HOW DO AIRPLANES FLY?
                                                          


Many people wonder how is it possible that a huge piece of metal such as airplane can actually takeoff & fly in the air. Some people can't comprehend how is this possible. This goes back to my theory of not understanding the industry leads to some mental anxiety & phobias about the unknown in aviations. The more you understand the better relax you will feel, and this will reduce your anxiety level. Basically airplanes have four types of forces working against it listed below.

                                                               LIFT
                                                                  ^
                                         THRUST<--             --> DRAG
                                                                  I
                                                            WEIGHT 

So when engineers design airplanes they design it with the four forces kept in mind. They want to design airplanes that will reduce as much drag as possible. Thats why the landing gear sucks up into the fuselage of the airplane so as to reduce drag, and increase speed. Other things designers do are make the fuselage as aerodynamic streamline as possible. Thats why aircraft fuselages are shaped like a tube because airflow must flow smoothly over it. Car designers are taking notice of aerodynamics shapes too. More cars today are being designed with aerodynamics in mind so that way cars could benefit with savings on gas mileage. Aircraft designers back in the 1950's decided to swept aircraft wings back which further reduced drag, and increase the speed margin of airplanes significantly. But what makes an airplane fly is simple. Its lift, and pressure differential. A Dutch born mathematician named Bernoulli contributed a lot to aviation. In the 17th century he wrote Bernoulli's principles about lift. Basically, what he discovered was when air flows across a cross section of a wing the air divides over the wing with part of the air stream flowing above the wing, and the rest flowing beneath the wing. One thing different about this air stream is the flow of air over the top part of the wing will travel faster than the airflow beneath the wing. Thats because it has more distance to travel. The energy of the air steam is constant. The only thing that changes is the pressure of the airflow. The top part of the wing will have less pressure then the bottom half therefore causing a net force in the upward direction.. We call this Lift! When thrust is greater than drag, then we get forward momentum.  In physics, the law of motion states for every action theres a reaction. The engines create thrust by squeezing air into a compressor blade that further squeezes the air into a series of more compressor blades. The air then becomes further hot, and mixes into the air/fuel mixing chamber igniting the fuel & exhaust gases that flow out of the engine turbine creating thrust. Getting back to lift, you could demonstrate this in your car by sticking your hand out the window while driving. You will feel the pressure. Well just imagine when you tilt your hand slightly, you will feel even more pressure exerted on your hand. Similarly, when the pilot pulls back on the yoke he exerts that same pressure on an airfoil/wing called an elevator which pushes the airplane up on takeoff. Here is a great diagram below of Bernoulli's principle ,and wing diagram of lift.

                                  

Now look as the airfoil/wing start to lift off the ground. The air over the top must travel faster over the wing creating low pressure, & therefore lift.

                                  


Now that you understand lift, then you could understand that if an engine quit, that has no bearing on the airplane flying. It will not drop out of the sky. It simply becomes a glider. The space shuttle is a glider when it comes back to orbit. It glides to a landing after every mission. So when you understand these principles of lift, it will help you reduce anxiety the next time you fly.