Aerodynamics Flashcards

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1
Q

What are the 4 Forces of Flight?

A
  • Lift
  • Weight
  • Thrust
  • Drag
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2
Q

How is Lift generated?

A
  • It is generated by the wings
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3
Q

What are the Theories of Lift?

A
  • Pressure Difference
  • Newton’s Third Law
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4
Q

What is Pressure Difference?

A
  • The upper surface of the wing is curved while the lower surface is relatively flat. The air flowing over the top camber increases in speed, decreasing pressure. The air flowing beneath the wing slows down, increasing pressure. The high pressure wants to move to the area of low pressure which pushes up on the wing
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5
Q

How does Newton’s Third Law apply to the wings generating lift?

A
  • The wing’s downward push results in an equal and opposite push back upward
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6
Q

What is Bernoulli’s Principle?

A
  • As the speed of a fluid increases, its pressure will decrease and vice versa
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7
Q

How is Thrust generated?

A
  • It is generated by the propeller
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8
Q

How does the Propeller generate thrust?

A
  • The propeller is a rotating airfoil so it essentially produces thrust the same way wings produce lift
  • The propeller is twisted so it can produce equal thrust from the hub to the tip
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9
Q

How is Weight generated?

A
  • It is generated by gravity
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10
Q

How is Drag generated?

A
  • It is generated by the aircraft moving through air
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11
Q

What are the Types of Drag?

A
  • Parasite Drag
  • Induced Drag
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12
Q

What is Parasite Drag?

A
  • It is drag caused by the aircraft’s structure and material as it moves through air
  • It consists of skin friction, form, and interference drag
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13
Q

What is Skin Friction drag?

A
  • It is caused by the aerodynamic resistance due to the contact of moving air on the surface of the aircraft
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14
Q

What is Form drag?

A
  • It is the result of the aerodynamic resistance to the shape of the aircraft
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15
Q

What is Interference drag?

A
  • It is the drag that is generated by the mixing of airflow streamlines between airframe components
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16
Q

What is Induced Drag?

A
  • It is caused by generating lift
  • As the high and low pressure air flow off the wingtip, they try to mix resulting in wingtip vorticies. These vorticies create a downwash behind the trailing edge of the wing. This downwash is as if someone is pulling on the back of the aircraft
  • It becomes larger as AOA or lift increases
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17
Q

What are Wingtip Vorticies?

A
  • The rotary motion of air as it flows off the ends of the wingtips
  • The high pressure air from the bottom of the wing escapes moving upward and towards the lower pressure area. The two different air masses try to mix, resulting in a rotary motion
  • It increases as lift or AOA increases
18
Q

What is Wake Turbulence?

A
  • The distrubed air that forms behind an aircraft as it flys through the air
  • It consists of wingtip vorticies and jet wash
  • It slowly falls and widens
19
Q

Wake Turbulence Avoidance

A

Takeoff

  • Rotate prior to the point at which the larger aircraft rotated and then turn out to the left/right of their path
  • You can also wait 3 minutes

Landing

  • Land after the point where the larger aircraft landed
20
Q

What is Ground Effect?

A
  • When an aircraft is close to Earth’s surface, its downwash is reduced. This means there is less induced drag and more lift
  • It causes an aircraft to float while landing and a plane to prematurley takeoff
21
Q

What is a Stall?

A
  • The sudden reduction in lift when the critical AOA is exceeded
  • When an airplane exceeds its critical AOA, too much airflow separates from the wing causing it to not generate enough lift
  • Planes can stall at any airspeed; it just depends on the AOA
22
Q

Stall Recovery

A
  1. Pitch nose-down to decrease the angle of attack
  2. Reduce the bank by leveling the wings
  3. Add power as needed
  4. Return to the desired flight path
23
Q

What is the Angle of Attack (AOA)?

A
  • The angle between the chord line and relative wind
24
Q

What is the Chord Line?

A
  • The imaginery line connecting the leading and trailing edge of the wing
25
Q

What is Relative Wind?

A
  • The direction of the wind in relation to the wing
26
Q

What is a Spin?

A
  • An aggravated stall which results in rotation about the longitudal axis
  • One wing is more stalled than the other causing it to rotate
27
Q

Spin Recovery

A

PARE

  • Power Idle
  • Ailerons Neutral
  • Rudder Opposite
  • Elevator Down
28
Q

What are the Turning Dynamics?

A
  • The aileron on the side you are turning to goes up reducing lift while the other aileron goes down increasing lift. Newton’s Third Law also applies when the alierons go up and down
  • You have to add backpressure in a turn due to some vertical compenent of lift being turned into horizontal compenent of lift
29
Q

What is a Slip?

A
  • A maneuver performed to lose altitude quickly without gaining too much speed
30
Q

How do you perform a Slip?

A
  • Bank into the wind while simultaneously yawing the nose in the opposite direction
31
Q

What is a Skid?

A
  • When the tail of the airplane moves away from the center of a turn
32
Q

What is a Dihedral?

A
  • The upward angle of the wings
33
Q

Why is a Dihedral good?

A
  • It makes the plane more stable
  • It causes the plane to return to a neutral position
34
Q

What are the Left Turning Tendencies?

A
  • Torque
  • P-Factor
  • Spiraling Slipstream
35
Q

Explain what Torque is

A
  • It is caused by Newton’s Third Law
  • The crankshaft turns to the right resulting in an equal force to be exerted to the left
36
Q

Explain what P-Factor is

A
  • It is caused by the downward turning propeller creating more thrust resulting in the plane yawing to the left
  • The downward turning propeller takes a “bigger bite of air” because it has a greater AOA, resulting in it creating more thrust
37
Q

Explain what the Spiraling Slipstream is

A
  • The air flowing around the fuselage hits the vertical stabilizer on the left side causing the plane to yaw to the left
38
Q

What is the Right Turning Tendency?

A
  • Gyroscopic Precession
39
Q

Explain what Gyroscopic Precession is

A
  • The result of applying a force to a gyroscope (in this the spinning propeller) and having that force act 90 degrees later in the direction of rotation
  • When your pulling back on the yoke during takeoff roll, there is a force being applied to the propeller when its at the 6 o’clock position. This causes a force to act on the propeller at the 9 o’clock position, resulting in the plane yawing to the right
40
Q

What is Load Factor?

A
  • The ratio of lift an aircraft produces to its weight
  • It basically measures how much stress or how much work the wings have to do in order to keep the plane in the air
41
Q

How is Load Factor increased?

A
  • Maneuvering such as turns, climbs, or descents
  • Weight increase
  • Speed increase
  • Turbulence
42
Q

What is the VG Diagram?

A
  • It describes the realtionship between airspeed and load factor
  • We get our V-speeds from it