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Part 2: Fundamental knowledge Q1. This following Schliren photograph shows the flow structure around around two supersonic projectiles. Evaluate the projectiles speed at sea-level temperature and pressure. Q2. Write your definition of drag, and explain what induced drag is. Bonus if you can explain how to minimize it. Q3 Scketch a wing shape that would give a trianglular distribution of lift. Justify your answer Ly 0 -b/2 Wing b/2 Problem 1. An experimental thin airfoil has the following characteristics: • zero-lift at -2 degrees angle of attack. ⚫stall angle 13 degrees angle of attack. 1. What is the lift at an angle of attack of zero degrees? 2. What is the maximum lift coefficient? Bonus: Explain the validity of your answers (theory, assumptions, ...)/nProblem 2. Consider a supersonic wedge, flying at M=2, P=1atm and T=288K. The flow generates an oblique shock. The shock wave angle is ẞ=60°. 1. What is the angle that the flow turns after the oblique shock? 2. Calculate the Mach number behind the oblique shock. 3. Calculate P,Po, T and To behind the oblique shock 4. Further downstream, the flow crosses a normal showckwave, Calculate P,Po, T and To behind this normal shockwave. 5. At what Mach number does the oblique shock becomes detached? Note: In order to get full points for each question and problem, you must show your work and answers should have units (when applicable) and the right number of significant figures. Problem 3. A supersonic Pitot tube indicates a total pressure of 8.8 atm (after a SW) and a static pressure of 0.9atm (before SW). Temperature of the air is 10 °C Determine: 1. Free-stream Mach number 2. Free-stream Velocity/nProblem 4. The Kremer prize consisted in flying a human-powered aircraft to fly a figure eight around two markers one half mile apart, starting and ending the course at least 10 feet (3.0 m) above the ground. In 1977, Paul MacCready won the prize. In 1979, he won again the Kremer prize flying across the channel, from England to France. The plane, called the Gossamer "Albatross" had the following characteristics: Flight speed: 4.6 m/s Wing Size: span= 29m, Cord length =1.5m Evaluate: Mass (without pilot): 95kg Mass (Pilot): 66kg Drag Coefficient: 0.046 1. The lift coefficient for level flight (Bonus if you can recommend an airfoil) 2. The power required by the pilot. Note: the power is equivalent to the drag x velocity. Paul MacCready won the Kremer prize

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