Warm-Up – 12/3 – 10 minutes

Warm-Up – 12/3 – 10 minutes Utilizing your notes and past knowledge answer the following questions: • What are the three flight situations in which a stall may occur? • In a turn what must be applied to the yoke/stick to increase the aircraft AOA and if excessive AOA occurs in a turn what may happen to the aircraft? • To balance an aircraft aerodynamically, what is located aft of CoG and what does this make the aircraft “naturally feel?” • If ice is allowed to form on the airfoil what is increased and what is decreased as a result? • What design factor is utilized on a propeller blade to keep thrust more nearly equalized along this length?

Questions / Comments

Warm-Up – 12/3 – 10 minutes Utilizing your notes and past knowledge answer the following questions: • What are the three flight situations in which a stall may occur? • In a turn what must be applied to the yoke/stick to increase the aircraft AOA and if excessive AOA occurs in a turn what may happen to the aircraft? • To balance an aircraft aerodynamically, what is located aft of CoG and what does the make the aircraft “naturally feel?” • What happens to the airfoil shape if ice, snow or sleet is allowed to form on the airfoil and what effect does this have on the airflow? • If ice is allowed to form on the airfoil what is increased and what is decreased as a result?

Aerodynamic Forces in Flight ManeuversStalls • There are three flight situations in which the critical AOA can be exceeded: low speed, high speed, and turning.

Warm-Up – 12/3 – 10 minutes Utilizing your notes and past knowledge answer the following questions: • What are the three flight situations in which a stall may occur? • In a turn what must be applied to the yoke/stick to increase the aircraft AOA and if excessive AOA occurs in a turn what may happen to the aircraft? • To balance an aircraft aerodynamically, what is located aft of CoG and what does the make the aircraft “naturally feel?” • What happens to the airfoil shape if ice, snow or sleet is allowed to form on the airfoil and what effect does this have on the airflow? • If ice is allowed to form on the airfoil what is increased and what is decreased as a result?

Aerodynamic Forces in Flight ManeuversStalls • In a turn, additional lift is acquired by applying back pressure to the elevator control. • This increases the wing’s AOA, and results in increased lift.

Aerodynamic Forces in Flight ManeuversStalls • If during a turn the AOA becomes excessive, the aircraft stalls.

Warm-Up – 12/3 – 10 minutes Utilizing your notes and past knowledge answer the following questions: • What are the three flight situations in which a stall may occur? • In a turn what must be applied to the yoke/stick to increase the aircraft AOA and if excessive AOA occurs in a turn what may happen to the aircraft? • To balance an aircraft aerodynamically, what is located aft of CoG and what does this make the aircraft “naturally feel?” • What happens to the airfoil shape if ice, snow or sleet is allowed to form on the airfoil and what effect does this have on the airflow? • If ice is allowed to form on the airfoil what is increased and what is decreased as a result?

Aerodynamic Forces in Flight ManeuversStalls • To balance the aircraft aerodynamically, the CL is normally located aft of the CG. • This makes the aircraft inherently nose-heavy, downwash on the horizontal stabilizer counteracts this condition.

Aerodynamic Forces in Flight ManeuversStalls • If ice is allowed to accumulate on the aircraft during flight the weight of the aircraft is increased while the ability to generate lift is decreased.

Basic Propeller Principles • Propeller blades are twisted to change the blade angle in proportion to the differences in speed of rotation along the length of the propeller, keeping thrust more nearly equalized along this length.

THIS DAY IN AVIATION • December 3 • 1928 — Pacific Air Transport starts daily mail, passenger and express service between Oakland and San Jose, California, 38 miles.

THIS DAY IN AVIATION • December 3 • 1945 — A DeHavilland “Sea Vampire” fighter becomes the first purely jet-powered airplane to operate from an aircraft carrier, when Lieutenant-Commander E. M. “Winkle” Brown lands his aircraft on the HMS Ocean in England

December 2013

Chapter 4 – Aerodynamics of Flight FAA – Pilot’s Handbook of Aeronautical Knowledge

Today’s Mission Requirements • Mission: • Identify in writing the forces acting on an aircraft in flight. • Describe how the forces of flight work and how to control them with the use of power and flight controls essential to flight. • Describe in writing how design, weight, load factors, and gravity affect an aircraft during flight maneuvers. • EQ: Describe the importance of Aeronautical Knowledge for the student pilot learning to fly.

Torque and P-Factor • “Torque” (the left turning tendency of the airplane) is made up of elements which cause or produce a twisting or rotating motion around at least one of the airplane’s three axes.

Torque and P-Factor • The elements are: • 1. Torque reaction from engine and propeller, • 2. Corkscrewing effect of the slipstream, • 3. Asymmetric loading of the propeller (P-factor).

Torque Reaction • The internal engine parts and propeller are revolving in one direction, an equal force is trying to rotate the aircraft in the opposite direction.

Torque Reaction • When the aircraft is airborne, this force is acting around the longitudinal axis, tending to make the aircraft roll.

Torque Reaction • NOTE: Most United States built aircraft engines rotate the propeller clockwise, as viewed from the pilot’s seat.

Torque Reaction • When the aircraft’s wheels are on the ground during the takeoff roll, an additional turning moment around the vertical axis is induced by torque reaction. • The takeoff roll is corrected by the pilot’s use of the rudder or rudder trim.

Corkscrew Effect • The high-speed rotation of an aircraft propeller gives a corkscrew or spiraling rotation to the slipstream.

Corkscrew Effect • At high propeller speeds and low forward speed (as in the takeoffs and approaches to power-on stalls), this spiraling rotation is very compact and exerts a strong sideward force on the aircraft’s vertical tail surface.

Corkscrew Effect • When this spiraling slipstream strikes the vertical fin it causes a turning moment about the aircraft’s vertical axis. • The more compact the spiral, the more prominent this force is.

Corkscrew Effect • As the forward speed increases, however, the spiral elongates and becomes less effective.

Corkscrew Effect • It is the pilot’s responsibility to apply proper corrective action by use of the flight controls at all times. • These forces must be counteracted regardless of which is the most prominent at the time.

Asymmetric Loading (P-Factor) • When an aircraft is flying with a high AOA, the “bite” of the downward moving blade is greater than the “bite” of the upward moving blade.

Asymmetric Loading (P-Factor) • This moves the center of thrust to the right of the prop disc area, causing a yawing moment toward the left around the vertical axis.

Asymmetric Loading (P-Factor) • Since the propeller blade is an airfoil, increased velocity means increased lift. • The downswinging blade has more lift and tends to pull (yaw) the aircraft’s nose to the left.

Summary • To maintain positive control of the aircraft in all flight conditions, the pilot must apply the flight controls as necessary to compensate for these varying values.

1. Create (1) quiz question with answer about today’s lesson. 3. List 3 things you learned today. 2. List 2 things you have questions about today’s lesson. Lesson Closure - 3 – 2 - 1

Warm-Up – 12/3 – 10 minutes