Figure 6-14. Best angle of climb (VX) versus best rate of climb (VY).
Best angle-of-climb airspeed (VX)
gives the greatest altitude gain
in the shortest horizontal distance. Best rate-of-climb airspeed (Vy)
gives the greatest altitude gain in
a given unit of time.
rate of altitude gain. Trim is usually set at the V Y or
higher.
• Best angle of climb (V X)—performed at an airspeed
that will produce the most altitude gain in a given
horizontal distance. Best VX airspeed is lower than VY
but higher than minimum controlled airspeed. The VX
results in a steeper climb path, although the aircraft
takes longer to reach the same altitude than it would
at VY. The VX, therefore, is used in clearing obstacles
after takeoff. Since the VX is closer to the stall speed,
caution should be exercised using this speed to
climb so as not to stall the WSC aircraft close to the
ground with potentially catastrophic consequences.
[Figure 6-14]
Climbing flight requires more power than flying level,
as described in chapter 2. When performing a climb, the
normal climb speed should be established and the power
should be advanced to the climb power recommended by the
manufacturer. As the aircraft gains altitude during a climb,
the engine has a loss in power because the same volume of
air entering the engine’s induction system gradually decreases
in density as altitude increases.
During a climb, a constant heading should be held with
the wings level if a straight climb is being performed, or
a constant angle of bank and rate of turn if a climbing turn
is being performed. To return to straight-and-level fl ight,
when approaching the target altitude, increase the speed
to the cruise setting (if different) and decrease throttle for
level fl ight. After the aircraft is established in level fl ight at
a constant altitude and the desired speed, the aircraft should
be trimmed (if equipped with an in fl ight trim system).
In the performance of climbing turns, the following factors
should be considered.
• With a constant power setting, the same pitch attitude
and airspeed cannot be maintained in a bank as in
a straight climb due to the increase in the total lift
required.
• The degree of bank should not be too steep. A steep
bank signifi cantly decreases the rate of climb. The
bank should always remain constant.
• At a constant power setting and turning while climbing,
the WSC aircraft climbs at a slightly shallower climb
angle because some of the lift is being used to turn.
• Attention should be looking at outside references and
scanning for traffi c with no more than 25 percent of
the time looking at inside fl ight deck instruments.
There are two ways to establish a climbing turn. Either
establish a straight climb and then turn, or enter the climb
and turn simultaneously. Climbing turns should be used
when climbing to the local practice area. Climbing turns
allow better visual scanning, and it is easier for other pilots
to see a turning aircraft.
In any turn, the loss of vertical lift and increased induced
drag due to increased angle of attack becomes greater as the
angle of bank is increased. So, shallow turns should be used
to maintain an effi cient rate of climb. All the factors that
affect the aircraft during level (constant altitude) turns affect
it during climbing turns or any other maneuver.
Figure 6-15. Descent speeds and glide angles.
Descent at Minimum Sa
fe Airspeed
Steep Approach
Best Glide Partial Power De
scent
Common errors in the performance of climbs and climbing
turns are:
• A bank angle too high to achieve an effi cient climb.
• A speed too high to achieve an effi cient climb rate.
• A speed that is too low.
• Attempting to exceed the aircraft’s climb capability.
• Inability to keep pitch and bank attitude constant
during climbing turns.
• Attempting to establish climb pitch attitude by
referencing the airspeed indicator, resulting in
“chasing” the airspeed.
Descents and Descending Turns
When an aircraft enters a descent, it changes its fl ightpath
from level to an inclined plane. It is important that the pilot
know the power settings and pitch attitudes that produce the
following conditions of descent.
• Partial power descent—the normal method of losing
altitude is to descend with partial power. This is often
termed “cruise” or “en route” descent. The airspeed
and power setting recommended by the aircraft
manufacturer for prolonged descent should be used.
The target descent rate should be 400–500 fpm.
• Steep approach—the normal maneuver used to
descend at a steep angle. This is typically used to
descend for landing if higher than expected upon
approaching the runway. The throttle is set to idle
and the airspeed is increased so the excessive drag
allows the WSC aircraft to descend at the steepest
angle. The control bar is pulled in to achieve this steep
approach—the further the bar is pulled in, the steeper
the descent rate. Each WSC aircraft is different, but
pulling the control bar to the chest may be necessary
to achieve the required angle.
• Descent at minimum safe airspeed—a nose-high
descent. This should only be used for unusual
situations such as clearing high obstacles for a short
runway in an emergency situation. The only advantage
is a steeper than normal descent angle. This is similar
to the best angle of climb speed and should only be
used with caution because stalling near the ground
could have catastrophic consequences for the pilot,
passenger, and people/property on the ground.
• Glide—a basic maneuver in which the aircraft loses
altitude in a controlled descent with little or no engine
power; forward motion is maintained by gravity
pulling the aircraft along an inclined path, and the
descent rate is controlled by the pilot balancing the
forces of gravity and lift. [Figure 6-15]
Although glides are directly related to the practice of power-
off accuracy landings, they have a specifi c operational purpose
in normal landing approaches and forced landings after engine
failure. Therefore, it is necessary that they be performed more
subconsciously than other maneuvers because most of the
time during their execution, the pilot gives full attention to
details other than the mechanics of performing the maneuver.
Since glides are usually performed relatively close to the
ground, accuracy of their execution, the formation of proper
technique, and habits are of special importance.
The glide ratio of a WSC aircraft is the distance the aircraft,
with power off, travels forward in relation to the altitude
it loses. For instance, if it travels 5,000 feet forward while
descending 1,000 feet, its glide ratio is said to be 5 to 1.
The glide ratio is affected by all four fundamental forces that
act on an aircraft (weight, lift, drag, and thrust). If all factors
affecting the aircraft are constant, the glide ratio is constant.
Increasing Lift-to-Drag Ratio
Increasing Speed
Stall
LD-MAX
VNE
Figure 6-16. LDMAX.
Although the effect of wind is not covered in this section, it
is a very prominent force acting on the gliding distance of the
aircraft in relationship to its movement over the ground. With
a tailwind, the aircraft glides farther because of the higher
groundspeed. Conversely, with a headwind the aircraft does
not glide as far because of the slower groundspeed.
Variations in weight for an aircraft with a rigid wing
do not affect the glide angle provided the pilot uses the
correct airspeed. Since it is the lift over drag (LD) ratio that
determines the distance the aircraft can glide, weight does
not affect the distance. The glide ratio is based only on the
relationship of the aerodynamic forces acting on the aircraft.
The only effect weight has is to vary the time the aircraft
glides. The heavier the aircraft, the higher the airspeed must
be to obtain the same glide ratio. For example, if two aircraft
having the same LD ratio but different weights start a glide
from the same altitude, the heavier aircraft gliding at a higher
airspeed arrives at the same touchdown point in a shorter
time. Both aircraft cover the same distance, only the lighter
aircraft takes a longer time.
However, the WSC aircraft has different characteristics
because it has a fl exible airframe. As more weight is added
to the WSC wing, it fl exes more creating more twist in the
wing decreasing aerodynamic effi ciency, as discussed in
chapter 2. For example, a pilot is accustomed to a glide ratio
of 5 to 1 fl ying solo; a passenger is added, and this glide ratio
may decrease to 4 to 1. This decrease in glide ratio for added
weight is true for all descent speeds. The amount of decrease
in glide ratio varies signifi cantly between manufactures and
models because each wing fl exes differently. The more
fl exible the wing is, the greater the decrease in glide ratio.
Pilots should become familiar with glide ratios for their
aircraft at all speeds and all weights.
Although the propeller thrust of the aircraft is normally
dependent on the power output of the engine, the throttle is
in the closed position during a glide so the thrust is constant.
Since power is not used during a glide or power-off approach,
the pitch attitude must be adjusted as necessary to maintain
a constant airspeed.
The best speed for the glide is one at which the aircraft travels
the greatest forward distance for a given loss of altitude in still
air. This best glide speed corresponds to an angle of attack
resulting in the least drag on the aircraft and giving the best
lift-to-drag ratio (LDMAX). [Figure 6-16]
Any change in the gliding airspeed results in a proportionate
change in glide ratio. Any speed, other than the best glide
speed, results in more drag. Therefore, as the glide airspeed
is reduced or increased from the optimum or best glide speed,
the glide ratio is also changed. When descending at a speed
below the best glide speed, induced drag increases. When
descending at a speed above best glide speed, parasite drag
increases. In either case, the rate of descent increases and the
glide ratio decreases.
This leads to a cardinal rule of aircraft fl ying that a student
pilot must understand and appreciate: the pilot must never
attempt to “stretch” a glide by applying nose up pressure and
reducing the airspeed below the aircraft’s recommended best
glide speed. Attempts to stretch a glide invariably result in an
increase in the rate and angle of descent and may precipitate
an inadvertent stall.
To enter a glide, the pilot should close the throttle and
obtain the best glide speed. When the approximate gliding
pitch attitude is established, the airspeed indicator should
be checked. If the airspeed is higher than the recommended
speed, the pitch attitude is too low; if the airspeed is less than
recommended, the pitch attitude is too high. Therefore, the
pitch attitude should be readjusted accordingly by referencing
the horizon. After the adjustment has been made, the aircraft
should be retrimmed (if equipped) so that it maintains this
attitude without the need to hold pitch pressure on the control
bar. The principles of attitude fl ying require that the proper
fl ight attitude be established using outside visual references
fi rst, then using the fl ight instruments as a secondary check.
It is a good practice to always retrim the aircraft after each
pitch adjustment.
A stabilized power-off descent at the best glide speed is
often referred to as a normal glide. The fl ight instructor
should demonstrate a normal glide, and direct the student
pilot to memorize the aircraft’s angle and speed by visually
checking the:
1. Aircraft’s attitude with reference to the horizon.
2. Noting the pitch of the sound made by the air.
3. Pressure on the controls, and the feel of the aircraft.
Due to lack of experience, the beginning student may be
unable to recognize slight variations of speed and angle of
bank immediately by vision or by the pressure required on
the controls. The student pilot must use all three elements
consciously until they become habits, and must be alert when
attention is diverted from the attitude of the aircraft. A student
must be responsive to any warning given by a variation in
the feel of the aircraft or controls or by a change in the pitch
of the sound.
After a good comprehension of the normal glide is attained,
the student pilot should be instructed of the differences in
the results of normal and abnormal glides. Abnormal glides
are those conducted at speeds other than the normal best
glide speed. Pilots who do not acquire an understanding and
appreciation of these differences experience diffi culties with
accuracy landings which are comparatively simple if the
fundamentals of the glide are thoroughly understood.
Gliding Turns
Gliding turns have a signifi cant increase in descent rate than
straight glides because of the decrease in effective lift due to
the direction of the lifting force being at an angle to the pull
of gravity. Therefore, it should be clearly understood that the
steeper the bank angle, the greater the descent rate.
In gliding turns, the decrease in effective lift due to the
direction of the lifting force being at an angle to the pull
of gravity make it necessary to use more nose-up pressure
than is required for a straight glide. However, as discussed
earlier for steeper turns, airspeed must be maintained well
above stall speed which increases during turns or the WSC
could stall in the turn.
When recovery is being made from a medium or high banked
gliding turn, the pitch force which was applied during the turn
must be decreased back to trim, which must be coordinated
with the roll back to level.
In order to maintain the most effi cient or normal glide in a
turn, more altitude must be sacrifi ced than in a straight glide
since this is the only way speed can be maintained without
power. Attention to the front tube angle with the horizon and
the reference point on the front tube provide visual reference
of attitudes while gliding. [Figures 6-17 and 6-18]
Common errors in the performance of descents and
descending turns are:
• Failure to adequately clear the area.
• Inability to sense changes in airspeed through sound
and feel.
• Failure to maintain constant bank angle during gliding
turns.
• Inadequate nose-up control during glide entry resulting
in too steep a glide.
• Attempting to establish/maintain a normal glide solely
by reference to fl ight instruments.
• Attempting to “stretch” the glide by applying nose-up
pressure.
• Inadequate pitch control during recovery from straight
glides.
Pitch and Power
No discussion of climbs and descents would be complete
without touching on the question of what controls altitude
and what controls airspeed. The pilot must understand the
effects of both power and pitch control, working together,
during different conditions of fl ight.
As a general rule, power is used to determine vertical speed
and pitch control is used to determine speed. However,
there are many variations and combinations to this general
statement. Decreasing pitch and diving do provide a quicker
descent but is not typically used as a fl ight technique for long
descents. Changes in pitch through moving the control bar
forward and backward are used for maintaining level fl ight
in rising and falling air, and pulling back on the control bar is
used for a steep approach technique to lose altitude; however,
these techniques are used only for short durations and not
the primary altitude control for the WSC.
The throttle is the main control used for determining vertical
speed. At normal pitch attitudes recommended by the
manufacturer and a constant airspeed, the amount of power
used determines whether the aircraft climbs, descends, or
remains level at that attitude.
Steep Turn Performance Maneuver
The objective of the steep turn performance maneuver is to
develop the smoothness, coordination, orientation, division of
attention, and control techniques necessary for the execution
of maximum performance turns when the aircraft is near its
Figure 6-17. Pilot’s visual reference of pitch and roll—descending in a shallow bank.
Figure 6-18. Pilot’s visual reference of pitch and roll—continuing the shallow bank turn but raising the nose slightly with power application.
Notice the how the front tube has moved across the horizon and the nose has raised slightly with additional power application t o level
flight.
Figure 6-19. Steep turns.
performance limits. Smoothness of control use, coordination,
and accuracy of execution are the important features of this
maneuver.
The steep turn maneuver consists of a level turn in either
direction using a bank angle between 45° to 60°. This causes
an overbanking tendency during which maximum turning
performance is attained and relatively high load factors are
imposed. Because of the high load factors imposed, these
turns should be performed at an airspeed that does not exceed
the aircraft’s design maneuvering speed (VA). The principles
of an ordinary steep turn apply, but as a practice maneuver
the steep turns should be continued until 360° or 720° of turn
have been completed. [Figure 6-19]
An aircraft’s maximum turning performance is its fastest
rate of turn and its shortest radius of turn, which change
with both airspeed and angle of bank. Each aircraft’s turning
performance is limited by the amount of power its engine is
developing, its limit load factor (structural strength), and its
aerodynamic characteristics. Do not exceed the maximum
bank angle limitation in the POH. For example, a maximum
60° bank angle is a limit used by many manufacturers.
The pilot should realize the tremendous additional load that
is imposed on an aircraft as the bank is increased beyond
45°. During a coordinated turn with a 60° bank, a load factor
of approximately 2 Gs is placed on the aircraft’s structure.
Regardless of the airspeed or the type of aircraft involved,
a given angle of bank in a turn during which altitude is
maintained always produces the same load factor. Pilots must
be aware that an additional load factor increases the stalling
speed at a signifi cant rate—stalling speed increases with the
square root of the load factor. For example, a light aircraft that
stalls at 40 knots in level fl ight stalls at nearly 57 knots in a
60° bank. The pilot’s understanding and observance of this
fact is an indispensable safety precaution for the performance
of all maneuvers requiring turns.
Before starting the steep turn, the pilot should ensure that the
area is clear of other air traffi c since the rate of turn is quite
rapid. After establishing the manufacturer’s recommended
entry speed or the design maneuvering speed, the aircraft
should be smoothly rolled into a selected bank angle between
45° to 60° and the throttle increased to maintain level fl ight.
Always perfect the steep turn at 45° and slowly work up to
higher bank angles. As the turn is being established, control
bar forward pressure should be smoothly increased to
increase the angle of attack. This provides the additional wing
lift required to compensate for the increasing load factor.
After the selected bank angle has been reached, the pilot
fi nds that considerable force is required on the control bar
and increased throttle is required to hold the aircraft in level
fl ight—to maintain altitude. Because of this increase in the
force applied to the control bar, the load factor increases
rapidly as the bank is increased. Additional control bar
forward pressure increases the angle of attack, which results
in an increase in drag. Consequently, power must be added
to maintain the entry altitude and airspeed.
During the turn, the pilot should not stare at any one object.
Maintaining altitude, as well as orientation, requires an
awareness of the relative position of the forward tube and
the horizon. The pilot must also be looking for other aircraft
mainly towards the direction of the turn while glancing at the
instruments to make sure the airspeed and altitude are being
maintained. If the altitude begins to increase or decrease a
power adjustment may be necessary to maintain the altitude
if the bank angle and speed are maintained. All bank angle
changes should be done with coordinated use of pitch and
throttle control.
The rollout from the turn should be timed so that the wings
reach level fl ight when the aircraft is exactly on the heading
from which the maneuver was started. While the recovery
is being made, forward bar pressure is gradually released
and power reduced, as necessary, to maintain the altitude
and airspeed.
Common errors in the performance of steep turns are:
• Failure to adequately clear the area.
• Excessive pitch change during entry or recovery.
• Attempts to start recovery prematurely.
• Failure to stop the turn on a precise heading.
• Inadequate power management resulting in gaining
or loosing altitude.
• Inadequate airspeed control.
• Poor roll/pitch/power coordination.
• Failure to maintain constant bank angle.
• Failure to scan for other traffi c before and during the
maneuver.
Energy Management
The WSC aircraft has very little momentum because of its
relative light weight as compared to airplanes. Therefore, it
is important that pilots learn to manage the kinetic energy of
the WSC. Higher speed and higher power is higher energy.
Lower speed and lower power is lower energy. The ability
for a pilot to maintain high energy levels in turbulent air and
while near the ground is the basis for energy management
for WSC.
Energy management should fi rst be practiced at higher
altitudes. While maintaining straight-and-level flight,
power is increased and decreased, and pitch control must
be used. The pilot should start at the trim position and with
the appropriate cruise throttle setting. As power is smoothly
applied towards full throttle, the WSC aircraft pitch attitude
attempts to increase. The pilot should decrease the pitch to
maintain level fl ight. This results in a high energy level.
Once this application is held for a couple seconds, the pilot
should then smoothly reduce power to the cruise power
setting and increase pitch to maintain level fl ight. The WSC
aircraft is now back to at a lower trim/cruise power in a
medium energy level.
Again, increase power and reduce pitch to stay level attaining
a high energy level. Now, reduce power to idle and as the
nose lowers, increase pitch. The pilot must be aware of the
decreasing energy levels occurring during this phase of the
maneuver for this is usually a precursor to accidents when
approaching the runway. The pilot should recognize this
scenario and promptly apply the power as appropriate to
prevent the aircraft from descending. Additionally, the pilot
must be aware of the slow fl ight and stall characteristics to
prevent a stall and to maintain a specifi ed heading.
Once the student masters this maneuver successfully at
higher altitudes, energy management can be practiced with
low passes down the runway in calm winds at higher energy
levels, then at the lower trim/cruise power medium energy
level, and fi nally higher to medium trim/cruise power energy
levels. Low passes over the runway fi ne tunes the student’s
skills for energy management and is an excellent exercise to
prepare students for landings.
It is important to understand that higher energy levels should
be used while maneuvering near the ground especially
in turbulent or crosswind conditions. This is discussed in
Chapter 7, Takeoff and Departure Climbs, that higher energy
is recommended as the WSC aircraft lifts off and initially
climbs out from the runway.
Higher energy is also recommended for a power on approach
where the airspeed is higher than the normal approach
speed; and the power is higher than the normal approach
power. There is still a descent rate, but the WSC aircraft has
more overall energy to handle turbulence and crosswinds.