Oten Notes Engineering Studies Aeronautical Module

Gill Sans B emeritus railway locomotive room Studies HSC Course leg 6 aeronautic use science ES/S6 HSC 41097 P0022161 Ack back-to-backledgments This publication is copyright attainment Materials Production, Open Training and breeding Ne bothrk surmount Education, NSW Department of Education and Training, however it may contact on fabric from new(prenominal) sources which is non possess by Learning Materials Production. Learning Materials Production would like to ack at a whileledge the interest people and organisations whose solid has been engagementd. climb on of Studies, NSW Hawker de Havilland Page Aircraft federation Pty Ltd Bankstown transportdrome Padstow Aeroskills CentreAll reason qualified efforts find out downst notes integritys skin been made to obtain copyright permissions. All cl scrams depart be settled in good faith. Materials devlopment Paul So ars, Harry Taylor, Ian Webster Coordination Jeff Appleby mental ability edit John Cook, Josep hine Wilms Illustrations Tom Brown, Barbara Buining DTP Nick Loutkovsky, Carolina Barbieri Copyright in this material is reserved to the Crown in the right of the State of New southeastward Wales. Re productionion or transmittal in whole, or in part, more than or less separate than in accordance with provisions of the Copyright Act, is prohibited without the written pronouncement of Learning Materials Production. Learning Materials Production, Open Training and Education Net knead Distance Education, NSW Department of Education and Training, 2000. 51 Wen 2rth Rd. Strathfield NSW 2135. Revised 2001 staff contents field of view exclusively oerview .. iii Module all everyplaceview.. vii Module comp binglents .. vii Module outcomes x Indicative time x imaging requirements. xi Icons . cardinali polish xv Directive terms xix sidetrack 1 aeronautic engine room stove of the transaction and design musical com couch. 165 break open 2 aeronautic design science istory of flight. 137 circumstances 3 aeronautical design mechanics and fluid mechanics . 173 phonation 4 aeronautic design science materials . 149 Part 5 aeronautic technology communication .. 144 Bibliography 45 Module evaluation . 9 i ii emergence overview Engineering Studies Preliminary Course Ho workhold appliances authorizedises common appliances erect in the home. Simple appliances argon analysed to discover materials and their applications. Electrical principles, researching methods and techniques to communicate skillful breeding ar chime ind. The maidenborn student design business relationship is blameless travail an investigation of materials officed in a household appliance. Landscape products investigates design principles by emphasising on common products, much(prenominal) as lawnmowers and array hoists. The historical maturation of these types of products portrays he effect materials development and technological advancements generat e on the design of products. Engineering techniques of force analytic thinking atomic number 18 thread. irrelevant whirligigple methods argon explained. An engineer report is nabd that analyses lawnmower divisions. Braking brasss uses braking components and systems to describe engine room principles. The historical changes in materials and design ar investigated. The relationship surrounded by indispensable structure of iron and steel and the resulting engineering properties of those materials is detailed. Hydraulic principles ar described and examples provided in braking systems. Orthogonal force echniques argon progress true. An engineering report is completed that requires an digest of a braking system component. iii Bio-engineering both engineering principles and also the background of the bio-engineering trading. travels and current issues in this field be explored. Engineers as managers and ethical issues confronted by the bio engineer argon considered . An engineering report is completed that investigates a current bioengineered product and describes the associate issues that the bio-engineer would adopt to consider before, during and later this product development. Irrigation systems is the elective topic for the reliminary facultys. The historical development of irrigation systems is described and the jar of these systems on society discussed. Hydraulic summary of irrigation systems is explained. The effect on irrigation product range that has occurred with the intro of is detailed. An engineering report on an irrigation system is completed. iv HSC Engineering Studies modules cultured structures examines engineering principles as they yoke to civil structures, much(prenominal) as bridges and buildings. The historical ascertains of engineering, the strike of engineering innovation, and environmental implications are discussed with eference to bridges. Mechanical abridgment of bridges is use to introduce concepts of truss analysis and stress/strain. Material properties and application are explained with deferred payment to a frame of civil structures. Technical communication skills described in this module embroil assembly throw a miening. The engineering report requires a comparison of two engineering solutions to solve the kindred engineering situation. Personal and public transport uses bicycles, beat back vehicles and trains as examples to explain engineering concepts. The historical development of cars is used to demonstrate the develo pivotg material ist available for the engineer. The impact on society of these developments is discussed. The robotlike analysis of mechanisms involves the effect of friction. Energy and creator relationships are explained. Methods of laddering materials, and modifying material properties are examined. A series of industrial manufacturing processes is described. Electrical concepts, such as power distri entirelyion, are detailed are introduced. The use of freehand technical sketches. Lifting devices investigates the social impact that devices raging from complex cranes to simple car jacks, bemuse had on our society. The mechanic oncepts are explained, including the hydraulic concepts often used in raiseing apparatus. The industrial processes used to stochastic variable metals and the methods used to control physical properties are explained. Electrical requirements for many devices are detailed. The technical rules for instalmented orthogonal dra move are demonstrated. The engineering report is base on a comparison of two lifting devices. v aeronautic engineering explores the scope of the aeronautical engineering art. Career opportunities are considered, as well as ethical issues related to the profession. Technologies laughable to this engineering field are described.Mechanical analysis includes aeronautical flight principles and changeful mechanics. Materials and material processes concentrate on their applicatio n to aeronautics. The corrosion process is explained and stay techniques inclinationed. Communicating technical instruction exploitation both freehand and com stationer- assist gulp is infallible. The engineering report is based on the aeronautical profession, current projects and issues. Telecommunications engineering examines the history and impact on society of this field. Ethical issues and current technologies are described. The materials section concentrates on specialised esting, copper and its alloys, semiconductors and fibre optics. Electronic systems such as analogue and digital are explained and an overview of a variety of some other technologies in this field is supplantowed. Analysis, related to telecommunication products, is used to reinforce mechanical concepts. Communicating technical information using both freehand and computer-aided outline is required. The engineering report is based on the telecommunication profession, current projects and issues. co me in 0. 1 Modules vi Module overview Aeronautical engineering is the first guidance engineering module in the HSC course.The scope of the aeronautical engineering profession is investigated. Career opportunities are considered, as well as ethical issues related to the profession. Technologies grotesque to this engineering field are described. The mechanical analysis topics include aeronautical flight principles and fluid mechanics. Materials, and material processes concentrate on those roughly associated with the aeronautical engineer. The corrosion process is explained and preventative techniques listed. Communicating technical information using both freehand and computer aided potation are required. The engineering report is based on the aeronautical rofession, current projects and issues. Module components all(prenominal) module contains three components, the preliminary pages, the education/learning section and additional resources. The preliminary pages include module contents subject overview module overview icons glossary directive terms. realise 0. 2 Preliminary pages vii The t to each oneing/learning parts may include part contents introduction teaching/learning text and tasks exercises check list. think 0. 3 commandment/learning section The additional information may include module app decisionix bibliography additional resource module evaluation. get in 0. 4 Additional materials Support materials such as audiotapes, video cassettes and computer saucers ordain some clock accompany a module. viii Module outcomes At the end of this module, you should be functional towards being able to describe the scope of engineering and finely analyse current innovations (H1. 1) divergentiate between properties of materials and rationalize the selection of materials, components and processes in engineering (H1. 2) analyse and compound engineering applications in proper(postnominal) field and report on the importance of these to society (H2. 2) se appropriate written, spontaneous and presentation skills in the preparation of detailed engineering reports (H3. 2) investigate the limit of technological change in engineering (H4. 1) appreciate social, environmental and pagan implications of technological change in engineering and defy them to the analysis of specific problems (H4. 3) select and use appropriate management and planning skills related to engineering (H5. 2) demonstrate skills in analysis, synthesis and experimentation related to engineering (H6. 2) deplume from exhibit 6 Engineering Studies Syllabus, Board of Studies, NSW, 1999.Refer to for original and current documents. ix Indicative time The Preliminary course is cxx hours (indicative time) and the HSC course is 120 hours (indicative time). The pursuit table shows the approximate make sense of time you should spend on this module. Preliminary modules Percentage of time Approximate outcome of hours Household appliances 20% 24 hr Landscape products 20% 24 hr Braking systems 20% 24 hr Bio-engineering 20% 24 hr Elective Irrigation systems 20% 24 hr HSC modules Percentage of time Approximate number of hours Civil structures 20% 24 hr Personal and public transport 20% 24 hr Lifting devices 0% 24 hr Aeronautical engineering 20% 24 hr Telecommunications engineering 20% 24 hr thither are quintuple parts in Aeronautical engineering. Each part exit require exclusively al virtually four to five hours of work. You should aim to complete the module deep down 20 to 25 hours. x Resource requirements During this module you result indispensability to access a range of resources including technical drawing equipment drawing board, tee square, set squares (30? , 60? , 45? ), protractor, pencils (0. 5 mm mechanical pencil with B lead), eraser, p snap of compasses, p agate line of dividers calculating machine rule thumb tack or pin small theme of paper of thin cardboard p diffuse of pair of scissors cotton wool fiber wool reel. xi xii Icons As you work through this module you impart distinguish symbols cognize as icons. The answer of these icons is to gain your attention and to indicate particular types of tasks you need to complete in this module. The list be low-down shows the icons and outlines the types of tasks for Stage 6 Engineering studies. reckoner This icon indicates tasks such as researching using an electronic selective informationbase or calculating using a spread cerement. Danger This icon indicates tasks which may present a hazard and to proceed with care. Discuss This icon indicates tasks such as discussing a hitch or ebating an issue. Examine This icon indicates tasks such as reading an article or watching a video. Hands on This icon indicates tasks such as collecting data or conducting experiments. answer This icon indicates the need to write a response or draw an object. Think This icon indicates tasks such as reflecting on your experience or picturing yours elf in a situation. xiii Return This icon indicates exercises for you to bring to to your teacher w chick you energize completed the part. (OTEN OLP students will need to refer to their Learners leave for instructions on which exercises to return). xiv GlossaryAs you work through the module you will encounter a range of terms that cast off specific meanings. The first time a term occurs in the text it will push through in rough. The list below explains the terms you will encounter in this module. aerofoil any surface such as a wing, aileron, or stabiliser, designed to help in lifting or controlling an aircraft aileron special purpose hinged flap on the produce edge of a wing designed to control sideways balance autogyro early form of meat cleaver with a propellor and freely rotating horizontal vanes biplane aeroplane with two sets of wings, one preceding(prenominal) the other cambered arched or curved upwards in the middle oncurrent passing through the same point, foe exam ple, a number of forces are concurrent if an extension of the lines representing their directions all cross at the same point cowling removable cover on aircraft engine dredge the force, due to the relative air come, exerted on an aeroplane and tending to let down its send motion elevator a hinged, horizontal surface on an aeroplane, for the most part located at the tail end of the fuselage and used to control the front/backward tilt empirical data information from experience or experiment, not from any scientific or theoretical deduction wear down the condition of having experienced many cycles or epeated applications of stress that is lower than would comm scarcely be required to baffle calamity, but can cause failure under these conditions flap hinged or sliding section on the rear edge of a wing designed to control lift xv fuselage gyro gyroscopic device for keeping an object, such as a rocket, in stable controlled flight ICBM missile designed to confer a warhead from one continent to another interplanetary between planets, from planet to planet Mach 5 A speed that is five times the speed of figureable at the particular aggrandisement (the speed of full at sea level is approximately 380 meters per second or 1370 kmph) oment a force that tends to cause rotation because the object is fixed in position at one point or because the force is not utilise at the centre of gravity monoplane aeroplane with one set of wings nacelle outermost casing of an aeroplanes engine orbit high gearway of one body nigh another body under the influence of gravity payload burthen down being carried pitch angle that a propeller or rotor blade come upons with the air passing over it pressurisation increasing the air insisting in an aircraft cabin as altitude increases and the air pressure outside is too low for breathing radiolocation radio distance and ranging an instrument to take into account light when in that location is no visibility retrofit to inco rporate new parts and changes into old models think a method for joining solid weather sheet materials to a firmly support rotors the rotating blades on a helicopter that act as propeller and wing rudder broad flat wooden or metal piece hinged to the rear of an aeroplane for steering satellite a body revolving in some fixed path nigh another body gun xvi body of aeroplane Consists of small pellets in shot-peening these are dismissed onto a surface spar a stout pole such as those used for masts or booms etc on a boat. Also the principal(prenominal) member of the wing frame in an aeroplane stall hen an aircraft loses lift, ordinarily due to loss of relative air speed, and is in danger of reflecting streamlined made to a shape calculated to cause the least resistance to motion supercharger a device to force air into an aeroplane engine with pressure to overcome the reduction in atmospheric pressure at high altitudes and so maintain engine power as the aircraft climbs triplane an aeroplane with three sets of wings arranged one above the other wind burrow a box or render designed to drive a woful stream of air around an object or a scaled model of the object within it to determine the behaviour of the object in an airstream aw the motion of an aircraft about its vertical axis xvii xviii Directive terms The list below explains key words you will encounter in appraisal tasks and examination questions. account account for state reasons for, report on smash an account of narrate a series of events or transactions analyse identify components and the relationship between them, draw out and relate implications apply use, utilise, employ in a particular situation appreciate make a judgement about the value of assess make a judgement of value, quality, outcomes, results or size calculate ascertain/determine from acquaintn up facts, figures or information larify make clear or plain assort arrange or include in classes/categories compare show how things are si milar or different construct make, build, put unneurotic items or arguments contrast show how things are different or opposite critically (analyse/evaluate) add a degree or level of accuracy, depth, knowledge and understanding, logic, questioning, observation and quality to (analysis/evaluation) deduce draw conclusions define state meaning and identify essential qualities demonstrate show by example xix describe provide characteristics and features discuss identify issues and provide points for and/or against distinguish ecognise or note/indicate as being distinct or different from to note differences between evaluate make a judgement based on criteria determine the value of examine inquire into explain relate cause and effect make the relationships between things evident provide why and/or how extract choose relevant and/or appropriate inside information extrapolate infer from what is known identify recognise and name envision draw meaning from investigate plan, inquire into and draw conclusions about justify support an argument or conclusion outline sketch in general terms indicate the main features of predict suggest what may happen based on available nformation propose put in the lead (for example a point of view, idea, argument, suggestion) for circumstance or action back away present remembered ideas, facts or experiences recommend provide reasons in favour enjoin retell a series of events summarise express, concisely, the relevant details synthesise putting together various portions to make a whole stir from The New Higher School Certificate Assessment Support Document, Board of Studies, NSW, 1999. Refer to for original and current documents. xx Aeronautical engineering Part 1 Aeronautical engineering scope of the profession &038 engineering reportPart 1 contents Introduction 2 What will you learn?. 2 cathode-ray oscilloscope of aeronautical engineering.. 3 Unique technologies in aeronautical engineering .. 10 Current projects or innovations . 26 Health and safety issues 31 Training for the profession.. 5 Careers in aeronautical engineering 37 Relations with the community 40 Legal and ethical issues.. 45 Engineers as managers .. 46 The engineering report .. 49 Structure of a focus engineering report . 49 Sample engineering report . 51Exercise sheet . 61 Progress check 63 Exercise cover sheet 65 Part 1 Aeronautical engineering scope and engineering report 1 Arial Arial bold Introduction The purpose of this part is to introduce you to the scope and constitution of the aeronautical engineering profession. What will you learn? You will learn about the nature and scope of the aeronautical engineering profession current projects and innovations health and safety issues training for the profession career prospects unique technologies in the profession legal and ethical implications engineers as managers relations with the community. You will learn to define the responsibilities of the aeronautical engineer descr ibe the nature of work make in this profession examine projects and innovations from within the aeronautical profession analyse the training and career prospects within aeronautical engineering. Extract from Stage 6 Engineering Studies Syllabus, Board of Studies, NSW, 1999. Refer to for original and current documents. 2Aeronautical engineering Scopeofaeronauticalengineering Today, you would pay little attention to the sound of an over-flying aircraft, that is, if you noticed it at all. Yet less than ninety years ago allone around you would have looked skyward and wondered in awe at the sight. The aircraft of 90 years ago was not the advanced unit that you may soak up in the sky today. They were a combination of timber, wire, fabric and a utter(a) engine or two, flown on a wing and a requester. The designers of these aircraft were not aeronautical engineers as such. more(prenominal) often than not they were scientists or enthusiastic amateurs.The little knowledge they did p ossess was the collected result of a variety of experiments with kites and models conducted during the late 1800s and early 1900s. Often the over enthusiastic and over confident experimenters buffer storageed their less than airworthy designs to an early grave. Could this have been a form of natural selection? Many early workers used the empirical data collected from these many failures and a few successes to develop the first work aircraft. This was not always done with reference to pure theory and equations. fundamentally the cambered wing at a suitable angle of attack appeared to give good lift.Consequently many aircraft experimenters chose to concentrate on the cambered wing and other ideas that seemed to be a good idea at the time. However, scientists such as Dr Lancaster had developed and confirmed mathematical theories for phenomena such as lift propagation and induced knot well before the Wright Brothers first flew an aircraft. Todays aeronautical engineers good-tempere d use models. The test pilot project still has to be the first person to pilot the aircraft. However, the Concord and the FA 18 Hornet, could not be designed without extensive reference to aeronautical theory and use of sophisticated calculation.The test pilot will have already flown many hours in a flight simulator which emulates the predicted in-flight characteristics of the new aircraft. This therefore is the domain of the aeronautical engineer. Part 1 Aeronautical engineering scope and engineering report 3 Arial Arial bold itemization the general areas of knowledge that you think a group of aeronautical engineers would need to possess to design and build a complete aircraft. __________________________________________________________ __________________________________________________________ __________________________________________________________ _________________________________________________________ Did you answer? aerodynamics electrical and electronic systems mat erials technology hydraulics render engines and propulsion systems structural mechanics drawing and drafting skills. Before venturing further into the day to day complexities of being an aeronautical engineer you should take a step back to consider the aircraft as an engineered system. Aerodynamics An aircraft is not just a wing with a powerful jet engine strapped to it. moreover it is the product of a combined effort by hundreds of individual designers and engineers working toward a common goal.As aircraft grow more sophisticated no one person can fully understand every detail that goes into an aircrafts design. An aircraft before all other considerations is an aerodynamic entity. It is held aloft by the lift forces generated by the camber and angle of attack of the wing. It is restrained by drag out forces created by form and shape of the aircraft and induced through the process of generating lift. The everpresent hale of gravity will eventually pull all aircraft back to ea rth. The try of air around an aircraft is a complex thing to understand and at times it is difficult to predict.Aerodynamic theory helps predict the movement of air and the amount of lift generated but it is only a starting point. 4 Aeronautical engineering Aerodynamics is a major concern of aeronautical engineers but there are other equally important aspects to the profession. Reel attention-getting You will need a thumb tack or pin from the sewing cabinet a small sheet of thin cardboard a drawing compass and a pair of scissors. a cotton reel from the same place that you found the pin. Carry out the following steps 1 draw an 80 mm diameter hardening on the cardboard, then cut out the circle using the scissors 2 ush the thumb tack or pin through the center of attention of the cardboard disc so that the pointy end goes through as cold as it can go 3 pick up the cotton reel, place the pointy end of the tack or pin into the hole on the bottom side of the cotton reel and hold t he disk in place with your finger 4 blow through the top of the cotton reel and let go of the disk while you are still blowing. Blow Cotton reel Pin Cardboard disk Figure 1. 1 The disk on the cotton reel trick Part 1 Aeronautical engineering scope and engineering report 5 Arial Arial bold The disk should have remained in position until you stop blowing.When you stopped blowing the disk should have fallen down. Explain why the disk behaved the way it did. __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ ______ ___________________________________________________ Did you answer? Air moving over the disk had velocity and and then a dynamic pressure component. Benoullis predictions on total pressure would indicate that the static pressure above the disk in the moving air would therefore be lower than the pressure below the disk in still air, therefore the disk experiences lift. (The disk is pushed upwards by the higher pressure beneath it. ) 6 Aeronautical engineering Propulsion systems An aircraft requires a propulsion system to provide thrust (or in the case of a glider, a launching system to get it into the air in the first place).An engineer will have to decide the scoop up combination of engine and thrust device to attach to an aircraft. Identify engine types and thrust devices that are used on new or old aircraft. __________________________________________________________ __________________________________________________________ _______________________________________________________ ___ __________________________________________________________ Did you answer? Some of the engine types and thrust devices you may have place include internal combustion engine, jet engine, turbine, radial, propeller, fan, rotor and rocket.You will catch out more of propulsion systems in the mechanics and hydraulics part of this module. Stress-n-Strain Aeronautical engineers who design superbly aerodynamic aircraft that crash and burn because the wings fall off will not lead a successful career. The aeronautical engineer has to calculate and consider the forces present in all components of the aircraft. They then have to predict whether the material that the components are created from will capture that load without failure. This prediction moldiness(prenominal) be for the full portion manner of the aircraft.If a component is predicted to fail within the good life of the aircraft, the engineer will mandate when that component must be periodically replaced. The plunger engin es in light aircraft usually have a minor service after 100 hours operating time and a major service every 1000 hours operating time. A major service will involve a full strip-down of the engine. Many components, for example pistons, must be replaced whether or not they appear to be in serviceable condition. otherwise components will be subjected to testing. Part 1 Aeronautical engineering scope and engineering report 7 Arial Arial boldMaterials Linked to considerations of structural forces are the consideration and selection of appropriate materials. An aeronautical engineer will need to have a good knowledge of the manufacturing and service properties of the materials used on aircraft. An aircraft operates in a rough environment. During any flight an aircraft is subjected to constant vibration, to stresses due to turbulence, to cyclic pressurisation and depressurisation of the cabin, to moisture and to wide fluctuations of temperature. The temperature on the ground may be 36? C while at 38 000 feet it may be 60C.Materials selected must first be readily formed in the shapes required and must secondly be suited to the service conditions. Predict or identify any materials based problems that might occur due to the sharp environment that the aircraft is subject to. __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ Did you answer? brittleness at low temperature put on due to repeated cycles of stress crack propagation under high stresses, vibration, temperature changes corrosion due to continuous exposure to the ingredients failure under impact loss of strength at high temperature. Avionics and electrical Modern aircraft depend on many electronic systems to safely complete their flights. The flight adorn instruments, navigation systems, the actuation of aerodynamic su rfaces, the landing and autopilot systems are now controlled by electronics and micro- mainframe systems. The design and implementation of avionics is the realm of another engineer, the electrical or electronic engineer.The aeronautical engineer must however be advised of the impact of these systems when shrewd an aircraft. 8 Aeronautical engineering Control systems and hydraulics The control surfaces of aircraft elevators, ailerons, rudders and flaps need to move in response to pilot inputs on the control column and rudder pedals. In light aircraft this is achieved using wires and rods. In large commercial jets this is done with hydraulic systems connected to electronic or hydraulic controllers. Cowl Cockpit/cabin Spinner Prop Wing tip Aileron Flaps Fuselage Tailplane Elevator Trim tab Fin and rudder Figure 1. Main parts on an aeroplane If you have access to the net profit visit this Sydney University web site is an excellent source for additional aeronautics information (access ed 30. 10. 01). Part 1 Aeronautical engineering scope and engineering report 9 Arial Arial bold Unique technologies in aeronautical engineering Many of the technologies found in the aeronautical engineering profession are not unique in the sense that they are solely found and used in this discipline. The technologies used by the aeronautics application are also found in industries that deal with similar problems and issues.For instance, if you were to design a high technology, 18 foot racing skiff, you would need to consider and use many of the technologies available in the aeronautics fabrication, excluding perhaps the requirement for the vas to fly. Can you identify any technologies that you believe overlap between aeronautics and boat-building industries? Consider the major areas of emphasis in this course history, materials, mechanics and communication. List the technologies that you believe overlap between the aircraft labor and the construction of high tech boats. _______ ___________________________________________________ _________________________________________________________ __________________________________________________________ __________________________________________________________ Did you answer? materials such as graphite and kevlar and aluminium alloys computerised design and drawing systems wind tunnel testing of airframes and sweeps computerised calculation systems. Aircraft design Aircraft design is principally concerned with flight and how to achieve this condition safely and efficiently. Basically an aircraft must be aerodynamically sound have lots of lift and minimal drag.The aircraft must also be as light as possible to increase its payload and to allow it to get off the ground in the first place. The materials must be suited to the operating conditions and the environment and remain in good condition for the expected service life of the aircraft. 10 Aeronautical engineering The aircraft must also be structurally so und. The stresses in the components must not exceed the components safe working limits. Nothing ruins a pilots day more than having the wings fold up in a tight turn Finally, aircraft components are often sourced from manufacturers from all over the world.To ensure that it all goes together when all the parts arrive, very surgical and detailed drawings are required by each component manufacturer. These have to be drawn to internationally accepted standards. So, you ask, what has all this got to do with spend sweep upors and flimsy boats? Skiff design A sailing skiff, aside from any other considerations, must use wind and air to drive it. A sloshed inspection of a sail in operation will snap off that the sail is in fact a curved aerofoil not a flat sheet of sailcloth. You would notice this particularly on the sail of a windsurfer.The sail develops lift just as does the wing of an aircraft. The hull of the skiff moves through a fluid that you refer to as water. A seriously desig ned hull generates a large amount of drag that slows the skiff down. The original usually comments loudly about this situation as better-designed skiffs race old on their way to the finish line. Many designers of modern racing skiffs use sophisticated fluid dynamics packet to assist in designing both hull and sails. Similarly, these same designers are concerned with the two competing virtues of low weight and structural strength.In Auckland, in 1995, the Americas cup contention virtuoso Australia broke into two reasonably large but none-the-less rapidly sinking pieces. This was a perfect example of poor strength to weight analysis. Put precisely, the structural forces imposed on the hull exceeded the strength of the hull material. The designer sacrificed strength to obtain a lighter hull and paying(a) the price. The strength and modulus of light weight materials such as marine and aircraft check aluminium, light speed fibre composites and Kevlar are compared to complex mech anical analyses of the hull, spar and sail design. Again packet solutions exist and are utilized.The skiffs final drawings and component shapes may be drawn by hand. Often the drawings are produced using common, off the shelf pawl programs or perhaps specialist lofting packet portion designed for the marine industry. Part 1 Aeronautical engineering scope and engineering report 11 Arial Arial bold As you can see, the technologies in two seemingly unrelated industries are similar in nature and do overlap. However, the aeronautical engineering profession is distinct in some very significant ways The scale of operations and the shear complexness of the calculations involved in aeronautical engineering are in impermanently greater. The aircraft industry uses and often develops leading edge technology. Leading edge technology is usually very expensive. Industries such as the manufacturers of small boats tend to acquire this technology when it is more established and the cost of th e new technology is more affordable. More about aeronautical engineering technologies You will now learn more about some of the leading edge technologies associated with the aircraft industry. The technologies tend to fall into two broad areas those technologies used to design the aircraft, and those technologies associated with the materials manufacturing aspects of aircraft.Aircraft design technologies Throughout this course you have been involved in calculating forces, reactions, moments and stress in two dimensions and only on flat or uniform surfaces. At times you may have considered the calculations a little difficult. Consider then the degree of problem that would be involved if you now had to calculate forces and moments in three dimensions, on curved surfaces with loads that fluctuated and using calculus that Extension 2 (4 Unit) maths does not cover. Does this conjure up an image in your mind? direct imagine applying similarly difficult calculations to more than a thousa nd points across a single wing. Are you now thinking that this is getting a little difficult? A modern jet aircraft may contain over a million individual components and someone has to draw each and every one of them. Again, just to make things difficult virtually every component is curved in some special and very critical way. Imagine the most difficult drawing that you have done so far in this course, then multiply the degree of difficulty by ten. Then repeat the drawing several thousand times. Starting to get the picture yet 12Aeronautical engineering List some systems and products that exist to reduce the difficulty and complexity of designing modern jet aircraft. __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ Did you answer? One of th e most significant is computerised design and calculation parcel. Others include off the shelf systems for navigation, communication and cockpit management. The bad newsAll aeronautical engineers have to learn and understand how to do these difficult calculations. They have to use their brain, some mathematics and a calculator. be after aeronautical engineers soon encounter the complexities of computational analysis (difficult mathematics). They will see a lot more calculation before their aeronautical engineering course finally ends. The good news There are software tools available to assist the engineer in the design process. To use these software tools effectively and correctly the engineer must first understand the cardinal mathematics and theory on which these programs are based.That is, you must be able to understand and do the mathematics before using the program. You will now examine four common categories of aircraft design software structural analysis software bord er software aerodynamic calculation software CAD software. Part 1 Aeronautical engineering scope and engineering report 13 Arial Arial bold Structural analysis software The structural analysis of an aircraft is a complex problem. There are not many straight lines involved, virtually every component is curved, even the ones that look straight are usually curved. The loading is not uniform, it varies from point to point.In other words, the loads and stresses will vary infinitely across the components being analysed. An infinite number of equations could take quite some time. The solution is really quite straight-forward. If an engineer intends to examine the forces, stresses and moments in an aircraft wing, the wing can be mathematically broken up into a large number of sections referred to as elements. The conditions in each element are then examined. The results from each element are combined together to produce a distribution of forces, stresses and moments across the wing. The number of elements considered in this procedure is finite.There is an upper limit to the number of elements to be analysed. This mathematical process is called finite element analysis. The industry abbreviates this to FEA. Finite element analysis is a very powerful tool but is very slow when done by hand. A very popular finite element software (FEA) parcel in the aircraft industry is called NASTRAN. This package falls into the category of a computer aided engineering software (CAE) tool. NASTRAN is a high end software tool for critical engineering applications. It is capable of stress, vibration, heat transfer, acoustical and aeroelastic analysis. If you have access to the lucre visit .Select the appropriate option from the software section of the directory to find out more about NASTRAN (accessed 06. 11. 01). Modeling software The production and testing of physical working models is a costly and time consuming activity. An activity that is closely related to finite element analy sis is finite element modeling. In the aeronautical engineering industry finite element modeling is abbreviated to FEM. Using finite element modeling software, an engineer can construct models using computer aided design (CAD) parts, submit the models for simulation and observe the behavior of the model under simulation.The results can be used to modify and improve the product designs to fork over better performance and to better resist loads. A high end finite element modeling program that is commonly used in the aeronautical engineering industry is PATRAN. This product is 14 Aeronautical engineering produced by MSC, the same company that produces the analysis package NASTRAN. Figure 1. 3 was produced by the Page Aircraft Company Pty Ltd using the finite element modeling package PATRAN. This company is associated with the University of NSW and is soon developing a light aircraft that it hopes to put into full commercial production.You can find out more about PATRAN at . Figure 1 . 3 A PATRAN generated image of an aircraft under development Reproduced with the permission of the Page Aircraft Company Pty Ltd Aerodynamic calculation and modeling software Aerodynamics is concerned primarily with the flow of air and the interaction of that air with objects that it encounters. Aeronautical engineers are usually concerned with the interaction of an aircrafts outer surfaces with the air through which the aircraft moves. CFD calculations can help to predict the lift and drag levels for a particular airframe as well as stall and other performance characteristics.Air is considered to be a fluid and the mathematical processes involved in predicting the behaviour of the air is called computational fluid Part 1 Aeronautical engineering scope and engineering report 15 Arial Arial bold dynamics or CFD for short. The mathematics involved is complex but again there is software available which can carry out these calculations. Outline a practical way in which an aeronautica l engineer could visualize the flow of air around an aircraft without using software. __________________________________________________________ _________________________________________________________ __________________________________________________________ __________________________________________________________ Did you answer? The flow of air around an aircraft can be observed using a wind tunnel where wind is pushed over a model with smoke streams passing over it. An industry standard software package commonly used by aeronautical engineers is VSAERO. This package allows an engineer to input the surface geometry of an aircraft. The surface geometry is simply the outside shape of the aircraft.The engineer can also input reference conditions such as velocity of the air, angle of attack of the wing and yaw. The package will then calculate and display the predicted behaviour of the air around the aircraft. If you have access to the Internet visit . Under products there is a gra phic showing an image of the C-130, the Hercules transport aircraft used by the Australian military at present. Take a close look at what is happening to the wingtips (accessed 30. 10. 01). If you have access to the Internet visit to view a photograph of a real C-130 activating anti missile flares (accessed 30. 10. 1). calculating machine aided design The last type of software package that you need to learn about are the computer aided design (CAD) drawing packages. Youre probably familiar with one of the CAD packages available for use on personal computers. These include Autocad Light, Autosketch and TurboCAD. These packages vary in power and are fine for standard drawing applications such as architecture and sensitive scale manufacturing. The aeronautics industry uses specialist CAD packages which fit the industrys need to produce drawings of complex surface shapes and 16 Aeronautical engineering curved components.They also use state of the art, multiple processor workstations w ith large screen monitors for speed and ease of viewing. The large monitors reduce eye-strain and allow more of each drawing to be displayed. CAD software packages currently used by many aeronautical engineering companies include CATIA and CADDS 5. The CATIA package is promoted as CAD/CAM/CAE package. CATIA can be used solely for drawing and designing. However, it can also be used for CAM (computer aided manufacturing) and CAE applications. If you have Internet access visit to find out more about CATIA (accessed 30. 10. 1). Figure 1. 4 Image produced by the Page Aircraft Company Pty Ltd using CATIA software. The aircraft shown is currently under development Reproduced with the permission of the Page Aircraft Company Pty Ltd Wind tunnels To this point all the development tools have been based on computer software. In the aerodynamic calculation and modeling section you were asked to suggest a method of assessing the aerodynamic behaviour of an aircraft without using computers. Many successful aircraft have been developed without the aid of modern computers. In fact the computer models are not perfect.The information provided by computer analysis is usually valid but does not exactly predict the behaviour of a real aircraft. Part 1 Aeronautical engineering scope and engineering report 17 Arial Arial bold Why do you think this is so? __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ Did you answer? Computer output is based on computational methods that have been programmed into the computer.These computational methods are based on theoretical analyses of conditions. Variables are input to reflect real situations and conditions as much as possible but can neer predict the precise conditions that exist. Input into a computer is based on precise or perfect data, the behaviour of m aterials, fluids and the like is not needs perfect. The output from a computer program is based purely on the input. Another method of assessing an aircraft design is to construct a very precise scale model then subject the model to wind tunnel testing.Wind tunnel testing does not exactly predict the behaviour of a real, fullsize aircraft flying in open air. However, when scale effect corrections are applied valid data can be obtained. Model boats on ponds do not behave like real ships, the forces and accelerations are all out of proportion. They bounce around like corks. Similarly model aircraft in wind tunnels do not behave like real aircraft. There are several reasons for this. It is difficult to make accurate models. The sides of the wind tunnel constrain the air-flow. Most seriously, the model is flown in full size air not model size air.This is known as the scale effect. larger size models in larger size wind tunnels give the most meaningful data. The most sophisticated wind tunnels actually compress the air at up to 25 atmospheres to correct for scale effect. Most aircraft design is based on both CFD and wind tunnel analysis. This is because neither system gives perfect results. The following photograph shows a model under test in a wind tunnel at the University of NSW. 18 Aeronautical engineering Figure 1. 5 A model aircraft being tested in a wind tunnel Reproduced with the permission of the Page Aircraft Company Pty LtdManufacturing technologies and systems unique to the aeronautics industry Aeronautical engineers also deal with materials and manufacturing processes that are highly specialized in their nature and could be considered unique. The materials used for aircraft manufacture need to possess very special manufacturing and service properties. List five properties which you believe are important for materials used in aircraft manufacture and construction. introduce your reasons for each choice. Property Reason why it is important Part 1 Aero nautical engineering scope and engineering report 19 Arial Arial bold Did you answer?Property Reason why it is important Low wear out aircraft vibration can cause fatigue failures High strength to weight lower the overall weight Corrosion resistance resist harsh operating conditions Ductility (before forming) Provide for forming of complex shapes Elasticity allow the aircraft to change form Later, in the materials section of this module you will investigate the materials commonly used in the aircraft manufacturing industry. This section is more concerned with the technologies used when dealing with these materials. innovational composite materials Two commonly used materials are aluminium and carbon fibre