Part of Aircraft (4)

Part of Aircraft (4)

RUDDER

At the rear of the fuselage of most aircraft
one finds a vertical stabilizer and a rudder.
The stabilizer is a fixed wing section whose
job is to provide stability for the aircraft, to
keep it flying straight. The vertical stabilizer
prevents side-to-side, or yawing, motion of
the aircraft nose. The rudder is the small
moving section at the rear of the stabilizer
that is attached to the fixed sections by
hinges. Because the rudder moves, it varies
the amount of force generated by the tail
surface and is used to generate and control
the yawing motion of the aircraft.
The rudder is used to control the position of
the nose of the aircraft. Interestingly, it is
NOT used to turn the aircraft in flight.
Aircraft turns are caused by banking the
aircraft to one side using either ailerons or
spoilers. The banking creates an unbalanced
side force component of the large wing lift
force which causes the aircraft’s flight path to
curve. The rudder input insures that the
aircraft is properly aligned to the curved
flight path during the maneuver. Otherwise,
the aircraft would encounter additional drag
or even a possible adverse yaw condition in
which, due to increased drag from the control
surfaces, the nose would move farther off the
flight path.
The rudder works by changing the effective
shape of the airfoil of the vertical stabilizer.
As described on the shape effects slide,
changing the angle of deflection at the rear of
an airfoil will change the amount of lift
generated by the foil. With increased
deflection, the lift will increase in the opposite
direction. The rudder and vertical stabilizer
are mounted so that they will produce forces
from side to side, not up and down. The side
force (F) is applied through the center of
pressure of the vertical stabilizer which is
some distance (L) from the aircraft center of
gravity. This creates a torque
T = F * L
on the aircraft and the aircraft rotates about
its center of gravity. With greater rudder
deflection to the left as viewed from the back
of the aircraft, the force increases to the
right. If the pilot reverses the rudder
deflection to the right, the aircraft will yaw in
the opposite direction. We have chosen to
base the deflections on a view from the back
of the aircraft towards the nose, because that
is the direction in which the pilot is looking

Part of Aircraft (6)

Part of Aircraft (6)

ELEVATOR

At the rear of the fuselage of most aircraft
one finds a horizontal stabilizer and an
elevator. The stabilizer is a fixed wing section
whose job is to provide stability for the
aircraft, to keep it flying straight. The
horizontal stabilizer prevents up-and-down,
or pitching, motion of the aircraft nose. The
elevator is the small moving section at the
rear of the stabilizer that is attached to the
fixed sections by hinges. Because the elevator
moves, it varies the amount of force
generated by the tail surface and is used to
generate and control the pitching motion of
the aircraft. There is an elevator attached to
each side of the fuselage. The elevators work
in pairs; when the right elevator goes up, the
left elevator also goes up. This slide shows
what happens when the pilot deflects the
elevator.
The elevator is used to control the position of
the nose of the aircraft and the angle of attack
of the wing. Changing the inclination of the
wing to the local flight path changes the
amount of lift which the wing generates. This,
in turn, causes the aircraft to climb or dive.
During take off the elevators are used to
bring the nose of the aircraft up to begin the
climb out. During a banked turn, elevator
inputs can increase the lift and cause a tighter
turn. That is why elevator performance is so
important for fighter aircraft.
The elevators work by changing the effective
shape of the airfoil of the horizontal
stabilizer. As described on the shape effects
slide, changing the angle of deflection at the
rear of an airfoil changes the amount of lift
generated by the foil. With greater downward
deflection of the trailing edge, lift increases.
With greater upward deflection of the trailing
edge, lift decreases and can even become
negative as shown on this slide. The lift force
(F) is applied at center of pressure of the
horizontal stabilzer which is some distance
(L) from the aircraft center of gravity. This
creates a torque
T = F * L
on the aircraft and the aircraft rotates about
its center of gravity. The pilot can use this
ability to make the airplane loop. Or, since
many aircraft loop naturally, the deflection
can be used to trim or balance the aircraft,
thus preventing a loop. If the pilot reverses
the elevator deflection to down, the aircraft
pitches in the opposite direction.

Part of Aircraft (5)

Part of Aircraft (5)

AILERON

Aileron can be used to generate a rolling
motion for an aircraft. Ailerons are small
hinged sections on the outboard portion of a
wing. Ailerons usually work in opposition: as
the right aileron is deflected upward, the left
is deflected downward, and vice versa. This
slide shows what happens when the pilot
deflects the right aileron upwards and the left
aileron downwards.
The ailerons are used to bank the aircraft; to
cause one wing tip to move up and the other
wing tip to move down. The banking creates
an unbalanced side force component of the
large wing lift force which causes the
aircraft’s flight path to curve. (Airplanes turn
because of banking created by the ailerons,
not because of a rudder input.
The ailerons work by changing the effective
shape of the airfoil of the outer portion of the
wing. As described on the shape effects slide,
changing the angle of deflection at the rear of
an airfoil will change the amount of lift
generated by the foil. With greater downward
deflection, the lift will increase in the upward
direction. Notice on this slide that the aileron
on the left wing, as viewed from the rear of
the aircraft, is deflected down. The aileron on
the right wing is deflected up. Therefore, the
lift on the left wing is increased, while the lift
on the right wing is decreased. For both
wings, the lift force (Fr or Fl) of the wing
section through the aileron is applied at the
aerodynamic center of the section which is
some distance (L) from the aircraft center of
gravity. This creates a torque
T = F * L
about the center of gravity. If the forces (and
distances) are equal there is no net torque on
the aircraft. But if the forces are unequal,
there is a net torque and the aircraft rotates
about its center of gravity. For the conditions
shown in the figure, the resulting motion will
roll the aircraft to the right (clockwise) as
viewed from the rear. If the pilot reverses the
aileron deflections (right aileron down, left
aileron up) the aircraft will roll in the
opposite direction. We have chosen to name
the left wing and right wing based on a view
from the back of the aircraft towards the
nose, because that is the direction in which
the pilot is looking.

Part of Aircraft (3)

Part of Aircraft (3)

SPOILER

Spoilers are small, hinged plates on the top
portion of wings. Spoilers can be used to
slow an aircraft, or to make an aircraft
descend, if they are deployed on both wings.
Spoilers can also be used to generate a rolling
motion for an aircraft, if they are deployed on
only one wing. This slide shows what
happens when the pilot only deflects the
spoiler on the right wing.

1. Spoilers Deployed on Both Wings

When the pilot activates the spoilers, the
plates flip up into the air stream. The flow
over the wing is disturbed by the spoiler, the
drag of the wing is increased, and the lift is
decreased. Spoilers can be used to “dump” lift
and make the airplane descend; or they can be
used to slow the airplane down as it prepares
to land. When the airplane lands on the
runway, the pilot usually brings up the
spoilers to kill the lift, keep the plane on the
ground, and make the brakes work more
efficiently. The friction force between the tires
and the runway depends on the “normal”
force, which is the weight minus the lift. The
lower the lift, the better the brakes work. The
additional drag of the spoilers also slows the
plane down.

2. Spoiler Deployed on Only One Wing

A single spoiler is used to bank the aircraft;
to cause one wing tip to move up and the
other wing tip to move down. The banking
creates an unbalanced side force component
of the large wing lift force which causes the
aircraft’s flight path to curve.
If the airplane’s right wing spoiler
is deployed, while the left wing spoiler is
stored flat against the wing surface. The
flow over the right wing will be disturbed by
the spoiler, the drag of this wing will be
increased, and the lift will decrease relative to
the left wing. The lift force (F) is applied at
the center of pressure of the segment of the
wing containing the spoiler. This location is
some distance (L) from the aircraft center of
gravity which creates a torque
T = F * L
about the center of gravity. The net torque
causes the aircraft to rotate about its center
of gravity. The resulting motion will roll the
aircraft to the right (clockwise) as viewed
from the rear. If the pilot reverses the spoiler
deflections (right spoiler flat and left spoiler
up) the aircraft will roll in the opposite
direction. We have chosen to name the left
wing and right wing based on a view from the
back of the aircraft towards the nose,
because that is the direction in which the pilot
is looking.

Part of Aircraft (2)

Part of Aircraft (2)

FUSELAGE

The fuselage, or body of the airplane, is a
long hollow tube which holds all the pieces of
an airplane together. The fuselage is hollow
to reduce weight. As with most other parts of
the airplane, the shape of the fuselage is
normally determined by the mission of the
aircraft. A supersonic fighter plane has a
very slender, streamlined fuselage to reduce
the drag associated with high speed flight. An
airliner has a wider fuselage to carry the
maximum number of passengers. On an
airliner, the pilots sit in a cockpit at the front
of the fuselage. Passengers and cargo are
carried in the rear of the fuselage and the fuel
is usually stored in the wings. For a fighter
plane, the cockpit is normally on top of the
fuselage, weapons are carried on the wings,
and the engines and fuel are placed at the rear
of the fuselage.
The weight of an aircraft is distributed all
along the aircraft. The fuselage, along with
the passengers and cargo, contribute a
significant portion of the weight of an
aircraft. 
The center of gravity of the aircraft
is the average location of the weight and it is
usually located inside the fuselage. In flight,
the aircraft rotates around the center of
gravity because of torques generated by the
elevator, rudder, and ailerons. The fuselage
must be designed with enough strength to
withstand these torques.

Part of Aircraft (1)

Part of Aircraft (1)

1. WING

For any airplane to fly, one must lift the weight of the airplane itself, the fuel, the passengers, and the cargo. The wings generate most of the lift to hold the plane in the air. To generate lift, the airplane must be pushed through the air. The air resists the motion in the form of aerodynamic drag. Modern airliners use winglets on the tips of the wings to reduce drag. The turbine engines, which are located beneath the wings, provide the thrust to overcome drag and push the airplane forward through the air. Smaller, low-speed airplanes use propellers for the propulsion system instead of turbine engines.

2. TAIL

To control and maneuver the aircraft, smaller wings are located at the tail of the plane. The tail usually has a fixed horizontal piece, called the horizontal stabilizer, and a fixed vertical piece, called the vertical stabilizer. The stabilizers’ job is to provide stability for the aircraft, to keep it flying straight. The vertical stabilizer keeps the nose of the plane from swinging from side to side, which is called yaw. The horizontal stabilizer prevents an up-and-down motion of the nose, which is called pitch.

*Part of Wings and Tail

At the rear of the wings and stabilizers are small moving sections that are attached to the fixed sections by hinges. Changing the rear portion of a wing will change the amount of force that the wing produces. The ability to change forces gives us a means of controlling and maneuvering the airplane. The hinged part of the vertical stabilizer is called the rudder; it is used to deflect the tail to the left and right as viewed from the front of the fuselage. The hinged part of the horizontal stabilizer is called the elevator; it is used to deflect the tail up and down. The outboard hinged part of the wing is called the aileron; it is used to roll the wings from side to side. Most airliners can also be rolled from side to side by using the spoilers. Spoilers are small plates that are used to disrupt the flow over the wing and to change the amount of force by decreasing the lift when the spoiler is deployed. The wings have additional hinged, rear sections near the body that are called flaps. Flaps are deployed downward on takeoff and landing to increase the amount of force produced by the wing. On some aircraft, the front part of the wing will also deflect. Slats are used at takeoff and landing to produce additional force

3. FUSELAGE

The fuselage or body of the airplane, holds all
the pieces together. The pilots sit in the
cockpit at the front of the fuselage.
Passengers and cargo are carried in the rear
of the fuselage. Some aircraft carry fuel in the
fuselage; others carry the fuel in the wing