FUNDAMENTALS OF ROTOR AND POWER TRAIN MAINTENANCE-TECHNIQUES AND PROCEDURES FM 1-514 (English Edition) [Kindle-editie] beoordelingen het boek quotes

Basic flight theory and aerodynamics are consideredin full detail when an aircraft is designed. The rotorrepairer must understand these principles in order tomaintain aircraft safely and to make repairs that arestructurally sound and aerodynamically smooth.AERODYNAMICSAerodynamics deals with the motion of air and withthe forces acting on objects moving through air orremaining stationary in a current of air. The sameprinciples of aerodynamics apply to both rotary-wingand fixed-wing aircraft. Four forces that affect anaircraft at all times are weight, lift, thrust, and drag:Weight is the force exerted on an aircraft bygravity. The pull of gravity acts through theaircraft’s center of gravity, which is the pointat which an aircraft would balance ifsuspended. The magnitude of this forcechanges only with a change in aircraft weight.Lift is produced by air passing over the wingof an airplane or over the rotor blades of ahelicopter. Lift is the force that overcomesthe weight of an aircraft so that it can rise inthe air.Thrust is the force that moves an aircraftthrough the air. In a conventional fixed-wingaircraft, thrust provided by the propellermoves the plane forward while the wingssupply the lift. In a helicopter both thrust andlift are supplied by the main rotor blades.Drag is the force of resistance by the air to thepassage of an aircraft through it. Thrust forcesets an aircraft in motion and keeps it in motionagainst drag force.Any device designed to produce lift or thrust whenpassed through air is an airfoil. Airplane wings,propeller blades, and helicopter main and tail rotorblades are all airfoils.