R05322101-flight-mechanics-ii

Set No. 1

Code No: R05322101

III B.Tech Supplimentary Examinations, Aug/Sep 2008 FLIGHT MECHANICS-II (Aeronautical Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Explain the following terms with examples i. Stability ii. Equilibrium. (b) Comment upon the requirements of stability of a i. Military fighter aircraft ii. Commercial passenger airplane.

[4+4+4+4]

2. (a) Three dynamic modes describe the lateral motion of an aircraft. What are they? Explain in detail. (b) Explain the orientation and position of an airplane in terms of a fixed frame of reference. Illustrate with sketch. [8+8] 3. (a) The use of stability derivatives is most conveniently demonstrated with missile or rocket configurations. Why? Give the explanation. (b) Show that

dβ / dt = (Y β / m U) β - r dr/dt=(Nβ / C) β+ (Nr /C) r

[8+8]

4. Explain the following terms (a) Down wash (b) Induced angle of attack (c) Effective angle of attack.

[4+6+6]

5. Using proper sketches, explain stick free longitudinal stability of an airplane. [16] 6. (a) Derive an expression for the normal load factor of an airplane in a steady constant speed, constant angular rate pull - up maneuver in a vertical loop when the airplane is at a flight path angle γ in the loop. (b) An airplane of mass 1.5 tonnes, flying at 250 kmph pulls up in a vertical circular loop of radius 1.2 km. What is the lift required for this maneuver of the airplane while at a flight path angle γ = 60 degrees to the horizontal? [8+8] 7. Derive the expression for the pedal force for the rudder of an airplane as a function of hinge moment coefficients. [16]

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Set No. 1

Code No: R05322101

8. Derive the equations of motion of an airplane constrained to the plane of symmetry at constant speed and also derive the characteristic equation of an airplane dynamics. Discuss the solutions. [16] ⋆⋆⋆⋆⋆

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Set No. 2

Code No: R05322101

III B.Tech Supplimentary Examinations, Aug/Sep 2008 FLIGHT MECHANICS-II (Aeronautical Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Roll accompanies yaw and yaw accompanies roll - elaborate the statement with sketches. [16] 2. Consider an object moving through space with no forces of any kind acting on the body. The body is initially moving relative to an inertial coordinate system with a velocity of V0 and is rotating about an axis normal to the velocity vector with an angular velocity of ω0 . Determine the position and orientation of the object as a function of time? [16] 3. The estimation of a flight vehicle’s stability and control characteristics is commonly performed via two sets of parameters. What are they? Explain. [16] 4. The location of the wing on the longitudinal axis of the fuselage is of considerable importance to its destabilizing influence. Multhopp proposed a formula to account for this phenomenon. What is that formula? Derive it with the support of sketches. [16] 5. Explain the aerodynamic forces on a stabilator configuration in stick free condition of an airplane. [16] 6. (a) Derive an expression for the normal load factor of an airplane in a steady constant speed, constant angular rate pull - up maneuver in a vertical loop when the airplane is at a flight path angle γ in the loop. (b) An airplane of mass 1.5 tonnes, flying at 250 kmph pulls up in a vertical circular loop of radius 1.2 km. What is the lift required for this maneuver of the airplane while at a flight path angle γ = 60 degrees to the horizontal? [8+8] 7. Derive the expression for the derivative of pedal force for the rudder of an airplane with yaw angle of the airplane. [16] 8. Explain pure convergence and pure divergence and damped and negatively damped oscillations in the case of an airplane. [16] ⋆⋆⋆⋆⋆

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Set No. 3

Code No: R05322101

III B.Tech Supplimentary Examinations, Aug/Sep 2008 FLIGHT MECHANICS-II (Aeronautical Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) What are static stability and dynamic stability? (b) With respect to an aero plane, explain the i. ii. iii. iv.

Longitudinal stability Lateral stability Directional stability and Control.

[8+2+2+2+2]

2. The aerodynamic forces and moments on the body are due to only two basic sources as given below. Explain them with sketches (a) Pressure distribution over the body surface (b) Shear stress distribution over the body surface.

[8+8]

3. (a) Explain the method of measurement of coupled aerodynamic stability and damping derivatives in a wind tunnel, with the help of sketches. (b) State and derive the condition for Prandtl - Glauert compressibility correction. [8+8] 4. The theory accounting for the effects of the fuselage and nacelle on the airplane stability is rather a complex one, especially when the interference effects of the wing and its flow pattern are taken into account. Two methods were used to predict these contributions. What are the two methods? Support your answer with required sketches and graphs. [16] 5. (a) What do you understand by the floating tendency of an elevator? (b) Obtain an expression for the free elevator factor Fe for the horizontal stabilizer of an airplane. (c) What is the effect of free elevator factor on the longitudinal stick free static stability of an airplane? (d) By what means can you change the free elevator factor of the elevator? [4+4+4+4] 6. (a) Derive an expression for the normal load factor of an airplane in a steady constant speed, constant angular rate pull - up maneuver in a vertical loop when the airplane is at a flight path angle γ in the loop. (b) An airplane of mass 1.5 tonnes, flying at 250 kmph pulls up in a vertical circular loop of radius 1.2 km. What is the lift required for this maneuver of the airplane while at a flight path angle γ = 60 degrees to the horizontal? [8+8] 1 of 2

Set No. 3

Code No: R05322101

7. Derive the expression for the pedal force for the rudder of an airplane as a function of hinge moment coefficients. [16] 8. Derive the equations of motion of an airplane constrained to the plane of symmetry at constant speed and also derive the characteristic equation of an airplane dynamics. Discuss the solutions. [16] ⋆⋆⋆⋆⋆

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Set No. 4

Code No: R05322101

III B.Tech Supplimentary Examinations, Aug/Sep 2008 FLIGHT MECHANICS-II (Aeronautical Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Explain, in respect of an aircraft, (a) Stability (b) Controllability and (c) Maneuverability.

[4+6+6]

2. Consider a tractor pulling a trailer of mass m. The trailer is attached to the tractor with an elastic tongue having a spring constant k. The tractor is moving along a straight and level roadway with a constant velocity V0 . Assuming that the total resistance force on the trailer is proportional to velocity squared, obtain a linearized differential equation for the position of the trailer. [16] 3. The estimation of a flight vehicle’s stability and control characteristics is commonly performed via two sets of parameters. What are they? Explain. [16] 4. Explain  indetail about the elevator control power with sketches. Derive the equam tion dC [16] = −at V ηt dCL T ail

5. Explain the aerodynamic forces on elevator - stabilizer configuration in the stick free condition of an airplane. [16] 6. Derive the following equation for elevator for trim of an airplane in a steady level turn: [16] 2 δe,Turns = δe,0 - [{ 2 n ( W / S ) } / ( ρ V C m,δ )] (d C m / d C L ) Fix - [ { ( 63 g lt ) / ( τ V2 ) } { n - (1 / n ) } ] 7. Derive the rudder power equation d C n / d δr = [ - a v (S v / S w ) (l

v

/ b) ηv ]

[16]

8. Write the characteristic equations for a pure yawing motion. Explain the terms involved. [16] ⋆⋆⋆⋆⋆

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