SCIENCE CONCEPT: Commercial and many military vehicles fly in different "speed ranges". Commercial airlines are subsonic (except the Concorde) and many military aircraft are transonic or supersonic. Because of the different Mach number range the vehicles look different and have differing abilities in flight. A duck can fly without an engine. What are the differences between the commercial, military, and duck flight? STUDENT OBJECTIVE: The student will explore the differences between a commercial aircraft flight, military aircraft flight, and duck flight. Questions concerning how long and what it will take to fly from coast to coast for each of them will be investigated. OVERVIEW: Students will examine and discover the differences between the commercial aircraft, military aircraft, and duck flight and their abilities and limitations. Students will graph the speed, flight patterns, and time it will take for each of the three of them to fly from the west coast to the east coast.

PREPARATION TIME: 20 minutes. LESSON TIME: 45 - 60 minutes. TEACHER PREP: Gather books at the library on commercial aircraft, military aircraft, and the flying abilities of duck and geese. WORDS TO KNOW: supersonic jet engines fuselage aviation technology Mach 1,2 and 3 aerodynamic construction air sacs shaft barbs barbules

Commercial aircraft improvements in the 1940's created what has become popularly known as the jet age. During the late 1940's airline engineers were working to improve on the crude jet engines built during World War II. This lead to the world's first large commercial jet airliner, the de Haviland Comet in 1952. While the Comet flew at nearly 500 miles per hour with little noise or vibration, disaster struck when two exploded in flight. One positive result of the Comet disasters were stronger bodies for all airlines. In April 1953 scheduled flights were begun from London to Tokyo using jet transportation. The flight distance was 10,200 miles with a flying time of 36 hours. The next jet age development was Britain's Vickers Viscount, a transport plane with propellers driven by jet engines. These turboprop planes also began carrying passengers in 1953. Many of the world's small airlines use turboprops today. While slower than jets, they are quieter and cheaper to build and run. The jet age also saw the emergence of jet engines used to power small planes. Small jets, such as the nine seat Cessna Citation III, are used chiefly for business purposes. They flight high, fast and smooth, are expensive to operate, but save willing clients valuable time. While engineering has played a key role in commercial aviation development, the basic shape of a medium sized airliner has changed little in the past 30 years.

Supersonic means faster than the speed of sound and planes that reach this speed are called "supersonics". The first supersonic transport airplane to fly was the Soviet's Tu-144. The first to carry fare-paying passengers, however, was the 1,450 mile per hour Concorde. The Concorde was built by Britain and France and went into service in 1976. It crosses the Atlantic ocean in less than half the time taken by other airliners, and holds the record for New York to London service with a time of just under 3 hours - a 3,480 mile flight.

While the early military flights were quite basic, the emergence of the Great War (World War I) would soon propel military aviation to new heights. These early machines had average speeds of about 60 miles per hour, flew at altitudes ranging from 3300 to 12,000 feet and had flight times lasting from about two to four hours. Their use in war ranged from photographing enemy positions to bombing the enemy and it's infrastructure. As opposing super powers battled for command of the air new and improved military aircraft emerged.

By the end of World War II substantial progress in many technical areas would alter the future of military aircraft design. Aircraft designers agreed that the piston engine was obsolete and that future fighters would have to be jet propelled. This realization opened up new realms of flight performance previously not even dreamed of. By 1951 the teams that had designed the F-86 and MiG-15 were designing the first fighter able to exceed the speed of sound, Mach 1, in level flight. By 1953 "Kelly" Johnson had outlined the Lockheed 83, an aircraft with a new J79 engine theoretically capable of reaching Mach 2 in speed. By 1954 Republic Aviation was well into the design of the monster XF-103 fighter to fly at Mach 3.7 or 2,445 miles per hour. Another notable design of the post World War II era was the Chance Vought F-8 Crusader. The Crusader was the first carrier plane to fly faster than 1,000 miles per hour and became the first plane to fly from the Atlantic to the Pacific at supersonic speed. The McDonnell F-4 Phantom was an even more advanced fighter. Noted as one of the most versatile and successful military jets of the early 1960's, the Phantom claimed over one dozen world records for speed and rate of climb. The Convair B-58 Hustler became the world's first supersonic bomber, blazing over targets at Mach 2. The Boeing B-52 Stratofortress followed the B-58 and was an eight engine strategic bomber with a 6,000 mile range that could easily be doubled with air-to-air refueling.

As can be expected, today's modern military aircraft are prime examples of increasingly complex and sophisticated systems. Today's modern aircraft are planes such as the McDonnell Douglas F-15 Eagle. A maximum speed of Mach 2.5 makes the F-15 one of the fastest operational fighters in the world. The Lockheed F-117A stealth fighter has an arrowhead shape and wouldn't stay airborne without fly-by-wire and stability augmentation systems. Then there is the SR71A which can fly at an altitude of 85,000 feet at speeds of 35 miles per minute and survey a 60 mile wide swath using it's sophisticated reconnaissance sensors.

Turning to ducks and their flying patterns! The migrations of waterfowl in spring and autumn are known to almost everybody. Millions of ducks, geese, and swans also migrate, although their movements may not be as well known as those of the Canadian geese. These birds do not spread at random over the landscape, but they have fairly well-established migration routes that, in turn, blend into fairly well-defined flyways. There are four such flyways in North America: Atlantic, Mississippi, Central, and Pacific. They were discovered by waterfowl biologists by plotting on maps the origin and recovery points of thousands of banded migratory ducks and geese.

Birds are considered nature's perfect flying machines. Every part of a bird is adapted to flying. their bodies are as streamlined as an airplane, enabling them to slip easily through the air. Their bones are strong, yet lightweight, because they contain many air sacs. The chest muscle, which operates the wings, is extremely large and powerful. Their wings are covered in tightly fitting feathers that trap air. The feathers have a stiff, straight part running through them called a shaft. On both sides of the shaft are vanes composed of barbs which are held together by barbules. The bird's wings, with each of its feathers, are shaped much like an aircraft's wing- curved on top and flatter underneath. This allows both wings to achieve lift in the same way. Most birds fly at low altitudes below 300 feet and only a few dozen species fly higher than 3,000 feet. The fastest flying creatures in level flight are ducks and geese, while the peregrine falcon is found to be the fastest when diving from great heights.

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