Forces on Aircraft in Flight

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Forces on Aircraft in Flight Flight Controls

• With stability fundamentals

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Lesson Objectives

• Identify the major components of an airplane and
  their functions
• Know the four forces of flight and explain how
  they are related
• Understand fundamental stability terms

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Contents

• Airplane Components
• Four Forces of Flight
• Flight Dynamics and Controls
• Stability

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Aircraft Components

• Fuselage
• Wing
• Empennage
• Landing Gear
• Powerplant
• Flight Controls

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Four Forces of Flight

• Lift
• Weight
• Thrust
• Drag

Source NASA Glen Research Center
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Forces on an Airplane
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Lift

• Lift is an aerodynamic force
• Lift must exceed weight for flight
• Generated by motion of aircraft through air
• Created by the effects of airflow past wing
• Aircraft lift acts through a single point called
  the center of pressure.

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Weight

• Weight is not constant
• varies with passengers, cargo, fuel load
• decreases as fuel is consumed or payload
  off-loaded
• Direction is constant toward earths center
• May be assumed concentrated at the center of
  gravity

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Thrust

• Forward-acting force opposes drag
• Direction of thrust depends on design
• Propulsion systems produce thrust
• Equal to drag in straight, constant speed flight

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Drag

• An aerodynamic force
• Resists forward motion
• Two broad drag classifications
• Parasite drag drag created by airplane design
• Induced drag by-product of lift generation
• Acts through the center of pressure

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Flight Dynamics and Controls

• Axes of Flight
• Longitudinal
• Lateral
• Primary flight controls
• picture location and functions
• activity, controlled glider flight

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Stability

• Center of Gravity
• Center of Pressure
• Longitudinal Stability
• Lateral Stability
• Directional Stability

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Activities and Exercises

• Build gliders for flight control experiments
• Worksheets