Wilbur Wright
and Orville Wright invented the airplane, which they patented as a
"flying machine". The first engine-powered airplane to fly was the
Kitty Hawk on December 17, 1903. Orville and Wilbur Wright, American
inventors and aviation pioneers, achieved the first powered,
sustained, and controlled flight of an airplane. Wilbur first became
interested in the idea of mechanical flight after reading of Otto
Lilienthal's successful gliding experiments in Germany.
In 1891 a German engineer Otto Lilienthal began experimenting with
hang gliders. Lilienthal took seriously the ideas advocated by Sir
George Cayley almost a hundred years earlier. Through an extensive
study of birds and bird flight, Cayley realized that the lift
function and the thrust function of bird wings were separate and
distinct, and could be imitated by different systems on a fixed-wing
craft. Lilienthal began his work on heavier-than-air craft not by
developing a complete airplane, but instead by focusing his efforts
on a fixed-wing glider.
Aerodynamic Forces
Airplane fly due to aerodynamic forces which are lift, weight,
thrust and drag.
Thrust = Drag
Lift = Weight
At above relationship, the plane will fly straight. If we increase
amount of drag and it becomes larger than the amount of thrust, the
plane will slow down. If the thrust is increased and becomes greater
than the drag, the plane will speed up. In the same way, if the
amount of lift drops below the weight of the airplane, the plane
will descend. By increasing the lift, plan will go upwards.
Thrust
Thrust is an aerodynamic force that must be created to overcome the
drag force. Thrust using Propellers, jet engines or rockets are used
to create thrust in airplanes.
Drag
Drag is an aerodynamic force that resists the motion of an object
moving through air and water. The amount of drag that airplane
creates depends size of plane, it’s speed and density of the air.
Weight
Weight of air plane forces the plane downwards.
Lift
Lift is the aerodynamic force that holds an airplane in the air. Due
to this force we can fly in the air.
The Longer Path Explanation
The top surface of a wing is more curved than the bottom surface.
Air particles that approach the leading edge of the wing must travel
either over or under the wing. Research has proved that the particle
traveling over the top goes a longer distance in the same amount of
time. It means they must be traveling faster.
The air which moves fast at the bottom of the wing surface creates
low pressure and the air which moves slowly at the top of the
surface creates high air pressure, that’s why high air pressure area
pusses the wing upwards. The Longer Path explanation is correct in
more than one way. First, the air on the top surface of the wing
actually does move faster than the air on the bottom -- in fact, it
is moving faster than the speed required for the top and bottom air
particles to reunite, as many people suggest. Second, the overall
pressure on the top of a lift-producing wing is lower than that on
the bottom of the wing, and it is this net pressure difference that
creates the lifting force.
The Newtonian Explanation
According to Newton’s Third Law, “For every action there is an
equal, and opposite, reaction. According to Newton, air molecules
behave like individual particles, and that the air hitting the
bottom surface of a wing behaves like shotgun pellets bouncing off a
metal plate. When individual particles strike to the bottom surface
, they deflect downwards, and in the reaction a opposite force push
the wing upward. In this way wings lift the airplane.
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