The Reason Planes Fly
Whenever I see a plane the first question
that comes to mind is "What is causing that thing to stay off of
Well I finally discovered the answer. When
a plane flys there are four forces at work that keep the plane flying.
These forces are lift, thrust, gravity, and drag.
Lift & Pressure
Airplane wings are created with a special
design called an airfoil. The airfoil design bulges out more on
the top than on the bottom. This causes the air that hit the wing to go
off into two different streams, one that goes over the top and one that
goes under and they both meet up in the back.
The air moving over the top of the wing
is caused to go faster than the slower moving air on the bottom. Faster
moving air has less pressure, so this causes the pressure on the bottom
of the wing to be greater and the plane is lifted. This effect is known
as the Bernoulli Principle. This principle was developed by Daniel Bernoulli
who was a Swiss mathematician and physician. He developed the principle
in the 18th century. When a plane creates lift it overcomes the force
of gravity that is pulling the plane down.
Air pressure plays a big part in flight
also. When you think about flight you have to realize that air pressure
is a force that is pushing on every square inch of an airplane. When a
plane is parked the air pressure is distributed evenly around the plane
surface. When the plane is in flight the pressure on top of the wings
pushes down less and the pressure on the bottom of the wings pushes more.
This is what causes the plane to feel a lift.
Another force that has a great part in flight
is drag. Drag is the force that is pulling the plane backwards. Drag is
created when the air collides with the airplanes wings and creates friction.
This friction causes the plane to slow down and feel a drag. When wings
are produced the designers have to make the wings create lift but also
minimize friction with the air.
Thrust is the force that causes a plane
to move forward and is created by the planes propeller or jet engines.
Thrust is created by a propeller by using the same concept as lift. The
propellor is specially shaped like an airfoil but it uses the lift to
pull the plane forward instead of pushing the plane up.