Posted 12-12-2005 at 12:22 AM

Small Aircraft Control Surfaces

By Yvonne Volante

Anyone who has held their hand out of a car into the wind to
play airplane already has a fundamental impression of control
surfaces on the airplane.

When the heel of the palm went down, the airpressure under the
hand pushed the hand up. That's called lift. The airflow
over/under the hand changes with the shape of the hand or
airfoil. If you had little cut-outs near your wrist, there
wouldn't be as much lift.

The tail section contains control surfaces for keeping the
plane stable and controllable.

1) Horizontal: The horizontal, non-moving part is called the
stabilizer, and it prevents uncontrolled up-and-down motion of
the nose. The small hinged sections on each side are called
elevators, which work in unison. It is controlled by the
cockpit control wheel/stick and increases or decreases lift.
When forward pressure is applied on the wheel, the elevators
move downward, which increases the length of the tail causing
more lift, which forces the tail upward, causing the nose to
drop. There is also a small hinged section in the elevator
which is controlled by a small vertical wheel on the cockpit
console which is used to finetune the elebator trim. Hense the
name trim tab.

2) Vertical: The vertical non-moving part which prevents the
nose from uncontrolled swinging side to side. The large hinged
section is the rudder. The rudder is controlled by the foot
pedals in the cockpit, and deflects the tail to the right or
left.

The wings generate most of the lift to hold the plane in the
air. Different models of aircraft will have wings of different
shapes and in different vertical locations. On a Cessna, the
wing is high, and on a Piper, it is low. On an F14, the can
change from a forward angle to "swept back".

On most small planes, the wings also carry the fuel.

There are many control surfaces on a wing:

1) The aileron is the hinged part of the back of the wing
towards the tip which is used to roll the wings from side to
side. There is one on each side of the plane and they work
opposite of each other. When one moves up, the other moves
down.

2) Flaps are the hinged sections on the back of the wing near
the fuselage. Flaps are deployed downward on takeoff and
landing to increase the lift produced by the wing and allows
the plane to fly at slower speeds.

3) Spoilers and Slats are used on high performance/commercial
aircraft and also changed the aerodynamics of the wing.

About the Author: Yvonne Volante, webmaster for
http://www.fixairplanes.com is a big fan of flying and flight
travel. She operates a web site that is devoted to flying and
aviation resources. Email her at yvonne@fixairplanes.com

Source: http://www.isnare.com