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Airplane Flying Handbook
Slow Flight, Stalls, and Spins
Stalls

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Airplane Flying Handbook

Preface

Table of Contents

Chapter 1,Introduction to Flight Training
Chapter 2,Ground Operations
Chapter 3,Basic Flight Maneuvers
Chapter 4, Slow Flight, Stalls, and Spins
Chapter 5, Takeoff and Departure Climbs
Chapter 6, Ground Reference Maneuvers
Chapter 7, Airport Traffic Patterns
Chapter 8, Approaches and Landings
Chapter 9, Performance Maneuvers
Chapter 10, Night Operations
Chapter 11,Transition to Complex Airplanes
Chapter 12, Transition to Multiengine Airplanes
Chapter 13,Transition to Tailwheel Airplanes
Chapter 14, Transition to Turbo-propeller Powered Airplanes
Chapter 15,Transition to Jet Powered Airplanes
Chapter 16,Emergency Procedures

Glossary

Index

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.

STALL CHARACTERISTICS
Because of engineering design variations, the stall
characteristics for all airplanes cannot be specifically
described; however, the similarities found in small
general aviation training-type airplanes are noteworthy
enough to be considered. It will be noted that the
power-on and power-off stall warning indications will
be different. The power-off stall will have less
noticeable clues (buffeting, shaking) than the
power-on stall. In the power-off stall, the predominant
clue can be the elevator control position (full up elevator
against the stops) and a high descent rate.

When performing the power-on stall, the buffeting will
likely be the predominant clue that provides a positive
indication of the stall. For the purpose of airplane
certification, the stall warning may be furnished either
through the inherent aerodynamic qualities of the
airplane, or by a stall warning device that will give a
clear distinguishable indication of the stall. Most
airplanes are equipped with a stall warning device.

The factors that affect the stalling characteristics of the
airplane are balance, bank, pitch attitude, coordination,
drag, and power. The pilot should learn the effect of the
stall characteristics of the airplane being flown and the
proper correction. It should be reemphasized that a stall
can occur at any airspeed, in any attitude, or at any
power setting, depending on the total number of factors
affecting the particular airplane.

A number of factors may be induced as the result of
other factors. For example, when the airplane is in a
nose-high turning attitude, the angle of bank has a
tendency to increase. This occurs because with the
airspeed decreasing, the airplane begins flying in a
smaller and smaller arc. Since the outer wing is
moving in a larger radius and traveling faster than the
inner wing, it has more lift and causes an overbanking
tendency. At the same time, because of the decreasing
airspeed and lift on both wings, the pitch attitude tends
to lower. In addition, since the airspeed is decreasing
while the power setting remains constant, the effect of
torque becomes more prominent, causing the airplane
to yaw.

During the practice of power-on turning stalls, to
compensate for these factors and to maintain a
constant flight attitude until the stall occurs, aileron
pressure must be continually adjusted to keep the bank
attitude constant. At the same time, back-elevator
pressure must be continually increased to maintain the
pitch attitude, as well as right rudder pressure
increased to keep the ball centered and to prevent
adverse yaw from changing the turn rate. If the bank is
allowed to become too steep, the vertical component
of lift decreases and makes it even more difficult to
maintain a constant pitch attitude.

Whenever practicing turning stalls, a constant pitch
and bank attitude should be maintained until the stall
occurs. Whatever control pressures are necessary
should be applied even though the controls appear to
be crossed (aileron pressure in one direction, rudder
pressure in the opposite direction). During the entry to
a power-on turning stall to the right, in particular, the
controls will be crossed to some extent. This is due to
right rudder pressure being used to overcome torque
and left aileron pressure being used to prevent the
bank from increasing.

 

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