How Does An Airplane Fly?
Even though there are so many different kinds of airplanes, they all fly in similar ways! Once you learn the basics, you can understand much about how any airplane flies.
The Four Forces of Flight
- Lift: Created by our wings
- Weight: The force of gravity
- Thrust: The forward force created by our propeller
- Drag: The force that slows us down. Our thrust acts against drag
What’s an Airfoil?
An airfoil is a surface that generates lift. The wings are the most noticeable airfoil on an airplane, but the propeller and flight controls are also air foils. Airfoils work by causing air to change speed as it goes over the surface, creating a pressure difference that becomes lift for a wing, or thrust for a propeller.
Engines
Engines come in different forms. They all work by sucking in air, compressing it, adding fuel and igniting the mixture. This creates an explosive forces that drives mechanical parts in a piston engine, or shoots out the back in a jet, creating thrust.
Piston Engine: The piston engine is similar to the engine found in a car. A metal disk called a piston moves back and forth in a hollow cylinder. At it moves, other parts of the engine introduce fuel and air and get rid of exhaust. The movement of the piston rotates a long shaft which is connected to the propeller. An engine usually has many pistons working together to turn the propeller.
Jet: A jet engine is made of a TON of little blades, which rotate to compress air. Once the air is compressed, the engine sends fuel into the air and ignites it. The large explosion of air from the back of the engine causes the airplane to move forward. It’s kind of like how letting go of the air in a balloon causes it to zip around the room!
Turboprop: A turboprop uses the power from a smaller jet engine to turn a very large propeller. Because propellers tend to be more efficient at slower speeds and lower altitudes, the turboprop is often ideal for short segment flights that aren’t long enough for a jet.
Flight Controls
Elevator: The elevator helps the airplane move up or down. When we move the elevator it points the nose up or down and the airplane follows. When we climb or descend, takeoff or land, the elevator is used to move the nose where we want it to go.
Rudder: The rudder helps us move the nose left and right. We mostly use the rudder to keep the nose aligned with the direction we want to move. It’s especially important when we land or takeoff in a crosswind, and when we turn.
Ailerons: Ailerons cause the airplane to roll and bank, which points our wings in the direction we want to go. When we need to turn, we use the ailerons and then use the rudder if we need to for aligning the nose with the direction of our turn.
Flaps: Flaps are used to add drag so that we can descend without picking up speed. Think about rolling down a hill on your bike: as you go downhill you go faster and faster. The same is true with airplanes. But, in an airplane, when we land we don’t want to be moving too fast. The flaps help us stay slow. They are sometimes also used for takeoff to help us takeoff with a smaller runway. They aren’t often used outside of for takeoff and landing.