The Parts of a Remote Control Aircraft

RC airplanes are made up of many different parts. Even if you buy an airplane that’s already assembled, you’re going to need to learn every part if you make more than one flight–because you’re going to break something, and then you’re going to have to fix it.

Don’t worry, airplanes only have a few parts, and they’re all user-replaceable. The parts are:

• Battery. Connects to the ESC and supplies the power for the motor, receiver, and servos. The bigger the battery, the faster the motor spins (if your ESC and motor can handle the power).

• Electronic Speed Control (ESC). Think of this as the power distribution center. It connects to the battery, the receiver, and the motor. Based on signals from the receiver, the ESC sends more or less power to the motor. The ESC sends power to the receiver, which the receiver uses to power the servos, using a built-in battery eliminator circuit (BEC). ESC’s have some intelligence, and won’t spin the motor when you first turn the transmitter on even if the throttle is turned up (to prevent you from hurting yourself). They also monitor the power coming from the battery, and cut the motor off before the battery runs completely out so that the battery will have enough power left to move the servos, allowing you to control your plane while you glide it in for a landing. You need a different ESC for brushed or brushless motors.

• Motor. Connects to the ESC and the propeller. Spins faster when the ESC gives more power. Electric motors can be brushed or brushless. Brushed motors typically have a gear that spins the propeller faster than the motor. Brushless motors, which last longer than brushed motors, usually connect directly to the propeller without a gear (they can spin much faster). The picture below shows a brushless motor.

• Propeller. Connects to the motor and spins, pushing wind behind it. The bigger the diameter, the more air the prop pushes with each spin. The deeper the pitch, the faster the prop pushes the wind. The picture above shows the propeller conneced with a prop saver, which lets the propeller bend instead of breaking when you crash the plane into something.
• Receiver. The radio that receives signals from your transmitter. Connects to the ESC and the servos, and sends them signals indicating how far the corresponding stick on the transmitter is being pushed. The receiver has a long wire hanging out of it–that’s the antenna, which receives the radio waves from the transmitter. The receiver has to be the same frequency as the transmitter. You control the frequency using a crystal, which can typically be swapped out.

• Servos. Turn a few degrees to move the control surfaces (the rudder, elevator, and ailerons) on the airplane. Connects to the receiver and the control horns. The first picture below shows two servos connected to a Slo-V fuselage–notice that the control wires (which connect to the control horns) are attached to the servos using “Z-bends”. The arm on top of the servo twists around the screw. Servos typically include several control arms in different shapes. The second picture shows a servo disconnected from an airplane. Beginner planes typically have two servos, while more advanced planes can have five or more servos.

• Control horns. Small pieces of plastic that connect to the control surfaces and, using a stiff control wire, the servos. The control horns connect to the control surfaces, which are the movable parts of the airplane’s wings and tails (the rudder, elevator, and/or ailerons) that control the direction of the airplane by pushing wind in different directions.

This diagram shows how the electrical components are connected:

And here’s a picture of a Slo-V (it’s like a Slow Stick with a V-shaped tail) with the wing off to show all of the parts. Click the thumbnail to view the full-sized picture.