1. 6.04 Laws and Forces Theory of Flight Instructor 40 Minutes
References: -Transport Canada Study and Reference Guide Glider Pilot - -FTGU pages 21-39
Instructor
40 Minutes

2. 6.04 Theory of Flight - Laws and Forces
MTPs:
Newton’s Laws of Motion
Four Forces
Equilibrium
Aerodynamic Couples

3. 6.04 Theory of Flight - Laws and Forces
BC Online Ground School Theory of Flight - Lift and Forces
MTPs:
Newton’s Laws of Motion
Four Forces
Equilibrium
Aerodynamic Couples 3

4. 6.04 Theory of Flight - Laws and Forces
BC Online Ground School Theory of Flight - Lift and Forces
Newton’s First Law:
A body persists its state of rest or of uniform motion will stay in motion unless acted on by an external unbalanced force. 4

5. 6.04 Theory of Flight - Laws and Forces
BC Online Ground School Theory of Flight - Lift and Forces
Newton’s Second Law
Force = mass x acceleration 5

6. 6.04 Theory of Flight - Laws and Forces
BC Online Ground School Theory of Flight - Lift and Forces
Newton’s Third Law
For every action, there is an equal and opposite reaction. 6

7. 6.04 Theory of Flight - Laws and Forces
BC Online Ground School Theory of Flight - Lift and Forces
What does Newton’s First Law have to do with gliders?
Uniform motion
Straight glide
Unbalanced forces
Spoilers
Ailerons
Elevator
Rudder
A body persists its state of rest or of uniform motion will stay in motion unless acted on by an external unbalanced force. 7

8. WHY? You will lift off sooner! Force = Mass X Acceleration
6.04 Theory of Flight - Laws and Forces
What does Newton’s Second Law have to do with going solo?
Weight and balance
What is one of the main differences you will notice when you go solo?
You will lift off sooner!
WHY?
Force = Mass X Acceleration 8

9. 6.04 Theory of Flight - Laws and Forces
What does Newton’s Third Law have to do with flight?
Movement of control surfaces push air and cause equal and opposite reactions to allow aircraft to manoeuvre
Downwash of air flowing over surface of wing causes equal and opposite reaction = LIFT 9

10. LEFT TURNING TENDENCIES

11. Torque
Newton's third law - For every action there is an equal and opposite reaction.
Greatest at - Low Airspeeds, High Power settings, High Angles of Attack [takeoff]

12. Propeller Slipstream
Effect of the airflow created by the spinning propeller striking the tail of the aircraft.
Causes aircraft to Yaw Left

13. Left turning tendencies
Torque: As the propeller spins clockwise the result is the aircraft rotating counter-clockwise.
(Newton’s 3rd Law at work here.)

14. Left turning tendencies
Slip stream: Airflow from the rotating propeller cork-screws around the aircraft hitting the fin on the left side pushing the tail right and nose left.

15. Left turning tendencies
Gyroscopic Procession:
A propeller acts like a gyro. Any force applied to a spinning gyro will act 90 degrees to the direction of the rotation. Raising the aircraft tail will apply a force to the top of the propeller arc, resulting in the force applied to the right of the arc, causing a yaw to the left.

16. Gyroscopic Precession
Reaction of a gyroscope in motion.
Force is felt 90 degrees ahead of the direction of rotation.
Creates a left yawing tendency, especially noticeable in tail wheel aircraft

17. Left turning tendencies
Gyroscopic Procession

18. P-Factor Yawing tendency due to asymmetrical propeller loading.
At high angles of attack the descending blade has more “bite”, providing more thrust.
Creates a adverse yaw to the left that must be corrected with right rudder input

19. 6.04 Theory of Flight - Laws and Forces
What are the four forces that act on a airplane?
Lift
Drag
Thrust
Weight 19

20. Thrust = horizontal component of lift
6.04 Theory of Flight - Laws and Forces
Gliders don’t have engines…how do they produce thrust?
An equilibrium can be maintained with only lift, drag and weight
Thrust is caused by steepening the glide angle (ie. nose down)
Thrust = horizontal component of lift 20

21. 6.04 Theory of Flight - Laws and Forces
Equilibrium:
A state in which opposing forces or influences are balanced.
Steady motion (ie. straight and level flight).
What happens when the four forces are not in equilibrium? 21

22. 6.04 Theory of Flight - Laws and Forces
Aerodynamic Couples
Parallel forces that do not pass through the same point
Couples cause a turning moment 22

23. 6.04 Theory of Flight - Laws and Forces
What is a moment?
Force at a distance
Measured in lbs feet
Think of a teeter-totter…
Pretend you are riding a teeter-totter with a friend who is much heavier than you
Do you need to sit closer or further away to be in equilibrium? 23

24. 6.04 Theory of Flight - Laws and Forces
Teeter-Totter Example
“Force at a distance” 24

25. 6.04 Theory of Flight - Laws and Forces
Aerodynamic Couples
Lift and Weight
Thrust and Drag 25

26. 6.04 Theory of Flight - Laws and Forces
Confirmation Check… 26

27. 6.04 Theory of Flight - Laws and Forces
What are Newton’s 3 Laws of Motion?
A body persists its state of rest or of uniform motion will stay in motion unless acted on by an external unbalanced force
Force = mass x acceleration
For every action, there is an equal and opposite reaction 27

28. 6.04 Theory of Flight - Laws and Forces
What is a couple?
Parallel forces that do not pass through the same point
Force at a distance 28

29. 6.04 Theory of Flight - Laws and Forces
What is equilibrium?
A state in which opposing forces or influences are balanced 29

30. 6.04 Theory of Flight - Laws and Forces
What have we learned today?
Newton’s Laws of Motion
Four Forces
Equilibrium
Aerodynamic Couples
Torque
P Factor
Gyroscopic Precession 30