The New Look Of Flying Machines Essay

, Research Paper

Most people are familiar with the Standard Configuration, the most common airplane design. However, recent revelations in both military and general aviation have shown at least a slight movement toward different arrangements of an airplane’s lift and control surfaces. These variations in aircraft structure include the canard configuration and the flying wing.

First, we must understand the basic principles of flight before any different configurations of lift surfaces can be discussed. In order for any object to gain lift, it must have a force pushing it upwards which is greater than its weight. This force, called lift, results from the differing pressures on the upper and lower surfaces of the wing. The air that hits the leading edge of the wing separates. Part goes over the wing, and part travels underneath it. The top of the wing curves, or is cambered, causing the air passing over the top of the wing to go faster than the air passing under the wing. The lower surface of the wing is relatively flat, so air travels at, or near, its normal speed. Bernoulli’s Law says that as the speed of gas or fluid increases its pressure decreases (Pappas 2).

Therefore, there is a greater air pressure under the wing than there is above the wing. This greater pressure under the wing pushes the plane up. When this force exceeds the pull of gravity on the aircraft, flight is achieved.

Two other forces affect an aircraft’s movement through the air: thrust and drag. Thrust is the force provided by an aircraft’s power plant which pushes or pulls it forward through the air. Drag, which counteracts thrust, is the force of wind resistance against the aircraft. It is supplemented by various appendages on the aircraft, such as the wings, stabilizers, and the fuselage. The less drag there is on an aircraft, the faster and more economically it can fly. Drag can be reduced by eliminating items which disrupt airflow.

The wing, horizontal stabilizer and vertical stabilizer of an aircraft have, at their trailing edges, control surfaces which change the direction of flight by altering the lift characteristics of the surface which house them. The flaps, which are designed to increase the lift of the wings on take-off and landing, are lowered. The increased camber of the upper surface causes the air flowing across the wing’s upper surface to move even faster, decreasing the air pressure on the upper surface. This increases the force on the bottom of the wing and increases the lift. The ailerons, which control the rolling motion of the plane, shift in opposite directions. When the airplane is to turn to the right, the aileron on the left wing lowers, increasing the lift on that wing. At the same time, the aileron on the right wing is raised, which creates an opposite-lift effect, and the aircraft “rolls” to the right. The opposite is true for a left turn. The rudder works similarly: to yaw to the right, the rudder swings right, creating a greater pressure on the right side of the vertical stabilizer. This causes the tail of the plane to shift to the left, and the plane pivots about the vertical axis, pointing the nose right. The opposite is true for left yaw. Elevators, which control the pitch of the plane, work differently for each configuration. They will be discussed separately.

Today, the Standard Configuration is the most prevalent design of personal, commercial and military airplanes. The main wing is located about a third- or half-way from the nose of the aircraft, close to the center of gravity, and serves as the lateral axis. The empennage at the tail of the plane consists of the horizontal stabilizer and the vertical stabilizer.

The horizontal stabilizer provides lateral stability and houses the elevator, which controls the pitch of the aircraft. In the Standard Configuration, because the horizontal stabilizer and the elevator are aft of the lateral axis. A downward motion of the elevator increases the lift of the airplane’s tail. As the tail rises, the plane pivots on the lateral axis, and the nose points downward. An upward motion of the elevator decreases the lift of the tail, pushing it downward. The aircraft pivots in the opposite direction, causing the plane to climb. The vertical stabilizer gives longitudinal stability and houses the rudder, which controls the aircraft’s bearing, or yaw.

The Standard Configuration is the most common and most popular design “because a relatively small and light surface can be made to provide control and stability over a fairly wide range of centers of gravity, with economy of effort and a fairly modest penalty in weight (Stinton 389).

The Canard Configuration, a second arrangement of aircraft lift and stabilizing surfaces, is named for the canard, or “forward-wing,” which is the basis of its design.

After nearly forty years of more-of-the-same aircraft design, general aviation is suddenly breaking the mold and racing into the future with new planes that challenge traditional thinking (Popular Science 74).

The tail-first idea is not new. Many of the gliders built and flown by aviation pioneers such as Lilienthal and the Wrights were built on the Canard Configuration (Stinton 151). This configuration has not been used much in the past, but we may see more aircraft manufacturers moving to this design.

The operation of the elevators is opposite that