The Basics of RC Aerodynamics

In all aspects of aviation, from real airplanes to RC fliers, aerodynamics play an essential role. Without these laws a plane or other aircraft would never get off the ground. A basic understanding of aerodynamics can help any RC enthusiast with their passion.

rc heli

While most people believe that radio control is all about the transmitter, without understanding how these laws work a hobbyist may very well wreck his or her vehicle. A lesson learned before flying can be easier on the pocket.
Thrust 
Thrust in RC craft usually refers to the thrust created by the propeller. Unlike large real planes where the thrust is created by jet engines mounted on the wings. (With the exception of smaller prop planes).
The propeller forces air back toward the wings. This makes the plane move forward. Today only one propeller is used for many light aircraft, but when flight was just beginning the 1903 Wright Plane had two large scale ‘pusher’ propellers. Today’s aircraft have their propellers located in the front part of the engine while the 1903 version had its’ two behind the plane.
Drag 
Drag is used in many different vehicular sports – rather, the term is. The shape of a plane or other craft will affect how much resistance that must be overcome for the craft to be moved forward. Smooth surfaces and shapes allow the plane to cut through the air better as the drag is reduced. Parasitic drag is the technical term. It pays to remember that not only does the smoothness and shape of a plane crate drag, so does everything added to it. Wheels, landing gears, photography equipment, and more will all create drag.
Another type of drag is caused by the secondary effects of lift. Some of the lift pulling a craft into the air also pulls the plane backward which then causes the craft to slow. This second type of drag is called induced drag.
Weight 
Just as important as drag is weight. Much easier to understand than most aerodynamic laws, weight is the pull of gravity on an aircraft. The more weight, the more thrust and lift the craft will need in order to create lift. Weight is calculated into the manufacture of aircraft large and small. Adding things to an RC craft can significantly change how a craft will fly. If it will fly at all.
Lift 
Lift can be hard to understand compared to the other forces of aerodynamics. The concept can be simplified by this explanation:
When air flows over a wing shape, the speed on top of the wing is faster than the air flow underneath. This is important because the faster airflow causes there to be less pressure on the top of the wing while underneath the slowed air has more upward pressure. The upward pressure causes the wing and body of a plane to lift into the air.
Lift is also affected by the angle of the wing. When the wing is angled up, the air is deflected down. This pushes the plane into the air further. An example of deflection is during lift-off. Differential air flow lift is in motion when the plane is flying steadily.
Deflection can also be viewed when a plane comes in for a landing. The angle of the wings can cause a smooth landing or a straight drop into the ground. A seasoned operator will do their best to avoid the inevitable crashes of trying to land with a too steep angle.

As breakthroughs are made, more strides are being made with how these laws affect the RC aircraft world. Learn more about RC aircraft, such as collective pitch and fixed pitch, as well as surf our entire aircraft category for more information.