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Flight Control Systems (Conventional & Digital) & Enhanced Diagnostic Aid (EDNA)

2a. Identify principles of flight with at least 80% accuracy.


• Overview of Principles of Flight

– Basic Facts and Terms

– Controls and Surfaces

– Axes of Rotation


• Principles of Flight– Bernoulli’s Principle

• As air velocity increases, pressure decreases

• As air velocity decreases, pressure increases

• Venturi tube


– Density• As air is compressed, it becomes more dense

• Air has less density at high altitude

• Air expands as it is heated – occupies more space

• Changes in air density affect flight– Climate is cold, altitude is low = dense air

» Aircraft achieves takeoff speed more quickly

» Takes off with less runway

– High Altitude = low density (airplane flies faster)


– Humidity• Higher temperature of air – the more water it can

absorb

• Temperature the same – density of air varies with humidity

• Damp days– Density is less than it is on dry days

– Airplane requires longer runway for takeoff


– Relative Wind – the direction of the airflow with respect to the wing


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


– Airfoils• Any object designed to obtain a reaction upon itself

from the air through which it passes


– Wing Chord Line• Distance from the leading edge to the trailing edge

• Represented by a straight line called the chord line


– Camber• The curve or departure from the chord line

• Positive – Convex Surface

• Negative – Concave Surface


– Camber• Upper Surface – Always positive

• Lower Surface– Positive (usually)

– Zero

– Negative


• Producing Lift– High-speed flow is associated with low pressure

– Low-speed flow is associated with high pressure


– Airfoil is designed to increase the velocity of the airflow above the surface – decreases pressure above the airfoil

– Impact of air on lower surface increases pressure below

– Pressure differential causes lift


• Weight – the force of gravity acting downward upon anything that goes into the aircraft– Reduced as fuel is burned

– Reduced as missles and bombs are released

– Reduced the aircraft will climb


• Lift – acts vertically, by doing so counteracts weight– Increases to a certain point with

• AOA

• Air Density

• Airspeed

– Lift is increased – aircraft will climb

– Lift is reduced – aircraft will descend


• Drag – forward deterrent force (caused by the disruption of the airflow by the wings, fuselage and protruding objects)– Increases with

• Airspeed

• AOA (drag increases much more rapidly than lift as AOA increases)

– Decreases with increased altitude due to decrease in air density


• Thrust – the forward force produced by the jet engine that overcomes the force of drag– Increased thrust increases airspeed

– Decreased thrust is needed at higher altitude to achieve the same airspeed due to less air density and drag

– Thrust is decreased, airspeed will decrease


• Controls and Surfaces– Stick


• Controls and Surfaces– Mechanical/Electronic

Controls


• Controls and Surfaces– Electronic Controls


• Controls and Surfaces– Rudder Pedals


• Controls and Surfaces– Flap Controls


• Control/Surface Connection– Direct Mechanical


• Control/Surface Connection– Power Assisted Mechanical


• Control/Surface Connection– Powered, Electronically Controlled


• Flight Control Surfaces– Wings

• Primary means of providing lift for the aircraft


• Flaps– Attached to wings

– Moveable surfaces that provide increased lift


• Flaps– Trailing Edge Flaps


• Flaps– Leading Edge Flaps


• Ailerons– Moveable surfaces to provide roll control


• Horizontal Stabilizers– Provides stabilization against uncontrolled pitching of the

aircraft– Attached to aft section of aircraft


• Elevators– Moveable surfaces to provide pitch control

– Attached to trailing edge of horizontal stabs


• Moveable Horizontal Stabilizers– Entire Surface pivots to provide pitch control– Does not require elevators


• Vertical Stabilizers– Provides stabilization against uncontrolled yawing

of the aircraft


• Rudder– Moveable surfaces to provide yaw control

– Move symmetrically


• Combined Surfaces– Flaperon


• Elevons


• Speedbrake


• Axes of Rotation– Surfaces are normally “streamline” for straight

and level flight


• Roll– The longitudal axis is an imaginary line through

center of straight and level flight


• Roll– Movement about the axis is roll


• Roll– Roll is initiated by applying lateral pressure to the

side stick controller


• Pitch– The lateral axis is an imaginary line from the wing

tip to wing tip


• Pitch– Movement about about the axis is pitch


• Pitch– Pitch is initiated by applying fore and aft pressure

on the side stick controller


• Yaw– The vertical axis is an imaginary line through the

center of the aircraft from top to bottom


• Yaw– Movement about the axis is yaw


• Yaw– Yaw initiated using rudder pedals


• Trim


• Summary of Principles of Flight

– Defined Basic Facts and Terms

– Covered Controls and Surfaces

– Axes of Rotation