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31 Cards in this Set
- Front
- Back
payload
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term for passengers, luggage, and cargo
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torque
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tendency of the helicopter to turn in the direction opposite the main rotor direction
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flap
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upward or downward movement of the helicopter blade
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feather
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rotation of the blade around the spanwise action (pitch change)
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lead or lag
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fore or aft movement of the blade
aka: hunting or dragging |
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fenestron
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"fan-in-tail" antitorque system
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NOTAR
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air intake anti-torque system
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airfoil
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any surface which provides aerodynamic force when it interacts with a moving stream of air
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chord line
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imaginary straight line drawn from the leading edge to the trailing edge
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relative wind
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wind moving past the airfoil
direction always parallel, equal , and opposite to flight path of the airfoil |
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angle of attack
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angle between blade chord line and direction of relative wind
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pitch angle
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angle between chord line and plane containing rotor hub
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axis-or-rotation
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the imaginary line about which the rotor rotates. It is represented by a line drawn through the center of, and perpendicular to, the tip-path plane.
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tip-path-plane
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The imaginary circular plane outlined by the rotor blade tips as they make a cycle of rotation.
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aircraft pitch
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movement about helicopter's lateral (side-to-side axis), tipping helicopter forward or aft
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aircraft roll
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movement about helicopter's longitudinal axis (forward/aft axis), tipping helicopter to either side
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angle of attack
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angle between chord line and relative wind
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pitch angle
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angle between chord line and ref. plane containing rotor hub
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magnus effect
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pressure differential created by circulation around an object (e.g. a rotating cylinder)
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bernoulli's principle
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pressure differential on the air foil due to constriction of space (in a constricted tube)
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steady-state-flight
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when an aircraft is in straight-level, unaccelerated flight and all forces are in balance
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disc loading
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ratio of weight to the total main rotor disc area
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rotor disc area
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area swept by the blades of a rotor
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solidity ratio
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ratio of the total rotor blade area to the rotor disc area
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rotor blade area
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combined area of all the main rotor blades
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aircraft yaw
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movement of the helicopter about its vertical axis
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drag
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force that resists the movement of a helicopter through the air
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profile drag
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drag from the frictional resistance of the blades passing through the air
-does not change much w/ change of angle of attack -increases moderately with airspeed |
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induced drag
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drag from the airflow circulation around the rotor blade as it creates lift
-high pressure air and low pressure air meet, creating vortices at the blade tips, creating a downwash. This inclines total lift aft. -high with high angle of attack (thus, high at low airspeeds) |
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parasite drag
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drag created by friction of nonlifting components of the aircraft
-major cause of drag at higher airspeeds -varies with the square of the velocity |
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total drag
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sum of profile, induced, and parasite drag
-L/Dmax refers to the point where the lift-to-drag ratio is greatest |