2021 Army SIFT test question n answers graded A+ updated to pass
2021 Army SIFT testThe four aerodynamics forces. - correct answer Thrust, Drag, Weight and Lift Thrust - correct answer The forward force produced by the power plant/propeller or rotor. It opposes or overcomes the force of drag. As a general rule, it acts parallel to the longitudinal axis. Drag - correct answer A rearward, retarding force caused by disruption of airflow by the wing rotor, fuselage, and other protruding objects. Drag opposes thrust and acts rearward parallel to the relative wind. Weight - correct answer The combined load of the aircraft itself, the crew, the fuel, and the cargo. Weight pulls the aircraft downward because of the force of gravity. It opposes lift and acts vertically downward through the aircraft center of gravity (CG). Lift - correct answer Opposes the downward force of weight, is produced by the dynamic effect of the air acting on the airfoil, perpendicular to the flight path through the center of lift. The lift generated by an airfoil depends on what factors? - correct answer -Speed of airflow -Density of the air -Total area of the segment or airfoil -Angle of attack Types of Drag - correct answer -Profile Drag -Induced Drag -Parasite Drag -Total Drag Profile Drag - correct answer The frictional resistance of blades passing through the air. What is profile Drag composed of? - correct answer -Form drag- size/shape of blade -Skin friction- surface roughness Induced Drag - correct answer Generated by the airflow circulation around the wing as it creates lift. The major cause of Drag at lower airspeeds? - correct answer Induced drag Parasite Drag - correct answer Drag from components that don't create lift. What type of drag increases with airspeed? - correct answer Parasite Drag If you double your airspeed. How much would your parasite drag increase? - correct answer Four times! Parasite drag varies with the square of the velocity. Collective pitch control - correct answer Makes changes to the pitch angle of the main rotor blades simultaneously. What happens as the pitch control is raised or lowered? - correct answer There is a simultaneous and equal change of pitch in the main rotor blades. Throttle Control - correct answer The function of the throttle is to regulate engine rpm. The Governor - correct answer Is a sensing device that senses rotor and engine rpm and makes the necessary adjustments in order to keep rotor rpm constant. The correlator - correct answer is a mechanical connection between the collective lever and the engine throttle. Cyclic pitch control - correct answer The purpose of the cyclic is to tilt the tip-path plane in the direction of the desired horizontal direction. What does the cyclic control? - correct answer The rotor disk tilt versus the horizon, which directs the rotor disk thrust to enable the pilot to control the direction of travel. Antitorque pedals - correct answer Control the pitch and therefore the thrust of the tail rotor blades. Tail Rotor heading control - correct answer is used to control the heading of the helicopter while hovering or when making hovering turnings.
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