Aeronautical Engineering Review

AERONAUTICAL ENGINEERING REVIEW Aircraft Structures and Design Mock Board Examination Instruction: Select the correct answer and shade the letter of your choice on the answer sheet. STRICTLY NO ERASURES ALLOWED ON THE ANSWER SHEET. 1. A design airplane has a weight of 2,200 lb and a wing area of 90 ft2. It is to be certified as acrobatic category under FAR part 23. What is the negative limit maneuvering load factor in which the airplane must be designed for? a. 2.1 c. 2.5 b. 3.8 d. 3.0 2. A simply supported beam, 3 meters in length is acted upon by an upward uniformly distributed load along its entire length with a magnitude of 8 KN/m. What is the maximum shear imposed on the beam by the load? a. 12 KN c. 6 KN b. 24 KN d. 8 KN 3. A simply supported beam, 3 meters in length is acted upon by an upward uniformly distributed load along it entire length with a magnitude 8 KN/m. What is the maximum bending moment imposed on the beam by the load? a. 9 KN-m c. 18 KN-m b. 36 KN-m d. 6 KN-m 4. Structural members designed to support loadings applied perpendicular to their axes. They are long, straight bars having a constant cross-sectional area. a. Shafts c. Beams b. Plates d. Bulkhead 5. The test pilot of a design airplane observed that if the airplane is acted upon by a strong updraft, the airplane oscillates vertically. The airplane is: a. Dynamically stable c. Statically and dynamically unstable b. Statically stable d. Statically and dynamically stable 6. For a given aircraft at a given condition, the limit load is constant. The ultimate load is dictated by the factor of safety. Choose which of the following statements are CORRECT in relation to the factor of safety and ultimate load. a. As the factor of safety increases, the c. As the factor of safety increases, the ultimate load decreases. ultimate load increases. b. As the ultimate load increases, the factor of d. The factor of safety is constant at 1.5 safety decreases. therefore, ultimate load is also constant. 7. Normally designed to provide restraint against rotation and all translations; therefore, reactive forces and moments are developed along the directions where movements are not permitted. a. Fixed support c. Roller support b. Hinge support d. Wedge support 8. It is a structure composed of slender members joined together at their end points, in which the members are subjected to only axial loads. a. Beam structure c. Semi-monocoque structure b. Monocoque structure d. Truss structure 9. Members which are loaded so that they are compressed axially and therefore have developed within them compressive resistances or stresses. a. Beams c. Shafts b. Columns d. Trusses 10. It is a measure of the intensity of load acting on a definite plane passing through a given point in the material. a. Shear c. Stress b. Torque d. Strain 11. The axial strain in a member is always accompanied by a lateral strain of opposite sign. Thus, if a member stretches under load, its cross-sectional area becomes smaller at the same time. The relationship of the lateral strain to axial strain is expressed by: a. Modulus ratio c. Hooke’s Law b. Stress-strain relationship d. Poisson’s Ratio 12. A transverse load on a member tends to make the member rotate about an axis at a section away from that where the load is applied and normal to the axis of the member. If the member is restrained from rotating at any section other than that at which the load is applied, internal tension stresses are set up at one side of the member and compression at the other. At any section where such stresses are present the member is said to be subjected to: a. Torsion c. Bending b. Shear d. Compression 13. If loads are applied to a member so that it tends to twist about an axis, internal shear stresses are set up in the member at any section between the application of load and the reaction to resist the twisting force. In such a case the member is said to be subjected to: a. Torsion c. Bending b. Shear d. Compression 14. The ratio of shear stress to strain below the proportional limit is called shear modulus of elasticity or: a. Poisson’s Ratio c. Modulus ratio b. Stress-strain relationship d. Modulus of rigidity 15. The total moment due to internal stresses of a shaft or tube is equal in magnitude to the external torque,  G  2 2   r dA . The quantity  r dA is known as the:  L  and is given by the equation T   a. b. Polar moment of inertia Radius of gravitation c. d. Moment of inertia about a base Product of inertia about inclined axis through a centroid 16. The maximum anticipated loads in the entire service life-span of a flight vehicle is called: a. Ultimate loads c. Design loads b. Limit loads d. Imposed loads 17. This condition is obtained in a pullout at the highest possible angle of attack of the wing. The lift and drag forces are perpendicular and parallel respectively to the relative wind. a. Positive low angle of attack c. Negative low angle of attack b. Positive high angle of attack d. Negative high angle of attack 18. This condition occurs at the diving speed limit of the airplane, it may occur in an intentional maneuver producing negative load factor or negative gust condition. a. Negative low angle of attack c. Positive low angle of attack b. Negative high angle of attack d. Positive high angle of attack 19. A welded joint with members and their corresponding internal force as shown in Fig. A (see page 6). What is the magnitude and direction of the force in member F to maintain equilibrium condition? a. 3.5 KN, downward c. 1.414 KN, downward b. 1.14 KN, upward d. 2 KN, upward 20. A 6,300 lb airplane is in a steady glide with flight path at an angle of 20O below the horizontal. What is the LIFT and DRAG of the airplane? a. L = 5155 lb, D = 2920 lb c. L = 6120 lb, D = 3250 lb b. L = 5920 lb, D = 2155 lb d. L = 5209 lb, D = 2551 lb 21. When a load is applied to a member normal to its axis and the member is held fixed at another section, at any section between the load and reaction the particles on one side of the section tend to move in a transverse direction with respect to the other side; that is, they tend to slide by each other. This set up internal stresses in the member called: a. Shear stress c. Torsional stress b. Bending stress d. Tensile stress 22. A beam is loaded as shown in Fig. B (see page 6). What is the angle of inclination of the resultant reaction at A below the horizontal reference line? a. 18 degrees c. 8.0 degrees b. 80 degrees d. 81.2 degrees 23. During climb, the airplane accelerates at 48 ft/s2. If the weight of the airplane is 3,800 lb, what is the load factor? a. 1.27 c. 1.5 b. 2.44 d. 2.5 24. If the rivet shown in Fig. C (see page 6) has a shank diameter of 2.50 mm, what is the average stress in a section of the rivet between the two pieces of sheet at the given load? a. 153 Pa c. 15.3 MPa b. 153 KPa d. 153 MPa 25. A propeller shaft, 4 ft long and 1.5 inches diameter is subjected to a torque of 390 ft-lb. What is the deflection angle if the modulus of rigidity is 11x106 lb/in2? a. 0.47 degrees c. 14.7 degrees b. 1.47 degrees d. 4.7 degrees 26. If the skin of the wing torque box is constant at 1/16 inch and is subjected to torsional load of 2,000 ftlb, what is the shear stress? Refer to Fig. D (see page 6) a. 1,455 psi c. 174.5 psi b. 17,455 psi d. 14,550 psi 27. A design airplane intended to be certified as a commuter category under FAR part 23 has the following specifications: design gross weight is 3,100 lb, wing span is 34 ft, MAC is 4.75 ft, and maximum lift coefficient is 1.35 with flaps retracted. What is the required minimum cruise speed? a. 244 ft/s c. 144.6 ft/s b. 166.5 ft/s d. 157.7 knots 28. A design airplane intended to be certified as a commuter category under FAR part 23 has the following specifications: design gross weight is 3,100 lb, wing span is 34 ft, MAC is 4.75 ft, and maximum lift coefficient is 1.35 with flaps retracted. What is the required positive limit maneuvering load factor? a. 3.8 c. 2.1 b. 3.93 d. 4.4 29. For purpose of constructing the flight envelope of a design airplane under FAR part 23, the derived gust velocity for Vc gust line at 35, 000 ft is: a. 35.17 ft/s c. 37.15 ft/s b. 37.15 mph d. 37.15 knots 30. The swept back wing design is primarily intended to increase the critical Mach number of a supersonic aircraft but also useful in: a. Reducing induced drag c. Improving L/D ratio b. Increasing directional stability d. Reduce parasite drag 31. Where is the buttock line or buttline of an aircraft? a. a width measurement left or right of, and c. parallel to, the vertical centerline b. a width measurement left of, and d. perpendicular to, the vertical centerline 32. Where is fuselage station No. 137 located? a. 137 centimeters aft of the nose or fixed reference line b. aft of engine c. d. a height measurement left or right of, perpendicular to the horizontal centerline none of the choices 137 inches aft of the zero or fixed reference line 137 inches aft of the engine firewall 33. Which statement is true regarding a cantilever wing? a. No external bracing is needed. c. It requires only one lift strut on each side. b. It has nonadjustable lift struts. d. all of the choices 34. Buffeting is the intermittent application of forces to a part of an airplane. It is caused by_______. a. incorrect rigging of flaps c. an unsteady flow from turbulence b. incorrect rigging of ailerons d. all of the choices 35. Longitudinal (fore and aft) structural members of a semi-monocoque fuselage are called___. a. spars and ribs c. longerons and stringers b. spars and stringers d. bulkhead and formers 36. What of type loads causes the most rivet failures? a. bearing c. b. shearing d. head strain 37. What physical factors are involved in the aspect ratio of airplane wings? a. thickness and chord c. span and chord b. dihedral angle and angle of attack d. area and thickness 38. An airplane’s center of lift is usually located aft of its center of gravity ___________. a. so that the airplane will have a tail-heavy c. so that the airplane will have a nose-heavy tendency tendency b. to improve stability about the longitudinal d. to induce poor static stability axis 39. A well-designed rivet joint will subject the rivets to______. a. compressive loads c. shear loads b. tension loads d. bearing loads 40. What one major consideration in selecting an airfoil to be used for the tailplane design of an aircraft? a. lift curve slope c. maximum lift coefficient b. zero-lift angle of attack d. minimum drag coefficient