3-40. When an aircraft in flight increases its angle of attack,    which    of    the    following    actions    is accomplished? 1. The aircraft pivots on its longitudinal axis 2. The aircraft pivots on its lateral axis 3. The aircraft will turn to the right 4. The aircraft will turn to the left 3-41. When an aircraft in flight encounters a strong gusty, quartering wind on its nose, it tends to drift off course.  On what axis does the aircraft pivot when this action occurs? 1. The pitch axis 2. The yaw axis 3. The lateral axis 4. The longitudinal axis 3-42. The     main     difference     between     fixed-wing aircraft and rotary-wing aircraft is the way in which lift is achieved. 1. True 2. False 3-43. A  helicopter  uses  two  or  more  engine-driven rotors for lift and propulsion. 1. True 2. False 3-44. What is a symmetrical airfoil? 1. An airfoil that has a greater camber on the upper surface than on the lower surface 2. An  airfoil  that  has  less  camber  on  the upper surface than on the lower surface 3. An  airfoil  that  has  a  variable  center  of pressure 4. An   airfoil   that   has   a   fixed   center   of pressure 3-45. On an unsymmetrical airfoil, in what direction does  the  center  of  pressure  move  when  the angle of attack changes? 1. Forward only 2. Rearward only 3. Fore and aft 4. Inboard and outboard 3-46. What does a shifting center of pressure do to a rotor blade? 1. It causes it to move fore and aft un- con- trollably 2. It causes it to move up and down un- con- trollably 3. It causes the pitch of the blades to stabi- lize 4. It causes increased lift capabilities 3-47. By what means is lift controlled in a helicop- ter? 1. By increasing and decreasing the engine speed 2. By  increasing  and  decreasing  the  rotor speed 3. By increasing the pitch or angle of attack of the rotor blades 3-48. What  term  is  used  when  a  helicopters  main rotor is turning and no lift is being produced by the rotor blades? 1. Angle of attack 2. Ground idle 3. Zero thrust 4. Flat pitch 3-49. Directional control of a helicopter is achieved by what means? 1. By  tilting  the  helicopter  in  the  desired direction 2. By  tilting  the  main  rotor  in  the  desired direction 3. By  increasing  the  pitch  of  the  tail  rotor blades 4. By  decreasing  the  pitch  of  the  tail  rotor blades 3-50. By what means is hovering achieved in a hel- icopter? 1. By equalizing lift and drag only 2. By equalizing lift and thrust only 3. By equalizing thrust and weight only 4. By equalizing lift, drag, thrust, and weight 3-51. As the helicopter's rotor turns in one direction, the body of the helicopter tends to rotate in the opposite   direction. What   law   or   principle explains this action? 1. Newton's third law 2. Newton's second law 3. Newton's principle 4. Bernoulli's principle 3-12