RC Wiki

This page is for acronyms, abbreviations, and technical terms used in RC. Please leave out chat/IM acronyms like lol, IMHO, etc.

Electronic Terms[]

ESC - Electronic speed control

MSC - Mechanical speed control

BEC - Battery eliminator circuit. This eliminates the need for a receiver pack on electric models by taking power for the radio gear from the main drive battery.

NiCd - Nickel cadmium. A type of cell chemistry for rechargeable batteries.

NiMH - Nickel metal hydride. A type of cell chemistry for rechargeable batteries. Available in higher mAh (see below).

mAH - Milliamp hours. This is the capacity of your batteries. The larger the number, the longer it will provide power, assuming the same electronics and/or motor.

Pinion - This is the small gear attached to the motor shaft of an electric motor and meshes with the spur gear. It can be changed out with other gears with different tooth counts in order to manipulate the gear ratio.

Brushes - The part of an electric motor that delivers current from the motor leads to the commutator. They are stationary on the end bell, and must be replaced when they wear down.

Comm - Commutator. This is the part of the electric motor that carries current from the brushes to the windings. It is attached to the armature. After a while it becomes worn and blackened, and must be trued. this is done by turning the armature, in which a lathe is used to make the commutator smooth, clean, and perfectly round.

Turns - This is the number of times the armature wire is wrapped arond the armature. generally, lower turn motors are faster, while higher turn motors have more torque.

Winds - The number of strands in the armature wire. Motors usually have 1-4 winds. Turns and winds are noted in the format of '--x-', with the first number being the number of turns, and the second number being the number of winds. ex: 15x2 denotes a 15 turn, double wind motor.

Armature - The motor shaft of an electric motor, with the turns and winds attached. Also holds the comm.

BL - Brushless. A type of electric motor that does not use brushes. Instead of brushes, it has fixed windings on the motor can and rotating magnets on the motor shaft. It needs a special ESC, usually called a controller, to provide power.

Nitro Terms[]

Clutch bell/CB - This is the combined clutch bell and 'pinion' gear for a nitro engine on some models. It attaches to the motor shaft and rides on bearings. As engine RPM's rise, the clutch shoes engage the clutch bell, turning the rest of the drive train. It can also be changed to manipulate gearing. Most two speed clutch bells and some single speed clutch bells have pinion gears that thread onto them, so they can be changed without removing the whole clutch bell.

OWB - One way bearing, or roller clutch. This is a bearing that spins free in one direction, and locks in the other. It is used on electric starters, shaft starters, and pull starters on nitro engines to engage the starter shaft. There is also a one way bearing in two speed transmissions, to disengage the first gear after the second gear is engaged via the 2 speed clutch.

Starter box - A device to start engines, by placing the entire vehicle on the starterbox, and pressing down on it.

FOC - Forward only conversion. Just what it sounds like. It converts a reverse capable nitro vehicle into a forward only machine. This cuts down on rotating mass, and is mostly used in racing.

P/S - Piston/sleeve. These are most of the internals of a nitro engine. The sleeve forms the sides of the combustion chamber, and the piston moves up and down inside the sleeve, turning the crankshaft. Often when an engine loses compression, the piston and sleeve are to blame, and can be replaced. When the piston and sleeve are replaced, the new set must be broken in, just like when the engine was new.

HSN - High speed needle. Used to adjust the fuel/air mixture at high speeds.

LSN - Low speed needle. Used to adjust the fuel/air mixture at low speeds.

TDC - Top dead center. When the piston is at the very top of its stroke. In a new and/or well maintained engine, you should be able to feel significant pinch as the piston reaches TDC. this indicates a tight (well-sealed) fit between piston and sleeve. If the piston is left in this position after the engine is stopped, it can become stuck as the engine cools and contracts. This can be remedied by prying the flywheel around with a screwdriver.

BDC - Bottom dead center. When the piston is at the very bottom of its stroke. move the piston here to prevent it from getting stuck when the engine is stored.

BB - Usually means a 'Big block' engine.

ARO - [After run oil]]. Oil that is put in a nitro engine after is has been run and is being put away for the day. It keeps the engine from rusting as well as keeping it lubricated.

Nitro - Fuel that you put into the fuel tank on a nitro vehicle. It contains nitromethane (this is not "NOS"), oil, and methanol (methyl alcohol). It is available in various percentages of nitro and oil. For most applications, 20% nitro and 10-15% oil is used. There have been some stories of people accidentally putting this horribly expensive liquid into the washer fluid bottle on a real car. This should not be confused with gasoline, since many new people say gas instead of nitro, or just fuel. Gasoline powered rcs are also available.

Header - This aluminum exhaust coupling connects the engine's exhaust port to the tuned pipe.

Tuned pipe - This is an upgrade for any vehicle equipped with a muffler. It is designed to increase an engine’s power output. Different tuned pipes are available for different applications. Some provide increased top speed while others aid off-the-line power

Shared terms[]

Tranny - Transmission. Receives power through the spur gear and transfers it to the wheels. It sometimes features reverse and/or two or more speeds. Reverse is only found on nitro models, as electric motors can turn in either direction, and multi-speeds are sometimes used with electrics.

Diff - Differential. This is between the two halfshafts (axles) that connect to each wheel. It allow them to turn at different speeds to make turns smooth.

WOT - Wide open throttle. Applies to both nitro and electric models, although on electric models it is somewhat figurative. It just means that the throttle is at full.

TX - Transmitter. The radio you hold in you hand to control the model. Also used to refer to the transmitter crystal.

RX - Receiver. The small electronic device that receives signals from the TX and sends them to the servos/speed control. Also used to refer to the receiver crystal.

X-Tal/Crystal - The device the tunes your radio to a certain frequency. Also known as the 'channel' your radio is on. TX and RX crystals must be on a matching frequency for them to work together. Multiple models can be operated in one area (track, bashing spot, etc.) if they are on different channels.

LHS - Local hobby shop. This is the place down the street/across town where you can go to buy parts and get help and advice in person. Most are staffed by knowledgeable people who know their stuff and give good advice, but beware, this is not always true.

Spur gear - The large (usually plastic) gear that meshes with the clutch bell or motor. It is on the primary shaft of the transmission, or mounted to the center diff, and can be used to manipulate gearing. Slipper slutch components are usually combined with the spur gear mount.

Slipper clutch - This is just a clutch that is normally attached to or is a part of the spur gear. It is locked at most times, but will slip when too much stress is applied.

Articulation - The ability of an axle to move relative to the chassis.

Pivot ball - A metal ball with a hex head and screw threads on the end. A ball cup attaches over the ball end to create a pivot point.

Bleeding - It is necassary to remove all the air and any excess oil when rebuilding shock absorbers. This is known as bleeding the shocks.

Contact patch - The area of a tire that is exposed to the ground at any given moment.

Damping - The rate on which a shock is compressed or rebounds. This is changed by using different shock oil weights and changing the number f holes in the shock piston.

Bearing - This is essentially a metal ring with tiny balls inside that allow for rotating shafts to soin more efficiently.

Camber - Refers to the angle of the tires in relation to the ground.

CG or COG - This is Center of gravity. This is greatly considered when thinking of the stability of a vehicle.

Chassis - Made from aluminum, plastic composites, or carbon fiber, this is the platform to which all other components attach.

Exponential, Exponential rate, or Throttle/Steering curve - This refers to servo travel That isnt directly proportional to the dgree of control output from the transmitter.

Foam inserts - These are foam pieces available in different densities that fit between the tire and rim on the inside to help the tire keep its shape and contact with the ground, just like air does in your car tire.

Hinge pin - This is a rod that connects the suspension arm to the bulk head to alow it to pivot up and down with the suspension.

Types of RC[]

Truggy - A combination of a Monster truck and a 1/8 scale Buggy

Stadium truck - A small race truck powered by either nitro or electric power

Monster truck - A large, usually 4WD truck, with large wheels, long suspension travel, multi-speed trannys (usually), and a powerful engine. Usually Nitro, some are available in electric.

Buggy - A low slung, fast vehicle built for handling but not necessarily large jumps. Available in 1/8 scale (usually nitro powered) and 1/10 scale (usually electric).

Mini/Micro vehicles - an ultra-small RC vehicle.