircraft down; therefore, it should be kept in
continuous motion with suffi cient power while lining up for
the takeoff roll.
Takeoff Roll
As the aircraft is aligned with the takeoff path, takeoff power
is applied smoothly and rapidly. As the aircraft accelerates,
the control bar is moved full forward to the front tube to
establish a positive angle of attack and to reduce the weight
supported by the nosewheel because any lift on the wing
takes load off of the landing gear.
When the aircraft is held at a nose-high attitude throughout
the takeoff run and as speed increases and lift develops, the
wings progressively relieve the wheels of more and more of
the WSC’s weight, thereby minimizing the drag caused by
surface irregularities or adhesion. If this attitude is accurately
maintained, the aircraft virtually fl ies itself off the ground,
becoming airborne at airspeed slower than a safe climb speed
because of ground effect. [Figure 7-14]
Lift-Off and Initial Climb
After becoming airborne, the nose should be lowered very
gently with the wheels clear but just above the surface to
allow the aircraft to utilize ground effect to accelerate to VY,
or VX if obstacles must be cleared. Extreme care must be
exercised immediately after the aircraft becomes airborne and
while it accelerates to avoid settling back onto the surface.
An attempt to climb prematurely or too steeply may cause the
aircraft to settle back to the surface as a result of losing the
benefi t of ground effect. An attempt to climb out of ground
effect before suffi cient climb airspeed is attained may result
in aircraft incapacity to continue climbing as the ground effect
area is traveled, even with full power for lower powered WSC
aircraft. Therefore, it is essential that the aircraft remain in
ground effect until at least VX is reached. This requires a feel
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Weight-Shift Control Aircraft Flying Handbook(92)
