Up, Up and Away! - Airplanes

The airplanes unit begins with a lesson on how airplanes create lift, which involves a discussion of air pressure and how wings use Bernoulli's principle to change air pressure. Following these lessons, students learn how airplanes are controlled and use paper airplanes to demonstrate these principles. Students learn about different kinds of airplanes and then design and build their own balsa wood airplanes based on what they have learned.

In designing airplanes, trains, cars, rockets and bicycles—nearly everything that moves through the air—engineers must understand Bernoulli's principle. The forces caused by moving air enable airplanes to fly and trains to slow. Engineers take advantage of the nature of air pressure so their designs of these and many other applications, function correctly, efficiently and safely. Engineers manipulate air pressure to create lift; they design wings so that the air moves faster over the top than under them, causing aircraft to lift during takeoff and during flight.

Weight is another important aspect of aircraft design that engineers take into consideration. Every additional part or piece on an airplane adds weight that makes it harder for it to overcome the force of gravity. So, when engineers design airplanes, they minimize weight when choosing materials and parts, while still assuring strength and safety. Engineers also design systems that create an action called thrust (utilizing Newton's third law of motion). To create thrust, engineers may use propellers, jets or rockets; the heavier the airplane, the more thrust required to move it.

When designing airplanes, engineers also keep in mind the force of drag and the principle of energy conservation. Since drag slows down airplanes and makes them less efficient, the goal is to design planes that reduce drag. The process of iterative design helps engineers learn from the mistakes of previous designs. Engineers often build small-scale aircraft models to test how they fly, avoiding the expense of testing at full-size, and they experiment with many different designs to find the best one. Engineers also use computer models to test aspects of their designs before they build the real thing; this is less expensive, easier and quicker since they can learn from the mistakes on the small-size, inexpensive models.

Engineers take into consideration the purpose of the airplane when they design it. Over the years, engineers have advanced the design of airplanes so they are more sophisticated and specialized. Engineers also design aircraft support systems and structures, such as runways, airports and support vehicles.

When designing new airplanes, engineers follow the steps of the engineering design process, and use invention techniques such as brainstorming, to come up with new ideas. Since engineers almost always work in teams, the ability to work together to come up with ideas and solutions is important. Engineers share their thoughts and build upon each others' ideas to come up with creative design solutions.