Wings Of An Airplane example essay topic

One of the first things that is likely to be noticed during a visit to the local airport is the wide variety of airplane styles and designs. Although, at first glance, it may be seen that airplanes look quite different from one another, in the long run their major components are quite similar. These similarities lie in the fuselage, wing, empennage, landing gear, and powerplant. The four forces of flight which all planes have in common are lift, weight, thrust, and drag. The fuselage serves several functions. Besides being a common attachment point for the other major components, it houses the cabin, or cockpit, which contains seats for the occupants and the controls for the airplane.

The fuselage usually has a small baggage compartment and may include additional seats for passengers. When air flows around the wings of an airplane, it generates a force called "lift" that helps the airplane fly. Wings are contoured to take maximum advantage of this force. Wings may be attached at the top, middle, or lower portion of the fuselage. These designs are referred to as high-, mid-, and low-wing, respectively. The number of wings can also vary.

Airplanes with a single set of wings are referred to as monoplanes, while those with two sets are called biplanes. To help fly the airplane, the wings have two types of control surfaces attached to the rear, or trailing, edges. They are referred to as ailerons and flaps. Ailerons extend from about the midpoint of each wing outward to the tip.

They move in opposite directions - when one aileron goes up, the other goes down. Flaps extend outward from the fuselage to the midpoint of each wing. They always move in the same direction. If one flap is down, the other one is also down. Th empennage consists of the vertical stabilizer, or fin, and the horizontal stabilizer.

These two surfaces are stationary and act like the feathers on an arrow to steady the airplane and help maintain a straight path through the air. The rudder is attached to the back of the vertical stabilizer. Used to move the airplane's nose left and right. Actually, using the rudder and ailerons in combination during flight to initiate a turn. The elevator is attached to the back of the horizontal stabilizer. During flight it is used to move the nose up and down to direct the airplane to the desired altitude, or height.

Most airplanes have a small, hinged section at the back of the elevator called a trim tab. Its purpose is to relieve the pressure it must be held on the control wheel to keep the nose in the desired position. In most small airplanes, the trim tab is controlled with a wheel or a crank in the cockpit. Some empennage designs vary from the type of horizontal stabilizer.

They have a one-piece horizontal stabilizer that pivots up and down from a central hinge point. This type of design, called a stabilator, requires no elevator. Move the stabilator using the control wheel, just as in an elevator. When you pull back, the nose moves up; when you push forward, the nose moves down. An antiservo tab is mounted at the back of the stabilator, to provide a control "feel" similar to what you experience with an elevator.

Without the antiservo tab, control forces from the stabilator would be so light that it might might be "over controlled" the airplane or move the control wheel too far to obtain the desired result. The antiservo tab also functions as a trim tab. The landing gear absorbs landing loads and supports the airplane on the ground. It typically is made up of three wheels. The two main wheels are located on either side of the fuselage. The third may be positioned either at the nose or at the tail.

If it is located at the tail, it is called a tail wheel. In this case, the airplane is said to have conventional landing gear. Conventional gear is common on older airplanes, as well as on some newer ones. It is desirable for operations on unimproved fields, because of the added clearance amid the propeller and the ground.

However, airplanes with this type of gear are more difficult to handle during ground operations. When the third wheel is located on the nose, it is called a nosewheel. This design is referred to as tricycle gear. An airplane with this type of gear has a steerable nosewheel, which you control through use of the rudder pedals. Landing gear can also be classified as either fixed or retractable. Fixed gear always remains extended, while retractable gear can be stowed for flight to reduce air resistance and increase airplane performance.

Just as shock absorbers are needed on a car, some shock absorbing device is needed on the landing gear. Shock struts are designed for this purpose. They absorb bumps and jolts, as well as the downward force of landing. Airplane brakes operate on the same principles as automobile brakes, but they do have a few significant differences.

For example, airplane brakes usually are located on the main wheels, and are applied by separate pedals. Because of this, operating the brake on the left independently of the brake on the right, or vice versa is possible. This capability is referred to as differential braking. It is important during ground operations when you need to supplement nosewheel steering by applying the brakes on the side toward the direction of turn. In fact, differential braking is extremely important on conventional gear airplanes, since some do not have a steerable wheel. In small airplanes, the powerplant includes both the engine and the propeller.

The primary function of the engine is to provide the power to turn the propeller. It also generates electrical power, provides a vacuum source for some flight instruments, and, in most single-engine airplanes, provides a source of heat for the pilot and passengers. A firewall is located between the engine compartment and the cockpit to protect the occupants. The firewall also serves as a mounting point for the engine. During flight, the four forces acting on the airplane are lift, weight, thrust, and drag. Lift is the upward force created by the effect of airflow as it passes over and under the wings.

It supports the airplane in flight. Weight opposes lift. It is caused by the downward pull of gravity. Thrust is the forward force which propels the airplane through the air.

It varies with the amount of engine power being used. Opposing thrust is drag, which is a backward, or retarding, force that limits the speed of the airplane. Lift is the key aerodynamic force. It is the force that opposes weight. In straight-and-level, un accelerated flight, when weight and lift are equal, an airplane is in a state of equilibrium. If the other aerodynamic factors remain constant, that airplane neither gains nor loses altitude.

When an airplane is stationary on the ramp, it is also in equilibrium, but the aerodynamic forces are not a factor. In calm wind conditions, the atmosphere exerts equal pressure on the upper and lower surfaces of the wing. Movement of air about the airplane, particularly the wing, is necessary before the aerodynamic force of lift becomes effective. During flight, however, pressures on the upper and lower surfaces of the wing are not the same. Although several factors contribute to this difference, the shape of the wing is the principal one. The wing is designed to divide the airflow into areas of high pressure below the wing and areas of comparatively lower pressure above the wing.

This pressure differential, which is created by movement of air about the wing, is the primary source of lift. The weight of the airplane is not a constant. It varies with the equipment installed, passengers, cargo, and fuel load. During the course of a flight, the total weight of the airplane decreases as fuel is consumed. Additional weight reduction may also occur during some specialized flight activities, such as crop dusting, fire fighting, or sky diving flights.

In contrast, the direction in which the force of weight acts is constant. It always acts straight down toward the center of the earth. Thrust is the forward-acting force which opposes drag and propels the airplane. In most airplanes, this force is provided when the engine turns the propeller.

Each propeller blade is cambered like the airfoil shape of a wing. This shape, plus the angle of attack of the blades, produces reduced pressure in front of the propeller and increased pressure behind it. As is the case with the wing, this produces a reaction force in the direction of the lesser pressure. This is how a propeller produces thrust, the force which moves the airplane forward. To increase thrust by using the throttle to increase power, thrust exceeds drag, causing the airplane to accelerate.

This acceleration, however, is accompanied by a corresponding increase in drag. The airplane continues to accelerate only while the force of thrust exceeds the force of drag. When drag again equals thrust, the airplane ceases to accelerate and maintains a constant airspeed. However, the new airspeed is higher than the previous one.

When the thrust is reduced thrust, the force of drag causes the airplane to decelerate. But as the airplane slows, drag diminishes. When drag has decreased enough to equal thrust, the airplane no longer decelerates. Once again, it maintains a constant airspeed.

Now, however, it is slower than the one previously flown. As it has been seen, drag is associated with lift. It is caused by any aircraft surface that deflects or interferes with the smooth airflow around the airplane. A highly cambered, large surface area wing creates more drag (and lift) than a small, moderately cambered wing. If the airspeed is increased, or angle of attack, the drag and lift increases.

Drag acts in opposition to the direction of flight, opposes the forward-acting force of thrust, and limits the forward speed of the airplane. Drag is broadly classified as either parasite or induced. In conclusion, the basic construction of planes are really quite similar and all planes need the four forces of flight so that they are able to fly. These things are quite unique in their own way but without these things the planes would never be able to fly or even be built.