AVATIONTHEORY

AVATIONTHEORY created by nermin zimic UMSL 2013

UMSL printing

All Rights Reserved Copyright ÂŠ 2013 The copy righted portions of this book may not be reporoduced in any form by any means without the written content of the publisher.

Printed in Saint Louis, Missouri April, 2013

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Physical Properties of Air

Theory of Flight

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Controlling Surfaces

Model of Parts

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FOREWORD

The Aviation Theory exhibit covers the basic information of aircraft, explaining how each part works and what it contibutes. Each section has been explained in a logical sequence so that the audiance may advance step by step and build a solid foundation for increased knowledge. The viewers understanding of the explanations and descriptions given in the test greatly enhanced by the use of numberous illustrations. The catalog itself covers the same information and may be used by students for self-advancement or by anyone else who is interested in the basics of the flight theory.

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PHYSICAL PROPERTIES OF AIR

The Atmosphere Air is a mixture of several gases. For ordinary purpose, it is sufficiend to say that air is a mixture of one fifth-oxygen and four fifths nitrogen. Pure, dry air contains about 78 percent (by volume) nitrogen, 21 percent oxygen, and almost 1 percent argon. In addition, it contains about 0.03 percent carbon dioxide and traces of several gases, such as hydrogen and helium. The atmosphere is the whole mass of air surrounding the earth, extending upward about 500 miles. It may be compared to a pile of blankets. Air in the higher altitutes, like the top blanked of a pile, is under less pressure then air ar the lower altitudes. Air at the eartchâ&#x20AC;&#x2122;s surface may be compared to the bottom blanket in a pile; it is supporting the weight of all the layers.

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Pressure We have seen that air is always pressed by the weight of the layers of air above it. Pressure may be defined as force acting upon an area. It is commonly measured in pounds per square inch. The atmospheric pressure at any place is equal to the weight of a column of water or mercury a certain number of inches in height.The pressure of atmosphere varies with the altitude of percetly dry air.

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Pressure Inches 30,000 ft. 8.88 5,000 ft. 24.89

10,000 ft. 20.58 20,000 ft. 13.75

m p= v

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Density Air can be compressed or it can be permitted to expance. When compressed, the same quantity of air requires lessspace. When the pressure decreases, the same quantity of air expands and occupies more space. Density is mass per unit volume.

p= density m= mass v= volume

Lower Density

Higher Density

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Humidity

Relative Motion

Humidity is a condition of moisture or dampness. The maxium amount of water vapor that the air can hold depends entirely on the temperature, the higher the temperature of the air, the more water vapor it can absorb. By itself, water vapor weights approximately five-eights as much as an equal volume.

Motion is movement. If an object changes its position, it is in motion. Any object can be located by its distance from adjacent objects, hence an objecet which has moved has changed its position with regard to some other object which has a fixed position, and relative motion has taken place.

Isacc Newton laws

Daniel Bernoulli principle

If an object is not moving, it will not start moving by itself. If an object is moving, it will not stop or change direction unless somthing pushes it.Objects will move farther and faster when they pushed harder.When an object is pushed in one direction, there is always a resistance of the same size in the opposite direction.

The Bernoulli Principle simply states that an increase of a flow results in a decrease of pressure. When air hits the leading edge the airflow above the wing travels faster than the flow below the wing. As the Bernoulli Principle states, the pressure below the wing will be higher than the air pressure above the wing.

Engine Pushed Forward

Flow Pushed Backward

Lower Pressure / Fast Airflow

Higher Pressure / Slow Airflow

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THEORY OF FLIGHT

Aerodynamics Theory of flights means simplified aerodynamics. Aero means pertaining to air, aircraft, aviation or aeronautics. Dynamics is that branch of physics which considers bodies in motion and forces that produce or change such motion. Four aerodynamic forces that act upon an airplane in flight are lift, weightgravity, thrust and drag.These four forces are continiously battling each other while an airplane is in flight. Gravity opposes lift, thrust opposes drag. In order to take off, aircrafts thrust and lift must be suffucient to over come its weight and drag. In level flight at constant speed, thrust exactly equals drag and lift exactly equals the pull of gravity. To land, an aircraftâ&#x20AC;&#x2122;s thrust must be reduced safely below its drag, and its lift is reduced to levels less than its weight.

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LIFT DRAG

THRUST

WEIGHT

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Weight

Thrust

Weight is a major factor in airplane construction and operation, and demands respect from all pilots. The force of gravity continually attempts to pull the airplane down toward earth. The force of lift is the only force that counteracts weight and sustains the airplane in flight. If the weight is greater than the lift generated, the airplane may be incapable of flight.

Thrust is the force which moves an aircraft through the air. Thrust is generated by the engines of the aircraft through some kind of propulsion system. Thrust is a mechanical force, so the propulsion system must be in physical contact with a working fluid to produce thrust. Thrust is generated most often through the reaction of accelerating a mass of gas.

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Lift Lift is the aerodynamic force that counteracts gravity and holds an airplane in the air. Most of the lift required by an airplane is created by its wings, but a certain portion is also generated by other parts of the aircraft, such as the fuselage. An airplane wing has a special shape, called an airfoil, that bulges more on top than on the bottom. That shape aids in flight, but is not the key. If this were all there were too it, then how could some planes fly uside-down? When air meets the wing, it splits into two streams, top and bottom.

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Lift

Airflow

Drag Drag is a force exerted on an object moving through a fluid; it is always oriented in the direction of relative fluid flow. Drag occurs because the fluid and the object exchange momentum when impacting, creating a force opposing the motion of the object.

Angle of Attack

Drag

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CONTROLLING SURFACES

Ailerons The ailerons on planeâ&#x20AC;&#x2122;s wings controll roll around the longitudial axis. They work together, simultaneously, tried to the control wheel, or stick, in the cockpit. When the control wheel is turned left, the aileron on the left wing goes up and the one on the right wing goes down. The opposite occurs when the wheel is turned to the right.

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Elevators The elevators on the horizontal portion of the tail of an airplane control the pitch of the plane, or its motion around the lateral axis. They are also tied to the control wheel in the cockpit. When the wheel is pulled back, the elevators move upward, causing the tail of the plane to move downward and the nose to pitch upward. When the wheel is pushed forward, the elevators move downward, causing the tail of the plane to rise and the nose to pitch downward.

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VERTICAL STABILIZER Control yaw

COCKPIT Command and controll

APU EXHAUST

HORIZONTAL STABILIZER Control pitch

LANDING GEAR

ENGINE INTAKE Generate thrust WING Generate lift

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COLOPHON

This catalog was designed by Nermin Zimic under the advisement of Bruce Sachs as an assigment for Advance Problems in Graphic Design 2. It was created using Adobe CS6 Indesign and Illustrator.

Typefaces: Din and Adobe Devangari. Source used: Aircraft Basic Science / Northdrop Aeronautical Institute First Copy Printed on April 1st 2013

Aviation Theory

Science Exhibit Booklet