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

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

6.04 Theory of Flight - Laws and Forces BC Online Ground School 6.04 Theory of Flight - Lift 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 6.04 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

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

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

6.04 Theory of Flight - Laws and Forces BC Online Ground School 6.04 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

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

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

LEFT TURNING TENDENCIES

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]

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

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

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.

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.

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

Left turning tendencies Gyroscopic Procession

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

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

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

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

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

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

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

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

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

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

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

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

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