Aerodynamics and Flight Characteristics Lecture PDF

Aerodynamics and Flight characteristics - Part 1- Classification of the course in the curriculum Aerodynamics and Flight Characteristics (Module 644-1) Date: Mondays and Thursdays, 4. DS (01:00 - 02:30) Room: POT 051...

Aerodynamics and Flight characteristics - Part 1- Classification of the course in the curriculum Aerodynamics and Flight Characteristics (Module 644-1) Date: Mondays and Thursdays, 4. DS (01:00 - 02:30) Room: POT 051 Exercises (Mondays) are embedded in the lectures Written exam (180 min) with calculator (no PDA or handheld) Contact: [email protected] Consultation time: Wednesday, 9:20 – 10:50 Information about the course: https://tu-dresden.de/bu/verkehr/ila/ifl/studium/lehrveranstaltungen/aerodynamik Registration and script via OPAL Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 2 Dr.-Ing. habil. Judith Rosenow Definitions Flight mechanics: behavior of bodies moving in the atmosphere with the help of aerodynamics. Flight Aero- Aerodynamics: part of fluid dynamics and describes the behavior of Mechanics dynamics bodies in compressible fluids, i.e. gases. Flight controls: the entire system for controlling aircraft around all Fluid three spatial axes. Thermo- Mechanics & dynamics Aeroelasticity is the umbrella term for the physical processes that Meteorology occur on structures around which air flows when aerodynamic loads interact with an elastic structure. -> not in the focus of this course Flight Control Aerolasticity Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 3 Dr.-Ing. habil. Judith Rosenow Overview of the course 1) Introduction 2) General Aerodynamics 3) Aerodynamics - Aerofoil 4) Flight Mechanics - Basics 5) Controls 6) Stability Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 4 Dr.-Ing. habil. Judith Rosenow Introduction Historical Overview Around 1500: Leonardo da Vinci's first "engineering" designs for flying machines Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 5 Dr.-Ing. habil. Judith Rosenow  Introduction Historical Overview around 1670: Francesco Lana di Terzi develops proposals for airships based on the "lighter than air" principle Francesco Lana de Terzi: (1631–1687, Lombardy) was an Italian Jesuit priest, mathematician, naturalist and aeronautics pioneer Professor of physics and mathematics at Brescia first sketched the concept for a vacuum airship has been referred to as the Father of Aeronautics Book: ”A theory of aerial navigation verified by mathematical accuracy" Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 6 Dr.-Ing. habil. Judith Rosenow Introduction Historical Overview 1709: Bartolomeu de Gusmao first model of a hot air balloon Paper balloon rises 4 meters into the air before the eyes of the King of Portugal. Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 7 Dr.-Ing. habil. Judith Rosenow Introduction Historical Overview - 21.11.1783: First ascent of a Montgolfier hot-air balloon in Paris; two people on board. - 07.01.1785: First crossing of the English Channel in a hot-air balloon. - Problem: No control of the direction of flight Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 8 Dr.-Ing. habil. Judith Rosenow Introduction Historical Overview Englishman Sir George Cayley: fundamental development of aerodynamic flight 1804 Model of a glider with a length of 1.6 meters 1809 first Unmanned flight Source: http://www.geschiedenisdc.nl/luchtvaart/cayley/cayley.htm Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 9 Dr.-Ing. habil. Judith Rosenow Introduction Historical Overview Sir George Cayley: Fundamental development of aerodynamic flight, 1804 model of a glider with a length of 1.6 m, unmanned flight in 1809 In 1809/1810, he published findings from the experiments under the title "Aerial Navigation" in Nicholson's Journal: "The whole problem of flight is within the following limits: 1. A surface must be made load-bearing for a given weight by applying a force against the resistance of the air 2. The pitched wing - equipped with a propulsion mechanism - that is the true principle of aviation." Engraving of the Aerial Steam Carriage, 1843 Source: https://elsecretodelospajaros.files.wordpress.com/2013/05/1843_engraving_of_the_aerial_steam_carriage.jpg Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 10 Dr.-Ing. habil. Judith Rosenow Introduction Historical Overview 1889: Otto Lilienthal published: "Bird flight as the basis of the art of flying” Carrying out systematic gliding flight investigations Data on the aerodynamic shape of the wings Elaborations on the development of lift and drag For "lifting power" curved wings are better suited than flat wings Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 11 Dr.-Ing. habil. Judith Rosenow  Introduction Lilienthal First gliding experiments: wingspan of 6 to 10 m, a wing area of approx. 14 m² standing exercises against the wind jumps from the springboard in the garden of his house On 9 August 1896, Lilienthal crashed from a height of about 15 m. The cause was a "solar gust" (a thermal detachment) NASM Archives photo Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 12 Dr.-Ing. habil. Judith Rosenow Introduction Brothers Wright From 1899 Wright brothers first functioning triaxial control system (Dreiachssteuerung) 1. Rudder (Seitenruder) to control the direction of flight (yaw movement) 2. Elevator (Höhenruder) to control the angle of attack and the longitudinal flight path inclination angle (climb or descent) 3. lateral control (Quersteuerung) via the twisting of the wings (roll motion) Powered maiden flight on 17.12.1903 (260m, National Air and Space Museum, Smithsonian Institution 59s, 16km/h) 5.10.1905 Flyer 3 already 39 min Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 13 Dr.-Ing. habil. Judith Rosenow  Introduction Brothers Wright In October 1900, the two brothers tested gliding flight with a biplane glider (Doppeldeckergleitflugzeug) First unmanned… …In the summer of 1901: manned gliding flights up to 100 m and with up to 35 km/h headwind, with the pilot operating the apparatus lying down dissatisfied because of poor flight stability with regard to the aileron and yaw axis Photo by Eric Long/NASM, National Air and Space Museum, Smithsonian Institution Online-Ausstellung: http://www.nasm.si.edu/wrightbrothers/index_full.cfm Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 14 Dr.-Ing. habil. Judith Rosenow Introduction Theoretical approaches Insights were not gained from theoretical predictions and practical verifications Transfer of natural principles (birds) to technical concepts From approx. 1890 (Lilienthal): Development of theoretical foundation of lift, controllability and stability Example of aerofoil Joukowski transformation: 1909 first lectureship in aviation: Ludwig Prandtl (Göttingen) http://math.fullerton.edu/mathews/c2003/JoukowskiTransMod.html Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 15 Dr.-Ing. habil. Judith Rosenow Introduction Field trials 1915: Aircraft test track of the DVL: 1916: Tower car with DVL Berlin-Adlershof aircraft for air preliminary tests with models in the resistance measurements Göttingen wind tunnel Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 16 Dr.-Ing. habil. Judith Rosenow Introduction Wind tunnel tests Messerschmitt Bf 109 (Me 109) Me 109 in the Braunschweig wind tunnel, side view 1939 - 755 km/h - 1800 PS 1989 - Grumman F8F-2 Bearcat - 850 km/h - 4000+ PS Source: DLR Archive Cologne Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 17 Dr.-Ing. habil. Judith Rosenow  Introduction Hugo Junkers Industrial research: Hugo Junkers, fundamental considerations on design and material properties Investigations into the construction of efficient and, from an operational point of view, profitable transport aircraft Already idea of a wing-only aircraft (thick, cantilever (freitragender) wing) 1910, patent on a physical design of the wings Thick wings can accommodate tanks, engines or cargo 1915 Development of the first all-metal aircraft J1 88 kW (120 PS), 170 km/h take-off mass 1080 kg length 8,6 m, wingspan 13 m Maiden flight: 12.12.1915 www.junkers.de Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 18 Dr.-Ing. habil. Judith Rosenow  Introduction Wing National Advisory Comitee for Aeronautics (NACA), State organisation Basic research in aviation, predecessor of NASA Conflict between drag (thickness of the airfoil, angle of attack), lift (curvature of the airfoil) and aeroelasticity (stability) of the airfoil http://www.desktopaero.com/appliedaero/airfoils1/airfoilhistory.html Source DLR-archive Göttingen Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 19 Dr.-Ing. habil. Judith Rosenow Introduction Classification of aircraft - Lift Aircraft with static lift (lighter than air) 𝐹!,#$%$ = 𝜌%&' − 𝜌(%# ∗ 𝑉 ∗ 𝑔 𝜌%&' …air density [kg/m3], V…Volume [m3], 𝑔… gravitational constant= 9.81m/s2 Hydrostatic pressure depends on the height of the location p= 𝜌 g h aerostatic Buoyancy = weight force of the deformation of the fluid (liquid, gas) On a body immersed in fluid with density rho, buoyancy force FL= 𝜌 g V V...the volume displaced by the body, 𝜌V...the mass of the fluid displaced by the body 𝜌gV...its weight force As soon as the weight force of the body is smaller than the lift force, the body rises Shape of the body does not matter (hydrostatic paradox) quantity of the surrounding fluid does not matter there must be fluid below the body (Archimedes' principle) Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 20 Dr.-Ing. habil. Judith Rosenow Introduction Classification of aircraft - Lift Aircraft with dynamic lift 𝜌 ∗ 𝑣 , ∗ 𝐴-&+( 𝐹!,)*+ = 𝑐! ∗ 2 An airfoil is a streamlined shape that is capable of generating significantly more lift than drag A flat plate can generate lift, but not as much as a streamlined airfoil, and with somewhat higher drag the flow over the upper surface is faster than the flow over the lower surface the curved upper surface acts as an obstacle to the flow, forcing the streamlines to pinch closer together, making the streamtubes narrower When streamtubes become narrower, conservation of mass requires that flow speed must increase Reduced upper-surface pressure and upward lift follow from the higher speed by Bernoulli’s principle https://en.wikipedia.org/ Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 21 Dr.-Ing. habil. Judith Rosenow Introduction Classification of aircraft - Lift Bernoulli‘s principle: increase in the speed of a fluid occurs simultaneously with a decrease in static pressure or a decrease in the fluid's potential energy can be derived from the principle of conservation of energy: in a steady flow, the sum of all forms of energy in a fluid is the same at all points This requires that the sum of kinetic energy, potential energy and internal energy remains constant -> an increase in the speed of the fluid (i.e. an increase in its kinetic energy (dynamic pressure)) occurs with a simultaneous decrease in the sum of its potential energy (including the static pressure) and internal energy https://en.wikipedia.org/ Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 22 Dr.-Ing. habil. Judith Rosenow Introduction Classification of aircraft - Lift Aircraft Aircraft with According to the principle of lift generation Aircraft with aerostatic lift aerodynamic lift WITH WITHOUT WITH Drive WITHOUT Drive system Drive system system Drive system According to the presence of a drive system Glider Airships Balloons Free balloons Captive balloons According to the type of lift generation Rotorcraft Fixed-wing aircraft Helicopter Gyrocopter Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 23 Dr.-Ing. habil. Judith Rosenow Introduction Classification of aircraft - Lift Helicopter Gyrocopter Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 24 Dr.-Ing. habil. Judith Rosenow Introduction Classification of aircraft - Lift Commercial aircraft Glider Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 25 Dr.-Ing. habil. Judith Rosenow Introduction Definition - Aerodynamics Aerodynamics The study of the physical laws that apply to flowing, compressible gases and bodies around which gas flows e.g. air resistance, lift Air forces are under consideration of the laws of flow (magnitude, direction, point of application, dependence on influencing variables) Tasks of aerodynamics Investigating the relationships between forces and moments acting on the body Deriving laws Calculation of the magnitude and direction of the forces and moments as a function of the influencing variables Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 26 Dr.-Ing. habil. Judith Rosenow Introduction Definition - Aerodynamics Goal: Generation of lift and thrust To overcome weight force and compensation of resistance to movement Dependence on physical properties of air: Pressure, density, temperature, compressibility, viscosity Geometric shape of the aircraft components Shape of the airflow Speed, angle of attack, angle of sideslip Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 27 Dr.-Ing. habil. Judith Rosenow Introduction Definition - Aerodynamics 𝐹L 𝐹L …lift force 𝐹" 𝐹. …drag force 𝐹% …resulting force Undisturbed 𝐹! Incident flow velocity v∞ Angle of attack α Center of pressure (DP) Chor d (Pr ofilse hne ) Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 28 Dr.-Ing. habil. Judith Rosenow Introduction Definition – Flight mechanics Flight mechanics Describes movements of aircraft, especially movements of aircraft in the air (flight) and on the ground (taxiing) Investigation of flight conditions under consideration of the laws of motion Aim of flight mechanics Presentation of fundamental relationships of the movement of aircraft Two groups: Flight performance, which is a measure of efficiency (horizontal flight speed, service ceiling, angle of climb, etc.) Flight characteristics (operational behavior), which is a measure of safety (e.g. stability, stall behavior) Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 29 Dr.-Ing. habil. Judith Rosenow Introduction Definition – Flight mechanics Unaccelerated level flight: v = const. 𝐹L (a=0) 𝐹T 𝐹D 𝐹𝑮 Point mass model Pressure point = center of gravity Lecture Aerodynamics Flight Mechanics Institute of Logistics and Aviation, Chair of Air Transport Technology and Logistics Folie 30 Dr.-Ing. habil. Judith Rosenow