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RC Glossary


New to the RC Hobbies? What does buggy, bulkhead, nitro mean in radio control car hobbies? Check out the glossary for remote control cars below.


  • S --

  • Saddle Pack (Battery Pack) --
  • Refers to a battery pack assembled with 2 rows of?2 or more?batteries placed side to side. These rows may be separated to allow one half of the pack to be mounted on one side of the chassis, and the other half on the other side. Many on road models are designed to use only saddle packs. A 6 cell saddle pack may resemble: lll lll or ll llll

  • Sanyo --
  • "A manufacturer of batteries around the world. Long considered the """"top"""" manufacturer, since the days of the 1700 mAh type cells. They have recently released the RC3000H Ni-MH cells, which compete directly with the Panasonic 3000 Ni-MH cells."

  • Scale --
  • "For RC hobbyists, this refers to the general size of the car. Many companies offer radio control cars in several different sizes: 1/18, 1/12, 1/10, 1/8, 1/5 and 1/4 scale.?The smaller the number after the """"1"""", the larger the actual scale car is. For example, a 1/18 scale car is about 9 inches (23cm) long, while a 1/5 scale car can be up to 36 inches (91cm) long! Most cars are of the 1/10 scale size (because the cost of manufacture and ownership is balanced to the controllability of the car), but there are many types of kits that fall under this size label: Buggy, Truck, Monster Truck, Touring Car and more."

  • Sedan --
  • In general terms, this refers to a 4-door car that has a separate trunk. In RC terms, this refers to a car that is generally 1/10 scale in size, and is the most popular form of on-road RC racing in the world right now. These kits started out modeling the cars that formed the DTM racing league in Germany in the early 1990's, but (because of interchangeable bodies) now can represent anything from the latest LeMans racer, to street trucks, to the newest cruiser on the road.?

  • Self Tapping Screw --
  • This is a split point, coarse threaded screw often supplied with RC kits. This screw is used to tap the holes in plastic or composite parts before assembly.

  • Sensored (Brushless Motor) --
  • These motors use a separate (plug in) wire harness to communicate with the ESC. A Hallls sensor inside the motor tells the ESC exactly where the rotor is in it's rotation, then the ESC energizes the correct coil to move the rotor along. Due to the ESC's ability to read where the rotor is at any given time, sensored brushless motors are able to achieve full power from a dead stop, as well as offering a more precise throttle control than sensorless brushless motors at low speeds. The following wire coding is pretty much the industry standard for sensored systems: BLUE wire = TAB A on motor, YELLOW wire = TAB B on motor, ORANGE wire = TAB C on motor.

  • Sensored (ESC) --
  • An ESC that utilizes an extra wire (or wires) to sense a brushless motor's rotor position. Unless otherwise stated, a sensored ESC can not be used with a sensorless brushless motor. The following wire coding is pretty much the industry standard for sensored systems: BLUE wire = TAB A on motor, YELLOW wire = TAB B on motor, ORANGE wire = TAB C on motor.

  • Sensorless (Brushless Motor) --
  • As the name implies, this is a brushless motor that doesn't use a sensor to detect the position of the rotor. Instead, the ESC detects the rotor position through EMF (Electromagnetic Feedback - the alternating voltage created by a motor's rotation). From a dead stop, the ESC must energize 2 coils to center the rotor, then fire the coils in sequence to bring the motor up to speed. This hinders acceleration and low speed throttle control compared to sensored motors. However, unlike sensored motors, sensorless motors can be used with a variety of ESC's.

  • Sensorless (ESC) --
  • An ESC that detects the position of a brushless motor's rotor through the existing 2 power wires. Sensorless ESC's can usually run sensored or sensorless motors.

  • Serevo Saver --
  • The steering servo's superhero. This is a spring loaded device that replaces the servo horn or is integrated into the steering bellcrank. It 'saves' the gears of the steering servo during hard impacts by allowing a small amount of give to take place, while still remaining stiff enough to enable accurate steering. The tension of some servo savers is adjustable.

  • Series (Battery Wiring) --
  • S - Refers to wiring batteries with the positive (+) end of the first battery connected to the negative (-) end of the next battery. This increases voltage as cells are added, but not run time. This is the type of wiring used for nearly all RC batteries.

  • Series (Motor Wiring) --
  • A wiring method used for models with 2 motors and 1 speed controller. With series wiring, the positive (+) motor lead from the speed controller goes to the (+) side of the first motor. The negative (-) lead of the fist motor then goes to the (+) side of the second motor. Finally, the (-) lead of the second motor goes to the (-) side of the speed controller. This method increases torque and run time at the expense of top speed. 2 identical motors wired in this fashion would act as 1 motor at 2 times the number of turns (2 19T motors would act as 1 38T motor), but both motors would operate at 1/2 RPM while drawing the same amps. The doubled rating (38T instead of 19T) should be used to determine if your speed controller's motor limit is exceeded.

  • Servo --
  • "A small box full of motorized gears that turns the steering and/or throttle linkage in an RC car. Available in a range of strengths and speeds, with the faster/more powerful servos more expensive than slower/weaker servos.""Stock servos"""" usually cost about $12-15 (US dollars) and are the standard servos that are included with most radio sets. These servos are fine to get a kit running, but in the future you may want to upgrade to stronger servos, especially for racing or for the steering of a large-tire off-road kit like our Nitro RS4 MT."

  • Servo Arm - Servo Horn --
  • The 'arm' of a servo. A servo horn has splines in the center allowing it to mesh with the splines on the servo output shaft. The horn transfers the servos' movement to the linkage, and usually has a variety of linkage mounting locations to adjust throw. Different manufacturers use a different number of splines on the output shaft, and a matching horn (or adapter) must be used. There are 3 basic spline designs - 23 spline (SANWA / ACOME, JR, KO PROPO, and AIRTRONICS), 24 spline (HITEC), and 25 spline (FUTABA).

  • Servo Motor --
  • The small electric motor inside a servo that moves the servo gears. Servos commonly use coreless motors.

  • Servo Port --
  • Refers to the slots (or pins) of a receiver where the servo, battery, ESC, and other electronics are plugged into.

  • Servo Reverse--
  • This feature is available on most transmitters. As the name implies, it allows the user to reverse the direction of a servos' movement when compared to input from the radio. Thus, turning the radios' wheel left will cause the model to turn right, and visa versa. Servo reversing is handy when the servos' mounting location or angle causes it to react the opposite of what is intended.

  • Servo Speed --

  • Set Up Wheels --
  • These are thin, machined aluminum 'rims' (some may even have O ring 'tires') that are used with a set up board. Set up wheels offer much more accuracy than common tire/rim systems when it comes to suspension measurements. They may look cool, but they get lousy traction.

  • Shaft Drive --
  • Refers to a 4WD model that uses a driveshaft to transfer power to the front and rear wheels. For off road models, this is the norm, since the amount of suspension travel would render belts useless. But, for on road models (i.e. touring cars), the debate between whether shaft drive or belt drive is the best is never ending. In essence, shaft drive models tend to be more responsive and less likely to be 'jammed' by debris that belt drive models, but they are not as efficient and have additional rotating mass.

  • Shaft Start --
  • A starting system for nitro engines using a shaft (similar to a large dogbone axle) that is spun by a hand held unit or cordless drill. The shaft is inserted into the rear of the engine, spinning the crank and turning the engine over. Shaft start systems offer a low relative weight compared to other onboard starting systems, but are useless if you forget the handheld unit or drill (or if the batteries in either goes dead).

  • Shell --
  • Another term for a car body.

  • Shock - Damper --
  • Refers to the entire shock assembly, including the body, spring, shaft, oil, piston, ect. The shocks are what holds the model up, keeping it from dragging ass everywhere, as well as helping absorb the impact of bumps and ruts while allowing the model to stay stable.

  • Shock --
  • See Damping

  • Shock Absorber --
  • The complete assembly of a shock damper that includes the shock body, cap, spring, shaft and connectors.

  • Shock Angle --

  • Shock Angle --
  • Move the upper end of the shocks up, and you should get more bite, or grip, at that end. Lay the shocks further down, and you will loosen that end of the car.

  • Shock Bladder --
  • HPI touring car shocks use a shock bladder to assist in bleeding the shocks properly, and to make sure the

  • Shock Body --
  • The wide cylindrical part of a shock absorber that contains the shock oil, shock piston and o-rings, topped by the shock cap and sometimes a shock bladder.

  • Shock Body --
  • The main part of a shock. The shock body is the hollow 'tube' that houses the shock piston and upper part of the shock shaft, as well as the shock oil. Depending on the type of shock used, the body may also house a bladder, or have a reservoir perched on top. There are 2 basic types of shock bodies - standard (smooth), which uses preload spacers, and threaded, which uses threaded collars to adjust pre load.

  • Shock Cap --
  • A part that contains the O rings that the shock shaft slides through. The cap screws onto the shock body, and can be removed and replaced to fill the shock with oil.

  • Shock Cap --
  • Usually a threaded top (or bottom, on some shocks) that closes the shock body and keeps the shock oil inside. Usually sealed with an o-ring, some shocks use a shock bladder to help keep the oil pressure inside at a constant level.

  • Shock Collar --
  • This is simply a collar that slides over the shock body and holds the upper end of the shock spring in place. On threaded shock bodies the collar resembles a nut, allowing it to be screwed up or down on the body to decrease or increase spring preload (a.k.a. ride height).

  • Shock End --
  • A captured rod end that screws onto the lower part of the shock shaft for mounting to the suspension arm. The spring retainer rests on the shock end.

  • Shock Limiter --
  • A small plastic disc (or slice of fuel tubing) slid over the shock shaft to limit the total travel of the shock. Shock limiters are almost always placed inside the shock body, between the piston and seals, to limit the amount of rebound a shock has. This may help the model feel more 'planted' over small bumps or rhythm sections.

  • Shock Matching Tool --
  • A gauge used to ensure that built shocks rebound to the same length. A pair of shocks are mounted to the matcher, and a pivoting dial and sliding ruler determine whether or not the shocks 'match'. To get the shocks to match, you can adjust the rebound by bleeding the stiffer shock or by adjusting the shock ends.

  • Shock Oil --
  • A petroleum- or silicon-based oil that is available in different degrees of thickness, used to fine-tune the damping of a shock absorber. As the shock shaft travels up and down, the piston moves up and down also, so the oil must flow through the holes in the piston. The smaller the holes are in the piston, the slower the piston is able to move, and with larger holes the piston is able to move faster. When you are starting out racing and you want to try adjusting your shock settings, you should try changing your springs first, then your piston/shock oil combination.

  • Shock Position - Shock Angle --
  • On many models, there are various mounting positions for the shocks on the shock towers (upper mount) and suspension arms (lower mount), allowing the shocks to be mounted at various angles. Basically, 'laying the shocks down' (mounting them at a more horizontal angle) provides more stability while cornering and quicker response, but sacrifices the model's ability to absorb large jumps or bumps without bottoming out. 'Standing the shocks up' (mounting them at a more vertical angle) allows the model to absorb jumps and bumps better and improves traction, but increases body roll when cornering. When altering shock position, it is best to start with the upper mount (where the change is more noticeable while entering turns). Altering the lower position actually affects the leverage of the shocks, and should be reserved for more dramatic changes.

  • Shock Shaft --
  • The long metal rod that sticks out of the shock body, usually with a pivot piece on the end that mounts to a suspension arm. The other end (inside the shock body) has a shock piston on it.

  • Shock Shaft --
  • The shaft that slides in and out of the shock body. The lower part of the shaft is threaded to accept the shock end, while the upper part may have grooves (for E clips) or threads (for a nut) to hold the shock piston.

  • Shock Shaft Pliers --
  • Padded pliers designed to hold the shock shaft while installing or removing shock ends without marring it. Nothing tears up O rings and spills shock oil like a scratched or dented shaft.

  • Shock Spring --
  • The coil spring that usually surrounds the shock body of an oil-filled shock. Some shocks consist of just the spring (like a pan car front shock).

  • Shock Spring --
  • The coiled spring that slides over the shock body and is held in place by the spring retainer and shock collar. The spring is what actually holds the model up, and provides the rebound action for the shock. Shock springs are available in a variety of sizes for different models, as well as various rates (stiffnesses) for fine tuning - some springs are even available with a progressive rate (the spring becomes stiffer as it compresses). Shock springs are an important suspension tuning aid, and spring rates can vary between the front and rear of a model.

  • Shock Travel --
  • This does not refer to shock spacers that clip to the shock body, compressing the spring. There are two ways to limit shock travel: Spacers inside the shock, under the piston on the shock shaft or an o-ring or two on the outside of the shock body, on the shock shaft above the spring retainer. The inside spacers limit how far down the shock can extend, and the more you have, the shorter the shock gets at its full length, but you may have to change your ride height. The outside spacers (be sure to use old o-rings!) remove shock travel without compromising the shock length or ride height, so the shock can still deal with dips in the track, but stroke is lessened.

  • Side Plates --
  • The sides of a wing, they help direct air over the wing and help in stability. Larger side plates help in stability on a long straight section but can affect the turning ability. Smaller side plates aid in turning but don't provide as much straight-line stability.

  • Side Skirt --
  • The part of the body panel that is under the door. This term usually refers to an extension of this panel that lowers the effective 'body ride height'. Helps keep air from getting underneath the car, and helps channel air underneath the car from the front to the rear, increasing downforce.

  • Silicone --
  • A type of synthetic rubber that is heat-resistant and more durable than standard or natural rubber.

  • Sleeve --
  • Refers to an internal part of a nitro engine, which the engine's piston slides up and down in. If the engine's sleeve is replaced, the piston must also be replaced and the engine broken in. Sleeves in 2-stroke RC car engines are either nickel-plated or chrome-plated. Nickel plating offers cheaper parts but it can wear out faster. Chrome plating is more expensive but worth it for racing.

  • Slipper --
  • A short term for the slipper clutch

  • Slipper Clutch --
  • A traction control device that uses metal plates and a fiber pad that controls how much power is transmitter from the drive gears of an RC car to the rest of the drive train. Used mainly on off-road kits.

  • Speed Controller --
  • Another name for electronic speed controller

  • Speedo --
  • Another name for electronic speed controller

  • Spindle --
  • A non rotating axle used for the front tires on 2WD models. When using a spindle, the bearings (or bushings) are located in the rims instead of the hub carrier.

  • Spiral Cut Gear --
  • In RC, spiral cut gears are almost exclusively used as diff gears. A spiral cut gear has the teeth angled (curved), increasing the tooth contact patch (improving durability) and providing a smoother, more efficient mesh. Spiral cut gears are more complex and expensive to make that common gears, which makes them rare in the RC realm.

  • Spoiler --
  • An angle on the rear of a car that is built into the body lines of the car, or bolted on. No space exists between the spoiler and the bodywork. Examples include stock car bodies and some HPI bodies like the Mazda Miata and Peugeot 406 Coup?. A front spoiler is technically an air dam. The angle that the spoiler contacts the air is the 'angle of attack'.

  • Spring Rate --
  • This basically refers to the stiffness of a set of springs. If you want more traction at one end, put on a softer set of springs. If you want less traction, harder springs. If you are bottoming out or the track is really bumpy and the soft springs can't extend fast enough to make the tires contact the surface, put on stiffer springs. If you change the spring rate by a large margin, you'll probably have to switch out the oil or pistons too.

  • Spur Gear --
  • The large (usually plastic) gear that a pinion gear or clutchbell turns to provide power to a car or truck drivetrain. Available in different pitches. Many newcomers to the RC hobby will ask about metal spur gears to prevent gear stripping, however it is usually gear mesh that determines if the gear strips out or not.

  • Squid --
  • The RC hobby includes many different types of plugs and connectors for batteries, and none of these connectors seem to match up - this is where the squid comes in handy. A squid is simply a connector or plug with a bunch of wires soldered together that lead to a variety of plugs. The main plug is connected to the battery charger (this is usually a Tamiya plug), and one of the other plugs goes to the matching battery connector. Of course, the more types of batteries you have, the more plugs you will need on your squid to match up with the battery plugs. No matter what the ladies say, the size of your squid is important.

  • Stagger (Batteries) --
  • Refers to installing custom split battery packs in EP models with more cells on one side of the chassis than the other (such as 4 cells on one side and 2 cells on the other side). This is usually done to tune weight balance or due to space constraints. Some saddle packs have a staggered layout.

  • Stagger (Tires) --
  • A common tuning option used by oval racers, stagger refers to running tires on one side of the model with a different circumference than the tires on the other side. A negative (-) stagger means the inside tires (the left tires on left turn tracks) are larger than the outside tires (this is virtually never used). A positive (+) stagger means the outside tires (the right tires on left turn tracks) are larger than the inside tires, which aids steering response and helps keep the model level in turns.

  • Stainless Steel --
  • A treated steel that is impervious to rust. For RC applications, it is mainly used to make screws or collars.

  • Stall --
  • This is what happens when a nitro engine stops running. Stalling is usually caused by improper fuel mixture, flame out, excessive resistance (such as the flywheel jamming when a model bottoms out), or simply running out of fuel. Also see AXLE STALL

  • Standard Narrow --
  • see width, wheel

  • Starter Box - Bump Box - Bump Starter --
  • This is what is used to start nitro engines that don't have an onboard starter (or to supplement onboard systems if you left something at home or just discovered your EZ Start batteries are dead). It is basically a motor, batteries to power the motor (such as 1 or 2 stick packs or a gel cell), and a rubberized wheel - all housed in a convenient box. To start the engine, the model is aligned on the box then pressed down to start the starter motor, this spins the rubberized wheel, which engages the flywheel, which turns the engine over. This is the type of starting system preferred by die hard racers since it eliminates all the extra weight and drag of onboard starting systems. You will still need a glow driver and need to lug around the box (and charged batteries). Also note that many starter boxes are designed to be used with certain types of models (such as 1/8 buggies or on road cars), and some models can't be started with a starter box due to flywheel position (i.e. most monster trucks).

  • Starting Grid --
  • "The order the cars are lined up at the start of a race. Most races are started with """"Le Mans Starts"""", meaning the cars start from a dead stop."

  • Steel --
  • Not used very often throughout a modern RC kit, steel is a strong yet heavy metal that is still used in some critical parts of today's RC kit. Typical places you can find steel on an RC car: pinion gears, turnbuckles or threaded rods, axles, dogbones, ball ends, screws and lock nuts.

  • Stepped Wheel (RIM) --
  • "Refers to a short course (SC) truck rim with a 2.2"""" size on the outside and a 3.0"""" size on the inside. The rim abruptly changes sizes near the center of the rim. This helps maintain scale looks, but requires multiple tire inserts."

  • Stock (Motor) --
  • Refers to a high turn motor (usually 20T+) with a machine wound armature and adjustable timing.

  • Straightaway --
  • Normally refers to the longest, straightest part of a race track. If there is any place to go full throttle, this is it!?

  • Stroke --
  • The distance a piston travels from BDC (bottom dead center) to TDC (top dead center) in a nitro or gas engine. May also be used to refer to the total compression range of a shock.

  • Suspension --
  • Refers to the components used to 'hold up' or suspend the chassis of a model. This usually refers to the arms and springs, but may include other components (especially those that aid in tuning), such as the hub carriers, turnbuckles, and control arms. When referring to suspension, this may also include the type of hubs used, such as C hub, pivot ball, or solid axle.

  • Suspension Arm --
  • Suspension arms are used on models with independent suspensions. They attach to bulkheads or pivot blocks on the chassis, and support the hub on the outer end. Lower suspension arms also have the lower mounting locations for the shocks. There are two basic types of suspension arms used in RC - The A arm (common on pillow ball models with dual wishbone suspensions) and the H arm (common on C hub models and models that utilize an upper camber link).

  • Suspension Link --
  • On solid axle monster trucks and rock crawlers, the suspension link holds the axle straight and keeps it from rotating front to back. This link is is usually a rod (with rod ends) or a machined alloy part, and some may be 'bent' or angled to increase ground clearance. A suspension link will have a mounting location near the outside of each axle, as well as a mounting location on the chassis (which may be on the outside or inside of the chassis, depending on the link style). Suspension links may either be 3 link or 4 link, depending on the model.

  • Swaybar - Anti Roll Bar - Anti Swaybar - Stabalizer Bar --
  • This is a wire or blade that connects the left and right suspension arms of a model and hinges on the chassis. Swaybars reduce body roll and create a smoother load transfer from one side of the model to the other while cornering. Swaybars may be used on off road or on road models, and may be used on the front suspension, rear suspension, or both. There are two basic types of swaybars - wire and blade. Wire swaybars are the most common (and the only type used on off road models). They are basically formed spring steel wire that twists to create tension. A thicker wire = a stiffer swaybar, while a thinner wire = a softer swaybar (a.k.a. swaybar rate). Blade swaybars are machined pieces (usually machined from spring steel) that resemble a flat leaf spring. Blade swaybars are used with on road models (almost exclusively 1:8 scale on road), and flex to create tension. As with wire swaybars, a thicker blade = a stiffer swaybar, while a thinner blade = a softer swaybar. In general, swaybar rate should match shock spring rate - stiffer swaybars with stiffer springs, and softer swaybars with softer springs. The following represents basic swaybar tuning:

    - FRONT (STIFFER SWAYBAR) - This is good for twisty tracks with a high bite surface. A stiffer front swaybar increases rear traction and steering response while cornering, but reduces front traction and off power steering. Great for increasing corner exit speeds.

    - FRONT (SOFTER SWAYBAR) - A softer front swaybar (or a rear swaybar with no front swaybar) increases turn in while braking, but reduces rear traction and steering response. Great for overtaking while entering corners by allowing late, hard braking.

    - REAR (STIFFER SWAYBAR) - This is good for tracks with long sweepers and a medium to high bite surface. A stiffer rear swaybar increases front traction and steering response, but decreases rear traction. Great for passing on long, high speed corners.

    - REAR (SOFTER SWAYBAR) - This is good for low bite (loose or loamy) tracks. A softer rear swaybar (or a front swaybar with no rear swaybar) increases rear traction and reduces oversteer. Great for increasing corner speed and helping to prevent spin outs.

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