Activating (Arming) Switch
A safety feature/switch that prevents an electric motor from accidentally turning on. (Sometimes also known as ‘Throttle Cut’)
Adjustable Function Rate (AFR)
AFR allows endpoint adjustment independent of Dual Rate or Exponential settings.
Adjustable Travel Volume (ATV)
ATV allows you to independently pre-set the maximum travel of a servo on either side of neutral.
An undesirable tendency for an aircraft to yaw in the opposite direction of the bank/ roll. This is most common when flying at low speeds with high angles. Adjusting the ailerons can help reduce the yaw.
Science of air in motion. Good aerodynamics means that an object (aircraft) is highly optimized and efficient when traveling through air.
Aerobatic/ 3D Plane
Aerobatic RC planes are designed and tailored for aerobatic maneuvers. They are built with larger control surfaces and most sport a mid-wing configuration; combined, these qualities enable them to pull off extreme maneuvers at both high and low speeds.
Ailerons are a control surface (hinged flap) that can be found on the outer rear of each wing panel and work in opposite directions. When the right aileron is up, the left aileron is down. This generates more lift on the left-wing pressing the aircraft to roll to the right. Used in conjunction with the rudder, this allows your aircraft to turn in the air.
The Aileron Extension (AKA servo extension) is a cable with connectors on either end which goes between the receiver and a servo. This allows the servo to be placed at a greater distance from the receiver than the cable that comes on the servo will allow. It also permits easier removal of a wing when the servo that controls the aileron is mounted in the wing and the receiver is in the fuselage (which is usually the case).
Adds rudder control when the aileron is inputed from the transmitter aileron stick.
Air Bleed Screw
Screw for adjusting the amount of air allowed to bleed into the carburetor during idle.
The Airfoil is the cross-sectional shape of the wing. The front of the airfoil is the leading edge and is usually a rounded section. The back of the airfoil is the trailing edge and usually tapers to nearly a point. The distance between the two is the wing chord. The top surface of the airfoil is usually always curved to allow smooth airflow and produce lift.
AM (Amplitude Modulation)
The primary means of modulation in R/C until recently. The control information is transmitted by varying the amplitude of the signal. Modern RC uses Frequency Modulation.
AM (Amplitude Modulation)
The primary means of modulation in R/C until recently. The control information is transmitted by varying the amplitude of the signal. Modern RC uses Frequency Modulation.
The Academy of Model Aeronautics is the official national body for model aviation in the United States. AMA organizes more than a thousand model competitions throughout the country each year and certifies official model flying records on a national and international level.
Angle of Attack (AOA)
The angle between the chord of the wing and the relative wind that strikes the airfoil. An optimum AOA will provide efficient lift for an aircraft; however, an overly high AOA (critical angle) will cause an aircraft to stall.
The downward inclination of an aircraft’s wing. Anhedral gives enhanced roll authority and is mostly used on fighter planes for extreme maneuvers.
The telescoping tube that transmits electrical signals.
ARF (Almost Ready to Fly)
An abbreviation designated to the Kit/Build (completion) level of an RC aircraft. An ARF model requires moderate assembly time and will require you to separately buy an RC radio (TX/RX), batteries, power system, ESCs, and servos.
ARR (Almost Ready to Run)
An abbreviation designated to the Kit/Build (completion) level of an RC vehicle. An ARR model requires moderate assembly time and will require you to separately buy an RC radio (TX/RX), batteries, power system, ESCs, and servos.
ATS (Automatic Tail System)
A radio mixing function that allows you to set the amount of tail rotor when the throttle/ pitch is increased or decreased.
State of flight in which the main rotor system of a helicopter or other rotary-wing aircraft turns by the action of air moving up through the rotor, as with an autogyro, rather than engine power driving the rotor.
An (imaginary) line passing through a body about which the body revolves around.
A component used to cover the rear of the crankcase of an engine.
Extra weight added to an aircraft to help it penetrate better in windy weather or to increase its speed. Ballast is usually added in tubes in the inner portion of the wings or in the fuselage at the center of gravity.
A lightweight yet durable wood used for making RC models.
To fully charge and discharge a battery to erase battery memory.
A device used to monitor the state of batteries.
Bush Planes (Bush Flying)
The terms bush plane, bush flying, and bush flyer simply refer to any fixed-wing aircraft that are specifically designed to be flown in remote areas. These remote areas - dubbed “the bush” - are otherwise inaccessible by ground or water transportations; hence, you can imagine just how harsh and unforgiving these terrains can be.
A super-strong, quick bonding adhesive glue.
The maximum amount of energy a battery can store measured in Milliamp Hours (mAh).
Device in an internal combustion engine that maintains the proper air-to-fuel ratio for combustion.
Cubic Centimeter - normally used to refer to the size/volume of an engine.
An (imaginary) line drawn through the center of the aircraft from the nose through the tail.
Center of Gravity (CG)
The balancing point of an aircraft used primarily to determine optimum stability.
Channels refer to the number of functions on the RC model that you can control - they go from 2 channels all the way up to 20+ channels.
A hand-held stick used to start a model airplane engine.
The clevis connects the wire end of the pushrod to the control horn of the control surface. A small clip, the clevis has fine threads so that you can adjust the length of the pushrod.
Located in the fuel tank, a clunk is a weighted mechanism that ensures the intake line has a steady supply of fuel.
The ability to vary the main blade pitch when the throttle is increased or decreased.
Constant Drive Tail
A special autorotation clutch that will always drive the tail rotor even when the engine is off or in "Hold".
The arm that connects the control surface to the clevis and pushrod.
The moveable hinged parts on the wing and tail that enables an aircraft to roll (aileron), pitch (elevator), or yaw (rudder).
The input sticks on a radio transmitter used to control your RC model.
The skin of an aircraft applied to the airframe. There are commonly two types: fabric and plastic film. Plastic, once applied, gives a durable and shiny finish and requires no further treatment. Fabric covering usually requires a layer of paint to finish.
The main body of an engine
Critical Angle of Attack
The angle of attack at which smooth airflow over the top of the wing stops.
Primarily used in gliders for spoiler action by mixing the flaps and ailerons. It is necessary for the ailerons to be using separate servos, plugged into separate channels, and the flap servo to be independent of both aileron channels. Upon applying Crow Mixing, the flaps go down while both ailerons go up.
Crucifix refers to a stabilizer that is mounted partway up the fin. This is a compromise between the conventional tail and the T-tail combining some of the advantages of both.
An electronic device that determines the channel or frequency that the equipment is working. With no crystal, a transmitter will not transmit at all.
Constant Velocity Axle
Constant Velocity Drive
The section of the crankcase where combustion takes place.
Decibels, a unit normally used to measure sound.
When an aircraft is in flight gliding, without the engine running, it is called a dead stick.
Discharge Rate (C)
The C Rating is a safety gauge that tells you the maximum current - measured in amps - you can draw without damaging your batteries.
A radio mixing function that enables the different settings for a pair of channels.
This type of mixing is accomplished by having separate servos on each aileron, plugging one into the aileron channel and the other into another unused channel. The two channels can be programmed to both operate from the aileron control stick, however, the travel volume for each aileron may be adjusted separately giving more deflection in one direction (usually up) than in the other.
Dihedral is the angle formed when both wing panels of a fixed-wing aircraft are slightly angled upwards. This upward “V” angle gives an aircraft greater lateral stability. If a disturbance (such as a gust of wind) causes one wing to dip, the lower wing will produce more lift and push your aircraft back into level.
Direction of Flight
The relative direction of the wing in relation to still air.
Dual Aileron Extension (Y-Harness)
The Y-Harness is a cable that plugs into a single channel in a receiver and two servos. This allows both servos to be operated from the same channel.
Dual Conversion refers to the method in which the receiver processes the incoming signal. Generally, a Dual Conversion receiver is less prone to outside interference and is the preferred type of receiver.
Dual Rates (D/R)
Dual Rate allows the modeler to choose between two different control sensitivity. With the dual-rate switch in the "OFF" position, a 100% servo throw is available for maximum control response. In some more sophisticated systems, this "OFF" position may be adjusted to provide anywhere from 30% to 120% of a normal full throw. In the "ON" position, servo throw is reduced, and the control response is effectively desensitized. The amount of throw in the Dual Rate "ON" position is usually adjustable from 30% to 100% of total servo movement. The modeler can tailor the sensitivity of his model to his own preferences.
EDF (Electric Ducted Fan)
A type of power system used commonly for RC jets – they allow for much more powerful flying than your regular electric motors.
A small motor commonly used to start an aircraft’s engine.
A caustic material found in batteries.
A Control Surface commonly located on the horizontal tail panel. Elevators – as the name implies – control the elevation or pitch of your plane. When the elevators are tilted down, the tail receives more lift and the nose of the plane is pitched downwards. Conversely, when the elevators are tilted up, more force is exerted on the tail, pushing the tail down while pitching the nose of the plane upwards.
Elevator Mixing (Elevon)
Mixes the Elevator and Aileron functions, especially useful for delta-wing models where the elevator and ailerons are the same control surfaces. Each surface is connected to a separate servo (one servo plugged into the aileron channel and the other plugged into the elevator channel), the surfaces will act as both ailerons and elevator, depending on the position of the controls.
Couples the Elevators and Flaps such that when control is input to the elevators, the flaps will move in the opposite direction. This permits the model to perform tighter maneuvers in the pitch attitude.
EPA (End Point Adjustment)
A radio function wherein you can adjust the high and low end of a channel’s travel.
Electronic Speed Control (ESC)
An electronic component that controls and regulates the speed of an electric motor; without it, your RC model will not run.
Term used to refer to the whole tail unit of an aircraft.
A two-part resin/hardener glue that is commonly used to put models together. Epoxy is extremely tough.
Expanded Scale Voltmeter (ESV)
Device used to check the voltage of a battery pack.
Exponential Rate is where the servo movement is not directly proportional to the amount of control stick movement. Over the first half of the stick travel, the servo moves less than the stick. This makes control response milder and smooths out level flight and normal flight maneuvers. Over the extreme half of the stick travel, the servo gradually catches up with the stick throw, achieving 100% servo travel at full stick throw for aerobatics or trouble situations.
An electronically programmed mechanism in most PCM radios which automatically returns a servo(s) to neutral or a pre-set position in case of malfunction or interference.
The Fin, also known as the "vertical stabilizer", is the fixed vertical surface at the rear of (tail) an aircraft that provides yaw stability.
Term used to describe conventional aircraft with “fixed-wings” as opposed to those with rotating wings, such as helicopters.
Mixes the Flap and Aileron functions so that when each aileron is connected to a separate servo (one servo plugged into the aileron channel and the other plugged into the flap channel), the surfaces will act as both ailerons and flaps, depending on the position of the controls.
Referring to a wing where the lower surface of the wing is primarily flat between the leading and trailing edges. This type of wing has a high lift and is common on trainer planes.
A flex cable is a special type of pushrod which is very flexible and can bend around corners even more easily than a flexible pushrod. These are generally made with a metal cable running inside a plastic tube and are popular in controlling the engine throttle.
The box in which you store and transport your flying equipment is called a flight box.
Flight Pack or Airborne Pack
These interchangeable terms describe the radio equipment that is installed on the airplane. Flight Pack can also refer to an eclectic plane’s main battery.
A flying stab is where the stabilizer/elevator is one complete unit that all moves to control the aircraft in pitch.
The terms "floatplanes" and "seaplanes" are sometimes used interchangeably. Floatplanes and seaplanes are planes that could land and take off from water.
FM (Frequency Modulation)
The common method used in transmitting signals which are less prone to interference than AM (Amplitude Modulation). Information is transmitted by varying the frequency of the signal.
Material used to mitigate an aircraft’s vibrations to protect the aircraft’s battery and receiver.
FPV (First Person View)
A method used to control an RC model from the driver’s (first person) view. An FPV camera will be needed for this method.
A marker that is mounted on your transmitter to indicate the frequency your system is operating on to alert other modelers so as not to cause interference.
A rubber bulb used to transfer fuel to model tank.
Fuel Overflow Line
This line pressures the fuel tank and provides an even fuel flow to the engine. It also functions as an overflow line when the fuel tank is full.
Fuel Pickup Line
This line connects the fuel tank to the carburetor, usually with a clunk on the tank end to keep the fuel flowing while the aircraft is in flight.
The body of the plane. In a commercial aircraft, this is where you would find passengers or cargo. In an RC model, the fuselage houses your batteries, radio equipment, and servos.
Gigahertz, normally used to refer to the frequency band (2.4 GHz) which most RC models use.
Gimbal (or Stick)
Term used to refer to the control stick on a radio transmitter.
There are generally two types of RC gliders: pure gliders and powered gliders. Pure gliders don’t have a power source to generate thrust but rely solely on the wind and thermals - hot air pockets - to stay airborne. A powered glider is a glider with a propeller.
A ratio defined by the distance traveled in a horizontal direction relative to the vertical distance dropped on a normal glide. A 10 to 1 glide ratio means that the aircraft would lose one foot of altitude for every ten feet of distance traveled.
Glow Plug Clip/Battery
A 1.2-volt battery with a clip that is connected to your engine’s glow plug used to start the engine. You remove it once the engine is running smoothly.
A device consisting of wires, switches, and a fuse that connects a motor to a battery.
The component which forms the end of the compression chamber of the engine.
Term used to describe an airplane that has its wings mounted on the top of the fuselage. High wing configurations are normally found on trainer planes as they give greater stability.
Hinges are the moving blades on the control surface that allow you to control the airplane's movement. All hinges must be glued properly and securely to prevent the airplane from crashing.
Usually found on the tail of a plane, the horizontal stabilizer prevents the up-and-down (pitching) of the plane.
The amount of pitch needed to hover a helicopter. On average, this is about 5 degrees. Most helicopter radios will have a knob on the transmitter to vary the amount of pitch at the present hovering stick position.
The amount of throttle needed to hover a helicopter. On average this is about 50% throttle. Most helicopter radios will have a knob on the transmitter to vary the amount of throttle at the present hovering stick position.
In the hobby, you will find three types of RC jets: propeller-driven jets, EDF (Electrical Ducted Fan) jets, and turbine jets. RC jets are built for scale-like performance - high speed and high agility.
KV (Kilovolt): Primarily used with brushless motors. Also appearing as kV or Kv depending on the manufacturer. One of several measures used to calculate the characteristics of an electric motor, it represents the rpm per volt performance of a motor. For instance, a 4000KV motor can be expected to produce roughly 28,000 rpm with 7 volts of power.
Lift divided by drag expressed as a ratio. Essentially the same as a glide ratio. Think of L/D as a glide slope, then, for a given amount of distance the sailplane moves forward, it drops a certain amount.
The wheel and gear assembly the airplane uses to land. It is typically attached to the bottom of the fuselage.
The front edge of a flying surface.
Lithium Polymer, commonly used to refer to LiPo batteries.
mAh (Milliamp Hour)
A measure of a battery's capacity. The larger the number of milliamps, the longer the battery cell will last.
The speed at which a sailplane loses altitude most slowly. Usually expressed in feet per minute.
The control stick configuration with the rudder and elevator being controlled by the left stick while the right stick controls the throttle and ailerons.
The control stick configuration with the ailerons and elevator being controlled by the right stick while the left stick controls the rudder and throttle.
The section of the crankcase used to mount the engine to the airplane.
AKA silencer is a device used primarily to reduce the noise emitted by an internal combustion engine. Mufflers are usually required by R/C Clubs.
Mechanism within the carburetor that adjusts the fuel mixture and throttle.
NiCd / NiCad
Abbreviation referring to Nickel Cadmium, the chemical compound used in rechargeable batteries.
Nickel Metal Hydride, normally used to refer to NiMH batteries.
Short for nitromethane, a fuel additive that improves an airplane's high-speed performance. Check your engine's instructions to determine the ideal nitro content for your engine.
A small electronic device that is wired into a long servo extension to reduce radio interference and to boost the control signal going to the servo. These are recommended for use where long servo leads are necessary.
National Organization for Racing Radio Controlled Autos; based in North America.
Part of the landing gear that is attached to the nose of the fuselage. The nose gear is usually connected to the rudder servo to help you steer the airplane on the ground.
NPS (Non-Pull Start)
A method to start a nitro engine. RCs without a pull start system have an opening in the chassis that provides access to the flywheel. The RC is placed on top of a starter box that has an electric-powered spinning rubber disk sticking out of it that makes contact with the vehicle's flywheel and rotates it to start the engine.
Pulse Code Modulation, the control information is in the form of a digital word rather than just a pulse width as in standard AM or FM. Using PCM adds additional protection against interference from various sources.
This usually refers to a type of battery charger that automatically shuts off when a battery is fully charged.
Pitch refers to the rotation of the aircraft around a side-to-side axis. It can be thought of as the “up and down” or “nodding” motion of an airplane.
The horizontal plane on which the airplane’s nose is raised or lowered. By adjusting the elevator, you can raise the airplane's nose above the pitch axis (climb) or lower it below the pitch axis (dive).
PNP (Plug & Play)
An abbreviation designated to the Kit/Build (completion) level of an RC model. A PNP model requires minimal assembly time and will come with servos, power system (motor), and ESC.
Polyhedral refers to the multiple angle wing panels made with the horizontal. A wing with a polyhedral has more than two wing panels and the angle of the wing changes at each joint.
Prop shaft (Propeller shaft)
The main crankshaft which transfers the power of the engine to the propeller.
PS (Pull Start)
A method to start a nitro engine. A pull cord is attached to the nitro engine, and you pull the T-handle attached to the starter cord assembly to spin the flywheel and start the engine.
A rod normally made from metal that is connected to the servo and control surface which enables the movement from the servo to the control surface.
A means by which a pushrod may be connected to a servo. The connector is mounted onto a servo arm and the pushrod wire is secured by means of a set screw.
The receiver unit in an RC model receives your signals from the transmitter and passes the instructions along to the servos to enable movement.
Direction that the air molecules strike the leading edge (front) of the wing.
ROAR (Remotely Operated Auto Racing)
Sanctioning body of competitive radio-controlled car racing based in the United States and Canada.
A roll motion can be considered as the up and down movement of the wings of the aircraft; animation here.
The horizontal plane on which the airplane’s wings are raised or lowered. By adjusting the ailerons, you can drop a wingtip below the roll axis and cause the airplane to bank or roll.
RTF (Ready to Fly)
An abbreviation designated to the Kit/Build (completion) level of an RC aircraft. An RTF model will have everything you need out-of-the-box. RTF models are geared to complete beginners.
RTR (Ready to Run)
An abbreviation designated to the Kit/Build (completion) level of an RC vehicle. An RTR model will have everything you need out-of-the-box. RTR models are geared to complete beginners.
A control surface found on the vertical tail panel and it is used to steer the nose of the aircraft left or right – the yaw of the plane. When the rudder is angled to the right, the nose of the plane reciprocally turns to the right and vice versa. This is caused by a disruption of airflow: when the rudder is deflected to a side, a force is exerted which pushes the tail of your aircraft in the opposite side yawing the nose in the desired direction.
Scale planes are models that replicate real aircraft but at a much smaller scale – e.g., a 1:15 scale plane would mean that the plane is 15 times smaller than the real thing.
A rotary actuator that enables movement in an RC model. Servos can be regarded as the muscles of your model as they facilitate all directional movements.
Servo Control Arms
The plastic (sometimes metal) output horns mounted to the output shaft on your servos. These come in various sizes and styles for different control applications. Most servos will come with an assortment of arms so you can customize them to your own specific control needs.
Servo Output Arm
A removable arm or wheel that connects the servo to the pushrod. Also called servo horn.
SFG (Side Force Generator)
Used to increase rudder authority which enhances the performance in 3D aerobatics maneuvers.
This is another special unit that is attached to the autorotation clutch that will let the main blades turn the tail rotor when the engine is off or in "Hold". The difference between this and a "Constant Drive Clutch" is that this one will "Slip" a little so the tail rotor while spinning will not load the main rotors as much while in the "Hold" function doing an "Autorotation".
Snap Roll Button
A function found on more complex radios and is used to perform a snap roll maneuver by simply pressing one button. The function is usually programmable to give a combination of rudder, elevator, and aileron control.
The nose cone that covers the propeller hub.
A control surface more commonly found on gliders and jet aircraft which is used to slow down the aircraft and decrease lift. They are rarely found on conventional aircraft. They may be mounted on either the top or bottom of the center portion of the wings.
A sport plane is the next level up from an RC trainer and can be thought of as a hybrid between a trainer and an aerobatic plane. Unlike scale planes or warbirds which are modeled after real planes, a sport plane can literally be anything; hence, they are designed purely for function e.g., for speed, agility, or aerobatics.
The fixed horizontal or vertical surface at the rear of an aircraft which provides pitch and/or yaw stability.
The sudden reduction or loss of lift resulting from exceeding the critical angle of attack.
A radio function that allows very precise electronic centering of servos.
Symmetrical airfoils are normally found on aerobatic planes. Because they have the same upper and lower shape, an equal amount of lift and downward force are generated regardless of the orientation. So, if you were performing a roll or flying inverted, no unwanted force will derail your maneuvers.
A device that measures the engine’s RPM (rotations per minute) by counting light impulses that pass through the spinning propeller.
Electronic modules that enable you to collect data such as flying speed, heat, voltage, and more.
Naturally occurring hot air pockets that make the perfect spot for gliders to fly and stay airborne.
A liquid that solidifies; used to prevent screws from loosening due to vibration.
Throttle Stop Screw
A screw used to set the lower limit of the throttle movement.
A small metal hook commonly found/ mounted on the bottom of the glider fuselage at approximately the center of gravity.
Designed to fly with high stability at low speeds, a trainer RC plane allows new users some extra reaction time as they learn to control the airplane’s movements.
The device (remote control) used on the ground to transmit instructions to your RC model. There are generally two types of transmitters: stick (used mostly for RC aircraft) and surface (used mostly for RC cars or boats).
Slides used to adjust control surfaces during flight.
An airfoil configuration which has the lower surface of the wing curved inwardly almost parallel to the upper surface. This type of airfoil produces a great deal of lift but is not common in RC models.
A special tail configuration where the horizontal stabilizers and elevators are mounted at an angle between 30 and 45 degrees in a V-shape and the vertical fin is eliminated entirely. The stabilizers provide stability in both pitch and yaw while the moveable surfaces provide directional control in both pitch and yaw.
Used when there is a V-Tail on the aircraft rather than the conventional elevator and rudder. Each control surface of the V is connected to a separate servo. Operating the elevator control stick will move both surfaces up for the back stick or both surfaces down for the forward stick. Moving the rudder control stick left will move the left surface of the V down and the right surface up. Moving the rudder control stick to the right will move the left surface of the V up and the right surface down.
Variable Trace Rate (VTR)
A radio function similar to exponential except it uses two linear responses to determine the servo sensitivity on the first and second half of the control stick movements.
Also known as the fin, the vertical stabilizer is the vertical surface of the tail which gives the airplane stability while in flight.
VPP (Variable Pitch Propeller)
A type of propeller where the blade pitch can be adjusted during flight depending on the situation; ultimately, this enhances efficiency.
The term warbirds generally refer to any vintage aircraft that has served in the military. Technically, this encompasses all planes that have seen action in any wars, however, RC warbirds are mostly from WW2. Some of the most popular RC warbirds include the P-51 Mustang, the Spitfire, and the Vought F4U Corsair.
The round retaining piece that anchors the wheels in place on the axle.
The total surface area of the wing of the aircraft, usually calculated by the wingspan times the wing chord, although more complex calculations are used on unconventional wing plans.
The distance from the front or "leading edge" of a wing to the back or "trailing edge".
Weight of the aircraft divided by the wing area. It is measured in ounces per square foot.
Wing Seating Tape
Wing seating tape is mounted on the fuselage wing saddle where the removable wing fits and isolates the wing from vibration as well as to form a seal to keep exhaust gases from entering the structure.
The maximum distance from wingtip to wingtip.
The very outer end of a wing.
The very outer end of a wing.
Abbreviation for Crystal which is an electronic device that determines the channel or frequency that the equipment is working. With no crystal, a transmitter will not transmit at all.
A yaw motion is a side-to-side movement of the nose of the aircraft which is controlled by the deflection of the rudder.
The vertical plane through which the aircraft’s nose passes as it yaws to the left or to the right.
The wire ends of some pushrods have Z-shaped bends, which attach to the servo.
Used for crimping wire ends into Z bends.