Aerofoil - How Wings Work Tasks - Book Report/Review Example

Aerofoil - How Wings Work Tasks Aerofoil - How Wings Work Tasks Introduction In designing operational airplane wings, the most indispensable factors to consider involve size and shape. Size and shape are essential in enabling efficient movement of airplane through space by minimizing resistance to the moving air. It is imperative for airplane designers to comprehend mechanisms leading to generation of drag and lift. Comprehensive understanding of how airplane wings operate in relation to their design is authoritative in realization an efficient aircraft. Question 1 In modern education and society different misconceptions exists in relation to the process of generation of aerofoil lift. The first misconception relates to Bernoulli Effect and Newton’s laws concerning generation of lift. Some individuals believe that design of wing shape depends on Bernoulli Effect while Newton’s Laws largely defines airfoil’s angle of attack. In reality, both wing shape and angle of attack directly relates to Newton’s Laws and Bernoulli Effect. Therefore, both the forces remain essential in generation of lift depending on angle of attack and wing shape. The second misconception relates to the curvature of both lower and upper surfaces of airfoil during generation of lift (Beaty 1). Individuals tend to believe that during generation of lift, the there must exist a stronger curvature of the upper surface than lower surface of the airfoil. However, it is indispensable to understand that lift can even result from symmetrical airfoil including acrobatic airplanes. In addition, generation of lift can similarly result from paper airplanes, fabric airfoils, and flat plywood that have inherently more curvature within the bottom surfaces than the top parts. Curvature is imperative in generation of lift but differentiation of possibility of more curvature is not essential if the airfoil remains comprehensively designed. The third misconception relates to deflection of air during generation of lift. People tend to believe that there exists possibility of generating airplane lift without downward deflection of air. Such believe is inherently incorrect mainly because it would contravene conservation of law of momentum. Not deflecting air downwards would result into the airfoil staying within the air without emitting air mass downwards that would violate law of conservation momentum. It is only balloons that uses buoyancy forces that without ejecting mass remains aloft. However, airplane wing do not operate by buoyancy forces and must deflect air downwards during generation of lift. Question 2 There exist two basic explanations for the process of generation of lift. The first explanation relates to downward deflection of flow in combination with Newton’s laws. Lift generation also results from Bernoulli principles in combination with speed of airflow. However, the two explanations only explain certain aspects of lift generation. In reality, generation of lift results from both downward deflection and changes in flow of speed. Lift generates because of action and reaction forces that impacts pressure difference on the airfoil’s surface. During generation of lift the airplane shape and angle of attack operates in conjunction with downward flow of air (Gülçat, 2010, p. 4). According to the third Newton’s laws of motion, a force produces an equivalent and opposite reaction. Similarly, during generation of lift, air generates an opposite and equal reaction force to the airplane movement (Gudmundsson, 2013, p. 274). Consequently, the action and reaction forces results into air pressure difference on airfoil surfaces causing generation of lift. It is imperative to note that air pressure exerts on both the upper and lower surfaces an equivalent inward pressure. The flowing air raises pressure on the airfoil’s lower surface while reducing pressure on the upper surface of airplane wing in reaction to resistance by the plane. The inherent high pressure on the lower surfaces causes an upward upper force that pushes the airplane compared to the downward force that exerts least force. Consequently, imbalance in the forces results into an upward lift of the airplane. Question 3 The figure above shows shape and design of an airfoil. The airfoil has a rounded leading edge, systematically curved upper and lower surfaces, and a trailing curved sharp edge. The airfoil’s top surface has a design that gives it greater curvature than the bottom sections. The inherent design and shapes have various significances in relation to operation of an airfoil. a) Normally, airplanes have rounded leading edges to assists in generation of more lift and dragging effects. The combination of a trailing sharp edge and rounded leading edge provides significant smooth flow of air around the airfoil to facilitate movement and generation of lift. Air flows around the leading rounded edge surface moves smoothly within a defined streamline. The air finally spills on the trailing edge consisting of lower and high pressure on the upper and lower surfaces of the plane. Besides providing an applicable surface for airflow, the rounded leading edge enables rejoining of airflow at the top and bottom of the airplane. It is imperative to note that a sharp leading edge would disrupt airflow and create abnormal imbalance in air pressure and consequently movement of airplane. Moreover, a sharp leading edge has the ability of preventing spilling upwards of air due to inability of air to make shaper turns around objects. b) More camber and thickness within the middle of low medium speed airfoils is imperative in generation of the greatest lifts at lower speeds. Normally, airplane designers add more thickness on the upper parts of the camber depending on the required strength and desired speed. Thickness of the leading rounded edge is critical in design of supercritical airplanes that enables them to have maximum strength possible of supporting its high speed. In addition, the thickness is imperative in shocking supersonic flow backs that consequents from supersonic speeds. Therefore, it is imperative to understand that besides providing strength to the airplane, thickness of the camber is authoritative in supporting the high speeds of supercritical airfoils (AV8N 1). c) Normally, movement of airplane requires smooth flow of air around the surface of the plane. Smooth flow of air requires uninterrupted streamline inherently supported by the shape. Consequently, the airplane has a tapered rear at the trailing edge to support the streamline flow of air and resultant rejoining of flowing air from leading edge. Therefore, the tapered rear provides airplane balance by enabling smooth drop of air from the bottom and top of the rounded leading edge. It is fundamental to note that the less thickly tapered rear enables reduction of drag effect resulting from flowing air on surfaces of the plane. d) The flatter bottom part of the airplane is imperative in generation of underneath high pressure through reduction of flow of air. The created high pressure is vital in airplane lift generation. Similarly, effective camber design is imperative in generation of airplane lift. The inherent curvature formed on the surface of airplane defines a camber. In most cases, the bottom parts remain less cambered compared to top surface. Such camber design is essential in faster flow of air on the airplane wing top in comparison to the underneath surfaces. Resultantly, the air pressure on the top would remain lower compared to the bottom part causing difference that generates a lift. Therefore, a camber provides curvature that is authoritative in generation of airplane lift even at slow speeds. Question 4 a) Formation of curvature on an object is vital in generation of a lift by changing the direction and flow of air. Creation of asymmetric form depends on the inherent flow of air resultantly from the curvature. The inherent airflow results into both lift and drag that acts on opposite directions. Because of absence of curvature and airplane shape characteristics, a house brick cannot generate lift. Besides absence of airfoil characteristics, the inherent weight of the brick resists movement of air that would otherwise generate a lift. In addition, the house brick weight also prevents creation of dragging effect. b) Because of the inherent surface curvature of a saucer, it would generate lift. The curvature assists in generation of both dragging and lifting influence to airflow (IOP 3). The saucer has an airfoil cross-sectional shape that can generate a consequent lift. The shape moves in air through generation of lift causing spinning effect within airflow. Spinning effect assists in maintaining constant movement of the saucer within the air. c) Just like a brick, a ball has no airfoil characteristics and cannot generate lift. In addition, the ball has no ability to form curvature on its surface that can create asymmetric form from disruption of airflow. It is imperative to note that airflow on a ball’s surface involves streams of laminar flow that have only viscous drag. Therefore, a football cannot generate a lift but only spin. Normally, a resultant drag during spinning of a ball moves in the direction of airflow as presented below. Question 5 A drag remains as a horizontal force that acts in parallel to an airfoil flight path in opposition to its movement and results from viscous friction. Drag that also experiences effects of thrust forces result from various opposite acting forces relative to movement of the airfoil. Normally, a drag consists of three main types including parasitic, wave, and lift-induced drag. Induced drag In most cases, induced drag exists on airplane surfaces including wings and horizontal tail that normally generates lift. It is imperative to note that generation of lift results into induction of drag. As an airplane speed increases, induced drag similarly rises especially with increased angle of attack. Air flowing on both the bottom and top surfaces of the airplane meets at wingtips to create vortexes that cause formation of induced drag. Parasitic Drag While induced drag results from airplane parts that directly generate lift, parasitic drag results from sections including tires, windshield, and rivets that have no elaborate contribution to generation of lift. Due to the inherent parts of a plane, parasitic drag consists of three main forms including form drag, skin-friction drag, and interference drag. Form drag results from frontal surfaces resistance to airflow reduced through streamlining of airfoil surfaces. However, skin-drag resistance results resistance of normal surfaces of the airplane to the flow of air. Skin-drag can inherently remain reduced through smoothening of surfaces of airfoil to minimize resultant friction by using modified smooth paints, flush riveting, and waxing. Resistance to the flow of air by the remaining parts of airfoil including wings, fuselage, and empennage results into formation of interference drag. Question 6 Boundary layer defines the layer of air within the bonding surface experiencing viscosity (Babinsky and Harvey, 2011, p. 19). During movement of airfoil, boundary layer forms as a plane between non-viscous air and the viscous forces resulting within the area of flow mainly in relation to Reymonds number. During formation of boundary layer, air molecules flowing close to airfoil surfaces remains stuck resulting into decrease in motion of those above. As molecules stuck on the surface and those on top collide, movement slows causing formation of a thin fluid layer (NASA 1). Question 7 The circular patterns of rotating air forming behind aircraft in the process of lift generation define wingtip vortices. There exists a relationship between formation of induced drag and wingtip vortices resulting from streams of airflow rejoining on the trailing wingtips of an airplane. Normally, wingtip vortices form on each wing trailing edge. Generation of aerodynamic lift causes formation of wingtip vortices on the trailing edges due to the flow of air rejoining from camber surfaces. The difference in airflow on top and bottom surfaces of an airplane causes generation of aerodynamic lift and vortices. Air flowing on the bottom surfaces of an airplane normally would have higher pressure than that on top. Meeting of the two streams of air with difference in pressure causes disruption and consequent inward curling movements known as wingtip vortices visible from a lower pressure area. Question 8 Drag Equation Drag equation defines the formula employed in calculation of the dragging force effect experienced by airfoil in motion within enclosed volume of air. Specific conditions define applicability of drag equation including an assertion that the aircraft must have blunt form factor. Besides the aforementioned condition, use of the drag equation requires the inherent enclosed fluid to possess adequate amounts of Reynolds number. Large Reymonds number is imperative in production of turbulence at the wing of the airfoil. Lift Equation The above equation explains the formula of determining amount of attainable lift based on specific provisions. For instance, using the lift equation in calculation of lift generated depends on angle of attack specifications mainly for lift coefficient of the airplane wing. Question 9 a) b) Question 10 a) 2 degrees b) 12 degrees c) 3 degrees Question 11 Conclusion In conclusion, operation of aircraft depends on its inherent shape, size, and design. The design of the airplane must give provisions for a curvature and camber that are imperative in generation of lift. Design of an operational airfoil requires that it have a rounded leading edge alongside sharp trailing edge. In addition, the airfoil design must have a thicker camber on the leading rounded part. Thickness of the rounded part is authoritative in providing strength for generation of lift mainly for supercritical airplanes. Besides the thickness of the airfoil, designing the airplane with a leading rounded and trailing edge is imperative in balancing lift and drag forces that contributes to its movement. In addition, the surfaces of the airplane need to remain smooth to prevent formation of skin-drag that would otherwise resist movement of the plane. Understanding operation of airfoil also requires comprehensive knowledge of how generation of lift results. Normally, both Bernoulli Effect and Newton’s laws contributes to lift generation. A comprehensive understanding of operational of airfoil would help in designing workable wings, shape, and size. It is indispensable to note that designing a competent and workable airfoil wing requires comprehensive use and understanding of associated vital software including XFL5. Bibliography AV8N. 2005. Airfoils and Airflow. December 24, 2014. Accessed from http://www.av8n.com/how/htm/airfoils.html Babinsky, H., Harvey, J.K., 2011. Shock Wave-Boundary-Layer Interactions. Cambridge University Press, Cambridge, England. Beaty, William. 1996. Airfoil Lifting Force Misconception. Web. December 24, 2014. Accessed from http://www.amasci.com/wing/airfoil.html#parts Gudmundsson, S., 2013. General Aviation Aircraft Design: Applied Methods and Procedures. Butterworth-Heinemann, Waltham. Gülçat, Ü., 2010. Fundamentals of Modern Unsteady Aerodynamics. Springer Science & Business Media, New York. IOP Science. 2014. How do wings work?. Web. December 24, 2014. Accessed from http://iopscience.iop.org/0031-9120/38/6/001/pdf/pe3_6_001.pdf NASA Government. 2014. Airplane: Boundary layer. Web. December 24, 2014. Accessed from http://www.grc.nasa.gov/WWW/k-12/airplane/boundlay.html NASA Government. 2014. Airplane: Lift formula. Web. December 24, 2014. Accessed from http://www.grc.nasa.gov/WWW/k-12/WindTunnel/Activities/lift_formula.html NASA Government. 2014. Airplane: Modern Drag Equation. Web. December 24, 2014. Accessed from http://wright.nasa.gov/airplane/drageq.html NASA Government. 2014. Atmospheric Flight: The work of wings. Web. December 24, 2014. Accessed from http://quest.nasa.gov/aero/planetary/atmospheric/aerodynamiclift.html Read More