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36 Cards in this Set
- Front
- Back
When did the Wright brothers make their first flight? What were their names? What was the name of the aircraft?
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December 17, 1903. Orville and Wilbur.
Wright Flyer 1. |
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How much does 1 foot of cubic air weight?
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38g
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Illustrate the flow of air around an airfoil.
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.
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According to ____ Principles, an ___ in the speed of fluid occurs simultaneously with a ____ in pressure. Approx _/_ of the lift force generated is due to a pressure ____ ontop, and _/_ from a pressure ____ below.
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Bernoulli's, increase, decrease. 2/3, decrease, 1/3, increase.
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Lift force can be increased by _____, or _____.
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Making the air flow faster, increasing the angle of attack.
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Illustrate the angle of attack.
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.
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Explain lift.
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The phenomenon generated by an airfoil due to pressure differences above and below the airfoil surface.
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What is the angle of attack?
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The angle between the chord line of the airfoil and the relative airflow.
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What is the chord line?
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A straight line from the leading edge to the trailing edge of an airfoil.
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The center of pressure can be seen as a single point acting on the ____ ____ line at a ____ ____ to the _____ airflow, through which the airfoils ____ force is produced.
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chord line, right angle, relative, lifting.
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The position of the center of pressure is not ____, it depends on ____ ____ along the ____, which in turn depends on the ____ ____ ____. The ____ the ____ ____ ____, the further ____ the center of pressure is.
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fixed, pressure distribution, chord, angle of attack. Higher, angle of attack, forward.
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Illustrate the pressure distribution envelope around and airfoil.
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.
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Illustrate an airfoil, including the leading and trailing edges, chord length, chord, upper and lower cambers, angle of attack and relative wind.
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.
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What are the three types of drag?
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Profile drag (including form drag and skin friction) and induced drag.
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Explain form drag and illustrate.
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Caused by a body as it disturbs the air through which it passes.
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The overall shape of a streamlined body is called the ____ ____. This means the ____ of the body to its ____. A ratio of around ___ gives the least resistance.
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fineness ratio. length, width. 4:1
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The drag that is incurred as the air passes over and under the surface of the airfoils body is called ____ ____.
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skin friction
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____ drag is caused by the change in direction of the airflow. The ____ pressure under the wing flows to the ____ pressure above the wing, causing ____ at the wingtips. Another name for these is ____ ____.
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Induced. High, low, vorticies. Wake turbulence.
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Aspect ratio is the ratio of the ____ to the ____, i.e the ____ by the ____.
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span, chord, length, width.
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High aspect ratio = ____ lift.
Low aspect ratio = ____ lift. |
High (i.e gliders)
Lower (but capable of higher speeds) |
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What is a stall.
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A loss of lift due to the airflow over a wings upper surface breaking away when the wing exceeds the critical angle.
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What is the critical angle?
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Around 15'.
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The stalling angle is the ____ ____ ____ at which the ____ ____ ____ of an airfoil is at a maximum, and beyond which it begins to ____ owing to the airflow becoming ____ instead of ____.
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angle of attack, coefficient of lift, decrease, separated, streamlined.
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What are the four forces acting on a aircraft in flight?
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Lift, weight, drag, thrust.
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Illustrate the four forces acting on an aircraft in flight.
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.
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During ____ ____ ____ flight, all of the forces are in balance.
Lift = ____ , Thrust = ____ |
straight and level, weight, drag.
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Name the three primary control systems on an aircraft.
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Elevator, ailerons and rudder.
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The elevator controls the ____ of an aircraft. Forward movement of the control column moves the elevator ____, ____ the lift on that surface therefore pitching the nose ____.
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pitch, down, increasing, down.
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The ailerons control the ____ of an aircraft. They are positioned on the ____ ____ ____ of the mainplanes. When the left hand goes down the ____ aileron goes down, creating more lift on the ____ wing (and vice versa for the left wing) therefore rolling the aircraft to the ____.
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roll, outboard trailing edge, right, right, left
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The rudder controls the ____ of an aircraft. It is hinged to the rear of the ____ ____. When left rudder input is made, the rudder moves to the ____, creating a sideways lift and sending the tail to the ____, yawing the aircraft to the ____.
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yaw, vertical stabiliser, left, right, left.
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Flats and slats are examples of what?
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High lift devices.
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High lift devices reduce ____, ____ and ____ speeds. This ____ takeoff and landing distances.
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stall, takeoff, landing, reduces.
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Write the lift formula, and name each component.
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1/2p V S C
1/2p= half the value of air density V = airflow velocity squared S= wing span area C = coefficient of lift |
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What is the coefficient of lift?
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The lifting ability of a wing.
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The coefficient of lift depends on two things. What are they?
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The shape of the wing section, and the angle of attack.
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Flaps work by extending ____, therefore increasing the ____ ____ ( _ ), and increasing the ____ of the overall wing section (increasing the ____ value).
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chordwise, wing area, S, camber, C
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