ME110 Aeronautical and Automotive Systems


ME110  Aeronautical and Automotive Systems

Assignment Brief:

Part A: How do Aircraft Wings Work?

Part B: Using Aerofoils to Increase the Cornering Speed of a Car

IMPORTANT: Please read the coursework guide before working on your assignment

ME110  Aeronautical and Automotive Systems

Assignment Brief:

Part A: How do Aircraft Wings Work?
Assignment Part A:

How do Aircraft Wings Work? In this part of the assignment you will investigate the fundamental physics associated with the generation of lift forces using an aerofoil. You will also investigate the important aspects of aerofoil performance for aircraft using aerofoil analysis software. • Please write your final answers in the report template provided on studentcental • Please refer to the coursework guide provided on studentcentral • Please use equations, and your own diagrams, to support your answers

Tasks 1. Explain how an aerofoil generates lift.
2. Describe three common misconceptions about how lift is generated.
3. Consider the wing of a Cessna 150, where the aerofoil section at the root is a NACA 2412: a) Why is it rounded and not pointed at the front b) Why is it thicker in the middle c) Why is it tapered at the rear d) Why is it flatter underneath, with a camber making it curve on top? 4. What other shapes will generate lift?  a) Could a house brick? b) Could a football? 5. Define the common formulas for Lift & Drag and give example use of the equations.
6. Define the main types of aerodynamic drag.
7. Define laminar and turbulent boundary layers.
8. What are wingtip vortices and what causes them?
9. IMPORTANT: To do this part you need to use a computer with XFLR5 software installed. If you want to download a copy of XFLR5 on your own computer you can do so from here: http://www.xflr5.com/xflr5.htm For tips on how to use this software, see the XFLR5 user guide on student central.  Using the XFLR5 software, load a NACA 4 series aerofoil of your choice (eg NACA 2412) a) Generate a plot of CL vs. Alpha b) Generate a plot of CD vs. Alpha 10. By inspecting the plots generated in question 9: a) What angle of attack gives zero lift? b) What angle of attack gives maximum lift? c) If it flies upside down, what is the maximum lift, and at what angle of attack? 11. Include a screenshot of the aerofoil you have chosen in section nine.
Appendix As well as making your own information searches, please visit the following websites to aid your learning of aerofoil aerodynamics:
Lift Explanations https://www.grc.nasa.gov/www/k-12/airplane/lift1.html http://iopscience.iop.org/0031-9120/38/6/001/pdf/pe3_6_001.pdf
Incorrect Theory Explanations: https://www.grc.nasa.gov/www/k-12/airplane/wrong1.html http://amasci.com/wing/airfoil.html http://www.aviation-history.com/theory/lift.htm
General Fluid Mechanics: http://en.wikipedia.org/wiki/Bernoulli’s_principle http://www.cabrillo.edu/~jwelch/bernoulli/bernoulli-coanda.html http://lecdem.physics.umd.edu/f/f5.html
Wingtip Vortices: http://www.youtube.com/watch?v=uy0hgG2pkUs
General Lift Discussions: https://www.grc.nasa.gov/WWW/k-12/airplane/short.html http://hyperphysics.phy-astr.gsu.edu/hbase/fluids/airfoil.html http://en.wikipedia.org/wiki/Lift_(force)#Deflection http://physics.stackexchange.com/questions/46131/does-a-wing-in-a-potential-flow-have- lift/46134#46134 http://aviation.stackexchange.com/questions/21664/how-complete-is-our-understanding-of-lift
Aerofoil Database Links: http://m-selig.ae.illinois.edu/ads.html

ME110  Aeronautical and Automotive Systems  Assignment Brief:  Part B: Using Aerofoils to Increase the Cornering Speed of a Car
Assignment Part B: Using Aerofoils to Increase the Cornering Speed of a Car In this part of the assignment you will investigate the additional cornering speed that a car is capable of if aerofoils are fitted. The reference vehicle for this work will be a Formula One racing car. You are asked to calculate maximum cornering speeds with, and also without, aerofoils fitted.  This assignment introduces concepts such as centripetal force, angular acceleration, coefficient of friction, unit conversion, scaling and dimensioning, and problem solving. The objective of this work will be to learn how to analyse and present information in a meaningful way. You will need to refer to your lecture notes to tackle this problem. Please follow the general approaches set out in these lecture notes, in conjunction with learning materials obtained from the library or online (e.g. ScienceDirect). To help solve this task, you will also use NASA Foilsim software. Assumptions: • The car will be following a constant radius corner for each case considered:  (50m / 100m / 200m) • Car total mass is 640kg • Centre of gravity is 2/3 rearwards of the horizontally distance between the front and rear wheels • Maximum width of car = 1.8 m (As governed by FIA F1 Rules) • Coefficient of friction between the tyres and the road: 0.97 (Slicks in the dry) Tasks 1. Sketch out force diagrams for the vehicle with and without aerofoils fitted. What forces are present? What forces act between the tyre and road surface? 2. Calculate the maximum speed of the car around the three bend radii without aerofoils. Please use MS Excel to carry out your calculations. 3. Now investigate the new maximum cornering speed with aerofoils fitted; you will need to follow the following steps to design your own aerofoils: • To determine the chord and span of each aerofoil: Perform a Google image search to find a top view of a Formula One car. Then copy the image into a programme such as MS Paint and, taking the maximum overall width to be approximately 1.8 m as a scaling reference, measure the drawing to obtain dimensions for the wings and overall length. You will use these measurements as the basis of your calculations. Include this image in your report. • Open the NASA Foilsim internet-based software and experiment with the shape and flow options to design front and rear aerofoils which fit the car and provide maximum downforce without leading to flow separation (use span and chord dimensions as determined using the instructions above). Include screenshots in your report. For tips on how to use this software, see the Foilsim user guide on student central. 4. Calculate the new maximum speed for each of the three bend radii, accounting for the additional vertical load provided by the aerofoils. 5. Plot a set of graphs which concisely summarise all your findings (with and without aerofoils, for all three bend radii). 6. When the car is without aerofoils, and following a corner radius of 100 m, determine whether the front or the back tyres slip first.
Supporting Information: In conjunction with your lecture notes, the following diagrams and screenshots are intended to help you work through this assignment:
• Scaling and measurement using the top view of a Formula One car
http://isiforums.net/f/showthread.php/6098-Formula-Masters-(ISI)-Driving-Tips/page3

• Setting up constants for Excel spreadsheet calculations
1.8 m
L
2/3 x L
• Cornering load requirements
• Loads due to mass, gravity, and aerofoils
• Graphical description of cornering forces considered
Appendix Please visit the following websites to aid your learning of aerofoil aerodynamics applied to F1 cars:
F1 Rules and Regs: https://www.formula1.com/content/fom-website/en/championship/inside-f1/rules- regs/Bodywork_and_dimensions_and_Cockpit.html
Motorsport Aerofoil Information: http://atlasf1.autosport.com/2000/feb09/gray.html
http://www.f1-country.com/f1-engineer/aeorodynamics/f1-aerodynamics.html
https://www.formula1.com/en/championship/inside-f1/understanding-f1- racing/Aerodynamics.html

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