HOW AIRPLANES FLY

Teaching Outline

OBJECTIVE: To introduce the Basic Concepts of Aerodynamics by developing Bernoulli's Principle and applying it to the development of Lift by an airfoil. These concepts will be correlated to the function of the control surfaces.

OVERVIEW: This presentation uses a combination of demonstrations and guided discussion to lead the students from basic observations of the effect of air on different objects to the development of basic aerodynamic principles and concepts of controlled flight.

EQUIPMENT:

• Wright Flyer & B747 Pictures
• Sheet of paper (airplane internal and external components)
• Flex straw & Styrofoam ball
• Thread spool, business card & straight pin
• Hairdryer & ping-pong ball
• Model Airplane (with moveable control surfaces)
• Blackboard/whiteboard & chalk/markers
• Overhead projector & screen

SCHEDULE:

• Introduction: 02 min.
• Discussion of Wright Flyer to B747: 10 min.
• Demonstrations (sheet, straw, spool & hairdryer): 10 min.
• Development of Bernoulli's Principle: 05 min.
• Application of Bernoulli's Prin. (4 ways to increase Lift): 05 min.
• Jet Aircraft Landing Discussion: 05 min.
• Correlation to Flight Controls (elevator, ailerons, rudder): 05 min.
• Correlate to Propellers, Rotors, etc.: 05 min.
• Conclusion: 03 min.

TOTAL = : 50 min.

PLAN OF ACTION:

I. Introduction:

During this presentation, we will develop and discuss the basic principles of aerodynamics, which explain how airplanes maintain controllable flight. To do this, we will conduct three basic demonstrations to discover the basic concept of Lift. Based on our findings, we will then follow a logical process to correlate this information to all of

the aerodynamic principles of controlled flight. "We will literally develop all the basic aerodynamic principles needed to understand and explain How Airplanes Fly'?.

II. Wright Flyer & B747 Discussion (2 Overlays):

A. Wright Flyer & the Wright Brothers:

1. What? First flight of a heavier-than-air & controllable aircraft flying under its own power and carrying a person

2. Where? KittyHawk,NC

3. When? Dec. 17, 1903 ~ 10:35 AM

4. Who? Orville & Wilber Wright

a. Orville - first flight = 120 feet & 12 seconds

b. Wilbur - won coin toss & had first attempt on Dec. 14 - damaged airplane

c. Wilbur- second flight = 175 feet

d. Two more flights = 175 & 859 feet for 59 seconds

1. airplane damaged on landing - never flew again

2. Wright Flyer now on display at Smithsonian

5. More Details:

a. Air Speed = 32 mph

b. Wind Speed = 24 mph

c. Ground Speed = 8-10 mph

d. Altitude= 5-20 feet?

e. Width = 40 ft. 4 inches

f. Length=21 ft. I in.

g. Height = g ft. 4 in.

h. Weight = 605 E.W.

i. Motor = gasoline, water-cooled, four stroke, 12 h.p.

1. Motor built by Charlie Taylor

2. Charlie Taylor grew up in Lincoln & Keamey, NE

B. Boeing 747:

1. One of largest commercial airplanes flying today (100 years later)

a. Air Speed = Mach .8+ = 550-600 mph

b. Altitude = FL 390+ (over 7 miles)

c. Distance = 6-8000 miles

d. Length = 231 feet (almost twice Wright's first flight)

e. Width = 211 feet f. Height = 63 feet +

f. Weight= 800 - 900,000 lbs (400-450 small cars)

g. Passengers = 400-600 px

2. Wright Flyer - First Flight - Literally could have been inside!!!

C. SO, what holds up a B747??? AIR!!

1. Air is almost imperceptible - can't see, feel, smell

2. Yet, it is able to support a B747!

3. How? This is what we are going to find out

III. Demonstrations:

A. Sheet of paper demo.

1. Blow air over the top of the sheet

2. Discuss and note the action of the sheet of paper

B. Straw and Styrofoam ball demo.

1. Blow air through straw and balance the ball

2. Discuss and note the action of the ball

C. Hairdryer & ping pong ball demo.

1. Balance ball on stream of air

2. Discuss and note the action of the ball

 

D. Spool & card demo.

1. Blow air through spool with card on top

a. Pin through middle of card keeps it from sliding off

b. Be sure air is blown only through hole in spool

c. Works best if the spool is held vertically

2. Blow air through spool with card on bottom

IV. Discuss the effect of the air on the object in all scenarios

A. Draw illustrations of the movement of air related to the objects (Sheet, ball & card)

B. Show the 'moving air' and the 'non-moving air' in relationship to the object

C. Discuss the action of the object in relationship to the 'moving vs. non-moving air'

D. Determine the 'push' or 'pressure' in relationship to the 'moving vs. non-moving air'

E. Develop Class Principle: "Moving air exerts more 'push/pressure' than non-moving air"

F. Relate to Bernoulli's (Swiss Physicist) Principle: "As the velocity of a fluid (air) increases, its internal pressure decreases.

V. Discuss the shape of an airfoil & how Lift is developed

A. Draw airfoil on board

B Discuss airflow over the wing as ar airplane accelerates for takeoff (use model)

C. Draw 5 'lines' of air flowing over and under the airfoil

D. Select 5 'air particles' on these 'lines' of air and discuss their motion

1. Start under wing - no change

2. Then illustrate over wing & discuss positions of 'particles of air'

a. 'Air particle' over the top will travel farther

b. Assuming same speed - 'air particle' over top will not be at the same position as 'air particle' under the wing = vacuum

c. Laws of Nature do not allow a vacuum = 'air particle' over top must travel faster than 'air particle' under the wing

3. Bernoulli's Principle indicates LESS pressure on top = LIFT

VI. Discuss Four Ways to Increase Lift:

A. Increase Speed

B. Increase Wing size

C. Increase upper curvature (camber)

D. Increase Angle of Attack (AOA)- explain angle of attack

VII. Discuss Jet at Mach .82 slowing down for landing at 140 kts.

A. Draw wing with low camber - uses speed for LIFT

B. Reduce Speed (250 kts. Below 10,000) - OK for a while = increase angle of attack to maintain altitude

C. Reduce Speed to Landing Speed (140 kts) --AOA approaches Critical Angle = no longer able to use increase in AOA

1. Discuss stall - no longer smooth flow of air - sudden loss of lift

2. Discuss Critical Angle of Attack (17°) and Why

3. Discuss Slats & Flaps

4. Increase in Size and Upper camber

VII. Discuss Flight Controls

A. Ailerons

B. Elevator

C. Rudder

D. Speed Brakes/Spoilers

VIII. Discuss Aerobatic Airplanes, Propellers, Rotors and other aerodynamic devices

IX. Summary:

X. Lead into discussion of Boomerangs: