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Questions and Answers

What happens to the altimeter reading when flying from an area of high pressure to low pressure without adjustment?

  • The altimeter will show a steady altitude.
  • The altimeter will under-read the true altitude.
  • The altimeter will read accurately.
  • The altimeter will over-read the true altitude. (correct)

What is the primary force that opposes the forward motion of an aircraft?

  • Lift
  • Weight
  • Drag (correct)
  • Thrust

How does a high aspect ratio wing design primarily affect aircraft performance?

  • It decreases induced drag. (correct)
  • It reduces lift efficiency.
  • It leads to a larger center of gravity.
  • It increases drag significantly.

What is the critical angle of attack in terms of stall conditions?

<p>The angle at which the boundary layer separates from the wing. (D)</p> Signup and view all the answers

Which principle explains the generation of lift due to pressure differences over a wing?

<p>Bernoulli's Principle (C)</p> Signup and view all the answers

How does parasite drag primarily change as an aircraft's speed increases?

<p>It increases with speed. (D)</p> Signup and view all the answers

What is the result of turning the pressure knob of an altimeter to the left?

<p>It will lower the altimeter reading. (B)</p> Signup and view all the answers

Which of the following describes the relationship between lift and angle of attack?

<p>Lift increases with angle of attack until the critical angle is reached. (C)</p> Signup and view all the answers

Which factor does NOT affect the amount of lift generated by an aircraft?

<p>Engine size (C)</p> Signup and view all the answers

What effect does a higher aspect ratio of a wing have on drag?

<p>It reduces induced drag. (D)</p> Signup and view all the answers

What occurs when weight is positioned ahead of lift in an aircraft?

<p>The aircraft pitches down. (B)</p> Signup and view all the answers

Which type of drag is primarily a result of lift-generating components like wings?

<p>Induced drag (B)</p> Signup and view all the answers

Which wing design feature affects lift and stall characteristics based on its appearance from above?

<p>Planform (B)</p> Signup and view all the answers

What does the angle of incidence optimize for in an airplane?

<p>Efficient cruising (C)</p> Signup and view all the answers

Which axis is controlled by the elevators in an airplane?

<p>Lateral Axis (A)</p> Signup and view all the answers

What is defined as the aircraft's ability to return to steady flight after being disturbed?

<p>Dynamic Stability (B)</p> Signup and view all the answers

Which effect causes a left-turning tendency in an aircraft?

<p>Torque (B)</p> Signup and view all the answers

What component must be increased to maintain altitude during a turn?

<p>Vertical lift component (A)</p> Signup and view all the answers

What characterizes a spiral dive?

<p>Rapid descent with increasing airspeed (A)</p> Signup and view all the answers

What is the first step in recovering from a spiral dive?

<p>Close the throttle (A)</p> Signup and view all the answers

How does the airspeed in a spiral dive compare with that in a spin?

<p>Air speed continuously increases in a spiral dive (C)</p> Signup and view all the answers

What happens to the stall speed of an aircraft as its weight increases?

<p>Stall speed increases (C)</p> Signup and view all the answers

Which of the following factors decreases stall speed?

<p>Proper flap extension (A)</p> Signup and view all the answers

What is the primary action to initiate recovery from a spin?

<p>Neutralize the ailerons (C)</p> Signup and view all the answers

What does V_NO represent in airspeed limitations?

<p>Maximum safe speed for normal operations (A)</p> Signup and view all the answers

Which step is essential for stall recovery?

<p>Reduce engine power to idle (A)</p> Signup and view all the answers

During which phase is a spin characterized by predictable rates of rotation?

<p>Developed spin (A)</p> Signup and view all the answers

How does surface contamination, such as frost or ice, affect stall speed?

<p>Increases the stall speed (D)</p> Signup and view all the answers

What is the purpose of V_FE in airspeed limitations?

<p>Marks maximum speed with flaps extended (B)</p> Signup and view all the answers

What happens to the airspeed indicator if the PITOT system is blocked during a climb?

<p>Over reads (A)</p> Signup and view all the answers

Which instrument is affected by a blocked STATIC system by freezing at its current reading?

<p>Altimeter (A)</p> Signup and view all the answers

What kind of power source can gyroscopic instruments operate on?

<p>Positive air pressure pump (A)</p> Signup and view all the answers

What principle allows a gyroscopic instrument to maintain its position despite gimbal movement?

<p>Inertia (rigidity in space) (A)</p> Signup and view all the answers

How does a sudden acceleration affect the attitude indicator?

<p>Shows a pitch up (C)</p> Signup and view all the answers

Which gyroscopic instrument shows the relationship between the wings and nose of the airplane with the horizon?

<p>Attitude Indicator (C)</p> Signup and view all the answers

What happens to the Vertical Speed Indicator if the STATIC system is blocked?

<p>Stays at 0 (B)</p> Signup and view all the answers

Which property of gyroscopic instruments refers to the reaction of a force applied to a spinning gyroscope?

<p>Precession (B)</p> Signup and view all the answers

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Study Notes

Forces Acting on an Aircraft

  • Thrust: Force propelling aircraft forward, generated by engines and propellers
  • Drag: Opposes forward motion, categorized as:
    • Induced Drag: Generated by lift-producing components (wings)
    • Parasite Drag: Non-lift-related drag, including form drag and skin friction
  • Lift: Upward force opposing weight, generated by wings through air pressure differences
  • Weight: Downward force due to gravity, pulling the aircraft towards Earth

Lift

  • Bernoulli's Principle: Faster airflow over the wing's curved surface creates lower pressure above, lifting the aircraft
  • Newton's Third Law: Deflecting airflow downwards results in an upward lift force
  • Factors Affecting Lift: Air density, velocity, wing surface area, and angle of attack. Higher velocity and larger wings increase lift

Drag

  • Induced Drag: Caused by wingtip vortices, prevalent at slow speeds and high angles of attack
  • Parasite Drag: Increases with speed, consisting of form drag (caused by shape), skin friction, and interference drag
  • Ground Effect: Reduced drag near the ground as wingtip vortices are restricted

Thrust

  • Generated by propellers or jet engines, overcomes drag
  • Adjusting thrust controls airspeed

Weight

  • Acts through the center of gravity, balancing lift
  • Improper distribution affects flight stability and performance

Couples

  • Formed when forces like weight, lift, drag, and thrust act at parallel but separate points, creating turning moments
  • Weight ahead of lift causes nose pitch down
  • Drag above thrust causes nose pitch up

Wing Design

  • Airfoil Camber: Affects lift, deeper camber providing higher lift but more drag
  • Planform: Shape of the wing from above, affecting lift and stall characteristics (rectangular, tapered, elliptical, delta)
  • Aspect Ratio: Ratio of wingspan to chord length influencing induced drag. Higher aspect ratios reduce drag
  • Angle of Incidence: Fixed angle between wing chord line and airplane's longitudinal axis, optimized for efficient cruising

Axes of the Airplane

  • Longitudinal Axis (Roll): Controlled by ailerons, affecting banking and rolling movements. Lateral stability
  • Lateral Axis (Pitch): Controlled by elevators, affecting nose-up or nose-down movements. Longitudinal stability
  • Vertical Axis (Yaw): Controlled by the rudder, affecting left or right yaw movements. Directional stability

Stability

  • Affected by weight distribution, wing design, and control surface location
  • Dynamic Stability: Aircraft's ability to return to steady flight after disturbance. Poor balance between forces leads to instability

Propeller Effects

  • Torque: Propeller rotation causes a left-turning tendency countered by the rudder
  • P-Factor: Asymmetric thrust at high angles of attack causes yawing
  • Slipstream: Spiraling air from the propeller striking the tail causing yaw. Corrected with trim tabs or rudder

Climbing and Gliding

  • Climbing: Achieved by increasing angle of attack and applying power. Steady rate of climb establishes equilibrium.
  • Gliding: Controlled descent without engine power, using angle of descent and balance of lift, drag, and weight. Best glide speed maximizes range.

Turns

  • Lift is divided into vertical and horizontal components
  • The horizontal component acts as centripetal force, turning the airplane
  • The vertical component must be increased by pulling back on controls to maintain altitude

Spiral Dives

  • Steep, descending turn with excessive nose-down attitude
  • Rapidly increasing airspeed and rate of descent
  • Characteristics: Excessive angle of bank, rapidly increasing airspeed, rapid descent
  • Differences from Spins: Airspeed continuously increases in spiral dive, remains low and constant in a spin
  • Dangers: Risk of structural damage, high load factors during recovery
  • Recovery: Close throttle, level wings, ease out of dive, resume straight and level flight

Airspeed Limitations

  • V_S (Stall Speed): Minimum speed for maintaining steady flight
  • V_A (Maneuvering Speed): Maximum speed for safe abrupt control deflection or operation in turbulence. Decreases with reduced weight
  • V_FE (Flaps Extended Speed): Maximum speed permissible with flaps extended
  • V_NO (Maximum Structural Cruising Speed): Maximum safe speed for normal operations, designed for structural integrity in turbulent air
  • V_NE (Never Exceed Speed): Maximum speed for safe operation in smooth air, preventing structural failure

Stalls

  • Factors Affecting Stalls: Weight, center of gravity, turbulence, turns, flaps, surface contamination (frost or ice)
  • Stall Recovery: Lower nose, increase airspeed, return to stable flight conditions

Spins

  • Aircraft enters autorotation after stalling, characterized by simultaneous yaw, roll, and pitch around a spin axis
  • Stages of a Spin: Incipient Spin (stall to establishing spin), Developed Spin (stabilized with predictable rates), Recovery (breaking the spin)
  • Recovery Procedure: Idle power, neutralize ailerons, apply full rudder opposite spin, push control column forward, neutralize rudder and level wings once rotation stops

Pitot-Static Instruments

  • Airspeed Indicator: Uses pitot and static sources
  • Altimeter: Uses only static source
  • Vertical Speed Indicator: Uses only static source
  • Pitot Tube: Has three openings
    • Pitot source: Measures total pressure
    • Static source: Measures static pressure
    • Third opening: Equalizes pressures during pre-flight checks
  • If Pitot System is Blocked:
    • Airspeed Indicator: Over-reads in climb, under-reads in descent
    • Altimeter: No effect
    • Vertical Speed Indicator: No effect
  • If Static System is Blocked:
    • Airspeed Indicator: Under-reads in climb, over-reads in descent
    • Altimeter: Freezes at current reading
    • Vertical Speed Indicator: Stays at 0

Gyroscopic Instruments

  • Rotor rotating at high speed in a universal mounting (gimbal)
  • Types: Attitude Indicator, Heading Indicator/Directional Gyro, Turn Coordinator
  • Powered by: Vacuum, positive air pressure pump, or battery (electrical source)
  • Principles:
    • Rigidity in Space (Gyroscopic Inertia): Tendency of rotating object to remain in its plane of rotation
    • Gyroscopic Precession: Force applied to a spinning gyroscope causes reaction 90 degrees away in the direction of rotation

Attitude Indicator

  • Also Known As: Artificial Horizon
  • Function: Provides artificial horizon reference when natural horizon is obscured
  • Gyroscopic Property: Inertia (rigidity in space)
  • Power Source: Usually vacuum, some electrically driven
  • Shows: Degrees of pitch (nose up/nose down) and wing bank angle

Attitude Indicator Limitations

  • Requires at least 4" of suction for operational speed
  • Acceleration Error: Sudden acceleration causes "pitch up," deceleration causes "pitch down"

Heading Indicator

  • Mounted vertically, spins about its horizontal axis
  • Errors: Subject to precession errors, causing drift
  • Corrections: Gyro needs regular resetting using magnetic compass

Turn Coordinator

  • Combination of a turn indicator and a slip/skid indicator

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