G. Casey Cassidy
There have been many individuals, who have through an advancement of some technical skill or through the sheer inspiration of their personality, progressed the science of flight. Actually, too many to include in this discussion. Therefore, only a few representative individuals and their achievements will be noted. Each is a representative of their own particular time, and each evokes the spirit and essence of the “magic” of flight.
4.1
The Quest
As far back as 1480’s, Leonardo da Vinci had a curiosity and eye for life and its complexity. Flying was one of his strongest interests. Though never to fly himself nor to create a workable flying machine, da Vinci sensed the science behind flight. He writes, “A bird is an instrument working according to mathematical law, which instrument it is within the capacity of man to reproduce with all its movements but not with a corresponding degree of strength, though it is deficient only in the power of maintaining equilibrium (21). Leonardo da Vinci obviously felt that man could reproduce the mechanics of flight by imitating the birds. That he was wrong, and in fact constructed models that could never fly misses the point. His inquisitive mind and probing spirit acted as a catalyst for others after him. That these who followed da Vinci refined and in many cases discarded his ideas on flight only serves to illustrate that invention is very often an evolutionary process. We build as much on inspiration as we do on technically correct formulas.
Probably the first aerial voyage of any kind that man attempted successfully was in a balloon. In 1783 two gentlemen, Messrs. Rozier and Marquis d’ Arlandes, using the technology supplied by two brothers, Joseph and Etienne Montgolfier, set sail in a balloon for a brief trip across Paris. The technology behind this balloon trip was simple; heat causes expansion and consequently reduces the weight of air. This balloon was in reality a “floating chimney”, powered by burning straw(22). Though this flight lasted only 25 minutes over a distance of about five miles it did serve as a springboard for the imagination, and as a focus for the competitive, inventive spirit.
In 1785 Jean-Pierre Blanchard and Dr. John Jeffries crossed the English Channel for the first time by air using an improved balloon design.
Balloon designs (lighter than air) reached their peak in the form of the dirigibles. These were used for exhibition and warfare. More importantly, regular transatlantic traffic had been carried out for years. Had it not been for the horrible tragedy of the Hindenburg in 1937, both dirigibles and zeppelins may have enjoyed a greater success, even into our own time.
In 1896, the Langley Aerodrome Model No. 5 had demonstrated the possibility of mechanical flight. Designed by Professor Samuel Pierpont Langley, this model was powered by a small steam engine. This unmanned model made the first significant flight of any engine driven heavier-than air craft(23). It flew twice on the afternoon of May 6, 1896, launched from a houseboat on the Potomac River. Professor Langley’s later attempts at manned flight in a full-sized version of the Aerodrome were unsuccessful. Also launched from a houseboat anchored in the Potomac, the larger craft hit the water almost immediately after launch in October 1903. A second attempt in early December ended in similar fashion.
As a parallel to these powered attempts at manned flights, there was considerable energy being spent in flying using gliders. The most successful of these was the glider constructed by Otto Lilienthal in 1894(24).
Basically, gliders had a pilot hang between the wings by bars that passed beneath his arms. Lilienthal made glides of up to 1,150 feet in machines of this type. Despite his faith in the safety of his invention, Lilienthal was killed following a crash in one of his hang gliders.
Apparently, Lilienthal’s death was not in vain. It is reported that the aviation pioneers, Orville and Wilbur Wright had read about and were much impressed with Lilienthal’s experiments(25). These attempts at flight by Lilienthal had obviously acted as a strong incentive to the brothers Wright, to try their own flights with engine powered heavier-than air flights. Another great influence upon the Wrights was OctaVe Chanute. Chanute, a successful engineer, was himself very interested in gliders and powered flight. His knowledge of previous aerodynamic experiments and his encouragement acted as a strong motivator to Orville and Wilbur.
4.2
Mastery of Flight
Apparently, though mankind had dreamed of powered flight, and had worked hard at it for many years, interest in this being accomplished was slowly but surely fading. All previous attempts had ended in failure.
As it is with many experiments that appear solvable but continually end in failure over many years and many attempts, the invention of the airplane by the Wright brothers was from a design almost uniquely their own. The Wright brothers using the inspiration of Lilienthal, together with his awareness of the curved wing as superior to the flat wing, perfected the correct curvature of the wing, thereby removing an impediment to successful powered flight that had previously been little understood(26).
After much experimentation and reading, after much discussion and application of the laws of aerodynamics, as they themselves had investigated and solved, the Wright Brothers were on the doorstep of an event that would change the course of the world forever.
On December 17, 1903, the Wright Brothers successfully flew the first powered heavier than air craft. Their plane was an innovative combination of lightness and strength(27). The plane flew a distance of 120 feet on the first trial and their last flight covered 852 feet and lasted 59 seconds.
There is some apparent misunderstanding regarding the Wright brothers. There is the idea that the success was accomplished by two expert mechanics making an isolated test of a flying machine they just happened to be working on, something done in their spare time(28).
The Wrights had worked almost continuously for over five years, solving problems, difficult and minor, theoretical and technical. They labored over problems as diverse and complicated as wing warping control, integrated wing warp and rudder control, construction of their own aircraft engines and propellers, and of course their experiments in aerodynamics(29). As stated previously, the Wrights alone were able to test and understand the profound significance of an accurate airfoil.
4.3
Extending The Mastery of Flight
On May 20-21, 1927, twenty-five year old Charles Lindbergh made the first solo, nonstop transatlantic flight in his specially constructed plane, the Spirit of St. Louis.” The flight took 33 1/2 hours.
Lindbergh took off from Roosevelt Field, Long Island on the morning of May 20, 1927 and 33 1/2 hours later landed at Le Bourget Field near Paris, France to a hero’s welcome. One hundred thousand people were there to greet him.
His plane was constructed in such a fashion, that Lindbergh to see forward, had to either turn the plane or use a periscope; a gas tank was installed where the windshield normally would have been.
Lindbergh, not even counting the significant technical feats involved in his aircraft, epitomized the true and adventurous spirit of the men who took the next step in advancing the art and skill of flying. Lindbergh’s feat was accomplished a mere 24 years after the first successful flight of the Wright Brothers.
4.4
Extending The Mastery of Flight: The Sound Barrier
On October 14, 1947, a little more than 20 years after Lindbergh’s historic crossing of the Atlantic Ocean another milestone was reached in aviation history. Captain Charles “Chuck” Yeager, U.S. Air Force, flying his rocket powered craft, the Bell X-1, became the first person to fly faster than the speed of sound in a sustained, level flight. Remember, the speed of sound is 670 miles per hour! Only 44 years before, Orville and Wilbur Wright had managed to soar for the first time ever at a more modest speed of 35 miles per hour. Amazing!
4.5
Extending The Mastery of Flight: Human Power
In the summer of 1977, the seemingly impossible became possible. Though man did not exactly fly like the birds, he came close. In a craft flown over a “considerable” distance, powered by nothing more than his own stamina attached to bicycle pedals turning a propeller, mankind entered the age of human powered flight. This craft, the “Gossamer Condor” designed by Dr. Paul MacCready and Dr. Peter Lissamen, and piloted by Bryan Allen covered a closed course for seven minutes while skimming just a few feet above the surface of the ground.
Though the craft is small and fragile, it is decidedly “hi-tech”, using the latest (for that time) in composite materials, computer assisted design, and a small array of enthusiastic engineers, scientists, and support people. The sheer technical marvel of this flying machine coupled with the ingenuity and persistence of the people who designed, built, and flew it is not a brilliant but isolated feat, but a clear and natural progression of all who labored and dreamed about the marvel of flying before it.
This “first” of human-powered flight has itself been “outdone”, extended by the development of newer materials, designs, and ideas as embodied in the craft named the “Daedalus”. The “Daedalus” a human-powered craft like the Gossamer Condor” was successfully flown over a distance of 74 miles, skimming just a few feet above the Sea of Crete.
As we move into the 21st century, we can be justifiably
optimistic about our ability to solve present and unforeseen problems. Our inspiration can come from many reminders and testaments to the brilliance of the human mind and spirit, not the least of which is man’s fascination with and mastery of flight.
5.1
Vocabulary: Activities For Students
Have students look up definitions of these words. Use the words in sentences.
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Fluids
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Pitching
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Flight
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Rolling
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Force
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Ascend
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Elevation
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Rudder
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Counteract
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Flap
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Gravity
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Ailerons
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Streamlining
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Throttle
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Pressure
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Propulsion
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Airfoil
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Mach
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Lift
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Vortex
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Drag
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Weight
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Thrust
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Efficiency
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Ratio
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Angle
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Reaction
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Altitude
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Exhaust
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Fuselage
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Descend
6.1
Questions/Descriptions
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Why is the top half of a wing curved more than its underside?
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List the four forces that affect the flying of a plane. Briefly describe each.
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What do the terms pitching, yawing, and rolling mean as they relate to the flying of an airplane?
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What is meant by the “Angle of Attack”?
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What is meant by the “Magnus Effect”?
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When taking off from a runway, why does the pilot raise the nose of the aircraft?
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Why are propellers curved?
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What did the Wright Brothers understand and “perfect” that previous inventors failed to accomplish?
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Why do hot air balloons fly? Explain.
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Why was Lilienthal of such importance to the Wright Brothers?
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What is meant by the ratio of lift to drag?
7.1
Lesson Plan: Heating Air
Introduction The heating of air makes it expand, thereby making it lighter and rise.
Objective Students will be able to demonstrate that the heating of air makes it lighter and therefore rise.
Materials Balloon, electric light bulb, heating source.
Procedure Stretch a rubber balloon over the neck of a column which has been made from a used electric light bulb. Heat the column/container slowly with a small flame and observe how the balloon begins to fill up and expand.
7.2
Lesson Plan: Field Trip
Introduction Make arrangements for your class to take a field trip to the local airport. Have one of the officials explain and demonstrate the various parts of an airplane, taking special note to observe wings and propulsion systems. Plan for a question and answer session with your class and the pilot.
Objective Students will be able to discuss and describe the various parts of an airplane.
7.3
Lesson Plan: Research Paper
Introduction Students need practice in locating information, reading the information, comprehending the information and then writing about what they have read. Have students research: aerodynamics,balloon flight, Wright Brothers, Human Powered Flight.
Objective Students will be able to locate, read, discuss, and prepare a short research paper on subjects dealing with aerodynamics and flight.
7.4
Lesson Plan: Bernoulli’s Principle
Introduction Using Daniel Bernoulli’s principle of higher speed of a flowing liquid or gas, creating lower pressure, explain, demonstrate the concept of
lift.
Objective Students will conduct a simple experiment demonstrating the principle of lift.
Materials A dime; A small plate.
Procedures Place the dime about 1/2 inch from the edge of a table top. Position the plate a few inches from the coin on the tabletop. Blow a quick, strong blast of air across the top of the coin. The dime will leap into the air and with practice will land on the plate.
The blowing air across the top of the coin creates an area of low pressure. The atmospheric pressure in the room rushes in to fill the area of low pressure. This force provides the lift causing the coin to leap up and land on the plate.
7.5
Lesson Plan: Wright Brothers Model
Introduction In order for students to gain an appreciation for the accomplishments of the Wright Brothers while studying about them in a lecture format, the students together with the teacher can build a scale model of their powered airplane from a commercially available kit.
Objective Students will be able to observe and manipulate structures similar in reference to the plane constructed by the Wright Brothers. Students will gain an appreciation for the skill and work involved in building, direction following, team work and application of academic skills.
Procedure The Wright Flyer Kit No. 202 is available by mail order, may be purchased at various hobby shops and at the National Air and Space Museum in Washington, D.C. This model when constructed (plywood) will have a wingspan of 58 inches. The model is close to 1/8 scale and can be flown as a free flight glider or as a kite.
Materials Wright Flyer Kit No. 202, Scissors, X-ACTO knife, Model Glue, Elmer’s Glue
7.6
Lesson Plan: Powered/Glider Model
Introduction As a closing project, one which will be both enjoyable and important in terms of pulling together all of the previously learned and discussed material, the class will build a combination electric powered and glider airplane from a kit. This kit called the “Electra” will require about one month of construction time.
Objective Students will be able to observe, discuss and build an actual flying, powered (electric) aircraft from a model kit.
Procedure Classroom will purchase the “Electra Sailplane” from a local hobby shop. The “Electra” measures: wingspan 78”, length 41”, and weight 48 ounces plus motor. The plane is hand launched and has two mile range which includes loops, stalls, and glides. The “Electra” is radio controlled.
Materials
“Electra Sailplane Kit”
Various small tools.
8.1
Activity Field Trip
Class or various members of the class together with teacher will visit the National Air and Space Museum in Washington D.C. Exhibits include Wright Brothers Plane and Lindberg’s “Spirit of St. Louis”.
8.2
Slides
Slides taken at the National Air and Space Museum in Washington D.C. of the various aircraft under discussion will be used throughout the unit to highlight the various accomplishments under discussion. Students will be encouraged to make their own slides.
8.3
Book Reports
Students will read the biographies of any of the pioneers of aviation, Wrights, Lindberg, etc. and prepare a book report detailing the individual’s accomplishments.