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 liftActs vertically downward thru aircraft’s center of

gravity

Lift

Produced by the dynamic effect of air on the wing

Opposes weightActs perpendicular to flight path

Bernoulli’s Principle

Unrestricted tube

Restricted 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 liftFlow over airfoil imparts a downward flow to

air passing over itBy 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 pressureResults 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 pressureMeasured 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 drag

Even 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 friction

A 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 wingPropeller 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” propMany 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 whileFor 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 gyroscopeIn 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

Left Turning

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 effectiveFlow over elevator can be affected by flap

setting in high wing aircraftIf wing is aerodynamically stalled, ailerons

will be less or perhaps not effectiveYou probably can’t fly slow enough to make

the rudder ineffective