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14 Cards in this Set
- Front
- Back
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State Newton's First law
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A body at rest will remain at rest unless an outside force acts on it, and a body in motion at a constant velocity will remain in motion in a straight line unless acted upon by an outside force.
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State Newton's Second law
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If a force acts on a body, that body will experience acceleration in the direction of the force.
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State Newton's Third law
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For every action there is an equal and opposite reaction.
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Define Parasite Drag
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Parasite drag is caused by any aircraft surface which deflects or interferes with the smooth airflow around the airplane.
Parasite drag is normally divided into three types: form drag, interference drag, and skin friction drag. |
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Skin friction drag is...
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caused by the roughness of the airplane's surfaces. A thin layer of air clings to these rough surfaces and creates small eddies which contribute to drag.
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Interference drag is...
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occurs when varied currents of air over an airplane meet and interact. Placing two objects adjacent to one another may produce turbulence 50% to 200% greater than the parts tested separately.
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Form drag...
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results from the turbulent wake caused by the separation of airflow from the surface of a structure. The amount of drag is related to both the size and shape of the structure which protrudes into the relative wind.
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Induced drag is...
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generated by the airflow circulation around the wing as it creates lift.
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Total drag for an airplane is...
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the sum of parasite and induced drag.
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Name four left-turning tendencies
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1. Torque
2. P-factor (asymmetrical thrust) 3. Swirling slipstream from prop 4. Gyroscopic precession |
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Describe torque
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The clockwise action of a spinning propeller causes a torque reaction, which tends to rotate the airplane counterclockwise about it's longitudinal axis.
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Describe p-factor
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Asymmetrical thrust is caused by the higher angle of attack (greater "bite" of air) the descending blade (right side) takes compared to the ascending blade. Most pronounced at high power and angle of attack.
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Describe swirling slipstream
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As the propeller rotates, it produces a backward flow of air, or slipstream, which wraps around the airplane, striking the left side of the vertical fin and yawing the plane to the left.
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Describe gyroscopic precession
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Since the turning propeller is in effect a gyroscope, it exhibits rigidity in space and precession. As the tail is lifted, a force is applied to the top of the propeller arc. Since the reaction to a force applied to a gyro acts in the direction of rotation and approximately 90 degrees ahead of the point where the force is applied, the resultant force on the right side of the prop causes a yaw to the left.
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