Airframes, Aerodynamics, and Theory of Flight Flashcards

1
Q

Stresses - Compression

A

Crushing or squeezing parts together

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2
Q

Stresses - Tension

A

Stretching or pulling apart objects

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3
Q

Stresses - Shearing

A

Cutting or sliding an object apart

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4
Q

Stresses - Bending

A

Pulls one side of an object apart while squeezing the other side

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5
Q

Stresses - Torsion

A

Twisting Motion

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6
Q

Fuselage Type - Truss Type

A
  • Frame of wood beams or metal tubes (bolted or welded)
  • Frame carries load and fuselage stresses
  • Two types, Warren and “N” Girder
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7
Q

Fuselage Type - Monocoque

A
  • “Stressed Skin”
  • Skin carries some of the load
  • Perfect Stressed Skin: Skin carries ALL of the load
  • Formers maintain shape
  • Bulkheads carry load
  • Stringers run lengthwise and hold bulkheads together
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8
Q

Fuselage Type - Semi-Monocoque

A
  • Combination of stressed skin and formers or frame system
  • Includes a firewall, separates the engine compartment from the rest of the fuselage
  • Cessna 172
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9
Q

Chord

A

Straight line joining the leading and trailing edges of wing

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10
Q

Camber

A

Upper curvature of the wing

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11
Q

Span

A

Distance from wingtip to wingtip

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12
Q

Wing root

A
  • Inboard section of wing closest to fuselage
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13
Q

Load Factor

A

Actual load being imposed on the wings vs the weight of the aircraft

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14
Q

Spars

A

Run from wing root to tip and carry most of the load in flight

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15
Q

Ribs

A
  • Give shape to the wing and prevent twisting
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16
Q

False Ribs

A
  • Smaller ribs placed between leading edge and front spar
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17
Q

Compression Struts

A

Steel tubes placed between the spars to prevent compression/distortion of the wing

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18
Q

Drag/Anti-Drag Wire

A

Provide additional support to the wing

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19
Q

Wing Tip Bow

A

Curved metal tube giving the wingtip its shape

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20
Q

Semi-Cantilever Wing

A

Supported by external struts

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21
Q

Full Cantilever Wing

A

No external bracing

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22
Q

Stabilator

A

No fixed horizontal stabilizer

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23
Q

Canard

A

Horizontal stabilizer at front of aircraft

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24
Q

Control Systems

A

Ailerons - Torque Tube
Elevators - Push/Pull Rod
Rudder - Cable and Pulley

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25
Q

Nose Wheel Advantages

A
  • Greater visibility over the nose
  • Nose over tendencies eliminated
  • Greater maneuverability on ground
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26
Q

Tail Wheel Advantages

A
  • Less Drag
  • Cheaper and easier to build and maintain
  • Will sustain less prop damage
  • More suitable for ski operations
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27
Q

Brakes - What to look for

A
  • Hydraulic leak around main gear (red puddle)
  • Cracks in the pucks
  • Rusting over long periods due to lack of use
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28
Q

4 Forces

A
  • Lift acts 90º to wing span
  • Weight acts at C of G
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29
Q

Factors Affecting Lift

A
  • Angle of Attack
  • Velocity of the Airfoil
  • Density of the Air
  • Wing Area
  • Shape of the Aerofoil
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30
Q

Coefficient of Lift

A
  • Relative measure of aerofoil’s lifting capabilities
  • Varies with angle of attack and aerofoil type
  • Higher camber and flaps will yield greater CL
  • Increases up to critical angle of attack, the decreases rapidly (stall)
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31
Q

Total Drag

A

Induced Drag + Parasite Drag

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32
Q

Parasite Drag

A
  • Drag produced by any surface that doesn’t contribute to lift
  • Interference Drag (Joining of two or more parts)
  • Profile Drag (Form Drag + Skin Friction)
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33
Q

Form Drag

A
  • Drag created by shape of body
  • Reduce by streamlining
34
Q

Skin Friction

A

Drag created by tendency of air flowing over a surface to stick to it

35
Q

Wingtip Vortices

A

Greatest at low airspeeds, clean configuration, heavy

36
Q

Reducing Induced Drag

A
  • High Aspect Ratio (Ratio of span to average chord)
  • Winglets (Reduce airflow around wing tip)
  • Ground effect
37
Q

Conventional Airfoil

A
  • Different shapes and sizes
  • Maximum camber is about 25% chord from leading edge
38
Q

Laminar Airfoil

A
  • Maximum camber occurs at 50% chord
  • Maintains smooth laminar flow over greater percentage of chord
  • Used on higher speed aircraft
  • Stalls more violently at high angles of attack
39
Q

Planform

A

Shape of wing as seen from directly above

40
Q

Angle of Incidence

A

Angle at which the wing is permanently inclined to the longitudinal axis of the airplane

41
Q

Washout

A
  • Twist in the wing where the angle of incidence at the root is greater than at the tip
  • Improves stall characteristics by having wing root stall before wingtips
  • Enhances aileron control at low speeds
42
Q

Stall Strips

A
  • Strips attached to the leading edge of the wing near the root
  • Purpose is wing root area to stall first
  • Very similar to washout
43
Q

Wing Fences

A
  • Fin-like vertical surfaces attached to the upper surface of the wing to prevent spanwise airflow
  • Wing Fences improve slow-speed handling and stall characteristics
44
Q

Spoilers

A
  • Long narrow strips arranged spanwise along the top surface of an aerofoil
  • Purpose of spoilers is to increase drag and spoil lift
  • Can replace ailerons as a means of roll control
45
Q

Speed Brakes

A
  • Metal plates used on high speed aircraft to increase drag withou t decreasing lift
  • Located near trailing edge of airfoil
  • Used to slow the aircraft at high speed when unsafe to deploy flaps or landing gear
46
Q

Vortex Generators

A
  • Small vertical plates arranged across the upper surface of the wing
  • Purpose is to re-energize the boundary layer to reduce drag caused by turbulence airflow
47
Q

Slots

A
  • High lift device FIXED to the leading edge of an airfoil
  • Used to maintain stability and control at low speeds
48
Q

Slats

A
  • High lift device on the leading edge of an airfoil that is RETRACTABLE
  • Used to maintain stability and control at low speeds
49
Q

Flap Design - Split Flap

A

Creates a low pressure area between the wing and the extended flap to create more drag than the plain flap with lesser angles of deflection

50
Q

Flap Design - Fowler Flap

A

Combines camber change with an increase in wing area as well as the creation of a slot to obtain a smooth airflow

51
Q

Flap Design - Zap Flap

A

Increases wing area without creating the slot

52
Q

Flap Design - Double Slotted Flap

A

Combines camber changes and slots to obtain smoother airflow

53
Q

Servo Tab

A
  • Tab on trailing edge of control surface
  • Moves opposite to control surface
  • Eases amount of force required by pilot
54
Q

Anti-Servo Tab

A
  • Tab on trailing edge of control surface
  • Moves in same direction as control surface
  • Increases amount of force required by pilot
55
Q

Aileron Drag

A

In rolling the wings, down-going aileron increases the drag on that wing, causing adverse yaw

56
Q

Frise Ailerons

A

Up-going aileron projects into airflow, increasing form drag, balancing the induced drag on the down-going aileron

57
Q

Differential Ailerons

A

Up-going aileron moves through a greater angle than the down-going aileron, increasing form drag, balancing the induced drag on the down-going aileron

58
Q

Balanced Controls

A
  • Aerodynamic Balance (Extending part of control surface in opposing airflow to hold surface in position)
  • Mass Balance (Placing a mass ahead of the control surface hinge to prevent flutter at high speed)
59
Q

Static Stability

A

Initial Tendency to return

59
Q

Dynamic Stability

A

Overall tendency to return

59
Q

Longitudinal Stability

A
  • Stability about the lateral axis (or pitch stability)
  • Influenced by the horizontal stabilizer and C of G position
60
Q

Longitudinal Stability - Forward C of G

A
  • Positive Static Stability
  • More tail-down force required to balance weight ahead of the centre of pressure
  • Effective weight increases, stall speed increases, TAS decreases
61
Q

Longitudinal Stability - Less Forward C of G

A
  • Less Positive Static Stability
  • less tail-down force required to balance weight ahead of the centre of pressure
  • Effective weight decreases, TAS increases
62
Q

Longitudinal Stability - Aft C of G

A
  • Neutral Static Stability
  • No tail down force exerted
63
Q

Longitudinal Stability - Canard

A
  • Balancing force is ahead of the C of G
  • Horizontal stabilizer will always be a positive force
  • Less apparent weight, higher TAS
  • aerodynamically efficient, however engine gets disturbed airflow in rear of aircraft
  • Aft C of G more stable than forward C of G
64
Q

Factors Affecting Lateral Stability - Dihedral

A
  • Angle that a wing makes with the horizon
  • Sideslip is produced in a wingdrop
  • Lower wing meets relative airflow at greater angle of attack
  • Aircraft will tend to roll back to straight and level
65
Q

Factors Affecting Lateral Stability - Keel Effect

A

Occurs on high wing aircraft where the weight of the aircraft is primarily below the wing and acts as a pendulum to correct any lateral instability

66
Q

Factors Affecting Lateral Stability - Sweepback

A
  • Wing drops and creates a sideslip
  • Leading edge of the lower wing presents itself at an angle perpendicular to the relative airflow
  • Lower wing will create more lift, causing a roll back to straight and level
67
Q

Yaw Stability - Vertical Stabilizer

A
  • Creates a greater surface area aft of the C of G
  • Any disturbance from the desired direction is automatically corrected (weather vaning)
68
Q

Factors Affecting Lateral Stability - Sweepback

A

When aircraft is yawed, upwind wing has longer leading edge to the relative airflow, creating more drag on that wing, pulling the aircraft back straight

69
Q

Calculating stall speed in turn

A

= regular stalls speed * square root of load factor
- Load factor = 1/cos(bank)

70
Q

Adverse Yaw - Propeller Torque

A
  • Clockwise spinning propeller causes an opposite counter-clockwise rolling action on the airframe
  • Yaw to the left
71
Q

Adverse Yaw - Asymmetric Thrust/P-Factor

A
  • At high angles of attack, down-going propeller meets relative airflow at a greater angle of attack, producing more thrust on the right side of propeller
  • Yaw to the left
72
Q

Adverse Yaw - Gyroscopic Precession

A
  • Propeller acts as a gyro
  • Any force applied to spinning gyro acts as if that force had been applied from 90º in the direction of rotation
  • When aircraft pitches down, yaw to the left
  • Experienced by tail-wheel aircraft when tail wheel rises
73
Q

Adverse Yaw - Slipstream

A
  • Spiralling corkscrew of air strikes tail on left side
  • Causes nose to pivot to left when power setting is high
  • Reduction in power causes yaw to right
74
Q

Service Ceiling

A

Highest altitude at which an aircraft can maintain a 100 fpm climb

75
Q

Absolute Ceiling

A

Altitude at which an aircraft can no longer climb

76
Q

Center of Pressure

A
  • Point on wing where lift is assumed to act
  • Center of pressure shifts as the angle of attack changes
77
Q

Weight and the Stall

A
  • Higher the weight, higher the stall speed
  • Due to more downforce required, therefore increasing effective weight, needing more lift, higher angle of attack
78
Q

C of G and the Stall

A
  • Will stall at higher airspeed with forward C of G
  • Aft C of G has higher TAS
79
Q

Climbing Turns

A

Tendency to over-bank

80
Q

Descending Turns

A

Under banking Tendency