Unit 10 Airplane structure
Definition: A means of air transportation that is propelled by an internal combustion, turboprop, or jet engine.
Nature and Use
Airplanes fly with the help of the laws of physics and engineering. They come in all shapes and sizes and serve different purposes. Some aircraft are used for training; others are used for transporting goods and freight. Military aircraft are used in waging warfare. Passenger airliners are used for the daily transportation of travelers. Although airplanes have different designs and functions, all airplanes share common traits. The fuselage, or body of the aircraft, carries people, cargo, and baggage. Attached to the fuselage are the wings, which provide the lift to carry the aircraft and its payload. To balance the airplane in flight, the tail, or empennage, is very important. The landing gear allows the airplane to operate on the earth’s surface. The flight controls are used to maneuver the aircraft in flight. Flaps provide additional lift and drag for takeoffs and landings
The primary job of the fuselage is to provide space for the flight crew and passengers. The attachment of the wings and other load-bearing structures is also an important function of the fuselage.
Wings are as varied as other parts of the airplane. They come in different shapes and sizes, depending on the aircraft’s speed and weight requirements. A slower airplane may have a rectangular wing or a tapered wing. A rectangular wing is one in which the chord line, or cross section, of the wing, remains constant from the root of the wing near the body of the aircraft to the wingtip. A tapered wing is one that becomes narrower toward the tip. High-speed aircraft, such as jet transports, airliners, or fighter aircraft, have swept-wing designs. The purpose of the swept wing is to allow the airplane to fly at higher airspeeds.
The empennage is the tail structure of the aircraft, which includes the vertical stabilizer and rudder, along with the horizontal stabilizers and elevator. These essential components provide stability for the airplane in flight.
In order to move around on the earth’s surface, all aircraft have landing gear. The most common arrangement of the landing gear is the tricycle landing gear, in which the aircraft has two main wheels that extend from either the wing or the fuselage and a third wheel that extends from the nose of the aircraft.
The flight control system controls the aircraft in flight and comprises the devices that command movement of the aircraft around all three axes: longitudinal, lateral, and vertical. The elevator controls the airplane’s longitudinal movement about its lateral axis. In other words, it causes the airplane’s nose to go up or down. Finally, the rudder controls the airplane about the vertical axis.
Airplanes have flaps for both takeoffs and landings. Located on the inboard portion of the wing at the rear, flaps change the shape of the wing in a way that creates both lift and drag. The first half of travel, after takeoff, creates more lift than drag, whereas the last half of travel, before landing, creates more drag without a noticeable increase in lift.
The Power Plant
The internal combustion engine powers many of today’s light airplanes. The most popular arrangement of the engine is in the horizontally opposed configuration. The engine is air-cooled and typically arranged in a flat four- or six-cylinder configuration, allowing the best cooling for all of the cylinders.
"Aero" is a Greek prefix signifying air. Air is made up of a mixture of gasses, and thus is itself a gas. However, in all the reading about aeronautics you have done air is referred to as a fluid. For instance, air obeys the laws of fluid dynamics. The technical definition of a fluid states that a fluid is any substance that flows. Obviously water flows, but so does air and so do powders! So, technically speaking, air and powders are fluids. Most important to our study of aeronautics is the fact that air obeys the physical laws of fluids.
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