LS2022 23 Call1

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First name Last name Personal ID number Mark Launch systems (8 credits) Jan. 18th, 2023 First part - Closed book Each question is worth 1 point. The student must obtain at least 6 points otherwise the second part of the exam will not be corrected. WRITE THE ANSWERS IN THIS SHEET Scenario – Air-to-air missile We are considering a short range missile having the following properties: • Nominal flight Mach number: 1.0 • Release altitude 3000 m (255 K, 54 kPa) • Mass: 85 kg • Diameter: 15 cm • Length: 3 m • Guidance: infrared homing 1. You are discussing with another engineer how to improve the powered range. In the table you have some of his/her ideas. Do you agree? Mark them as true (T) or false (F) (correct anser +2, wrong answer -1, no answer 0) Even a slightly higher flight Mach number should improve the aerodynamic efficiency and, thus, the range A shorter missile should be beneficial Even if we keep constant all the other parameters, an increment of the thrust improves the range If we keep the same geometry, an increment of the sole propellant density (keeping other parameters constant) can bring to some improvement. Reduction of inert mass weight helps the increment of the range. 2. (Skip for MULTICHANCE) What are the most important requirements for this missile? (Three valid questions. The selection of a wrong answer invalidates the question.) Launch Systems Page 1 Readiness GPS navigation Green propellant High T/W ratio Long range Storability Multistaging Corning glass laser homing 3. Compute the turning radius of the missile if the lift coefficient is 2.5. Use the data described in the scenario. 4. What are benefits and drawbacks if we modify the body from circular to elliptical cross section? 5. What limits the boresight of a missile? Launch Systems Page 2…