References: FTGU 29th Pages 3-45, Pilot’s
Handbook of Aeronautical Knowledge
Chapters 1-3
1.
What are the main parts of the aircraft?
2.
How does a wing create lift?
3.
What is a slot and what does it do?
 Aircraft
controls
 Stability
 Aircraft
performance
 Stalls, spins, spiral dives and load factor
 Aircraft instruments



In a turn, the outside
wing travels faster than
the inside wing, creating
more lift (and therefore
more induced drag)
This creates an
imbalance that causes
the nose to swing to the
outside of the turn and is
called adverse yaw
This can be correct
through rudder inputs
and reduced by
modifying the ailerons
Source: Pilot’s Handbook of Aeronautical
Knowledge
When part of the
control surface is
placed ahead of the
hinge
 Aids in countering
adverse yaw in
aileron design

Source: From the Ground Up
Dynamic Balance
A mass (or weight) is
placed in front of a
hinge or control
surface
 This gives the surface
better stability in
flight

Mass Balance

The centre of gravity
of a control is placed
so that the surface is
balanced without any
airflow
Static Balance
Horn Balance
Mass Balance
1.
What are the axis of the aircraft?
2.
What is adverse yaw?
3.
What are the three types of balanced
controls?
 Tendency
of an aircraft to return to its
original position once disturbed without
intervention by the pilot
 Two main types of stability:


Static
Dynamic
 Inherent
stability: stability characteristics
built into the design of the aircraft
Static stability is the
initial tendency for an
aircraft to return to its
original position once
disturbed

Static Stability

Dynamic stability is
the overall tendency
of the aircraft to
return to its original
position through a
series of damped
oscillations
Dynamic Stability
Source: Pilot’s Handbook of Aeronautical Knowledge
 Positive

Will create forces or moments which will
eventually return to its original position
 Neutral

Stability:
Stability:
Stabilizing forces are absent. Aircraft will not
return to its original position but will not depart
further away either
 Negative

Stability: (Instability)
Will generate forces or moments which will
displace it further away from its original position
Source: Pilot’s Handbook of Aeronautical Knowledge
Source: Pilot’s Handbook of Aeronautical Knowledge
 Pitch
stability
 Around the lateral
axis
 Affected by 2
factors:


Source: Pilot’s Handbook of Aeronautical
Knowledge
Location of the C
.G.
Size and location
of the horizontal
stabilizer
 Roll
stability
 Around the longitudinal axis
 Affected by factors:




Dihedral
Keel effect
Sweepback
Distribution of weight
 Dihedral
angle is
the angle that the
wings make with
the horizontal
 If a wing is
displaced, the
down going wing
creates a higher
angle of attack
and lifts the wing
Source: Pilot’s Handbook of Aeronautical
Knowledge
 In
aircraft that
have a low center
of gravity, a
pendulum effect is
created
 When the aircraft
is rolled, the
weight pulls it
back to the centre
Source: Pilot’s Handbook of Aeronautical
Knowledge



In faster aircraft,
the wing is
sweptback for
aerodynamic
efficiency
This also increases
roll stability
A dropped wing will
swing perpendicular
with the relative
airflow, creating
more lift and
restoring it to level
flight
Source: Pilot’s Handbook of Aeronautical
Knowledge
 Proper
distribution of weight will aid in
keeping the aircraft level
 If too much weight is on one side, the
aircraft may not have enough aileron
authority to maintain level flight
 Yaw
stability
 Around the
vertical or normal
axis
 Affected by the
size and location
of the fin
Source: Pilot’s Handbook of Aeronautical
Knowledge
1.
What are static and dynamic stability?
2.
What is dihedral and what does it do?
3.
What factors affect longitudinal stability?
In North America,
propellers turn
clockwise when
viewed from the pilot
seat
 The reaction from
this spinning causes
the plane to roll
counter-clockwise to
the left

Torque
Source: Pilot’s Handbook of Aeronautical
Knowledge



Source: Pilot’s Handbook of Aeronautical
Knowledge
At high angles of
attack, the down going
blade meets the air at a
higher angle of attack
than the up going blade
More lift is produced on
the right side
This creates an
imbalance of force and
the aircraft yaws to the
left
Asymmetric Thrust (P-Factor)
When the propeller is
spinning, it acts like a
big gyroscope
 When a force is
applied to a
gyroscope, it acts 90
degrees in the
direction of rotation

Source: Pilot’s Handbook of Aeronautical
Knowledge
Precession
 When
force applied to spinning gyro, force
acts as if it was 90° in direction of rotation

As air is pushed back
from the propeller, it
flows back in a
corkscrew pattern
Slipstream
Source: Pilot’s Handbook of Aeronautical Knowledge
 The
ability for an aircraft to climb is
dependant on the ability to create excess
thrust
 There are three types of climbs that we use:



Best rate of climb
Best angle of climb
Normal climb
 Angle
Thrust

Lift

Increase: More lift,
less speed
Decrease: Less lift,
more speed
Drag
Weight
of Attack:
Source: Pilot’s Handbook of Aeronautical
Knowledge




When in a glide, there is no power from an
engine to produce thrust and gravity pulls
the aircraft down
In order to maintain equilibrium, lift must
act slightly forward to pull the aircraft
through the air
Best glide speed for range: Speed at which
the most distance will be covered for a
given loss of height
Best glide speed for endurance: Speed at
which the most time aloft will be given for a
given loss of height
Gliding = 3 forces (Weight, Lift, Drag)
Lift
Glide Reaction
= Resultant of lift
and drag, opposes
weight
Drag
Thrust = Horizontal
component of weight
Weight
Best Range Speed
Furthest distance per altitude lost
Best Endurance Speed
Most time in air per
altitude lost
- Longer Time
- Shorter Distance
- Shorter Time
- Longer Distance
1.
What are the four left turning tendencies?
2.
What is the difference between the best
rate and angle of climb?
3.
If you were gliding and wanted to stay
aloft for a long period of time, what speed
would you fly?





Lift acts 90 degrees to the wing
When the plane banks the lift vector is
tilted
Vertical lift force: Acts straight up and
maintains altitude
Horizontal lift force: Acts to the inside and
pulls the aircraft into the turn, known as
centripetal force
An apparent force is felt by the pilot that
pulls them to the outside of the turn, this is
called centrifugal force and is a product of
inertia
Source: Pilot’s Handbook of Aeronautical
Knowledge
 If
Bank angle is
increased in a
turn, the following
occurs:
a)
b)
c)
d)
Source: Pilot’s Handbook of Aeronautical
Knowledge
Higher rate of
turn
Smaller radius of
turn
Higher loading on
the wings
Higher stall
speed
 When
airspeed is
increased in a turn
the following
occurs:
a)
b)
Source: Pilot’s Handbook of Aeronautical
Knowledge
Slower rate of
turn
Larger radius of
turn



The lower wing meets
the airflow at a higher
angle of attack creating
more lift
Upper wing moves
faster and also creates
more lift
Two forces compensate
one another so angle of
bank remains the same
Descending Turn
Lower wing meets the
relative airflow at a
smaller angle of
attack and creates
less lift
 Upper wing moves
faster and creates
more lift
 Two forces act to
cause angle to
increase

Climbing Turn




Dead load: The weight of the aircraft on the
ground
Live load: The change in apparent weight of
the aircraft due to acceleration and turns
(the amount of force acting on the wings) in
the air
Load factor: Live load over dead load and is
expressed in G’s
When in level flight, the lift of the wings is
equal to the weight: Load factor of 1G
 Load

Factors in Turns
Angle of bank increase

Load factor increase
 60°
bank = 2 G's
 Dangers

High load factor


Possible structural failure
(overload)
Increased load factor

Increased stall speed
1.
Which force pulls the aircraft into the
turn?
2.
If you are in a turn and increase your angle
of bank, what will happen to your turn
radius and turn rate?
3.
If you are in a turn and decrease your
airspeed, what will happen to your turn
radius and turn rate?
A
stall occurs when the wing cannot produce
sufficient lift to maintain flight
 In order to produce enough lift, the airflow
over the wing must be smooth
 When the angle of attack increases to a
certain point, the airflow becomes turbulent
and separates from the wing
 This angle is known as the critical angle of
attack
Source: Pilot’s Handbook of Aeronautical Knowledge






Weight: As weight increases, stalling speed
increases
C of G location: The further forward the C of G
is, the higher the stall speed
Turbulence: Vertical gust can cause the critical
angle of attack to be exceeded
Turns: Increasing the angle of bank increases
loading and stall speed
Flaps: Deploying flaps will decrease stall speed
Contaminants: If the wing is dirty or has ice on
it, it will disrupt airflow and increase stall
speed
1.
When will an aircraft stall? (Hint...angle)
2.
What factors affect stall speed?
3.
What is the formula used to determine
stall speed?
 As
load factor increases, stall speed
increases
 Formula to determine stall speed:
VSTurn  Vs n
 Where:
VS Turn is the stall speed in the turn
VS is the stall speed in level flight
n is the load factor
 Referring
to the table below, we can
calculate the stall speed of a Cessna 172
in a 30 degree turn:
Degree of Bank (°)
Load Factor (G’s)
Square Root
15
1.04
1.02
30
1.15
1.07
45
1.41
1.19
60
2.00
1.41
75
3.86
1.96
VS  47kts 1.15
VS  47kts(1.07)
VS  50kts
 An
aircraft will stall if the critical angle of
attack is exceeded, regardless of airspeed or
attitude
 An aircraft will stall at the same indicated
airspeed regardless of altitude
 Defined
as auto-rotation that develops after
an aggravated stall
 If yaw is introduced during a stall, the inside
wing will produce less lift and stall, causing
it to drop
 As the wing drops, it’s angle of attack is
increased, causing it to stall further and
increase drag, which creates more yaw
 The nose then drops and auto-rotation sets in
 Steep,
uncoordinated descending turn with
an excessive nose down attitude
 Characteristics of a spiral dive are:




Steep nose down attitude
Excessive angle of bank
Rapidly increasing airspeed
Increasing G loading
 To
differentiate from a spin, here are the
characteristics of a spin:


Airspeed is constant and low
G loading is constant
1.
What are the characteristics of a spin?
2.
What are the characteristics of a spiral
dive?
3.
What is load factor?


Pitot tube: Provides dynamic pressure to the
instruments, consists of a tube that is inline
with the direction of flight
Only the airspeed indicator is connected
to the pitot tube
Static port: Provides static pressure to the
instruments and is a hole located on the
aircraft that is out of the way of direct
airflow or turbulence
The altimeter, vertical speed indicator
and airspeed indicator are connected to
the static port



Measures the height
of the aircraft above
sea level (ASL)
Has a stack of
aneroid capsules (or
wafers) that are
calibrated for a
standard day
As the aircraft
climbs into less
dense air, the
capsules expand and
move linkages that
move the needles

Pressure Error:


Temperature Error:


Pressure changes with
location and the
altimeter setting must
be changed along the
route of flight
Capsules are calibrated
for 15°C and will be
affected when the
temperature differs
Mountain
effects/gusts:

Mountain ranges act
like a venturi speeding
up the wind and
lowering pressure
Indicates how fast the
plane is going
through the air (not
over the ground)
 Operates by taking
the difference of
static and dynamic
pressure
 Indicates the dynamic
pressure created by
forward motion of the
aircraft

 White
arc – Flap
operation speed
range
 Green arc – Normal
operation range
 Yellow arc –
Cautionary speed
range (calm air)
 Red line – Maximum
speed (never
exceed)
 Vso
– Stall speed in
landing
configuration
 Vs – Stall speed
clean
 VFE – Flap operation
speed
 VNO – Normal
operation speed
 VNE – Never exceed
speed

Indicated airspeed (IAS) – Read on ASI


Calibrated airspeed (CAS)


Compressibility error – Air compressing in high
speed flight
Equivalent airspeed (EAS)


Position error – Due to position on the aircraft
Density error – Non-standard pressure and
temperature
True airspeed (TAS) – Actual speed of the
aircraft through the air
ICE T...Pretty Cool Drink





Indicates the rate of
climb or descent in feet
per minute
Comprised of a
diaphragm connected to
the static port
Diaphragm is inside a
housing with a calibrated
leak
Measures the change in
pressure between the
diaphragm and the
housing
There is a lag time of up
to 6-9 seconds
1.
Which instrument(s) are connected to the
pitot tube?
2.
How does an altimeter work?
3.
What are the different types of airspeed
and what do they mean? (Hint...drink)
 Comprised
of two
north seeking
magnets that float
inside a fluid filled
chamber
 Since the earth is
a big magnetic,
the compass will
always point to
magnetic north
 Wheel
or rotor that spins at high speed
 They can be mounted in gimbals or within a
fixed plane
 All gyroscopes experience the effects of
Rigidity in space and Gyroscopic Precession
 Heading
indicator, artificial horizon, turn
and bank indicator
 If
a gyroscope is
placed within a
universal gimbal
and spun, it will
rotate along the
same plane
regardless of how
the gimbal moves
 Also
known as
gyroscopic inertia
 If
a gyroscope is
tilted or has a force
applied to it, the
force will be “felt”
90 degrees in the
direction of rotation
 The gyroscope will
then rotate parallel
the direct of the
applied force
1.
How does a VSI work?
2.
How does a compass work?
3.
What are the two gyroscopic principles
that instruments use?




Shows the current
heading of the aircraft
Relies on the principle of
rigidity in space
As the aircraft turn, the
gyro remains stationary
and the aircraft turns
around the gyro
Because of friction and
the rotation of the earth
(apparent precession),
the heading indicator
must be reset every 15
minutes
 Provide
pitch and
bank information
 Acts as a “window
through the clouds”
 Relies on the
principle of rigidity
in space to rotate
and pitch the
horizon as the
aircraft banks and
pitches




Indicates the rate of
turn to the pilot
Relies on the
principle of
precession
Comprised of a
gimbal mounted
vertically
When a plane yaws,
precession forces the
gyro to tilt left or
right and move the
needle on the face




Indicates the rate
of turn to the pilot
Relies on the
principle of
precession
Comprised of a
gimbal that is
canted 30 degrees
This allows the
instrument to react
to roll and yaw



Located on the
bottom of the turn
and slip indicator
and the turn
coordinator
Ball indicates
whether the
aircraft is slipping
or skidding
Balanced by a
combination of
centrifugal force
and gravity
1.
Which instrument(s) use the principle of
rigidity in space?
2.
Which instrument(s) use the principle of
precession?
3.
What forces move and balance the
inclinometer?
1.
Where are the elevators and what do they
do?
2.
What affects lateral stability?
3.
What factors affect stalls?
4.
Which instrument(s) are connected to the
pitot tube?
5.
What is precession?
 Today





we’ve covered:
Aircraft controls
Stability
Aircraft performance
Stalls, spins, spiral dives and load factor
Aircraft instruments
 Your
next class will be on meteorology