JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II AIRCRAFT PERFORMANCE Previous Question Paper (April - 2018 - R16)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
PART - A
Define flight path and flight velocity.
Answer
A flight path is the trajectory or path traced by the center of gravity of an aircraft through the atmosphere. Flight velocity is the instantaneous speed of the aircraft relative to the surrounding air, represented as a vector defining both magnitude and direction.
Discuss Few points about standard atmosphere where a/c can fly.
Answer
The standard atmosphere provides a reference model for aircraft performance. Key points include: 1) It assumes a constant lapse rate in the troposphere (6.5 K/km). 2) Pressure, density, and temperature decrease with altitude, which directly impacts engine thrust and aerodynamic lift. 3) It serves as a baseline for calibrating flight instruments and comparing performance data across different aircraft.
Prove that ‘The fuselage by itself experiences substantial drag’.
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How do lift, drag and moment coefficients vary?
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Define endurance and give a suitable example.
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Illustrate the effect of drag divergence on maximum velocity.
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Consider an airplane flying at an altitude of 30,000 ft at a velocity of 540 mi/h. calculate its energy height.
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Compare and contrast instantaneous and sustained maneuvers.
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Define Take -off parameter.
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Demonstrate the method of calculating approach distance using force diagram for an airplane on the landing approach flight path.
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PART - B
On a certain day the pressure at sea level is 758 mm of mercury (101059 N/m2) and the temperature is 25°C. The temperature is found to fall linearly with height to -55°C at 12km and after that it remains constant upto 20 km. Calculate the pressure, density and kinematic viscosity at 8km and 16km altitude.
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Ascertain that the lateness under any perturbed schedule is no greater than the lateness under the original unperturbed schedule.
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Explain the analysis techniques that are used to compute the performance characteristics of an airplane.
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Define the design lift coefficient for an airfoil.
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Explain the main functions of a swept wing with a suitable diagram.
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What is the drag polar and how is it useful in aircraft stability and control?
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Consider a straight wing of aspect ratio 6 with an NACA 2412 airfoil. Assuming low-speed flow, calculate the lift coefficient at an angle of attack of 6°. For this wing, the span effectiveness factor e1=0.95.
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Calculate the minimum velocity of the Gulfstream IV at sea level based on (a) the low-speed intersection of the thrust available and the thrust required curves and (b) the stalling velocity. This airplane is equipped with single-slotted Fowler trailing-edge flaps. The wing sweep angle is 27° 40'.
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Describe any six types of high-lift devices with suitable diagrams.
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Does the low-speed intersection determine the minimum velocity of the airplane for steady, level flight? Justify.
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How does the minimum turn rate is obtained?
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For the conditions of maximum turn rate, derive the expressions for (i) the load factor (ii) the velocity (iii) the maximum turn rate.
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Explain the two performance characteristics of the greatest importance in turning flight.
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Consider an airplane in an accelerated climb. At a given instant in this climb, the specific excess power is 120 ft/s, the instantaneous velocity is 500 ft/s, and the instantaneous rate of climb is 3,000 ft/min. Calculate the instantaneous acceleration.
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Elucidate all the factors that affect actual landing distance.
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Specify the ways of calculating ground roll using a suitable diagram.
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For the BD-5J, calculate the total landing distance, starting with the clearance of a 50-ft obstacle, assuming the landing weight is the same as the takeoff gross weight. The runway is firm dirt with brakes-on coefficient of rolling friction of 0.3. The approach angle is 4°.
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