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Helpful RC Terms And Definitions


A style of flying fixed-wing RC aircraft that involves maneuvers where the plane hovers and flies below its minimum stalling speed, with the plane depending on the power of its motor rather than on lift from its wings to keep it in the air.

Academy of Model Aeronautics

Commonly called the “AMA”, it is the leading and largest organization for model aircraft builders and fliers in the United States. It represents the United States to international flying organizations and it lobbies for model aircraft interests with local, state, and federal governments and agencies. It also operates a model airplane museum, oversees contest regulations, produces and distributes a magazine and provides insurance protection for most model-airplane-related risks.

Adverse yaw

On some aircraft, attempting to use the ailerons to bank in one direction — say to the left as in beginning a left turn — causes the aircraft to yaw in the other direction, in this case to the right. The primary cure, discovered by the Wright brothers, is to use rudder to counteract the yaw. Another fix is to design the ailerons to move more up than down.


A control surface, usually attached to or part of the trailing edge of the wing, used to cause the plane to roll. With standard ailerons, raising the left aileron and simultaneously lowering the right aileron will result in a bank to the left.


A vertical cross-section of the wing, i.e., what you would see if the wing were cut by a vertical knife while the plane was flying straight and level and you looked at the wing from where the wing tip used to be. The shape of the airfoil can have significant influence on the flying qualities of an airplane.


See Academy of Model Aeronautics.

Angle of attack

If you picture a wing as a flat sheet of material, the angle between that sheet and a line parallel to the oncoming wind.

Angle of incidence

If you picture the wing as a flat sheet of material, the angle between the wing and the centerline of the fuselage.

ARF Almost Ready To Fly

A model airplane kit that requires only a few hours of assembly before it is ready to fly. Typically, some preparation of the parts is required, glue may have to be used, radio equipment must be installed, and the motor or engine may or may not be installed by the manufacturer. Many accessories needed for flight such as wheels and propellers are included. The transmitter is usually not included as part of the kit.


(1) The orientation of an aircraft. See pitch, roll, and yaw. (2) A description of the author.

Brushed motor

The most common and least expensive form of electric motor used in model airplane propulsion. If an electric motor is not designated “brushless” then it is almost certainly a brushed motor. See Brushes. Also see Brushless.


A part of brushed electric motors, they convey current to the rotating element (the armature) and also mechanically effect the switching on and off of the armature’s wire-coil electromagnets which, in turn, cause the armature to rotate.

Brushless motor

A form of electric motor which does not contain brushes. They are favored because of their greater power-to-weight ratio, longevity and higher efficiency than electric motors that have brushes. Armature wire-coil electromagnets are fixed and are energized in sequence, causing magnets fixed to the prop shaft to spin the shaft.


A small part, made of plastic or metal, which is used to attach a pushrod to a control horn or to a servo arm. Typically, it screws onto the pushrod and clips onto the control horn so that at the field, the position of the control surface can be easily adjusted by unclipping the clevis from the horn and screwing or unscrewing it to adjust the length of the pushrod assembly.

Expanded scale voltmeter.

A kind of voltmeter designed to measure  a specific, narrow range of voltage.


A human appendage designed to be whacked by model plane propellers and glued to model plane assemblies by cyanoacrylate adhesives.


An aircraft that derives the majority of its lift from wings that do not flap or rotate. This term is usually used to separate airplanes from helicopters.


(verb). A device is said to fly if it can move through the air at a constant speed along a straight line. To move in this way the device must generate a vertical force, which we informally call lift.

Lithium batteries

A kind of battery that, for a given capacity, weighs significantly less than alkaline, NiMH, or NiCd batteries.

Lithium-Polymer batteries

(Li-Poly). A kind of rechargeable lithium battery that can supply higher currents than other lithium-based batteries.


A device used primarily on glow engines (and sometimes other internal combustion model aircraft engines) to reduce the noise of their exhaust. It is recommended that mufflers always be used to protect the flier from ear damage, the neighbors from annoyance and the club from losing its field.


Familiar name for the North American P-51 single-seat fighter of WWII. Probably the second-most modeled aircraft in the United States.

Nickle-cadmium batteries (NiCd)

A kind of rechargeable battery often used to power transmitters, receiver packs in RC airplanes, and as motor batteries. They are becoming less popular in many applications and are being replaced by the lighter NiMH batteries and by still lighter Lithium batteries. Nicklecadmium batteries contain toxic metals and must be disposed of as hazardous waste.

Nickle-metal hydride batteries (NiMH)

A kind of rechargeable battery often used to power transmitters, receiver packs in RC airplanes and as motor batteries.


An airplane that obtains both its lift and thrust from flapping wings; a mechanical bird.

Piper Cub

(1) A two-seat aircraft introduced before WWII, probably the most-modeled aircraft in the United States. Its proportions are such that most models of this aircraft fly well. (2) The reason why paint and covering materials are available in yellow.

Radial engine (or Radial)

A kind of internal combustion engine or CO2 motor in which the cylinders are arranged like the spokes of a wheel. The cylinders are stationary with respect to the aircraft. See Rotary engine.

RC or R/C

Abbreviation for “radio control” or “remote control”.

Rotary engine (or Rotary)

An engine that has the same appearance as a radial engine (see Radial engine) but where the cylinders and crankcase rotate with the propeller.

RTF Ready-To-Fly

A model airplane kit that requires only minimal assembly before it can be flown. To be classified RTF, the motor (if there is a motor), radio equipment and all accessories should be installed by the manufacturer. It should require only attaching the wing and possibly the empennage with fasteners that take only a few minutes to install, such as bolts or rubber bands. RTF kits usually include the transmitter. You may have to charge any rechargeable batteries prior to flight. See ARF.


A condition of flight where a lifting surface, such as a wing, stops producing a useful amount of lift, and the aircraft starts to fall. Stalls are always due to attempting to operate the surface at too high an angle of attack.

Stalling speed

Because there is no particular speed at which a plane will stall, this term is often misused. However, there is a minimum stalling speed below which a plane cannot fly using only the lift from its wings. Attempts to fly straight and level below that speed will cause the aircraft to stall.