Version 1.0, 15 May 2011 Stage 1, Module 1 Copyright © 2011 Ted Dudley

Course and Objectives Objective: Gain the necessary aeronautical skill, knowledge and experience to meet the requirements of a Private Pilot certificate with an Airplane Category rating and a Single-Engine Land class rating Four Stages of 5-6 modules each:  Stage 1: Introduction to flying  Stage 2: Solo  Stage 3: Cross-country flight  Stage 4: Preparation for checkride

VFA Reqs, Procedures, Regs

Grading Criteria, Expectations Maneuver Grades  1. Describe (monkey see)  2. Explain  3. Practice  4. Perform (monkey do)  5. Not observed

Stage 1 Objectives -Ground The student will become proficient in, and have an understanding of:  Forces acting on an airplane  Stability and control  Training airplane (airframe, engine, systems, flight instruments)  Basic flight maneuvers  Flight information  Flight physiology  Regulations

Stage 1 Objectives - Flight The student will become proficient in, and have an understanding of:  Flight training process  Training airplane  Preflight  “Special Emphasis Areas” (per PTS)  Taxiing  Four basics of flight (straight and level, turns, climbs, descents)  Use of sectional  Collision avoidance  Slow Flight  Stall series  Steep Turns  Instrument scan

Forces Acting on an Airplane

Weight The combined load of the airplane and everything in it Pulls the airplane towards the earth’s center because of gravity Opposes lift Acts vertically downward thru aircraft’s center of gravity

Lift Produced by the dynamic effect of air on the wing Opposes weight Acts perpendicular to flight path

Bernoulli’s Principle Unrestricted tubeUnrestricted tube Restricted tubeRestricted tube As the velocity of a moving fluid (liquid or gas) increases, the pressure within the fluid decreases

Bernoulli’s Principle As the velocity of a moving fluid (liquid or gas) increases, the pressure within the fluid decreases

Newton’s Third Law Bernoulli isn’t all there is to lift Flow over airfoil imparts a downward flow to air passing over it By Newton’s Third Law (equal and opposite reaction), this imparts an upward force on the airfoil

Streamline and Turbulent Flow (Streamline Flow)

Static Air Pressure Air exerts a pressure equally in all directions at any point in the atmosphere This is called static pressure Results from the weight of the air molecules above that point; it decreases with a gain in altitude This is what an altimeter measures, usually through the static port(s)

Dynamic Air Pressure Air has mass (from its molecules); air in motion has dynamic (kinetic) energy which is converted to pressure the moment a body tries to stop it or slow it down This is called dynamic pressure Measured by the pitot tube; includes static pressure at that point, too

Lift and Airspeed Lift varies with the square of velocity – double the speed, get 4x lift

Airfoil Shapes

Angle of Attack The angle between the wing chord line and the relative wind

Aerodynamic Force As Angle of Attack increases…  More lift for a given airspeed  Center of pressure moves forward

Drag A rearward, retarding force caused by disruption of airflow by the wing, fuselage, and other protruding objects Opposes thrust

Total Drag Total drag is comprised of…  Parasite drag, which is made up of  Form drag  Interference drag  Skin friction drag  Induced drag

Form Drag The portion of parasite drag generated by the aircraft due to its shape and airflow around it Big form dragLittle form drag

Interference Drag Comes from the intersection of airstreams that creates eddy currents and turbulence, or restricts smooth airflow Example: the intersection of the wing and the fuselage at the wing root Significant interference dragEven more interference drag

Skin Friction Drag The aerodynamic resistance due to the contact of moving air with the surface of an aircraft A little skin frictionA lot of skin friction

Induced Drag The aerodynamic process that makes lift also induces drag, primarily due to generation of wingtip vortices More lift always means more induced drag; drag is the “price you pay” for lift The lower the airspeed, the greater the angle of attack (AOA) required to produce lift equal to the aircraft’s weight and, therefore, the greater induced drag Varies inversely with the square of the airspeed – double the speed, get ¼ the induced drag

Total Drag

Lift/Drag Ratio The amount of lift generated by a wing or airfoil compared to its drag Varies with angle of attack; there is one AOA that maximizes L/D for a given wing Also happens to be the glide ratio – distance traveled divided by altitude lost with no thrust For your training aircraft, L/D max is around 9 This means you glide 9 feet forward for every foot of altitude; 9 miles forward for every mile of altitude

Lift/Drag Ratio Decreasing Airspeed

Wing Camber Camber is a measure of curviness of a wing cross section More camber generally means more lift

Flaps Wing flaps effectively increase camber of the wing Results in increased lift at low speeds and increased drag

Leading Edge Devices Also increase a wing’s effective camber, lift, and drag (Also called a slat)

Spoilers Devices on top of the wing that spoil lift and increase drag

Thrust The forward force produced by the powerplant/ propeller Opposes drag

Propeller Consists of two or more blades and a central hub to which the blades are attached Each blade is essentially a rotating wing Propeller blades are like airfoils and produce forces that create the thrust to pull, or push, the aircraft through the air

Propeller Forces

Propeller Efficiency The ratio of thrust horsepower (how much power is turning the prop) to brake horsepower (how much power is converted to thrust) Propeller efficiency varies from 50 to 87 percent, depending on how much the propeller “slips” Pitch is the distance which the propeller would screw through the air in one revolution if there were no slippage

Propeller Slip The difference between the geometric pitch of the propeller and its effective pitch

Controllable-Pitch Props Also called “variable-pitch” prop Many propellers can change pitch by varying the angle between the blades and the prop hub You won’t be flying any of these for a while For training, you’ll have a fixed-pitch prop

Propeller Effects on Takeoff Most single engine aircraft rotate the prop clockwise with respect to the pilot sitting behind it The direction of rotation causes forces that must be corrected for These forces include:  Torque effect  Gyroscopic effect  Slipstream effect (corkscrew effect)  P-Factor

Torque Effect Prop turns clockwise; by Newton’s Third Law (equal and opposite reaction), aircraft wants to roll counterclockwise On the ground, this puts more weight on the left tire Like leaning into the turn on a snowboard, this tries to turn you left

Gyroscopic Effect Applying force to a gyroscope’s axis results in a force aligned 90 degrees to that axis Propeller is a pretty good gyroscope In the case of an airplane rotating the prop in the direction we are, this means that pitching down results in a left yaw Normally this is a factor primarily in a tailwheel airplane (Piper Cub)

Corkscrew Effect The high-speed rotation of an aircraft propeller gives a corkscrew or spiraling rotation to the slipstream At high propeller speeds and low forward speed this spiraling rotation is very compact and exerts a strong sideward force on the aircraft’s vertical tail surface This results in a left yaw

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 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

Descending blade Aircraft motion Relative Wind Aircraft motion Angle of attack Descending blade Angle of attack “P” Factor 44

Propeller Effects on Takeoff All the above effects (Torque, Gyroscopic, Corkscrew, P-Factor) result in a tendency to yaw left during takeoff The solution to correct for all these is right rudder How much?  Enough to keep the airplane on runway centerline while rolling  Enough to keep the ball centered when airborne

Static Stability Static stability and maneuverability are inversely related

Dynamic Stability

Airplane Equilibrium Your training aircraft has both positive static stability and positive dynamic stability in all three axes

Longitudinal Stability Depends on size and location of the wing and tail surfaces in relation to center of gravity More stable to have CG forward of CL

Longitudinal Stability and Speed

Lateral Stability - Dihedral

Vertical Stability

Aircraft Flight Controls Elevators control movement about the lateral axis (pitch) Ailerons control movement about the longitudinal axis (roll) Rudder controls movement about the vertical axis (yaw)

Elevators

Ailerons

Rudder

Control Effectiveness Control effectiveness depends on velocity of laminar (streamlined) air moving over the control surface Faster flow = more effective Flow over elevator can be affected by flap setting in high wing aircraft If wing is aerodynamically stalled, ailerons will be less or perhaps not effective You probably can’t fly slow enough to make the rudder ineffective