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The Physics of Flight. Ancient Dreamers. Legends of flight attempts date to 2000 B.C. Many believed flying was for the mythical gods Others tried to copy bird flight-unsuccessfully Chinese invented kites about 1000 B.C. 17 th century A.D. kites carried soldiers aloft
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Ancient Dreamers • Legends of flight attempts date to 2000 B.C. • Many believed flying was for the mythical gods • Others tried to copy bird flight-unsuccessfully • Chinese invented kites about 1000 B.C. • 17th century A.D. kites carried soldiers aloft • Leonardo da Vinci, 15th century Italian artist • First recorded scientific study of aeronautics • Experimented to prove feasibility of mechanical flight • Drew sketches and plans to construct flying machines
Ancient Dreamers • Leonardo da Vinci • Daedalis & Icarus Italian artist and scientist Leonardo da Vinci (1452-1519) gathered data on the flight of birds and developed concepts of the propeller, the parachute, and heavier-than-air craft.
The Quest for Flight • By 17th Century, ancient ideas inspired scientific theories and experiments • Characteristics of the atmosphere and the discovery of gasses and properties led to lighter-than-air balloon experiments • Airships needed power and direction control • Glider flying increased the understanding of flight forces, wing geometry & controls
Definition: Aerodynamics Aerodynamics is a branch of fluid mechanics that deals with the motion of air and other gaseous fluids, and with the forces acting on bodies in motion relative to such fluids
Bernoulli’s Principle • According to Bernoulli’s Principle, as the velocity of a fluid increases the pressure exerted by the fluid decreases.
Air Flow Past a Wing • The air speed is greater over the upper surface, as indicated by the closer streamlines, 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. • If the angle is too great, turbulence reduces lift and increases drag.
Powered Flight Breakthrough • Experiments showed basic ingredients of flight are: sufficient power, lift , control • Wright’s successfully applied theories of lift and drag to practical use in powered gliders • Progress (and a conventional designs) came with lighter materials and drag reduction
Breakthrough The Main Events • Sir Hiram Maxim • power, lift, control • Wright brothers • Glen Curtiss • 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 • War speeds up technology development • Airplane speed, loads increased • Large manufacturing base developed The Main Events Congressional medal of Honor winner Captain Eddie Rickenbacker went on to be a pioneer in civil aviation, too
After the War • 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 • Lift • Weight • Thrust • Drag Source: NASA Glen Research Center
Lift • 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 • 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 • May be assumed concentrated at the center of gravity
Drag • An aerodynamic force • Drag is also called air resistance. • the force that pulls the plane backward. • Two broad drag classifications • Parasite drag: drag created by airplane design • Induced drag: by-product of lift generation • Acts through the center of pressure
Thrust • Forward-acting force opposes drag • Direction of thrust depends on design • Propulsion systems produce thrust • Equal to drag in straight, constant speed flight
Stability • Center of Gravity • Center of Pressure • Longitudinal Stability • Lateral Stability • Directional Stability
Definition: Aeronautics • Aeronautics is the design and construction of aircraft and • The theory and practice of aircraft navigation
Definition: Aerospace Engineering • Aerospace engineering is closely allied to aeronautics and aeronautical engineering but • Includes the study and development of rocket engines, satellites, and spacecraft
Activities and Exercises • Build gliders for flight control experiments • Worksheets