Q1.Duration – 3 Hrs a) Explain how you would go about the comparative configuration study of different types of airplanes, if your task is to undertake a conceptual design of a 300 seater medium range passenger aircraft? (30 marks) b) What would be the main ‘Design Drivers’ that would govern the design of the aircraft from the beginning till end, through various stages of design? (30 marks) c) Why is it that when you add a small weight correction to compensate for the mismatch between ‘available empty structural weight’ and ‘theoretical empty structural weight’, the final weight, after iterations, varies disproportionately? (40 marks) Q2. Duration – 3 Hrs a) What are the various performance aspects that can be specified by mission requirements? Explain each of them briefly (40 marks) b) What are the steps involved in a “Conceptual design ‘of an aircraft? (40 marks) c) What are the different Design Drivers? Name a few of them Q3. (20 marks) Duration – 3 Hrs a) First step in the design of a new aircraft is to obtain an estimate of the Takeoff weight WT0. Explain how you would arrive at a tentative starting point for the takeoff weight by referring to Jane’s book? (30 marks) b) What are the constituents which make up for the total weight of an aircraft and in what proportion? (30 marks) c) Explain briefly the various flight phases considered in the flight plan, to assess the fuel weight at the end of each phase. Draw a neat schematic to show the phases (40 marks) (L/D). Duration – 3 Hrs a) What are ‘Fuel fraction estimates’ (or ‘Fuel weight fractions’)? (20 marks) b) Explain how you would estimate the fuel weight fraction during (i) Start up & Takeoff and (ii) Climb & acceleration to cruise phases ( 20 marks) c) Fuel weight fraction during cruise out to destination is given by Breguet’s range equation: R = (V/C). a) What is ‘structure factor’? What is its significance? Duration – 3 Hrs (15 marks) b) How do you find the available empty structural weight for an aircraft? What would you do if the available empty structural weight is less than the theoretical required empty structural weight at the end of iteration? (45 marks) c) How will you find the total weight of fuel required to be carried on the aircraft to meet the conditions imposed by the design driver. Duration – 3 Hrs a) What do you understand by ‘Loiter’? Why is it necessary to provide loiter time for every aircraft? (20 marks) b) Loiter E is given by the endurance equation E= (1/C) . for reciprocating engined aircraft. Ln [Wi/Wf]. for jet engine What does each symbol stand for in the above equation? Explain briefly the procedural steps for Jet Engine to work iteratively for one iteration from start up till landing. What are the conditions for maximising endurance for a reciprocating engine? (60 marks) c) How do you find the fuel weight fraction for the landing phase? (20 marks) Q6. (60 marks) Q5. (L/D).Q4. Explain each of the terms.s (40 marks) . Ln [Wi /Wf]. (1/ CLmax). (20 marks) Duration – 3 Hrs a) What do you understand by “Wing Loading’? What are its units? What are the representative values of wing loading for a long range transport aircraft and for a combat fighter? (30 marks) b) Which parts of a flight plan are affected by the wing loading? (30 marks) c) What is the effect of wing loading on takeoff . given the cruise Mach number and cruise altitude at which the aircraft is expected to cruise? How will you estimate the values of Design CL bandwidth? What criterion would you look into while selecting an airfoil with matching drag polar graph connecting C D Vs CL? (40 marks) b) What is the effect of Aspect Ratio on (L/D)max? Draw a representative graph connecting (L/D)max and Mach number for different aspect ratios.Q7. Duration – 3 Hrs a) How will you find the cruise velocity of the aircraft. (40 marks) c) What all constitute total takeoff weight WTO? What are the two categories of payload? Q8. given that the takeoff parameter TOP is given by TOP = (W/S)TO. What are the various terms involved in the equation? Why is take off distance more critical than landing distance? (40 marks) . (1/). (W/T)TO. How would you find the maximum thrust at full throttle of the engine? (30 marks) c) Explain how you would find the equivalent thrust required at max rpm at sea level.4) aircraft II. Explain the terms involved and also indicate what would be the source for obtaining the data on parameters mentioned and for selection of a matching engine. ( 40 marks) . maximum thickness-to-chord ratio. low subsonic (MCruise= 0. given that TH = (TSL). Draw a schematic of a wing cross section and planform views that illustrate these parameters. average chord length. Duration – 3 Hrs a) How would you find the drag due to wing for an aircraft in cruise? (30 marks) b) Explain the method to find the thrust required at cruise altitude. a) Design of a wing consists of selecting the airfoil cross section shape. (PH/ PSL).8) III. taper ratio and the sweep angle. (40 marks) b) Briefly analyze the effect of each of these parameters on the aerodynamic performance ( 30 marks) c) The choice of airfoil section type that is most suitable for a design depends on the general type of aircraft. NACA series 6 airfoils for supersonic military aircraft (30 marks) Q10. Discuss the characteristics that make the choice of NACA airfoil types given below as the best fit for the following types of mission requirement: I. NACA Supercritical airfoils for high subsonic speed aircraft (MCruise=0. NACA five-digit series: for smaller.Duration – 3 Hrs Q9. (SL/ H). Aspect ratio.