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Stability and Center of Gravity Rott Q4 Week 5 7th grade science

middle school science

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Stability and Center of Gravity Rott Q4 Week 5 7th grade science

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  1. I can explain the forces of flight.

  2. Don’t forget homework due on Friday. No late work will be accepted.

  3. Stability and Center of Gravity

  4. Forces of Flight What is Stability? Your Center of Gravity Review the Scientific Method Paper Airplane Stability Experiment Understanding the Results At Home Activities—Engineering Design Challenges Topics

  5. Forces of Flight

  6. OUR FORCES AFFECT THINGS THAT FLY: Weight is the force of gravity. It acts in a downward direction—toward the center of the Earth. Lift is the force that acts at a right angle to the direction of motion through the air. Lift is created by differences in air pressure. Thrust is the force that propels a flying machine in the direction of motion. Engines produce thrust. Drag is the force that acts opposite to the direction of motion. Drag is caused by friction and differences in air pressure.

  7. https://www.brainpop.com/technology/transportation/flight/

  8. Four Forces of Flight

  9. What is stability?

  10. Stability Experiment IS THE STICK STABLE OR UNSTABLE?

  11. Where is your center of gravity?

  12. Scientific Method What is the Scientific Method? Why do we use it?

  13. Question Scientific Method Hypothesis Experiment Data Analysis Conclusion

  14. What effect does changing the center of gravity have on an aircraft?

  15. Hypothesis: Changing the center of gravity on an aircraft affects the stability of the aircraft.

  16. We’ll change the center of gravity on the paper airplane and compare the results as it flies towards a target. Procedure: We’ll add weight (changing the average location of weight in the paper airplane) to three different locations and observe the results. Nose of aircraft Center of aircraft Rear of aircraft

  17. Independent Variable: The factor(s) changed by the scientist.

  18. Dependent Variable: The outcome that the scientist observes.

  19. Controlled Variable: • The factor(s) the scientist keeps the same. • Uncontrolled Variable: • The factor(s) the scientist cannot control.

  20. Let’s Watch the Experiment

  21. Paper Airplane Experiment Results: Front Center of Gravity CL Cg

  22. Paper Airplane Experiment Results: Middle Center of Gravity CL Cg

  23. Paper Airplane Experiment Results: Back Center of Gravity CL Cg

  24. Review: How is gravity and stability related?

  25. Lift vs. Gravity

  26. Lilienthal Glider Where is the center of gravity on the glider? How stable is the glider?

  27. Why is it important to find the Center of Gravity in aircraft?

  28. Which plane is the most stable?

  29. Airplanes are designed with stabilizers The main purpose of the tail is to provide stability. If tilted by a gust of wind, a stable airplane tends to recover, just as a ball lying at the bottom of a bowl will roll back to the center after being disturbed. A vertical stabilizer, or tail fin, keeps the airplane lined up with its direction of motion. Like the vertical stabilizer, the horizontal stabilizer helps keep the airplane aligned with its direction of motion.

  30. Can you answer these? • What are the Four Forces of Flight? • What is Stability? • What is Center of Gravity? • How are Gravity and Stability linked in aircraft?

  31. Engineering Design Challenges

  32. Resources for Further Study: • Short video about the center of gravity • Stem in 30 video about the Wright Brothers • Pilot's Handbook of Aeronautical Knowledge, Chapter 10, Weight and Balance • There is actually a 3D printed tool you can use to test stability of planes if you are in the classroom. Check it out!

  33. Additional Slides for Completing the Experiment in the Classroom

  34. Rules: Build and Test Your Paper Airplane • The Classroom is a NO FLY ZONE! • Takeoffs are controlled by Air Traffic Control (ATC). • Follow all ATC Directions at all times. • Stay within the taxiway boundaries. • Violators will be sent back to the ramp. Have a Safe Flight!!

  35. Test Hypothesis Which binder clip location causes the airplane to fly most accurately?

  36. Graph the Results 6 5 4 3 • Successful Flights through the hoop(number of times) 2 1 • FRONT • CENTER • BACK • Placement of Binder Clip

  37. Summarize & Share Results In our experiment, we found . . .

  38. Control Surfaces How do we make an airplane turn?

  39. Parts of an Airplane • The fuselage is the body of an aircraft • The landing gears are the wheels on an aircraft • The propeller is located (in this image) on the nose of the aircraft, but can also be seen on the wings of aircraft • Jet planes have jet engines. Can be found on the nose, fuselage or wings of a jet plane. • The tail of the aircraft has two parts—the rudder (vertical stabilizer) and the elevator (horizontal stabilizer) • On the wings, you can see the flapsand ailerons—these help control the plane in flight

  40. Control Surfaces Moveable surfaces on an airplane’s wings and tail allow a pilot to maneuver an airplane and control its attitude or orientation. These control surfaces work on the same principle as lifton a wing. They create a difference in air pressure to produce a force on the airplane in a desired direction.

  41. Control Surfaces One control surface is located on the wings of the aircraft (ailerons-blue). On the vertical stabilizer, you have the rudder (red). On the horizontal stabilizer, you have the elevator (yellow). These control surfaces allow the planes to move around three axes.

  42. 3 Axes of Flight: imagine three lines running through an airplane and intersecting at right angles at the airplane’s center of gravity. The movement of the plane around these axes is pitch, yaw and roll. The lateral axis is controlled by the elevator (yellow). Lateral movement looks like a pitch of the aircraft’s nose up and down. The vertical axis is controlled by the rudder (red). The rudder controls the aircraft’s nose and yaws it from side-to-side. The longitudinal axis is controlled by the ailerons (blue). Airplanes use ailerons to turn by rolling slightly and banking to a side.

  43. The Rudder A yaw motion is a movement of the nose of the aircraft from side to side. On the vertical tail fin, the rudder swivels from side to side, pushing the tail in a left or right direction. A pilot usually uses the rudder along with the ailerons to turn the airplane. A rudder is used more for stabilization than turning--ailerons do the greater part of the turn!

  44. The Ailerons A rolling motion is an up and down movement of the wing tips of the aircraft. On the outer rear edge of each wing, the two ailerons are flaps that move in opposite directions, up and down, decreasing lift on one wing while increasing it on the other. This causes the airplane to roll to the left or right. To turn the airplane, the pilot uses the ailerons to tilt the wings in the desired direction. When you make a turn on your bike, you usually lean into the turn. Airplanes have to do the same when they bank during a turn.

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