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by using the air rudder and the ailerons, always maintaining
a precise planing attitude with elevator. The
ailerons are positioned into the turn, except when
aileron into the wind is needed to keep the upwind wing
from lifting.
Step taxiing should only be attempted in areas where the
pilot is confident there is sufficient water depth, no floating
debris, no hidden obstructions, and no other water
traffic nearby. It can be difficult to spot floating hazards
at high speeds, and an encounter with a floating log or
other obstruction could tear open a float. Your seaplane
is not as maneuverable as craft that were designed for
the water, so avoiding other vessels is much more difficult.
Besides the obvious danger of collision, other
water traffic creates dangerous wakes, which are a
much more frequent cause of damage. If you see that
you are going to cross a wake, reduce power to idle
and idle taxi across it, preferably at an angle. Never
try to step taxi in shallow water. If the floats touch
bottom at high speed, the sudden drag is likely to flip
the seaplane.
From either the plowing or the step position, when
power is reduced to idle, the seaplane decelerates quite
rapidly and eventually assumes the displacement or
idle position. Be careful to use proper flight control
pressures during the deceleration phase because as
weight is transferred toward the front of the floats and
drag increases, some seaplanes have a tendency to nose
over. Control this with proper use of the elevator.
TURNS
At low speeds and in light winds, make turns using the
water rudders, which move in conjunction with the air
rudder. As with a landplane, the ailerons should be
positioned to minimize the possibility of the wind lifting
a wing. In most airplanes, left turns are somewhat
easier and can be made tighter than right turns because
of torque. If water rudders have the proper amount of
movement, most seaplanes can be turned within a
radius less than the span of the wing in calm conditions
or a light breeze. Water rudders are usually more effective
at slow speeds because they are acting in comparatively
undisturbed water. At higher speeds, the stern
of the float churns the adjacent water, causing the water
rudder to become less effective. The dynamic pressure
of the water at high speeds may tend to force the water
rudders to swing up or retract, and the pounding can
cause damage. For these reasons, water rudders should
be retracted whenever the seaplane is moving at high
speed.
The weathervaning tendency is more evident in seaplanes,
and the taxiing seaplane pilot must be constantly aware of
the wind’s effect on the ability to maneuver. In stronger
winds, weathervaning forces may make it difficult to turn
Figure 4-7. On the step. The attitude is nearly level, and the weight of the seaplane is supported mostly by hydrodynamic lift.
Behind the step, the floats are essentially clear of the water.
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downwind. Often a short burst of power provides sufficient
air over the rudder to overcome weathervaning.
Since the elevator is held all the way up, the
airflow also forces the tail down, making the water
rudders more effective. Short bursts of power are
preferable to a longer, continuous power application.
With continuous power, the seaplane accelerates,
increasing the turn radius. The churning of the water
in the wake of the floats also makes the water rudders
less effective. At the same time, low cooling airflow
may cause the engine to heat up.
During a high speed taxiing turn, centrifugal force
tends to tip the seaplane toward the outside of the turn.
When turning from an upwind heading to a downwind
heading, the wind force acts in opposition to centrifugal
force, helping stabilize the seaplane. On the other
hand, when turning from downwind to upwind, the
wind force against the fuselage and the underside of
the wing increases the tendency for the seaplane to lean
to the outside of the turn, forcing the downwind float
deeper into the water. In a tight turn or in strong winds,
the combination of these two forces may be sufficient
to tip the seaplane to the extent that the downwind float
submerges or the outside wing drags in the water, and
may even flip the seaplane onto its back. The further
the seaplane tips, the greater the effect of the crosswind,
as the wing presents more vertical area to the
wind force. [Figure 4-8]
When making a turn into the wind from a crosswind
condition, often all that is necessary to complete the
　
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