The Physics of Flight Myths and Legends of

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The Physics of Flight

The Physics of Flight

Myths and Legends of Flight n Icarus and Daedalus – Daedalus- engineer imprisoned by

Myths and Legends of Flight n Icarus and Daedalus – Daedalus- engineer imprisoned by King Minos. – With his son, Icarus, he made wings of wax and feathers. – Daedalus flew successfully from Crete to Naples – Icarus, flew too near to the sun. The wings of wax melted and Icarus fell to his death in the ocean. n Pegasus – Mythological Winged horse

Ancient Dreamers n Legends of flight attempts date to 2000 B. C. – Many

Ancient Dreamers n Legends of flight attempts date to 2000 B. C. – Many believed flying was for the mythical gods – Others tried to copy bird flight-unsuccessfully n Chinese invented kites about 200 - 500 B. C. – 17 th century A. D. kites carried soldiers aloft – WWI – Kites were used to spy on enemies – Buddhists Monks used them to “avert evil spirits and insure rich harvests”

Ancient Dreamers Leonardo da Vinci n Engineer, Scientist, Inventor and Artist n Italian artist

Ancient Dreamers Leonardo da Vinci n Engineer, Scientist, Inventor and Artist n Italian artist and scientist Leonardo da Vinci (14521519) gathered data on the flight of birds and bats To develop concepts of the propeller, the parachute, and heavier-than-air craft.

n Leonardo da Vinci, 15 th century Italian artist – First recorded scientific study

n Leonardo da Vinci, 15 th century Italian artist – First recorded scientific study of aeronautics – Experimented to prove feasibility of mechanical flight – Drew approximately 500 sketches and plans to construct flying machines

Other Da Vinci Inventions n n n Bicycle Armored “Car” Giant Crossbow Boats Water

Other Da Vinci Inventions n n n Bicycle Armored “Car” Giant Crossbow Boats Water Skis Eight Barreled Machine Gun n n n Anemometer – wind speed Helicopter – “Arial Screw” More Accurate Clock Robotic Knight Scuba Gear Revolving Bridge

The Quest for Flight By 17 th Century, ancient ideas inspired scientific theories and

The Quest for Flight By 17 th Century, ancient ideas inspired scientific theories and experiments n 1783 – Studies of the atmosphere and the discovery of gases and properties led to balloon experiments n – – – n First balloon - silk balloon with a basket First passengers - a sheep, a rooster and a duck Rose up to 6000 feet, traveled for over 1 mile Glider flying increased the understanding of flight forces, wing geometry & controls

Understanding Flight n How do Birds Fly? ? ? – – – Wing Design

Understanding Flight n How do Birds Fly? ? ? – – – Wing Design Hollow Bones Large Lungs Air Sacs Strong Muscles

Aerodynamics? • Aero – means Air • Dynamics – means Motion • Aerodynamics –

Aerodynamics? • Aero – means Air • Dynamics – means Motion • Aerodynamics – the study of air in motion • Important Point: Air is “Viscous” Uh, that means it’s Sticky

Definition: Aerodynamics A branch of fluid mechanics that deals with the motion of air

Definition: Aerodynamics A branch of fluid mechanics that deals with the motion of air and other gaseous fluids

Airfoil n A structure with curved surfaces – designed to give the best ratio

Airfoil n A structure with curved surfaces – designed to give the best ratio of lift to drag in flight – The basic form of the wings, fins, and horizontal stabilizer of most aircraft.

Forces and Vectors • • • A force may be thought of as a

Forces and Vectors • • • A force may be thought of as a push or pull in a specific direction. A force is a vector quantity so a force has both a magnitude and a direction. When describing forces, we have to specify both the magnitude and the direction.

Airplane Parts Vertical Stabilizer Empennage (Tail) Wing Horizontal Stabilizer Engine Fuselage (Body)

Airplane Parts Vertical Stabilizer Empennage (Tail) Wing Horizontal Stabilizer Engine Fuselage (Body)

Bernoulli’s Principle n As the velocity of a fluid increases the pressure exerted by

Bernoulli’s Principle n As the velocity of a fluid increases the pressure exerted by the fluid decreases.

Air Flow Past a Wing n The air speed is greater over the upper

Air Flow Past a Wing n The air speed is greater over the upper surface and the air pressure is lower there and the wing is lifted When the wing is angled upward, air deflected from its lower surface provides additional lift. n If the angle is too great, turbulence reduces lift and increases drag. n

Powered Flight Breakthrough Experiments showed basic ingredients of flight are: sufficient power, lift ,

Powered Flight Breakthrough Experiments showed basic ingredients of flight are: sufficient power, lift , control n Application of theories of lift and drag to practical use in powered gliders n Progress (and a conventional designs) came with lighter materials and drag reduction n

Breakthrough The Main Events n Sir Hiram Maxim – power, lift, control Wright brothers

Breakthrough The Main Events n Sir Hiram Maxim – power, lift, control Wright brothers n Glen Curtiss n – Improved designs, promoted aviation December 17, 1903, near Kitty Hawk, North Carolina, Wilbur and Orville Wright made the world's first successful powered, free, controlled, sustained flights in a heavier-than-air craft.

World War I The Main Events War speeds up technology development n Airplane speed

World War I The Main Events War speeds up technology development n Airplane speed and loads increased n Large manufacturing base developed n

After the War n n n Veteran pilots kept interest alive Commercial aviation catches

After the War n n n Veteran pilots kept interest alive Commercial aviation catches on Dramatic design advances Beginning of rocket flight Invention of the jet engine

Four Forces of Flight n Lift n Weight n Thrust n Drag Source: NASA

Four Forces of Flight n Lift n Weight n Thrust n Drag Source: NASA Glen Research Center

4 Forces of Flight

4 Forces of Flight

Weight Center of Gravity (CG)

Weight Center of Gravity (CG)

Drag Newton’s 1 st Law Applies

Drag Newton’s 1 st Law Applies

Thrust Newton’s 3 rd Law Applies

Thrust Newton’s 3 rd Law Applies

Lift Thrust Drag Weight Newton’s 3 rd Law Applies

Lift Thrust Drag Weight Newton’s 3 rd Law Applies

Think About It It’s “Tug-a-War” The motion of the airplane through the air depends

Think About It It’s “Tug-a-War” The motion of the airplane through the air depends on the relative strength and direction of the forces we’ve discussed. If the 4 forces are balanced, the aircraft cruises at constant velocity and altitude. If the forces are unbalanced, the aircraft accelerates in the direction of the largest force.

Lift n n n Lift is an aerodynamic force Lift must exceed weight for

Lift n n n Lift is an aerodynamic force Lift must exceed weight for flight Generated by motion of aircraft through air Created by the effects of airflow past wing The top of an airplane wing is curved, so that air has to travel further to reach the trailing end of the wing. Therefore, the air on the underside of the plane is exerting more pressure, causing the plane to lift.

Weight n Weight is not constant – varies with passengers, cargo, fuel load –

Weight n Weight is not constant – varies with passengers, cargo, fuel load – decreases as fuel is consumed or payload off-loaded Direction is constant toward earth’s center n May be assumed concentrated at the center of gravity n

Drag An aerodynamic force n Drag is also called air resistance. n n the

Drag An aerodynamic force n Drag is also called air resistance. n n the force that pulls the plane backward. n Two broad drag classifications – Parasite drag: drag created by airplane design – Induced drag: by-product of lift generation n Acts through the center of pressure

Thrust n Forward-acting force opposes drag n Direction of thrust depends on design n

Thrust n Forward-acting force opposes drag n Direction of thrust depends on design n Propulsion systems produce thrust n Equal to drag in straight, constant speed flight

Stability Basics n Center of Gravity n Center of Pressure – Average location of

Stability Basics n Center of Gravity n Center of Pressure – Average location of pressure – Changes with plane movement n Longitudinal Stability n Lateral Stability n Directional Stability

Remember: Center of Gravity for People

Remember: Center of Gravity for People

Definition: Aeronautics n Aeronautics is the design and construction of aircraft and n The

Definition: Aeronautics n Aeronautics is the design and construction of aircraft and n The theory and practice of aircraft navigation

Definition: Aerospace Engineering n Aerospace engineering is closely allied to aeronautics and aeronautical engineering

Definition: Aerospace Engineering n Aerospace engineering is closely allied to aeronautics and aeronautical engineering but n Includes the study and development of rocket engines, satellites, and spacecraft

What’s Next? ?

What’s Next? ?