Introduction to Aerospace Engineering 1
Introduction to Aerospace Engineering o Course Contents Principles of Flight History Fundamental Thoughts Standard Atmosphere Aerodynamics Overview Aircraft Performance Stability and Control Propulsion Structures Rocket & Spacecraft Trajectories and Orbits 2
Introduction to Aerospace Engineering o Course Evaluation Quizzes 20% Assignment 10% Mid-term Exam 30% Final Exam 40% Resources: Lectures & Lecture Slides Book: Introduction to Flight John D. Anderson 3
Principles of Flight o Three ways to counter gravity 4
o Ballooning 5
o Ballooning Principle of floating exploited with hot air (although they thought it was a special gas) 6
o Ballooning Today s balloons: essentially the same 7
o Ballooning Which type provides more lift? Helium or hot air? Why? How many helium-filled party balloons can you safely carry before you become airborne? 50-100-1000-10,000? What altitude can you reach with a balloon? 8
George Caley; Wilbur Wright; Orville Wright; Samuel Langley 9
o 19th Century - unpowered Leonardo da Vinci (1452-1519) The original Renaissance Man: painter, inventor, writer Sketched several aerospace vehicle concepts 10
o 19th Century - unpowered Sir George Cayley (1773-1857) Considered Father of aviation Cayley had identified two very important factors related to flight: One is that the drag vector is parallel to the flow and the lift vector is perpendicular to the flow Cayley identified for the first time that lift is generated by a region of low pressure on the upper surface of the wing. In addition, he demonstrated that cambered wings (curved surfaces) generate lift more efficiently than a flat surface. In 1804 designed and built a model monoplane glider; In 1849 built a large gliding machine 11
o 19th Century - unpowered Otto Lilienthal (1848 1896) Was fascinated with the flight of birds (Storks); Started experiment in 1867 Important source of inspiration and information for the Wright brothers Collected aerodynamic data, and emphasized that curvature of a bird s wings is key to flight Made more than 2000 flights between 1891 and 1896 Build more than a dozen gliders Build his own hill in Berlin Largest distance 250 meters Died in a glider accident in 1896 No filmed evidence: film invented in 1895 12
o 19th Century - unpowered Otto Lilienthal (1848 1896) 13
o Hang Glider 14
o Question With Gliders you have to run to generate enough lift often down hill to make it easier. Is the wind direction of any influence? 15
o Question With Gliders you have to run to generate enough lift often down hill to make it easier. Is the wind direction of any influence? 16
o Beginning of 20th Century Samuel Pierpont Langley - (1834 1906) Astronomer and Director of the Smithsonian, became interested in flight in his 50s Remembered as one of the most unlucky trail blazers in flight history In 1896 one of his heavier-than-air machines, Aerodrome no. 6, became the first to achieve sustained unmanned flight. Aerodrome no. 6 flew 1280 meters at about 48 km/hr over the Potomac River in Washington, D.C. Langley received a government contract to build and fly a heavier-than-air machine with a pilot on board. However, his attempts to fly a manned aircraft were not so fortunate The Great Aerodrome was built and was launched by catapult from a houseboat anchored in the Potomac River. Front wing badly damaged. Second attempt even worst. Rear wing and tail completely collapsed during the launch. Charles Manley, the pilot, nearly drowned before he could be rescued from the wreckage in the ice-covered Potomac. After this near disaster, Langley did not attempt any further flights. Spent more than $50,000 of federal funds; was ridiculed by the press and Congress 17
o Beginning of 20th Century The Wright Brothers: December 17, 1903 first manned, powered Heavier than Air flight, Kitty Hawk, North Carolina 18
o Beginning of 20th Century The Wright Brothers: 1903 first powered Heavier than Air flight Printing firm & Bicycle shop Interested in flying (inspired by Lilienthal gliders) Did a lot of investigations: Build a wind tunnel to test planes Timing (readiness of technology) Pressure of Samuel Pierpont Langley The engine 12 Horse Power The propeller (2 counter rotating propellers) - Perfected in wind tunnel! 19
o Beginning of 20th Century The Wright Brothers: 1903 first powered Heavier than Air flight Several factors that led to the Wright Brothers success. They invented a means for a pilot to steer the aircraft effectively to maintain three-axis control of roll, pitch, and yaw. They conducted flight experiments with kites and gliders for several years before the powered flight By 1902, they were the most experienced glider pilots in the world. They built a wind tunnel and tested models of their aircraft in their bicycle shop in Dayton, Ohio. The data that they collected related to drag and lift were more accurate than any before Some features/dimensions: Aircraft: weight of 275 kg 344 kg (incl. engine) Length 6.4 m; Wingspan: 12.2 m; (efficient wing due to wind tunnel) Wing area 48 m2 Longest distance (first flight): 260 meters Flying time was 59 sec. Flyer had later models (larger engines; improved wing surfaces) 20
o Beginning of 20th Century The Wright Brothers: 1903 first powered Heavier than Air flight 21
o Beginning of 20th Century Influence of Wright s Flyer The Flyer series of aircraft were the first to achieve powered & controlled heavier-than-air flight The Flyer design depended on wing warping and a horizontal stabilizer, features which would not scale and produced a hard-to-control aircraft; Later: ailerons by Curtiss and Farman Highly efficient wings and propellers, which resulted from the Wrights' exacting wind tunnel tests 22
o > 100 years later 23
Fundamental Thoughts o A Flowing Gas 24