Dynamics of Airplane Flight
is a physical substance which has weight. It has molecules which are constantly
moving. Air pressure is created by the molecules moving around. Moving
air has a force that will lift kites and balloons up and down. Air is a
mixture of different gases; oxygen, carbon dioxide and nitrogen. All things
that fly need air. Air has power to push and pull on the birds, balloons,
kites and planes. In 1640, Evangelista
Torricelli discovered that air has weight. When experimenting
with measuring mercury, he discovered that air put pressure on the mercury.
Francesco Lana used
this discovery to begin to plan for an airship in the late 1600s. He drew
an airship on paper that used the idea that air has weight. The ship was
a hollow sphere which would have the air taken out of it. Once the air
was removed, the sphere would have less weight and would be able to float
up into the air. Each of four spheres would be attached to a boat-like
structure and then the whole machine would float. The actual design was
Hot air expands and
spreads out and it becomes lighter than cool air. When a balloon is full
of hot air it rises up because the hot air expands inside the balloon.
When the hot air cools and is let out of the balloon the balloon comes
Wings Lift the Plane
Airplane wings are
curved on the top which make air move faster over the top of the wing.
The air moves faster over the top of a wing. It moves slower underneath
the wing. The slow air pushes up from below while the faster air pushes
down from the top. This forces the wing to lift up into the air.
Laws of Motion
If an object is not moving, it will
not start moving by itself. If an object is moving, it will not stop or
change direction unless something pushes it.
Objects will move farther and faster
when they are pushed harder.
When an object is pushed in one direction,
there is always a resistance of the same size in the opposite direction.
Forces of Flight
Four Forces of Flight
Lift - upward
Drag - down and backward
Weight - downward
Thrust - forward
the Flight of a Plane
How does a plane fly?
Let's pretend that our arms are wings. If we place one wing down and one
wing up we can use the roll to change the direction of the plane. We are
helping to turn the plane by yawing toward one side. If we raise our nose,
like a pilot can raise the nose of the plane, we are raising the pitch
of the plane. All these dimensions together combine to control the flight
of the plane. A pilot of a plane has special controls that can be used
to fly the plane. There are levers and buttons that the pilot can push
to change the yaw, pitch and roll of the plane.
To roll the plane to the right
or left, the ailerons are raised on one wing and lowered on the other.
The wing with the lowered aileron rises while the wing with the raised
Pitch is to make a plane descend
or climb. The pilot adjusts the elevators on the tail to make a plane descend
or climb. Lowering the elevators caused the airplane's nose to drop, sending
the plane into a down. Raising the elevators causes the airplane to climb.
Yaw is the turning of a plane.
When the rudder is turned to one side, the airplane moves left or right.
The airplane's nose is pointed in the same direction as the direction of
the rudder. The rudder and the ailerons are used together to make a turn
How does a Pilot
Control the Plane?
To control a plane a pilot uses several
The pilot controls
the engine power using the throttle. Pushing the throttle increases power,
and pulling it decreases power.
of plane in roll
raise and lower the wings. The pilot controls the roll of the plane by
raising one aileron or the other with a control wheel. Turning the control
wheel clockwise raises the right aileron and lowers the left aileron, which
rolls the aircraft to the right.
Picture of plane Yaw
to control the yaw of the plane. The pilot moves rudder left and right,
with left and right pedals. Pressing the right rudder pedal moves the rudder
to the right. This yaws the aircraft to the right. Used together, the rudder
and the ailerons are used to turn the plane.
of Plane Pitch
which are on the tail section are used to control the pitch of the plane.
A pilot uses a control wheel to raise and lower the elevators, by moving
it forward to back ward. Lowering the elevators makes the plane nose go
down and allows the plane to go down. By raising the elevators the pilot
can make the plane go up.
The pilot of the plane pushes the
top of the rudder pedals to use thebrakes. The brakes are used when
the plane is on the ground to slow down the plane and get ready for stopping
it. The top of the left rudder controls the left brake and the top of the
right pedal controls the right brake.
If you look at these motions you
can see that each type of motion helps control the direction and level
of the plane when it is flying.
Sound is made up of molecules of
air that move. They push together and gather together to form sound
waves . Sound waves travel at the speed of about 750 mph at sea level.
When a plane travels the speed of sound the air waves gather together
and compress the air in front of the plane to keep it from moving forward.
This compression causes a shock wave to form in front of the plane.
In order to travel faster than the
speed of sound the plane needs to be able to break through the shock wave.
When the airplane moves through the waves, it is makes the sound waves
spread out and this creates a loud noise or sonic boom. The sonic
boom is caused by a sudden change in the air pressure. When the plane travels
faster than sound it is traveling at supersonic speed. A plane traveling
at the speed of sound is traveling at Mach 1or about 760 MPH. Mach
2 is twice the speed of sound.
Sometimes called speeds of flight,
each regime is a different level of flight speed.
||Regimes of Flight
Most of the early planes were only
able to fly at this speed level. Early engines were not as powerful as
they are today. However, this regime is still used today by smaller planes.
Examples of this regime are the small crop dusters used by farmers for
their fields, two and four seater passenger planes, and seaplanes that
can land on water.
This category contains
most of the commercial jets that are used today to move passengers and
cargo. The speed is just below the speed of sound. Engines today are lighter
and more powerful and can travel quickly with large loads of people or
MPH - Mach 1 - Mach 5).
760 MPH is the speed of sound. It
is also called MACH 1. These planes can fly up to 5 times the speed of
sound. Planes in this regime have specially designed high performance engines.
They are also designed with lightweight materials to provide less drag.
The Concorde is an example of this regime of flight.
MPH - Mach 5 to Mach 10).
Rockets travel at speeds 5 to 10
times the speed of sound as they go into orbit. An example of a hypersonic
vehicle is the X-15, which is rocket powered. The space shuttle is also
an example of this regime. New materials and very powerful engines were
developed to handle this rate of speed.
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