Aircraft

Analyses
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