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Flying Handbook Menu > Slow Flight, Stalls, and Spins > Stalls > Use Of Ailerons/Rudder In Stall
Recovery
Different types of airplanes have different
stall characteristics. Most airplanes are designed so that the
wings will stall progressively outward from the wing roots (where
the wing attaches to the fuselage) to the wingtips. This is
the result of designing the wings in a manner that the wingtips
have less angle of incidence than the wing roots. [figure4-4]
Such a design feature causes the wingtips to have a smaller
angle of attack than the wing roots during flight.Exceeding
the critical angle of attack causes a stall; the wing roots
of an airplane will exceed the critical angle before the wingtips,
and the wing roots will stall first. The wings are designed
in this manner so that aileron control will be available at
high angles of attack (slow airspeed) and give the airplane
more stable stalling characteristics.
When the airplane is in a stalled condition,
the wingtips continue to provide some degree of lift, and the
ailerons still have some control effect. During recovery from
a stall, the return of lift begins at the tips and progresses
toward the roots. Thus, the ailerons can be used to level the
wings.
Using the ailerons requires finesse to avoid
an aggravated stall condition. For example, if the right wing
dropped during the stall and excessive aileron control were
applied to the left to raise the wing, the aileron deflected
downward (right wing) would produce a greater angle of attack
(and drag), and possibly a more complete stall at the tip as
the critical angle of attack is exceeded. The increase in drag
created by the high angle of attack on that wing might cause
the airplane to yaw in that direction. This adverse yaw could
result in a spin unless directional control was maintained by
rudder, and/or the aileron control sufficiently reduced.
Even though excessive aileron pressure may
have been applied, a spin will not occur if directional (yaw)
control is maintained by timely application of coordinated rudder
pressure. Therefore, it is important that the rudder be used
properly during both the entry and the recovery from a stall.
The primary use of the rudder in stall recoveries is to counteract
any tendency of the airplane to yaw or slip. The correct recovery
technique would be to decrease the pitch attitude by applying
forward-elevator pressure to break the stall, advancing the
throttle to increase airspeed, and simultaneously maintaining
directional control with coordinated use of the aileron and
rudder.
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