Air Forces: The Science of Flight

What To Do

Activity Prep

• Print Papertang™ instructions (1 per group) and Final Worksheets (1 per participant). 
• Set-up the PowerPoint (to be used throughout the entire workshop). 
• Draw the table for Activity 1: Calculating Lift on the classroom board, if available.

Demonstration: Paper Ball Toss

• Have one participant crumple one piece of paper into a ball while another participant prepares a paper aircraft.
• Both participants will attempt to glide their crafts through the air. 
• Ask the group to compare the flight of the two attempts: 
  • What factors affected their flight path?
  • What forces act on an aircraft when at rest?
  • During take off? 
  • While in flight?
• Introduce the four forces of flight and discuss how they must balance to keep an aircraft in the air. The four forces of flight are: 
  • Weight 
  • Lift
  • Thrust
  • Drag

Weight

• Distinguish between mass and weight.
• Demonstrate how to calculate the weight of a fully loaded 747-400 (mass of 400,000kg) on the classroom board (Fweight = mass x gravitation). 
  • Weight control was the key in the Wright Brothers (Wilbur and Orville Wright) design of the first successful airplane. 

Activity 1: Calculating Lift

• Explain that an aircraft will fly when lift is greater than weight.
• On the classroom board, show the amount of lift required to get a fully loaded 747- 400 off the ground (Flift must be greater than Fweight ). 
  • Therefore, Flift must be greater than 3.92 x 106 N
• Working in small groups or as a class, calculate Fweight of five aircrafts below.

• Introduce Newton’s Laws of Motion:
  • Newton’s 1st Law (Law of Inertia): Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it. 
  • Newton’s 2nd law: the acceleration of an object is directly proportional to the net force acting upon it (Fnet = mass x acceleration).
  • Newton’s 3rd law: for every action there is an equal and opposite reaction.
• Explain why when lift and weight are equal, acceleration is zero and the aircraft will maintain a constant vertical velocity. 
• Explain how lift is produced by the wings of the aircraft. 
  • The resulting opposite reaction from the deflected air over the wings (downwash) produces lift. 
• Introduce Bernoulli’s principle, which is based on the pressure differences caused by the shape of the wind traveling through the air.
  • The pressure difference between the upper surface of the wing (low pressure) vs the underside of the wing (high pressure) causes the wind to push upward, creating lift. 
• Ask “Did the Space Shuttle need winds to fly in space?”.
  • Because there is no air in space, there is no air to generate lift. The wings are only used for landing. 
• Discuss methods to maximize lift. 

Thrust

• Introduce thrust: a force that is created as the engines push air back with the same force that the air moves the aircraft forward. 
• Explain how thrust is produced by propellers vs jet engines.

Drag

• Introduce drag: the force that opposes thrust (Newton’s 3rd Law). Discuss the two types of drag (parasitic vs induced). 
• Explain that according to Newton’s 2nd law, when an aircraft is flying at a constant horizontal velocity, thrust and drag must be equal and opposite.
• Discuss when planes use the least and most amount of fuel.
• Discuss vertical flight (helicopters and some fixed-wing aircrafts).

Exploration: Paperang™ Flight Competition

• Give each group a piece of paper. 
• Using pages 11-25 in the Paperang™: Paperang™ Paper Aircraft System, go through the steps of making a Paperang™. Encourage groups to make their own designs.
  • A facilitator should create their own Paperang™ along with the groups to provide them an example of what each step should look like.
• Bring the group to the designated area (i.e., gym or hallway) to compete in the Paperang™ Flight Competition.
• Have each group designate a “pilot”. All “pilots” will form a line to fly their Paperang™ and all other participants should stand on the sidelines. 
• A facilitator should stand 5m away from the “pilot”, acting as the target. Each “pilot” will take a turn flying his/her Paperang™ towards the target.
• The other participants will estimate and record the distance the Paperang™ traveled. 
• After the groups have flown twice, participants will complete the Paperang™ Flight Competition Worksheet. 
• To wrap-up, discuss why some groups Paperang™ flew farther than others. 
  • Was their design flawless?
  • Did they follow all the instructions flawlessly?
  • Did they add more or less weight to the design?
  • Did the “pilot” have good technique in launching the Paperang™?

Wrap-up

• Review the four forces of flight and discuss how the forces change during different phases of flight. Reminder: weight is always vectored towards the center of the earth while the other forces are relative to the direction of travel of the aircraft.
  • Forces are balanced during cruising (constant velocity).
  • A slight dive (landing) occurs when drag + weight > lift + thrust.
  • Climbing (take-off) occurs when drag + weight < lift + thrust.
• Discuss possible careers related to the topics covered and what they would need to do (schooling, experience, etc…) to get into those careers.