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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.

HelicoptersObjectives:

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

A

B

C

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.

-+ +-

LIFT

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?

Relative Airflow

Angle of Attack

Chord

Lift

Helicopters

Climbing – How can the ‘Wing’ produce more Lift?

Relative Airflow

Angle of Attack

Chord

Lift

Increase AoA Chord

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

Rotor Head

BladesTail Rotor

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

Hand Throttle

The Hand Throttle

The Collective Pitch Lever often contains a

Hand Throttle (like on a motor bike).

The Collective Pitch Lever

All Blades are changed by the same Angle.

Rotor Blade

THE COLLECTIVE PITCH LEVER

Torque Reaction - Yaw

What can be done to stop this?

Fuselage Torque Reaction

Torque Reaction - Yaw

A Tail Rotor is added to counter the Torque Reaction.

Which Control is used for this?

Balancing Force

Airflow

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

Thrust

The ‘Disc’ is tilted,

producing a horizontal component of Thrust.

Thrust

Lift

Horizontal Flight

The Rotor Disc can be tilted forward,

back, left, right depending on the

position of the Cyclic Control.

Horizontal Flight

HelicoptersObjectives:

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.