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FEAR OF FLYING

In this the third, and final part, of Fear of Flying we will add the necessary propulsion to make the whole airplane that we have "built" fly. But that's not all the powerplants do. It's the engines make the airplane "live".

TAIL FEATHERS

First though, smaller aerodynamic surfaces will be added to the aft end of the fuselage. Think of these surfaces in two contexts; as complete surfaces, and as surfaces on which the aft, or trailing edge, is moveable. In each context these surfaces serve two entirely different functions.

There are two surfaces on the very aft end of the fuselage, one horizontal and one vertical surface. At first it might appear that there are three surfaces, one vertical, and one extending from each side of the tailcone (the aft end of the fuselage) approximately 90 degrees to the vertical surface. Actually, the horizontal surface is a single surface extending through the tailcone. Pilots refer to these surfaces euphuistically as the "tail feathers" because they function very much like the fins on an arrow which used to be made from feathers. When taken as a whole, these surfaces generate aerodynamic forces that tend to return the airplane to straight flight when it is deflected due to a gust or turbulence. This provides the airplane with POSITIVE STABILITY.

Since an airplane operates in three dimensional space it must also be controllable about three axes. The LONGITUDINAL axis runs down the centerline of the fuselage. The VERTICAL axis is perpendicular to the longitudinal axis in the vertical plane. The LATERAL axis is perpendicular to both the longitudinal axis AND the vertical axis. (The point at which these three axes intersect is the center of gravity. Therefore, all changes in attitude occur about the center of gravity.)

The ailerons, moved differentially by the rotation of the control wheel in the cockpit and described earlier, control the attitude of the airplane about the longitidinal axis or ROLL axis.

In a like manner the aft approximately one third of the horizontal surface mounted on the aft end of the fuselage, called the ELEVATOR, is hinged to provide control about the lateral, or PITCH axis. The elevator is moved when the pilot pushes or pulls on the control wheel. The aft approximately one half of the vertical surface, called the RUDDER, is hinged to provide control about the vertical, or YAW axis. The rudder is moved by the rudder pedals by the pilot using his feet.

These surfaces are critical to aircraft stability and control. On the Morning of November 12, 2001 a European built Airbus A300-600 departed JFK Airport, New York for Santo Domingo in the Dominican Republic. Just after takeoff the vertical surface broke off the airplane. The airplane became uncontrollable and crashed into a residential area of Queens, New York.

How's this for fancy tail feathers?

If you would like more detailed information on how modern airliners fly read, "All You Ever Wanted to Know About Flying: The Passengers Guide to how Airliners Fly", by Julien Evans. You can purchase this book, Here

POWERPLANTS?

The powerplants on our airplane serve three functions. Primarily they provide power to push or pull the airplane through the air. Secondly, they provide compressed air to pressurize the cabin. And, they drive generators which, in turn, provide electrical power for everything from the flight instruments, to the cabin lights, and all the other things that keep us happy while we fly.

The engines, as they are commonly referred to, are actually composed of two separate components which make up the powerplant. The first of these components is a thrust producing device. On early airplanes this was the propeller. It's still a propeller, but on modern airplane powerplants its called the fan. The fan is nothing more than a high speed propeller. It's the first thing you see when you look into the inlet of the nacelle. (The nacelle is the sheet metal covering that encloses the powerplant.)

The second part of the powerplant is the engine. The engine powers the fan (or, propeller). On early airliners the engines were piston engines, today they are turbine or jet engines. The powerplants are referred to as turbofans because they are turbine engines powering (high speed) fans.

The primary function of the powerplant(s) is to continuously move huge amounts of air from in front of the airplane to behind the airplane. This action produces a reaction ("For every action there is an equal and opposite reaction" - Isacc Newton) which drives (thrusts) the airplane forward. Powerplant performance is therefore measured in pounds of thrust. Our airplane will require two powerplants of approximately 40,000 pounds of thrust each! The following picture shows such an engine.

As air is moved through the engines of modern jetliners a large quantity of it is compressed. This means that its pressure is increased and it becomes hot. Part of this compressed air is cooled down and then used to pressurize and heat the cabin and provide a "shirt sleeve environment" for the passenger and crew.

If you would like more information on cabin air systems and how they work, Click Here

Large quantities of the hot high pressure air is is allowed to flow into the hollow leading edges of the wings as well as the lips of the engine nacelles to prevent ice buildup.

This compressed air is also used by a separate system, called an Air Cycle Machine(ACM) to cool the cabin during warmer times of the year.

Electrical power, what can be said about electrical power. The engines turn generators that produce electrical power used for many things in the airplane including microwave ovens, interior lighting, TV sets, VCR's, telephones, navigation equipment, weather radar, communications radios, and exterior lighting.

SUMMARY

There you have it! In as brief (brief not necessarily complete) and concise a manner as I could think of. The purpose being that if one understands, "How can something so big stay in the air?" then maybe, just maybe one can fly through the air with a little less apprenhension. Think about it and if something in this treatise is completely incomprehensible or incomplete write me and I will do my best to clear up whatever it is, for you.

Thanks for taking your time to read what I have written.

For more information on the greatest commercial airplanes in the world, Click Here.
FEAR OF FLYING PART THREE - MAKING THE WHOLE THING FLY In this the third, and final part, of Fear of Flying we will add the necessary propulsion to make the whole airplane that we have "built" fly. But that's not all the powerplants do. It's the engines make the airplane "live". TAIL FEATHERS First though, smaller aerodynamic surfaces will be added to the aft end of the fuselage. Think of these surfaces in two contexts; as complete surfaces, and as surfaces on which the aft, or trailing edge, is moveable. In each context these surfaces serve two entirely different functions. There are two surfaces on the very aft end of the fuselage, one horizontal and one vertical surface. At first it might appear that there are three surfaces, one vertical, and one extending from each side of the tailcone (the aft end of the fuselage) approximately 90 degrees to the vertical surface. Actually, the horizontal surface is a single surface extending through the tailcone. Pilots refer to these surfaces euphuistically as the "tail feathers" because they function very much like the fins on an arrow which used to be made from feathers. When taken as a whole, these surfaces generate aerodynamic forces that tend to return the airplane to straight flight when it is deflected due to a gust or turbulence. This provides the airplane with POSITIVE STABILITY. Since an airplane operates in three dimensional space it must also be controllable about three axes. The LONGITUDINAL axis runs down the centerline of the fuselage. The VERTICAL axis is perpendicular to the longitudinal axis in the vertical plane. The LATERAL axis is perpendicular to both the longitudinal axis AND the vertical axis. (The point at which these three axes intersect is the center of gravity. Therefore, all changes in attitude occur about the center of gravity.) The ailerons, moved differentially by the rotation of the control wheel in the cockpit and described earlier, control the attitude of the airplane about the longitidinal axis or ROLL axis. In a like manner the aft approximately one third of the horizontal surface mounted on the aft end of the fuselage, called the ELEVATOR, is hinged to provide control about the lateral, or PITCH axis. The elevator is moved when the pilot pushes or pulls on the control wheel. The aft approximately one half of the vertical surface, called the RUDDER, is hinged to provide control about the vertical, or YAW axis. The rudder is moved by the rudder pedals by the pilot using his feet. These surfaces are critical to aircraft stability and control. On the Morning of November 12, 2001 a European built Airbus A300-600 departed JFK Airport, New York for Santo Domingo in the Dominican Republic. Just after takeoff the vertical surface broke off the airplane. The airplane became uncontrollable and crashed into a residential area of Queens, New York. How's this for fancy tail feathers? If you would like more detailed information on how modern airliners fly read, "All You Ever Wanted to Know About Flying: The Passengers Guide to how Airliners Fly", by Julien Evans. You can purchase this book, Here POWERPLANTS? The powerplants on our airplane serve three functions. Primarily they provide power to push or pull the airplane through the air. Secondly, they provide compressed air to pressurize the cabin. And, they drive generators which, in turn, provide electrical power for everything from the flight instruments, to the cabin lights, and all the other things that keep us happy while we fly. The engines, as they are commonly referred to, are actually composed of two separate components which make up the powerplant. The first of these components is a thrust producing device. On early airplanes this was the propeller. It's still a propeller, but on modern airplane powerplants its called the fan. The fan is nothing more than a high speed propeller. It's the first thing you see when you look into the inlet of the nacelle. (The nacelle is the sheet metal covering that encloses the powerplant.) The second part of the powerplant is the engine. The engine powers the fan (or, propeller). On early airliners the engines were piston engines, today they are turbine or jet engines. The powerplants are referred to as turbofans because they are turbine engines powering (high speed) fans. The primary function of the powerplant(s) is to continuously move huge amounts of air from in front of the airplane to behind the airplane. This action produces a reaction ("For every action there is an equal and opposite reaction" - Isacc Newton) which drives (thrusts) the airplane forward. Powerplant performance is therefore measured in pounds of thrust. Our airplane will require two powerplants of approximately 40,000 pounds of thrust each! The following picture shows such an engine. As air is moved through the engines of modern jetliners a large quantity of it is compressed. This means that its pressure is increased and it becomes hot. Part of this compressed air is cooled down and then used to pressurize and heat the cabin and provide a "shirt sleeve environment" for the passenger and crew. If you would like more information on cabin air systems and how they work, Click Here Large quantities of the hot high pressure air is is allowed to flow into the hollow leading edges of the wings as well as the lips of the engine nacelles to prevent ice buildup. This compressed air is also used by a separate system, called an Air Cycle Machine(ACM) to cool the cabin during warmer times of the year. Electrical power, what can be said about electrical power. The engines turn generators that produce electrical power used for many things in the airplane including microwave ovens, interior lighting, TV sets, VCR's, telephones, navigation equipment, weather radar, communications radios, and exterior lighting. SUMMARY There you have it! In as brief (brief not necessarily complete) and concise a manner as I could think of. The purpose being that if one understands, "How can something so big stay in the air?" then maybe, just maybe one can fly through the air with a little less apprenhension. Think about it and if something in this treatise is completely incomprehensible or incomplete write me and I will do my best to clear up whatever it is, for you. Thanks for taking your time to read what I have written.
	September 11, 2002