The Physics of Flight

Warm-Up Questions CPS Questions 1-2 Chapter 1, Lesson 2

Lesson Overview How lift is generated How weight affects flight How thrust affects an aircraft’s movement How drag slows an aircraft How the four forces of flight interact with each other Chapter 1, Lesson 2

Quick Write Octave Chanute’s expertise in designing bridges gave him the know-how to tackle some big questions in aviation, such as the structure of biplane wings. What skills have you acquired from school that you could apply to a hobby? (Note to teacher: Use “Pick a Student” button in CPS) Chapter 1, Lesson 2

How Lift is Generated Upward force on aircraft against weight Increasing aircraft’s forward motion Increasing airfoil’s angle of attack – up to stall speed Depends on aircraft’s shape, size, and velocity Chapter 1, Lesson 2 Reproduced from NASA/Glenn Research Center

How to Control Lift Pilots increase angle of attack to create more lift Angle of attack and velocity must be balanced to keep flight path level Air condition impacts the need for greater or lesser velocity to maintain lift Chapter 1, Lesson 2 Courtesy of NASA/Kim Shiflett

Activity 1: Controlling Lift Launch the airplane you created in Lesson 1 and observe the lift patterns Document your findings and answer the questions on the worksheet provided Chapter 1, Lesson 2

How Weight Affects Flight Acts through single point center of gravity Weight is a gravitational force on an object due to its mass Mass includes airplane parts, fuel, passengers and freight The more mass, the more resistance to moving Chapter 1, Lesson 2 Adapted from NASA/Glenn Research Center

Weight’s Major Challenges Overcoming an aircraft’s weight with lift Pilots constantly adjust for balance during flight Chapter 1, Lesson 2 Courtesy of NASA

Learning Check Questions CPS Questions 3-4 Chapter 1, Lesson 2

Activity 2: Center of Gravity Limit   Compute aircraft weight and center of gravity Answer questions about your calculations of moment, weight, and center of gravity Chapter 1, Lesson 2

How Thrust Affects an Aircraft’s Movement Thrust is a forward force that moves an aircraft through the air It’s opposite force is drag, the pull or slowing effect of air on an aircraft Chapter 1, Lesson 2 Courtesy of USN/PH1 Richard Rosser

Where Thrust Comes From   Engines provide powered aircraft’s thrust Thrust’s forward motion overcomes drag so airfoils produce lift Chapter 1, Lesson 2 Reproduced from NASA/Glenn Research Center

Adjusting Thrust Reduction in engine power while in level flight, drops thrust and aircraft slows When two forces are equal, pilot will fly at constant airspeed Chapter 1, Lesson 2

Adjusting Thrust, cont. To maintain balance between lift and weight, pilot must coordinate thrust and angle of attack at any speed Chapter 1, Lesson 2 Reproduced from US Department of Transportation/Federal Aviation Administration

How Drag Slows an Aircraft As aircraft moves through air, its boundary layer changes the shape of airflow over the aircraft Chapter 1, Lesson 2 Courtesy of Leon van Dommelen, FAMU-FSU College of Engineering

Types of Drag Parasite drag drains flight of needed energy Form drag includes items like antennas and engine covers Interference drag occurs when air currents flowing over various angles of an aircraft collide Skin friction drag can include anything on an aircraft’s skin that allows air molecules to stick to Chapter 1, Lesson 2 © Aaron Kohr/ShutterStock, Inc

Types of Drag, cont. Wingtip vortices produce induced drag Air flows above the tip and comes back in a downwash behind the wing pulling down and back on aircraft Chapter 1, Lesson 2 Courtesy of USAF/TSgt Russell E. Cooley IV

Learning Check Questions CPS Questions 5-6 Chapter 1, Lesson 2

Activity 3: : FoilSim III Lab Conduct experiments on airfoils in a virtual wind tunnel using NASA’s FoilSim III Answer questions pertaining to your adjustments to lift and drag variables Chapter 1, Lesson 2

How the Four Forces of Flight Interact with Each Other If forces are balanced, aircraft cruises at constant velocity If forces unbalanced, aircraft accelerates in direction of largest force To maintain constant speed, thrust and drag must remain equal For constant altitude, lift and weight must be equal Chapter 1, Lesson 2

Activity 4: Four Forces of Flight Label the appropriate force of flight on the worksheet illustration Write a short statement describing the force’s affect on flight Chapter 1, Lesson 2

Summary How lift is generated How weight affects flight How thrust affects an aircraft’s movement How drag slows an aircraft How the four forces of flight interact with each other Chapter 1, Lesson 2

Review Questions CPS Questions 7-8 Chapter 1, Lesson 2

Next…. Done – the physics of flight Next – the purpose and function of airplane parts Chapter 1, Lesson 2 Courtesy of USAF/CMSgt Gary Emery