The Theory Of Flight How an Aircraft Flies

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Get book...A & P General Technician Textbook Chapter 7 pg 236

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Bernoulli's Principle : states that as the speed of a moving fluid increases, the pressure within the fluid decreases. Air is considered a fluid as it reacts similarly to water

A venturi shows how this principle works As a fluid passes through the venturi two things happen (1) static pressure decreases (2) dynamic pressure increases

ClickClick for animation

Blowing air over a piece of paper also shows this venturi effect

This can be seen when you release the pressure in a garden hose or when you put your hand out a car window.

static pressure around us on earth on a standard day is 14.7 psi or in of mercury. This is the pressure that is on our bodies at all times

Show pin-pong ball example make Bernoulli's ball game

potential and kinetic energy potential has the energy stored kinetic is energy that derived from movment

The three ways storing potential energy are: By position, relying on gravity to move something to a lower point. By loading or distorting an elastic body (spring). In a chemical that can release energy. Examples of each : (raised hammer, fuel, hydrogen & oxygen or oil, battery or capacitor.)

How does the kinetic energy of stopping a car get released? (Heat). If a glider going fast in descent it flies upward untill it stops, where has the kinetic energy gone? (Its been converted to altitude).

Newton’s third law: "Every action has an equal and opposite reaction

Airfoils produce reaction with air

Lift: is determined by three factors (a) surface area (b) lift coefficient of the foil (which changes with angle of attack) (c) the dynamic pressure (speed) of the air.

Airspeed affects lift exponentially - if the speed doubles, the lift quadruples (square) The concord could fly at mach 2.2 It cut the flying time between London and N. Y. from 7 hr 40 min to 3 hr 25 min

Weight Heavy Light

Thrust Thrust SSC -set a land speed record in 1997 of 763 MPH Afterburners on this F-14 apply plenty of thrust

DRAG: Is a force that opposes thrust The B-2 is extremely aerodynamic

*The relationship between the speed of an object and the quantity of drag is exponential, *When speed is doubled drag is squared.

Write this down!!!!!!!!!!!! --Use a 1” thick piece of hard Styrofoam and cut into a 4” by 5 “ piece. --design your wing …start with it rough and file after the first run then sand after the second run. Lastly tweak the design during last set of runs -Cut an 11” piece of 3/16 dowel. Sharpen one end and insert 2” of the dowel into the forward (thicker) part of the wing. Glue it there. -When the glue is dry, mark with a pen up 4” on the other end of the dowel. Using the floor belt sander lightly sand the 4” section so it is less than 3/16 of an inch. - Let Her FLY!!!!!!!!!!!!!!!!!!!!!!!!!!

*Carry out roler coaster activity and rocket racer *Use flying fun toys *wind tunnel--build balsa wood wing

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Angle of attack: Is the angle between the air and the chord of the wing is controlled by elevator position

Angle of incidence: relationship of chord angle to longitudinal axis of aircraft. Angles of incidence of about 6 ̍ are common on most general aviation designs.

Stall: When the boundry layer of air separate and causes a sudden decrease in lift. Two men died in this crash as the a/c stalled on take off------click here for animation

Vortex Generators - reduce the possibility of layer separation by putting energy back into the air Vortex generators delay flow separation and aerodynamic stalling; they improve the effectiveness of control surfaces

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Helicopter rotor blade *The rotors on a Helicopter are essentially moving wings – hence the name rotory wing. *All other aircraft are called fixed wing

Click for helicopter animation Click for helicopter video

AXIS OF FLIGHT The axes of an aircraft are imaginary lines that pass through the center of gravity. Each axis has a specific location: nose to tail, vertical and wing tip to wing tip. The aircraft moves about each axis.

The longitudinal axis The axis that extends lengthwise (nose through tail) Rotation about this axis is called roll and is controlled through the ailerons

The lateral axis The axis that extends crosswise (wingtip through wingtip) Rotation about this axis is called pitch & is controlled through the elevator

The vertical axis The axis that passes vertically through the center of gravity (when the aircraft is in level night) Rotation about this axis is called yaw & is controlled by the rudder

The end *see shop mock up for the three axis of flight *wind tunnel project--build balsa wood airplane *make paper airplanes from web site: