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Principles of Flight
Principles of Flight
Learning Outcome 5:
Be able to apply the principles of flight and control
to rotary wing aircraft
Part 2
Questions
Blade Angle of Attack is between?
a. The Chord and Relative Airflow.
b. The Rotational Velocity and the Relative Airflow.
c. The Total Reaction and the Chord.
d. Lift and Drag.
Questions
Increasing speed with a fixed pitch propeller will?
a. Be more efficient.
b. Reduce efficiency.
c.
Make no difference.
d. Increase the Engine speed.
Questions
The Forces trying to alter the Propeller Blade
Angle of Attack are?
a. ATM and CTM.
b. CDM and ATM.
c. CTM and REV.
d. AOA and ATM.
Questions
The Resultant Forces that a Propeller produce are?
a. Lift and Thrust.
b. Thrust and Propeller Rotational Drag .
c.
Drag and Total Reaction.
d. Drag and Thrust.
Helicopters
Objectives:
1. State the method of generating Lift for a Helicopter.
2. List and Describe the following:
•
Blades, Rotor Head, Pitch Angle, Collective Pitch,
Rotor Disc, Cyclic Pitch, Tail Rotor, Hand Throttle,
Torque Reaction.
3. Explain how a Helicopter achieves Horizontal Flight.
4. Describe the Operation of the following Controls:
•
The Collective.
•
The Cyclic.
•
The Yaw Pedals.
•
The Hand Throttle.
Helicopters
How does a Wing produce Lift?
Do you remember the Wind-Tunnel?
Lift
A
+
-
B
+
C
Air enters at ‘A’.
On reaching ‘B’ it has increased in speed to get through the narrower gap.
At ‘C’ the air has returned to the same values as ‘A’.
If Speed increases then Pressure Drops & Vice Versa.
SO, HOW DOES THIS WORK AS A WING?
Lift
LIFT
A
+
-
B
+
A Wing works in the same way as the “Wind-Tunnel”.
Because the air is faster over the top surface, then
the pressure is decreased.
The Wing is now producing LIFT.
C
Helicopters
So, instead of moving a Wing
through the air, how about we
rotate the ‘Wing’!
Cross-sectional area of Blade
is the same shape as a Wing.
The rotating ‘Wing’ is now
producing Lift
Helicopters
How does a Helicopter Climb and Descend?
Lift
Relative Airflow
Angle of Attack
Helicopters
Climbing – How can the ‘Wing’ produce more Lift?
Lift
Increase AoA
Relative Airflow
Angle of Attack
Helicopters
Descending – How can the ‘Wing’ produce less Lift?
Lift
Decrease AoA
(Increasing or Decreasing Rotor Speed will also affect Lift Production).
Parts of a Helicopter
Blades
Tail Rotor
Rotor Head
Rotor Disc
Parts of a Helicopter
HELICOPTER CONTROLS
1. The Collective Pitch Lever.
2. The Hand Throttle.
3. The Cyclic Pitch Control.
4. The Tail Rotor Control (Yaw Pedals).
HELICOPTER CONTROLS
Controls
Cyclic
Controls
Collective
Controls
Yaw Pedals
Controls
Cyclic
Collective
Yaw Pedals
The Hand Throttle
Hand Throttle
The Collective Pitch Lever often contains a
Hand Throttle (like on a motor bike).
The Collective Pitch Lever
Rotor Blade
All Blades are changed by the same Angle.
THE COLLECTIVE PITCH LEVER
Torque Reaction - Yaw
Fuselage Torque Reaction
What can be done to stop this?
Torque Reaction - Yaw
Airflow
Balancing Force
A Tail Rotor is added to counter the Torque Reaction.
Which Control is used for this?
The Yaw Pedals
Moving the Yaw Pedals
will alter Blade Pitch
equally on all the Tail
Rotor Blades
Yaw Pedals
The Yaw Pedals can also be used to turn (yaw)
the Helicopter around the main Rotor.
Tail Rotors
Horizontal Flight
How does a Helicopter achieve this?
Horizontal Flight
Lift
Lift
Thrust
Thrust
The ‘Disc’ is tilted,
producing a horizontal component of Thrust.
Horizontal Flight
The Rotor Disc can be tilted forward,
back, left, right depending on the
position of the Cyclic Control.
Horizontal Flight
Helicopters
Objectives:
1. State the method of generating Lift for a Helicopter.
2. List and Describe the following:
•
Blades, Rotor Head, Pitch Angle, Collective Pitch,
Rotor Disc, Cyclic Pitch, Tail Rotor, Hand Throttle,
Torque Reaction.
3. Explain how a Helicopter achieves Horizontal Flight.
4. Describe the Operation of the following Controls:
•
The Collective.
•
The Cyclic.
•
The Yaw Pedals.
•
The Hand Throttle.
Questions
How does a Helicopter generate Lift?
a. Spinning the main rotor faster.
b. Spinning the main rotor slower.
c. Increasing the angle of attack of each rotor blade.
d. Decreasing the angle of attack of each rotor blade.
Questions
When a Helicopter rotor is driven in a circular motion
there is an opposing force, what is this force called?
a. Lift.
b. Torque Reaction.
c. Lift Reaction.
d. Drag.
Questions
What is the purpose of a Tail Rotor?
a. Counter Torque Reaction.
b. Reduce Drag.
c. Provide Thrust.
d. Control the Helicopter in the rolling plane.
Questions
What are the 3 controls a Helicopter uses to control
the aircraft’s attitude?
a. Collective, Cyclic, Yaw Pedals.
b. Ailerons, Rudders.
c. Cyclic, Elevators, Throttle.
d. Yaw Pedals, Fin, Rotor.

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