An Instructor’s Guide Teaching Basic Aerodynamics Teaching Basic Aerodynamics An Instructor’s Guide Table of Contents Title Page Introduction 1 Purpose 1 Pre-Work 1 Icons and Colors 2 Materials 2 Get the Class’s Attention 2 State the Objectives of the Class 3 Topic 1 -Introduction to Forces in Flight 3 (15 minutes) Topic 2 – Flight Science 5 (15 minutes) Topic 3 -Flight Surface Controls and Their Axes 7 of Motion (10 minutes) Activity Build and Fly Paper Airplanes 8 (10 minutes) Assessment – the Test 9 (10 minutes) Advanced Aerodynamics 9 (10 minutes) An Instructor’s Guide Teaching Basic Aerodynamics Teaching Basic Aerodynamics An Instructor’s Guide By Jeff Seeley EDIT 704 November 20, 2008 Introduction This is an instructor’s guide for teaching the fundamentals of flight called basic aerodynamics. The intended audience is a high school physics class, model airplane builders or someone interested in becoming a pilot. This instructor’s guide can be used by anyone at least 18 years old who has completed high school general science and physics courses. Flight experience is preferred. The recommended class size is from 2 to 15 students with a minimal age of 16 years old. It is highly recommended that students have completed high school level general science and preferably have high school level physics experience. Purpose This single class instruction teaches fundamentals of flight called basic aerodynamics. Its purpose is to explore and understand the basic knowledge of flight theory as it pertains to conventional airplanes. It includes three major categories of basic aerodynamic information (1) forces in flight, (2) flight science and (3) flight surface controls and flight axes. This instruction provides very basic aerodynamics information for people interested in learning about the exciting world of aviation. Pre-Work For the instructor: Review this entire instructor guide before attempting to teach the course on basic aerodynamics. The course uses an advance organizer (see last page to link and organize students’ current knowledge of science to new material on aerodynamics. For the instructor: assemble and become familiar with the enclosed balsa wood model airplane before starting the instruction. An Instructor’s Guide Teaching Basic Aerodynamics For the instructor: review and practice folding the Best Flying Paper Airplane in the World video at URL: http://www.youtube.com/watch?v=mGhI4J3Vrv0&feature=related For the students: No pre-work is required. Icons and Colors These icons are used in the instructor guide to facilitate instruction. This icon represents instructor attention or instruction. This icon represents student attention or action required. This blue colored line represents instructor action required. Materials • One balsa wood model airplane (enclosed) • One Advance Organizer on Basic Aerodynamics (1-page) handout for each student (see last page. Make one copy for each student) • Blank paper (3 sheets for each student) • One Basic Aerodynamics Test for each student (see page KK) • Teaching Basic Aerodynamics CD (enclosed) Get the Class’s Attention Stand quietly in front of the class, windup the propeller of the balsa wood model airplane and let it fly towards the back of the room. The class will watch it fly and descend, and then look at the instructor. Ask a student to retrieve the airplane and return it to you. Welcome the class to this course on the fundamentals of flight called basic aerodynamics. An Instructor’s Guide Teaching Basic Aerodynamics State the Objectives of the Class State the class objectives. At the end of this course, students will be able to: • Identify and describe the four forces that affect an airplane in flight • Describe the wing shape of an airplane and how it flies • Identify an airplane’s flight surface controls and their axes of motion Topic 1 -Introduction to Forces in Flight (15 minutes) The Wright brothers flew the first airplance in 1903. Since then, thousands of different types and models of airplanes have been built and flown. Ask the class to identify various types of airplanes and their common parts. Point out the parts on the balsa wood model airplane. Wings, tail, engine, propellor, cockpit, fuselage, wheels (on real airplanes), flight controls and other specific items. All airplanes have dealt with the same four forces in flight. Refer to the Advance Organizer on Basic Aerodynamics first figure, Forces in Flight. Ask for suggestions for correctly identifying these forces and note the correct answers. Weight, lift, thrust, and drag. Use the model airplane to demonstrate each force as it is discussed. Weight. The force pointing down is weight and it is caused by gravity. This force is very familiar to us because we feel it everyday. The force of gravity is always directed toward the center of the earth. This force acts on the airplane all the time, even when it is not flying. Have the students label the down arrow on their advance organizer Forces in Flight figure as weight. An Instructor’s Guide Teaching Basic Aerodynamics Lift. The force pointing upward is lift. Lift is the most complex and the hardest to understand. It takes air and motion to generate lift. As an airplance moves forward, the wings generate the lift required to lift the airplance into the sky. Weight counteracts lift. If an airplane weighs 2000 pounds including the airframe, fuel, passengers and payload, then it needs 2000 pounds of lift generated by the wings to get off the ground. We’ll cover how wings generate lift soon. Have the students label the up arrow on their advance organizer Forces in Flight figure as lift. Thrust. Recall the simple ingredients for creating lift – air and motion. Something needs to get that wing moving through the air before it can create lift. That’s where thrust comes in. Typically, engines (either jet or propeller) provide the thrust for an airplane. Ask the class what provides the thrust for the balsa wood model airplane. Propeller. Ask them what provides the thrust for a paper airplane. The throw. Have the students label the forward arrow on their advance organizer as thrust. Drag. When a person put a hand out the window of a car, he or she feels the resistance of the air. An airplane feels this resistance as it moves through the air too. This is friction drag. Ask the class to imagine running their hand across the smooth top of their desk. It would move easily. Ask them to imagine the desk is covered with sand paper and they run their hand across the desk. They would feel significant friction. Air molecules feel friction against each large or small thing that sticks out from the airplane’s skin – antenna, wheels, lights and even tiny rivets. Have the students label the backward arrow on their advance organizer as drag. Summarize and use the balsa wood model airplane to demonstrate the four forces in flight – weight, lift, thrust, and drag. An Instructor’s Guide Teaching Basic Aerodynamics Topic 2 -Flight Science (15 minutes) Ask the class what are the elements for creating lift. Air and motion. Refer to the Advance Organizer on Basic Aerodynamics second figure, Flight Science. Wing. Ask the class the name of the purple shape. Wing. Ask the class the name of the blue arrows. Air or wind. Have the students label the purple shape on their advance organizer Flight Science as wing and the open end of the blue arrow as air or wind. A law of physics proposed by Daniel Bernoulli, an 18th-century Swiss mathematician, is used to explain lift (although he never proposed his theory for that reason). Bernoulli discovered that the pressure of a fluid in motion decreases as the rate of movement of the fluid increases. An airfoil or wing which interrupts the flow of air is designed with a flat edge on bottom and a curved edge on top to accelerate the flow of air (which is a fluid) over its curved top surface. This decreases the pressure above the wing. The relatively flat underside of the wing maintains the speed of the air moving beneath it and results in a higher relative pressure on the underside of the wing. Two unequal forces -higher pressure under the wing and lower pressure above the wing results in higher pressure pushing upward on the wing. Ask the class what this force is called. Lift. Use the balsa wood model airplane to demonstrate lift. Have the students label (1) the downward arrows on their advance organizer Flight Science purple-colored wing as less pressure, (2) the up arrows as more pressure, (3) the top curved blue air/wind line as faster and the bottom straight blue air/wind line as slower. An Instructor’s Guide Teaching Basic Aerodynamics This reduced pressure effect is frequently felt when riding in a car. A sideward tug pulls on a car when it passes a large truck going in the opposite direction. The sideward tug is caused by air pressure. The passing vehicles form a constriction that speeds up the flow of air, reducing the air pressure between them. In this case the air is moving between the vehicles but it doe not matter which is moving--the air or the vehicles. The result is the same. Higher air pressure on the other side of the car pushes it toward the truck during the split-second as they pass. Tell the class that the lift off speed of a small airplane is 50 knots. Ask if the airplane will attempt try to fly in a strong wind? Yes and that is why we always tie airplanes down. Angle of Attack. The angle and speed at which a wing moves through the air determines the amount of lift created. The necessary lift can be created by an appropriate combination of wing angle and forward speed. The wing angle, known as angle of attack, is measured by the angle formed between the wing and the relative wind, which is the direction of the airflow in relation to the wing. Use the balsa wood model airplane to demonstrate high and low angles of attack. At a fixed weight, as airspeed decreases, a higher the angle of attack is needed to maintain level flight. As airspeed increases, the necessary angle of attack decreases. If airspeed decreases, the angle of attack must increase. The angle of attack can be increased to the point that it becomes so great that the air flowing over the upper surface of the wing can no longer follow the wing's curvature. This point is called a critical angle of attack and the turbulent flow of air over the wing causes the airplane to buffet violently and lose lift. An Instructor’s Guide Teaching Basic Aerodynamics Ask the class the result of this buffeting and loss of lift. Aerodynamic stall. Ask the class how an aerodynamic stall is related to the condition of the airplane's engine or movement. Not at all; it does not mean that the aircraft engine has stopped or that that the aircraft has stopped moving. Have the students label the top wing figure on their advance organizer Flight Science as low angle of attack, the next figure as medium angle of attack and the bottom figure as excessive angle of attack with broken airflow and loss of lift. Inverted flight. When an airplane flies upside down, the curved part of the wing with less pressure is below the flat part of the wing with higher pressure. The answer is that the pressure difference is created by tilting the wing into the airflow and increasing the angle of attack. As long as the wing is tilted into the oncoming airflow (relative wind) at a great enough angle, the wing will produce lift. It doesn't matter which surface of the wing--top or bottom--is facing "up." Aerobatic airplanes, which are built to fly upside down, have wings whose upper and lower surfaces are equally curved. Wings shaped this way make it easier to fly upside down because they don't need to be tilted as far to produce enough lift. Use the balsa wood model airplane to demonstrate inverted flight. Topic 3 -Flight Surface Controls and Their Axes of Motion (10 minutes) Refer to the Advance Organizer on Basic Aerodynamics bottom figure, Flight Surface Controls and Axes of Motion. An Instructor’s Guide Teaching Basic Aerodynamics Ask the class to list an airplane’s flight controls. Elevator, ailerons and rudder (the engine and propellor are not flight controls). Use the balsa wood model airplane to locate the flight controls and their effects on the airplane’s movements. Elevator. The elevator on the horizontal tail surface controls pitch -the attitude of the airplane. As the elevator tilts up or down, it decreases or increases the lift on the tail which tilts the nose of the airplane up or down. Ailerons. The ailerons located on the outer rear edge of each wing control roll around the centerline of the airplane. The two ailerons move in opposite directions, up and down, which decrease lift on one wing and increase lift on the other. This causes the airplane to roll left or right. Rudder. The rudder on the vertical tail fin controls yaw -movement about the vertical center axis of the airplane. As the rudder moves left or right, it pushes the tail in a left or right direction resulting in a aerodynamic slip. A pilot uses the rudder in combination with the ailerons to smoothly turn the airplance. Have the students label the airplane’s flight controls, elevator, ailerons and rudder, and the engine and propellor on their advance organizer Flight Surface Controls and Axes of Motion figure. Have them draw a line connecting Roll to ailerons, Pitch to elevator and Yaw to rudder. Activity – Build and Fly Paper Airplanes (15 minutes) Hand out two pieces of paper to each student. Ask the students to build and fly a paper airplane to demonstrate aerodynamic flight forces of lift, weight, thrust and drag. Suggest they use a paper airplane model they already know or have them make one following your directions. Building the Best Flying Paper Airplane in the World. Instruct the students to be precise with their paper folds and to thoroughly flatten all folds and creases. 1. Fold a sheet of paper in half lengthwise 2. Fold one corner of paper back to centerline 3. Repeat with facing corner 4. Fold both corners again to centerline 5. Fold tip of paper to cenertline on other end of paper 6. Fold tip of paper back leaving a one-inch wide fold across the middle 7. Turn paper airplane over and fold wingtips together below airplance 8. Fold the inside edge of wings back to centerline An Instructor’s Guide Teaching Basic Aerodynamics 9. Open wings and throw airplane Have the students experiment with their airplanes by modifying their design, bending the wings or changing the nose of their airplanes. Discuss how the modifications change the airplane’s flight path. Have the students (1) analyze and critique the various paper airplane models, (2) identify airplane components and axes of motion and (3) identify flight forces. Assessment – the Test (10 minutes) Hand out a Basic Aerodynamics Test to each student. Tell the students to put away their class notes. The test requires students to match flight forces, flight science components and flight surface controls and axes of motion to unidentified figures. Give the students 10 minutes to complete the test. The students take the test. After all students are finished, have the students grade their own test as they discuss and review the correct answers. Advanced Aerodynamics (10 minutes) Ask the students to identify other types of aircraft and flying machines. Answers should include helicopters, blimps, gliders, rockets and missiles. Discuss how these are similar to airplanes and how they are different from airplanes. Discuss their means of propulsion and flight controls. Reiterate that the forces of flight similarly affect all flying machines. End of Instruction An Instructor’s Guide Teaching Basic Aerodynamics Learning Theory and Strategy Use in this Instructor’s Guide Learning Theory. This aerodynamics instruction is based on the Gagné -Briggs instructional theory that relies on (a) analyzing tasks to be learned and (b) determining which of five categories or domains identifies the instructional conditions to support learning in that domain. Gagné-Briggs’ domains of learning outcomes are (a) intellectual skills, (b) cognitive strategies, (c) verbal information, (d) attitudes and (e) motor skills. The Gagné -Briggs instructional model includes nine events to ensure learning: 1. Gain attention 2. State objectives 3. Recall prior learning 4. Present content 5. Provide learning guidance 6. Elicit performance 7. Provide feedback 8. Assess performance 9. Enhance retention and transfer Learning Strategy. The Gagné-Briggs instructional model was chosen for this instruction because learning basic aerodynamics is a good example of a combination of verbal information and intellectual skills learning capabilities. Verbal information guidelines include stating, telling or describing facts, concepts, principles and procedures. Intellectual skills include rules to specify relationships among concepts and higher-order rules combining multiples rules. Both internal and external conditions enhance learning in both the verbal information and intellectual skills domains. My learning analysis for this instruction resulted in identifying the learning objectives and determining (internal) prerequisites (i.e., that the students have completed high school general science and preferably physics courses). Students must have a solid pre-existing set of organized general science or physics knowledge since aeronautical knowledge is hierarchically related to these basic sciences. An advance organizer is used in this instruction as an external condition to help place the new complex aeronautical information in context. It is utilized to present learning from simpler to more complex material. The Gagné-Briggs instructional model is applied in these nine events of this aerodynamics instruction: 1. Gain attention – model airplane is flown across the room 2. State objectives -see page 3 in the instructional guide 3. Recall prior learning – discussion of airplanes types, parts and flight science 4. Present content – present aerodynamics using the advance organizer 5. Provide learning guidance – combined with event 4 6. Elicit performance – students build and modify paper airplanes An Instructor’s Guide Teaching Basic Aerodynamics 7. Provide feedback – combined with event 6 to analyze and critique various paper airplane models. Identify airplane components and flight forces 8. Assess performance – administer and discuss test 9. Enhance retention and transfer – discussion on advanced aerodynamics including helicopters, blimps, gliders, rockets and missile