Understanding how an airplane flies

Whether you enjoy flying or dread it, at one time or another you may have wondered how an airplane flies. The question may come when you?re watching a plane take off or staring out the tiny window as the flight attendants demonstrate buckling a seat belt.

Before take-off, wouldn?t it be nice to watch a simple video on how a plane lifts into the sky and keeps us there for hundreds, sometimes thousands of miles?

A thorough answer to how an airplane flies is long enough to fill a book. If it were simple, the first settlers to America would have skipped the ships and hopped on a plane. Here?s a basic explanation of the basic principles that enable a massive metal vehicle to launch into the air and travel great distances.

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The four basic aerodynamic forces that make an airplane fly are: Weight, Drag, Thrust and Lift. Planes speed up when the thrust is greater than the drag and ascend when the lift is greater than the weight. For an airplane to fly straight the following equation must happen:

Thrust = Drag and Lift = Weight

Thrust 

Airplanes create thrust with propellers or jet engines. For example, propellers produce thrust by pulling air past the blades, which creates the powerful force that moves the plane forward.

Drag

Drag is the aerodynamic force that produces the resistance an object encounters when moving through air. Drag can slow an air plane when the air flow is opposite from the direction of a plane. The air planes narrow shape enables it to cut through the air easier as the more surface area an object has, the greater the drag will be.

Weight

This is the plane?s actual weight with fuel, passengers and luggage. Maximum takeoff weight for a 747 plane is 870,000 pounds.

Lift

Lift is the aerodynamic force that keeps an air plane in the sky. It?s created when a plan travels fast enough to lower the pressure on the wing?s top surface. The wing?s lower surface then has greater pressure, which lifts the plane into the air.

Once in the air, the plane?s design causes the air flow to travel faster, creating an area of low pressure for the plane to travel continuously. As the Aeronautics Learning Laboratory puts it, ?lift is that force which opposes the force of gravity (weight).?

To drastically oversimplify Newton?s laws, an airplane is able to fly when opposite forces push and pull one another. This is described by the Aeronautics Learning Laboratory as a tug of war.

References:
Aeronautic Learning Laboratory: How airplanes fly
RC Airplane World: How planes fly