Are you familiar with the different types of drag? All airplanes experience drag during flight. Along with weight, thrust and lift, it’s one of the four forces of flight.
Drag is the invisible force that opposes objects in motion. As airplanes move through the air, they will encourage resistance known as drag. There are several different types of drag, however. To learn more about these types and how they differ, keep reading.
Form Drag
Form drag is a type of parasitic drag that’s caused by the shape or form of an airplane. It’s the result of air moving around an airplane’s body, wings, tail and other components. Airflow over these components creates areas of low pressure, which slows down the airplane. Airplanes with a streamlined shape are less susceptible to form drag.
Skin Friction Drag
Skin friction drag is another type of parasitic drag. When air flows over the surface or “skin” of an airplane, it creates friction. The greater the friction, the more resistance the airplane will encounter. To minimize skin friction drag, airplanes are often designed with smooth, well-polished skin materials.
Interference Drag
A third type of parasitic drag is interference drag. It occurs in places where two or more aircraft components meet. For example, the area where the wings meet the fuselage or the tail meets the fuselage will likely create interference drag. These areas disrupt the flow of air, thereby creating resistance in the form of interference drag.
Induced Drag
There’s also induced drag, which isn’t classified as a type of parasitic drag. Induced drag is the result of air vortices. Airplanes generate lift from the difference in air pressure as air moves over and under the wings. Low-pressure air occurs below the wings, whereas high-pressure air occurs over the wings. When this occurs, air vortices will form that expose the airplane to resistance or induced drag.
Wave Drag
Finally, there’s wave drag. Wave drag occurs when airplanes approach the speed of sound. As near-Mach speeds, shock waves will form. These shock waves will expose the airplane to resistance. And like with the other types of drag mentioned above, wave drag slows down airplanes.
In Conclusion
There are many different types of drag, including form, skin friction, interference, induced and wave. Form, skin friction and interference are all types of parasitic drag. Induced and wave drag, on the other hand, are uniquely different. Regardless, they are all forms of resistance that oppose airplanes in motion.
