Physics of a Plane Crash :: physics airplane landing land

There is an old saying that any landing you can walk away from is a good landing. There is a lot of truth to this statement, especially if you are the one walking away. Here are the stories of two such landings that I am personally familiar with. Since they are both very similar in nature, they will be discussed simultaneously in the pages to follow. N9KF was a Model 1 Kitfox. It was built and flown by my father. The Kitfox is an experimental, homebuilt kit plane. Every plane, like every person, has a story. This is the story of N9KF or at least the story as I know it. NEWTON'S LAWS - A Brief Review Newton's First Law An object remains at rest/motion unless an external force acts upon it.(Newman) Newton's Second Law The acceleration of a body or object is directly proportional to the net force acting on the body or object and is inversely proportional to its mass. (F=ma)(Newman) Newton's Third Law For every action force, there is an equal and opposite reaction force.(Newman) Forces of Flight LIFT Lift is generated by the air flow around the plane's wing. This effect is explained mostly by Bernoulli's Principle which states that the pressure of the air decreases as the velocity of the air increases. The design of a plane's wing changes the airflow around the wing's surface. The air has farther to travel over the top of the wing than the air traveling below the wing. Therefore, the air traveling above the wing is traveling at a higher velocity than the air traveling below it. As air flows around the wing, a high pressure region with low air velocity is created below the wing, and a low pressure region with high air velocity is created above the wing. The difference between the two pressures generates the lift force. (JEPPESEN 1-11) Newton's third law, stated above, explains how the remaining lift force is produced. Lift is generated when the air hits and is deflected off of the underside of the wing. This deflection of air downwards, in turn, causes an upward lift force on the wing since there must be an "equal and opposite reaction force."(Newman) This force accounts for a relatively small portion of the total lift generated for a wing.(JEPPESEN 1-13) WEIGHT Weight is one of the opposing forces to lift. From Newton's second law, the weight of an object is the magnitude of the force of gravity on that object.