MODELING TERMINOLOGY
Here's a glossary of common RC airplane modeling terms and their definitions.

Aileron: roll control surface.

Airfoil: the shape of the wing's rib.

Angle of attack (AoA): the angle difference between the wing-chord line
and the relative wind.

Auxiliary channel: any radio channel function other than the four basics (aileron, rudder, elevator and throttle).


BEC (battery eliminator circuit): a feature of some speed control units that permits both the motor and the receiver to be powered by the same battery.

Bulkhead: a vertical former inside a fuselage.

CA (cyanoacrylate): a modern hobby adhesive that cures very quickly.

Center of gravity (CG): the balance point of a model airplane.

Control linkage: any linkage transmitting servo movement to a control surface.

Control surface: a movable surface such as elevator, rudder and aileron.

Dihedral: the upward sweep angle of the wing panels; it provides stability.

Doubler: a second piece of balsa or plywood added to the fuselage side to enhance strength.

Drag: air resistance that slows the model.

Elevator: pitch-control surface.

ESC (electronic speed control): the unit that controls the rpm of the motor.

Flare: a gradual increase in pitch angle to bleed off excess airspeed just before landing.

Fuselage: the main body of the airplane.

Horizontal stabilizer: the flight surface that supports the elevator and also helps to stabilize the model in pitch.

Leading edge (LE): the foremost edge of an airfoil or propeller.

Lift: the aerodynamic force generated by air flowing around an airfoil that is equal to or greater than the weight of the aircraft and acts opposite to the force of gravity.

Moment (nose moment, tail moment): refers to a distance on a model forward or aft of the balance point.

Over-control: excessive control inputs that overcompensate for unwanted model movement.

Receiver: the part of the radio system that converts radio signals sent by the transmitter into electrical impulses.

Rib: the internal, vertical portion of the wing that gives it an airfoil-shaped contour.

Rudder: the vertical control surface that controls yaw.

Servo: an electromagnetic device that moves the control surfaces and is controlled by the electrical impulses from the receiver.

Stall: the point at which the wing experiences a loss of lift; the aircraft will tend to drop abruptly.

Trailing edge (TE): the aft-most edge of an airfoil or propeller.

Transmitter: the hand-held part of the radio system that sends the signal to the receiver.

Trim: the adjustment of a model's control surfaces to obtain a stable and balanced flight performance.

Vertical fin: a fixed, vertical stabilizer that reduces the model's tendency to yaw about the vertical axis.

Wing chord (chord): the distance measured horizontally between the wing's LE and TE.

Yaw: the left or right movement of an aircraft's nose about its vertical axis.

Z-bend: shaped like a “Z,” it is the simplest way to connect a pushrod to a control horn or servo-output arm.