R/C CARS GLOSSARY TERMS
In addition to offering a wide variety of R/C parts, upgrades, and more! We strive to provide you with the best service in the industry. We feel it is our duty to not only provide you with great service, but we would also like to provide a reference guide for you to learn more about us and our industry. We are giving you the inside scoop to our company glossary so you can learn about R/C hobby just like us. We hope this guide is useful to you and will make you feel more confident about the features that our products provide. Enjoy!
GLOSSARY - ALL TERMS
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2-Wheel-Drive vs. 4-Wheel Drive
As in full-scale cars, there are two main drive types: two-wheel drive (2WD) where power is supplied to the two rear wheels, and four-wheel drive (4WD) where power is supplied to all four wheels. The 2WD vehicles are less expensive and require less overall assembly and maintenance than 4WD vehicles. Assembly and maintenance for 4WD vehicles tends to be more involved, though not necessarily more difficult; the trade-off is that 4WD vehicles offer better steering through turns.
2.4GHz
Spread Spectrum. The newest radio band available for R/C use, which operates at a higher frequency than noise. See also: FHSS and DMSS.
6061-T6 Alloy
Alloy is a mixture of two or more elements in which aluminum is the predominant metal. Aluminium alloys are used extensively due to their high strength-to-weight ratio; and 6061-T6 alloy is the most widely used grade for aluminum R/C parts. Unless specified, all GPM alloy parts are 6061-T6 grade alloy.
7075-T6 Alloy
Zinc is the primary alloying element in its component. It is stronger than 6061-T6 grade alloy. Parts can be made smaller or thinner due to better strength.
A Arm
This generally refers to the lower suspension arm of the car, although it can refer to the upper arm also. Often times resembles the letter “A”.
ABC / Non-Ringed
These letters stand for aluminum, brass and chrome or a composite such as nickel. These engines have an aluminum piston and a chrome or composite coated brass cylinder sleeve which allows them to be more efficient for higher performance. They have no piston ring and rely on a very tight piston/cylinder fit to obtain a piston/cylinder seal. New ABC engines are normally hard to turn over by hand. Because of the tight fit, it is very important that the engine is broken in properly.
ABN
Engine construction that consists of an aluminum piston, & a brass cylinder that has been nickel plated. Sometimes used today on higher perfomance engines.
ABS
A form of plastic that is easy to form but is not crash-resistant, however some of our 24mm wheels are made from ABS, which is slightly lighter than the high-impact nylon used in our other wheels.
Accelerate
To make the car move faster, either from a full stop or while it’s already moving.
Acceleration
A measure of how quickly a car can accelerate. Acceleration is affected by items like the weight of the car and its rotating mass.
Ackerman
The degree of difference in the steering angle between the inside and outside wheel when a vehicle is turning. Rudolf Ackerman is a man who worked out a steering system for horse-drawn carts, and we use his name today to describe the angle of the inside tire in relation to the outside tire when the wheels are turned to full lock- the farthest the wheels go to the left or right. Normally, when the front wheels are turned all the way left or right, the inside wheel is at a sharper angle than the outside wheel. If you extend the center line of each front tire to a point where the intersect and measure that angle, that is the Ackerman angle. Ideally, for perfect steering, the Ackerman angle will cross at the center line of the rear axle. In a wide turn, the front tires are not turned very far to the right or left, the inside wheel is not steering at a sharper angle than the outside wheel, and the Ackerman angle is not very wide. In a tight turn, the inside wheel is steering at a steeper angle than the outside wheel, and this is what is called the Ackerman effect. A bellcrank steering system approximates a way to copy the Ackerman effect, and is adequate for R/C cars because of tire slip, tire sidewall folding and other factors. Adjusting the Ackerman angle can be done by changing the length of the center link, also called the Ackerman link that connects the bellcrank steering arms, or changing the mounting location on the steering arms without changing the link length. Most racers won’t need to change the Ackerman angle, and actually it is best left to experienced racers who wish to try something new. Mounting the Ackerman link to the outer holes will result in a small Ackerman angle. Using the inner holes will increase the Ackerman angle. A smaller Ackerman angle (done by lengthening the Ackerman link or using the outer link holes) will give you more aggressive steering into a corner with a possibility of over steer at the middle of turn, when the most weight is on the outside tires. A larger Ackerman angle (achieved by shortening the Ackerman link or using the inner link holes) will give you more predictable and smoother steering.
Ackerman Link
The center link of the bell crank steering system that connects the two steering arms.
Adjustable Travel Volume (ATV)
ATV allows you to preset the maximum travel of a servo to either side from its neutral position. Such settings help tailor control action to suit your flying or driving style.
After-Run Oil
Just what it sounds like. After you’re done running your nitro engine, it’s recommended that you remove the glow plug and place a couple of drops of After-Run oil in the cylinder as well as in the carb throat.
Air Dam
An extension of the front bumper that blocks, or dams, too much air from getting under the car and producing lift. Most R/C bodies for Touring Cars have air dams built in.
Aluminum
In general terms, aluminum is a metal that is lighter than steel, but not as strong. It can be machined (cut on a machine) to replace many plastic parts of an R/C car, but is not recommended for replacing suspension arms.
AM
Short for Amplitude Modulation, an AM radio in R/C is considered a budget radio, what most newcomers to R/C will start out with. Most hobbyists will be fine with an AM radio, but some racers can benefit from FM or PCM radios. An AM radio will have more glitching than these other, more expensive radios.
Amp Hour
The electric charge transferred past a specified circuit point by a current of one ampere in one hour.
Angle of Attack
Refers to the angle that a surface contacts the air, usually mentioned when talking about spoilers and wings. A higher AOA helps solve over steer but increases drag and decreases top speed. A lower AOA is used to alleviate under steer and increase top speed.
Anodize
the process of adding color to the machined part.
Anti-squat
Refers to the angle of caster on the rear wheels. However, that angle prevents the squatting of the rear suspension, so ‘anti-squat’ it is. Anti-squat is most effective on acceleration from a stop, when much of the car’s weight is forced onto the rear suspension. Lifting the front of the hingepin of the rear arms gives a caster (anti-squat) angle, and helps to transfer the power that makes the car want to do a wheelie into forward motion.
Arcing
When voltage jumps from the brush to the commutator (or from one surface to another) due to poor or corroded contact between the two components. Arcing will cause excessive heat, resulting in premature brush and commutator wear.
Armature
Is the spinning part of an electric motor. Also known as the arm.
ARR
Some cars and trucks are available virtually prebuilt and will be indicated by the terms ARR (Almost-Ready-To-Run) or RTR (Ready-To-Run). The ARR/RTR vehicles cost a little more, but if you’re just not interested in building your car, this is an option for you. Most vehicles, however, come in kit form and require you to do the building. This may require a few evenings, but the familiarity you gain from assembly will make repairs, adjustments and modifications easier to make down the road.
Axle
What a wheel of a car spins or rotates on. A drive axle is an axle that is actually powered and turns the wheel (such as the rear axles on a rear wheel drive car), otherwise the wheel will spin on bushings or bearings on the axle.
Backmarker
Any racer that is getting lapped.
Ball Cup
A hollow plastic piece that snaps onto a ball end that provides a pivot point, usually for suspension movement. Using a ball cup/ball end assembly instead of a rigid system allows the car to absorb crash damage, so the ball cup will pop off instead of break. Ball cups are usually paired with turnbuckles for the ultimate in ease of use and assembly.
Ball Differential(Ball Diff)
A differential that uses a series of steel or carbide-steel ball bearings in a circle, pressed between two metal rings, to provide the differential action, allowing one wheel to rotate more than another in a turn. Ball diffs are easier to adjust than gear diffs but are harder to maintain, as they need checking every day of running and are not recommended for Nitro racers. Normally a screw on one side controls the tension between the metal rings, which controls how much the outside wheel in a corner can turn. The looser (to a point) a diff is, the more traction there is at that end of the car. To start tuning your car, set the ball diffs to the same tension at each end, and use the diffs only to fine-tune the car. Do not change the settings of your diffs first.
Ball Differentials or Gear Differentials
Ball differentials should be initially set to the kit specifications: the diff should be set so that the pulley is not be able to be turned with two flat head screwdrivers or Allen wrenches slid through the outdrive. A different type of differential is the One-Way Diff, which uses expensive one-way bearings to control wheelspin.
Ball End
A metal ball that has a hex (6-sided) and screw threads on one end. A ball cup will attach over the ball end to provide a pivot point.
Ballooned
Term refering to a LiPo battery that has been over charged or over loaded and has expanded in size due to the creation of gasses inside the packaging. Ballooned LiPo batterys should always be disposed of correctly and never re-used. Check your local authorities for a safe battery disposal site in your area.
Barrel Carburetor
the standard model engine carburetor, carried over from airplane engines when they were adapted for car use. For most hobbyists and racers this type of carburetor is fine, because it is simple to install and adjust. The throttle servo turns a barrel which has a hole through it, and this controls the amount of air going into the engine.A needle valve on the carburetor controls the amount of fuel going into the engine.
Batteries
A battery holds an electrical charge for future use by an electrical device. A single cell is a battery, a collection of cells is a battery pack. Batteries in use in the R/C hobby can contain alkaline materials (non-rechargeable, used for transmitter batteries), nickel-cadmium or nickel metal hydride. Each type of battery has its advantages and disadvantages, see the associated glossary entries for details.
Battery Eliminator Circuitry (BEC
A circuit that eliminates the need for a separate battery pack to power the receiver and servos. This circuitry can be found in speed controls as well as receivers.
Battery Pack
A collection of batteries that are joined together to combine the voltage of the batteries to power an electrical device. This term is used for electric R/C cars (normally a pack to power the motor) and also for Nitro cars (to power the servos controlling steering and throttle/brake).
BB
These letters usually designate a ball-bearing supported crankshaft in an R/C engine. This makes the engine run smoother and last longer. Ball-bearings are also used on wheels and other rotating parts on a car or trucks chassis, allowing the vehicle to roll more freely, which in turn, allows the Nitro engine or Electric Motor to power the vehicle to its fastest speeds.
BDC
Abreviation for Bottom Dead Center. When a piston is at the very bottom of it's stroke.
Bearing
A hollow metal donut that uses balls inside to increase the efficiency of a rotating shaft (like an axle). Highly recommended as the first option part for any kit equipped with bushings, bearings have become a standard accessory in most R/C kits today.
BEC
A circuit that eliminates the need for a separate battery pack to power the receiver and servos. This circuitry can be found in speed controls as well as receivers.
Bellcrank
The type of steering mechanism most common in R/C cars, trucks and buggies. It consists of two posts, one of which has a connection to the steering servo. This connection turns one of the steering arms, which is connected with an Ackerman link to a second steering arm. The left side steering arm is connected to the left steering knuckle with a turnbuckle, just as the right steering arm is connected to the right steering knuckle. Some bellcrank systems allow racers to alter the Ackerman angle, which can tune the steering effect of the steering system in different ways.
Big Block
In Rc terms, this refers to a .21cc engine or larger.
Billet
A large round bar stock used to manufacture aluminum parts.
Bled
After correctly assembling a shock absorber with no excess oil and no air bubbles, that shock absorber is considered properly bled.
Bleeding
The process of removing air and excess oil from shock absorbers. A properly assembled shock absorber is considered bled
Body
In Rc terms, the body is the thin, usually Lexan, clear plastic piece that covers the car and provides the shape of the car. Most bodies, especially on touring cars and some other vehicles, are easily interchangeable, so it’s possible to run a street truck body, then change it for a sedan body, then change that for a coupe body.
Body Clip
A pin or clip that holds the lexan shell/body of a radio control vehicle to the chassis of that vehicle.
Body Reamer
The body reamer is a must-have tool for creating perfect body post holes in Lexan bodies and other semi-soft materials.
Body Roll
The changing of the chassis’ angle in relation to the ground when going through turns or corners.
Bog
Verb - When a nitro engine stutters upon acceleration. Bogging can be caused by excessive fuel/lubricant in the air and fuel mixture (rich setting) or by too little fuel/lubricant in the mixture (called lean bog). Lean bog can lead to stalling and overheating, as too little fuel/lubricant is present to prevent friction, heat and wear
Bottom End
A vehicle’s acceleration rate from a dead stop, or the amount torque available from a motor depending on type of motor and gearing.
Brake
The system used to slow a car or bring it to a stop. In an electric car, the electronic speed control performs this function. In a nitro car, braking is normally provided by a disc brake and brake pads.
Brake Check
A driving tactic that is used to disturb a racer’s concentration. A car that is being followed closely by another car can abruptly slow down in a section of the track where braking normally doesn’t occur, causing the following car and other cars to swerve to avoid the car in front. Sometimes this works, sometimes it doesn’t!
Brake Fade
A term used when a car’s brakes heat up and provide less stopping power, forcing the driver to learn to brake earlier as a long race progresses. Upgrading to our Fiber Brake Disk will prevent brake fade for racers. Drilled brake disks look really cool, but we are not aware of any actual performance advantages they may have.
Braking
Usually used in sentences like under braking or need more or less braking this simply refers to the time when the car is actually using its brakes.
Braking Zone
The area of a track where cars are slowing down to approach a corner. Easiest to find at the end of a straight section. A track can have many braking zones.
Break-In
The process of running a nitro powered engine at idle speeds to prepare it for general use. The generally accepted method is to run the engine very rich (the exact needle valve adjustment will vary from engine to engine) for at least 3-4 tanks while the car is on a car stand. Running a fan over the engine and varying the idle speed slightly during break-in is also generally accepted. NOTE: As the engine breaks in, the speeds will pick up and you may have to richen the air/fuel mixture slightly. An engine isn’t fully broken-in until it has run about 10-15 tanks, at which point you will see its full potential.
Brush
A small rectangular piece of conductive metal that makes contact with the commutator inside an electric motor.
Brushless Motor
A DC motor that relies on an external ESC to operate. The ESC acts as speed control and as a "switcher" in place of a standard armature/brush assembly found in most DC motors.
Buggy
Among the more popular types of R/C cars, buggies are durable cars that can run on most surfaces. The most popular are rear-motor two-wheel drive (2WD) electric buggies and four-wheel drive (4WD) nitro and electric 4WD buggies are popular also.
Bulkhead
A part of the car that is generally connects to the chassis. During assembly, other parts are connected to the bulkhead, making the bulkhead one of the primary foundation pieces of the car.
Bump-Steer
The changing of steering angles while the suspension is moved through its range of travel. Generally, not a desired action.
Bushing
A metal donut that supports a rotating shaft (like an axle). Most bushings are metal, with most metal bushings made out of something called Bronze Oilite. This is a metal that is permanently lubricated.
C-Hubs (Caster Blocks)
Shaped like the letter "C", this part holds the front knuckles and placed on the front arms, connecting to the main chassis.
CA
An instant type glue that is available in various viscosities (Thin, Medium, Thick, and Gel). These glues are ideal for the assembly of wood airplanes and other materials. Note: Most CA glues will attack Styrofoam.
Calling Traffic
Some tracks have a policy of telling racers that are getting lapped that the leader of the race is coming up behind them. The backmarker is expected to move over and not interfere with the leader and any battles for position. However, not all tracks have this policy.
Camber
Seen from the front and rear of the car, the angle of the tires in relation to the ground; tires that are perfectly perpendicular to the ground (90 degrees) are said to be at ‘zero camber’. If the tops of the tires lean towards each other, the tires have negative camber, and if they lean out, the tires have positive camber. As a general rule, never have positive camber, and make sure the camber of, say, your front right wheel equals the camber of your front left wheel (make the camber angles on each axle match). If we were talking about oval racing, the rules would be different, but we’re not. Sedan racing, with it’s straights, turns and chicanes requires that, among other things, camber angles match. Usually one degree of negative camber on the fronts is good, because you want a good contact patch throughout a turn, and one or two degrees of negative camber on the rear wheels is fine. From there, experiment, one degree at a time.
Camber Link
Normally made up of a turnbuckle or threaded rod with a ball cup at each end. This allows the suspension arm and upright to flex a little more than an upper arm would.
Can motor
Inexpensive DC motor, generally with a fixed end-bell, internal carbon brushes and ferrite magnets. Used in lower cost/lower performance R/C applications.
Car Stand
Simply, this is something a R/C car will be on while work is being done to it. It can be as simple as a block of wood, or as complicated as a padded rotating stand with parts bins. Another main function of a car stand is to keep the wheels off the ground during breakin and while work is being done.
Carburetor
Called carb for short. The mechanism on an engine that controls the ratio of fuel and air that enters the engine. There are different types of carburetors:
Caster
Almost every car has some caster built-in. Caster is the angle that the car’s front wheels pivot on when turning. Most on-road Touring Car type kits use between 5 and 10 degrees of caster. Off-road kits like buggies and trucks have about 25 to 30 degrees of ‘kick-up’ on the front axles. More caster generally gives more steering going into a turn, but less coming out. The opposite is also true: less caster give less steering going into a turn (initial steering), but more steering as you exit. Caster also gives more stability on straightaways, but this effect is more pronounced in 2WD vehicles.
Caster Blocks
See C-Hubs.
CC
cc is a measurement of engine size.Only used with small engines. cc standing for Cubic Centimeter
Cell
Another term for batteries, but in a singular reference (such as, look at this cell), this generally refers to the nickel-cadmium or nickel-metal hydride batteries used in Rc cars.
Center of Gravity
can be shortened to CG or cg. A point in space that represents the central point of a car’s mass. If you don’t race or are just starting, the only thing you need to know about center of gravity is that if you have a high CG the car or truck will be easier to tip over in tight turns, especially at high speed. As you get more experienced in racing, you will learn to keep everything on the car or truck as low as possible to enhance handling.
Charger
Device used to recharge batteries, usually supplied with the radio if NiCd batteries are included. Chassis: The foundation of an Rc car or truck, this is the main portion of the car that everything attaches to. It can be made from woven graphite, molded plastic composites or aluminum. Normally it is flat with lightening holes cut into it but if molded from plastics it can have bent-up sides and other features.
Class
In radio controlled car racing, the class refers to the type of car you have, and what class it would race in. In general, there are Touring Car, Mini, 2WD buggies, 2WD trucks, 4WD buggies, Rally, Super-Size, Oval Pan Car, 1/10th scale Pan Car, 1/12th scale Pan Car and a couple of other classes. These classes are further divided by the mode of power, either Electric or Nitro. The some of the popular classes are electric and Nitro Touring Car, electric 2WD buggy, nitro 4WD buggy, Monster Truck, Truggy and Stadium Trucks. To just name a few. When deciding what type of kit you want to get for your first R/C kit, try to decide what type of kit and what type of power source you will get, this will narrow your selections down considerably!
Closed Cell Foam
A type of foam that is molded, normally used in Rc for molded inner foams. More expensive than open cell foam, it holds its shape better and if molded it does not move back and forth on a wheel.
Clunk
A weighted fuel pick-up used in a fuel tank to assure the intake line is always in fuel.
Clutch Bell
The equivalent of a pinion gear on a nitro engine, the clutch bell is on the end of the crank shaft and connects with the car’s spur gear(s). In a cutaway view, the clutch bell looks like a bell, which is where it gets the name. Inside the hollow part of the clutch bell are the clutch shoes, which will expand with engine RPMs to come in contact with the clutch bell, making it spin. This makes the spur gear turn, and the car moves forward!
Clutch Shoes
Clutch shoes are attached to the engine flywheel and expand under increasing RPM to contact the clutch bell. The clutch bell spinning makes the spur gear turn, and the car moves forward!
Color
GPM Racing aluminum parts can be anodized into 13 different colors! We have blue, silver, red, purple, black, gold, champaign, green, gun metal, titanium, golden black, pink and orange colors. Below are samples of different colors we supply.
Compound
When talking about tires, the firmer (harder) the compound, the longer life it will have, but it won’t have as much grip as a softer tire would. Most racers use a firm compound tire as the racing surface heats up during the day. A softer compound tire is best used when the track is cool, such as in the morning or late evening. Examples of these compounds include 20R tires (softest), 23R, 27R (medium), 33R and 35R (firmest).
Contact Patch
The footprint of the car’s tire, or the area of the tire that comes in contact with the ground at any given moment. Affected by camber, turning and acceleration. A wider contact patch (from wider wheels) does NOT mean you will automatically get more traction.
Coupe
In general terms, this refers to a 2-door car. Some Rc touring car body manufacturers offer bodies that represent full-size cars.
Crank Shaft
A part of a Nitro engine that is rotated by the piston, providing circular motion to the outer part of the crank shaft, which is attached to the flywheel and clutch shoes.
Crystal
The part of a radio system that tells the transmitter to emit a particular frequency, and also tells the receiver to look for a particular frequency. Crystals normally are packaged in pairs, because the receiver requires a different crystal than the transmitter. You must use the same frequency crystals in the transmitter and receiver to make the car respond correctly to your commands.
Current Limiter
An adjustment on an ESC to limit the current that the motor can draw during acceleration. This eliminates high, inefficient current spikes and reduces wheel spin.
CVD
An abbreviation for Constant Velocity Drive. CVD is a trademark of MIP (Moore’s Ideal Products, Inc.). MIP offers their CVD universal dogbones for many Rc Trucks and Cars. The main features of the MIP CVD’s are their improved efficiency over standard universal dogbones, ability to be rebuilt if an axle or bone is bent or damaged and ease of finding replacement parts.
Dampening
The resistance caused by fluid in a shock body when the piston moves through it
Damper Plate
See Shock Tower.
Damping
Damping is a highly variable part of car tuning. It’s affected by the strength of the shock spring (length and thickness of the wire, plus the number of coils), the size and number of holes in the shock piston, and the viscosity, or weight, of the oil in the shocks. The spring controls how hard the shock compresses, and both the piston and the oil control how quickly the spring pushes the shock to its full length (which can be limited by shock spacers), and so affect the quickness of the shock’s return. Stiffer springs need heavier oil and/or smaller-hole pistons to control the speed of the rebound, and bumpy tracks need lighter oil so the shocks, or dampers, can compress and rebound quickly. Softer damping gives more ‘stick’ on a particular wheel, but makes the car less responsive because the chassis takes longer to reset after a turn, and is also more forgiving to drive. Softer damping also reduces weight transfer at that wheel. Stiffer damping makes handling more responsive, but reduces traction to a particular wheel which can make the car slippery as the chassis snaps back into place after a turn. Stiffer damping also increases weight transfer at that wheel.
Delrin
Delrin is a man-made material patented by DuPont. It is a plastic that has the strength of metal. It is mbuch denser and stronger than nylon (a material commonly used in RC gears). Delrin performs significantly better than plastic, in their toughness (2x), endurance (100x) and elongation (2x).
Dialed
This is a slang term used in the 1/8 scale buggy world. It means that after all the hard work of tuning your suspension, shock oil, diff oil, and other adjustments, your buggy is finally tuned.
Diff Rings
The metal rings that the diff balls run against.
Differential
A system that transfers power equally from a shaft input to shaft outputs. A differential (or diff) allows the outside wheel of a car going through a corner to travel farther than the inside wheel, preserving corner speed and efficiency. There are two main types used in radio control cars:
Diode
A semiconductor device used to control the flow of electric charge. High-rated schottky diodes are used in single-direction ESCs to prevent back-EMF (voltage 'spikes') generated by the motor from entering the ESC.
Discharge
The act of draining a battery of its stored energy, either by running a vehicle or connecting the battery pack to discharge device.
DMSS
(Direct Sequence Spread Spectrum) — A 2.4GHz radio system which selects one (or two) of the available “free” frequencies and transmits only on the one(s) chosen. Like FHSS (Frequency Hopping Spread Spectrum) systems, it is resistant to electrical noise. See also: FHSS.
Dogbone
The shaft used to transfer power from a transmission outdrive to the drive axle. Because of the roll pins found at each end, the finished product resembles a dog bone.
Double Wishbone
A type of suspension design that uses two wishbone arms (parallel to the ground and each other : one for the main suspension arm and one for the upper arm) to help maintain a constant tire camber as the suspension is compressed. Most Rc cars have this type of suspension design, because, although it is expensive to have on a full-size car because of cost and space issues, on a miniature car where there is no concern over the space needed for a driver, it is much easier to make. Older Rc cars used different suspension technologies that are no longer in use today (at least in Rc) including swing-arm and trailing arm suspensions.
Downforce
The effect of air contacting the car body’s sloped surfaces. Downforce is created by the air dam, hood, windshield, roof, spoiler(s) and wing(s) of the car. More downforce increases drag and slows the car, but raises the tire temperature, making the car easier to drive. Less downforce raises the top speed by reducing drag. The car should be set up so that it can drive with minimal downforce.
Draft
In racing terms, draft is the area directly behind a car where the air is disturbed and there is very little wind. A real-world example would be putting your hand outside the window of your car, and moving it behind the side mirror, then out from behind the mirror. Behind the mirror is the draft.
Drafting
In racing terms, this is the act of following the car in front of you close enough that your car does not have to fight drag. This lessens the load on your engine or motor, and on a long straight section of the track your car and the car in front of you can go faster than another car on its own. In R/C racing, this is very rarely able to be used because of the size of the cars and the maneuverability of the cars, even on an oval track.
Drag
In car design, drag is the force of air that slows down the car. The lower the drag of the car (in other words, the more aerodynamically efficient it is), the faster the car can go while using the same amount of power.
Drag Link
Another term for Ackerman link
Droop
The measure of shock droop is the amount of uptravel the chassis will have if you weigh the car with its full running gear (servo, batteries, motor, etc.), settle the chassis (press down and release on the chassis), then lift each end until the tires lift off the ground. The total upward movement of the chassis at each end is measured as droop.
Dual Rate
An adjustment found on some radios which allows adjustment of the distance a servo arm will travel.
Dump
A. term used to describe when a battery’s charge is running out.
Dyno
An expensive piece of computerized equipment that measures the efficiency of a motor. Can be used to select the right gearing, but the dyno in this function is normally only used by pan car or oval racers.
E-Clip
A small device that holds cylindrical parts like hinge pins in place on the car.
Electric
This general term usually refers to the power source of the car, meaning it uses a battery pack
Electric vs. Gas Cars
Electric vehicles are the most popular choice in R/C car racing. They are quick, quiet, easy to build and comfortable for the beginning R/Cer to drive. The electric cars are powered with a rechargeable nicd battery that can be charged in as little as 15-20 minutes. A vehicle with a stock motor will provide about 6-8 minutes of run time; with a couple of batteries and a 15 minute charger, an electric car or truck is ready for hours of use. The popularity of Gas vehicles has increased tremendously over the last few years. The explosive power and acceleration of a gas powered car or truck is exciting to watch. Gas vehicles are powered by a small two-cycle engine burning glow fuel (not gasoline!), and many modelers enjoy the realistic sound and smell that goes along with gas powered racing. Some gas models can reach speeds over 50mph! The wider availability of pull-start engines and the new wave of 1/10 scale vehicles has made it much more affordable for the beginner to enter gas-powered racing.
Electronic Speed Controller
An electronic device that takes the power from the battery pack and the signal from the receiver and measures a certain amount of power to the car’s motor. Only used in electric R/C cars, boats and planes.
Endpoint Adjustment
This radio feature adjusts the length of servo travel in one direction (a single channel will have adjustments for two endpoints). If your car or truck can make a tighter left hand turn then it can a right hand turn, endpoint adjustments can correct the problem by allowing you to adjust the servo to travel the same distance in both directions. Endpoint Adjustment featured radios are recommended for cars and trucks with Nitro engines….it allows you to set the Carburetor and Brake settings just right.
Endpoint Adjustment
This radio feature adjusts the length of servo travel in one direction (a single channel will have adjustments for two endpoints). If your car or truck can make a tighter left hand turn then it can a right hand turn, endpoint adjustments can correct the problem by allowing you to adjust the servo to travel the same distance in both directions. Endpoint Adjustment featured radios are recommended for cars and trucks with Nitro engines….it allows you to set the Carburetor and Brake settings just right.
Engine
In Rc terms, this is a fuel-powered engine that provides the power for forward motion.
Epoxy
A two-part resin/hardener glue that is extremely strong. It is generally available in 6 and 30-minute formulas. Used for critical points in the aircraft where high strength is necessary.
ESC (Electronic Speed Controller)
An electronic device that takes the power from the battery pack and the signal from the receiver and measures a certain amount of power to the car’s motor. Only used in electric R/C cars, boats and planes.
Expanded Scale Voltmeter (ESV)
Device used to read the battery voltage of the on-board battery pack or transmitter battery pack
Fade
see Brake Fade.
Failsafe
A device that is built into a receiver or that plugs between the receiver and servos that prevents a runaway car in the case of battery failure or loss of signal.
Feint
When coming up on a corner, to make a quick maneuver in the opposite direction to get a better line through the corner.
FHSS: (Frequency Hopping Spread Spectrum)
A 2.4GHz radio system which switches from one “free” frequency to another every few milliseconds. While jumping from one to the other frequency, you are not spending much time on that frequency and this keeps out interference. See also: DMSS.
Field Charger
A fast battery charger designed to work from a 12-volt power source, such as a car battery.
Final Drive Ratio
The transmission ratio determined by combining the internal drive ratio and the spur/pinion combination with this formula: spur gear tooth count divided by pinion gear tooth count multiplied by the internal drive ratio or spur / pinion * internal drive ratio = final drive ratio. If you are trying to match the gearing of another driver who uses a different pitch pinion/spur combination (64 pitch instead of 48 pitch, etc.), or a driver that uses another brand of car, you can use this formula to get a better idea of what to use. Just get the internal drive ratio of the other car and find out the pinion/spur gears that are used, then adjust your gearing to match the final drive ratio of the other car. Remember to account for the motor being used, modified motors vary widely as more or less turns are used, and even stock motors are different from their construction, brush or spring usage, etc.
Fixed Link
A type of linkage that cannot be adjusted and is usually used in ready-to-run cars for camber and steering links. Easily replaced with turnbuckles for experienced racers who with to alter the car’s setup.
Flex
A measurement of how much a certain part will bend under varying degrees of pressure or force. Every part will bend or flex, some more than others.
Flooding
This is where there is too much fuel in the combustion chamber of an engine, causing it to choke and not fire, due to increasing pressure.
Flush
When a part is externally snug and tight against part and/or material
Flux
Actually rosin, but often referred to as “flux”; helps the flow of solder.
Flywheel
The flywheel helps the engine’s crank shaft maintain momentum and aids in idling. A heavier flywheel will aid in torque (pulling power and acceleration), while a lighter flywheel will aid in top speed but may cause trouble with engine idling.
FM
Short for Frequency Modulation, an FM radio in Rc is considered a better radio than the cheaper AM radios because an FM radio will have less glitching than an AM radio. Most hobbyists will be fine with an AM radio, but racers can benefit from FM or PCM radios.
Foam Donuts
Literally donut-shaped pieces of foam, these are mounted on wheels so that pan cars and touring cars can use them. Some race tracks are able to use foam tires (such as indoor carpet tracks for electric cars, or very smooth and clean outdoor tracks for nitro cars), but most racers use rubber tires. Foam tires have the advantage that inserts are not needed, they have better grip than rubber tires, they can last longer than rubber tires, and racers can use rollout calculations to figure out their gearing. However, ride height must be adjusted as the foams wear out, and on a 4WD car the wear must be closely monitored to make sure the car does not pull to one side as the car moves.
Foam Insert
A foam ring or donut that is used in soft compound tires for support
Foam Inserts
In the early days of Rc, tires were either foam (for on-road use) or hard rubber (for off-road). The foam donuts did not need inserts, and the off-road tires were hard enough that they could support the weight of the car without collapsing. As tire and car development continued, the tires got softer and required inner foams to make the tire keep its shape on the track. Touring car development followed the same trend as off-road tires: early tires were made of a hard enough rubber that no inner foam was necessary, and eventually tires got soft enough to require them. Most soft compound tires come with a open cell foam insert, while modern sedan racing tires since about early 1999 come with no foams at all, so racers can choose the best molded inner foam for their specific needs. If you do not race, you can use (and re-use, when the tire is worn out) the standard open cell foam insert that comes with your tires. If you do race, you would be well advised to ask around at your local track to find out what tire and insert combination works best!
Four Stroke (Four Cycle)
Although a 4-stroke engine has less power than a 2-stroke engine of comparable size, there are advantages to 4-stroke engines. They do not require a muffler and are often quieter than most 2-strokes are with a muffler. Lastly, the fuel economy is better.
Fuel Overflow Line (Vent)
The fuel line is either open to atmospheric pressure or attaches to the muffler pressure nipple to pressurize the fuel tank for better fuel flow to the engine. This is the line through which the fuel will overflow when the tank is full.
Fuel Pick Up-Line
The fuel line in the fuel tank through which fuel travels to the carburetor. Typically a flexible tube with a weight or “Clunk” on the end which allows it to follow the fuel with changes in aircraft attitude. This is the line through which the tank is filled.
Fuel Tubing
Flexible silicone tubing that provides a way for fuel to get from the fuel tank to the engine carburetor, and air pressure to get from the muffler or tuned pipe to the fuel tank.
Full-Size
After talking about Rc cars all day, you may want to discuss real cars with your friends : use the term full-size to make the distinction!
Gauge
A standard of measure used to determine the thickness of wire.
Gear
A general term that normally refers to either the spur gear or pinion gear.
Gear Differential (Gear Diff)
A differential that uses a series of gears to provide the differential action, allowing one wheel to rotate more than another in a turn. Gear diffs are harder to adjust than gear diffs but are much easier to maintain, because they must be sealed to keep the grease inside from coming off the gears. Tuning a gear diff can only be accomplished by changing the weight (viscosity) of the grease inside the gear diff case. The looser (to a point) a diff is, the more traction there is at that end of the car. To start tuning your car, set the ball diffs to the same tension at each end, and use the diffs only to fine-tune the car. Do not change the settings of your diffs first.
Gearing
In general terms, this refers to the ratio of the spur gear and pinion gear, when compared to the internal drive ratio of the car.
Getting Lapped
A term used when the lead car in a race is passing another car. That car loses a lapor goes a lap down to the leader. If you are getting lapped, it’s usually good form to let the leader get past you in a turn by going wide through the corner. This is even more important if the leader is battling with another car.
Glitch/Glitching
The term that refers to your car losing control temporarily, another term for interference. This happens when the signal from the radio transmitter to the receiver is interrupted for some reason.
Glow Plug
The heat source for igniting the fuel/air mixture in the engine. When starting the engine a battery is used to heat the filament. After the engine is running, the battery can be removed. The wire filament inside the plug is kept hot by the “explosions” in the engine’s cylinder. (See next heading and “Idle Bar” Plug.)
Glow Plug Igniter
A powered device (usually 1.2V), which connects to a glow plug. Used to ignite the filament in the glow plug in order to start the engine
Graphite
Graphite is a popular choice in R/C racing because of its advantages in weight and strength. It has a layered, planar structure that gives it a remarkable strength-to-weight ratio. They are more brittle than aluminum, and used in areas that do not have continuous impact. Graphite is mostly used for chassis, shock towers and plates.
Graphite
A stiff, lightweight, space age composite material commonly used for chassis, suspension arms, shock towers, and other parts of a vehicle’s chassis.
Groove
also known as the racing line, this is the fast way around the track. The quickest way to get around the track is not always a straight line from corner to corner. This term is usually most used in oval racing.
Grooving
Grooving no, not dancing! This is a term used to describe the way some tires have a tendency to develop a groove on the inner edge of the tread as they wear. This is less likely to happen to belted tires or tires with firm inserts. Grooving is also a condition that occurs when you have too much negative camber in your car.
Hairpin
A sharp, 180 degree turn on a track; when viewed from above, it resembles a hair pin.
Hardware
Articles made of metal used to assemble a vehicle, e.g., screws, nuts, washers, etc
Header
A bent piece of aluminum tubing used on Nitro cars that transfers exhaust gases from the engine case to the tuned pipe or muffler.
Heat Sink
Made of a heat conductive material, a heat sink is used to dissipate heat over an increased surface area.
Hinge Pins
They are metal bars that secure arms with knuckles. They are usually fastened by e-clips on both ends.
Hit (or to be hit)
Sudden radio interference which causes your model car or truck to drive in an erratic manner. Most often caused by someone turning on a radio that is on your frequency, but can be caused by other radio sources miles away.
Holeshot
A term used to describe the initial lead at the start of a race
Hook
When the rear end of the vehicle has a tendency to kick out when turning with the throttle on. Sometimes known as over steer.
Horizontal Load
When cornering, it is the force applied to an individual tire in the direction parallel with the road surface. Hub Carrier: Also called uprights, these are the parts of the suspension that hold the axles and bearings the wheels of the car turn on.
I.F.M.A.R.
International Federation of Model Auto Racing. The governing body that controls World Championship racing in R/C Cars. http://www.ifmar.org/
Idle Bar Plug
This type of glow plug has a “bar” across the tip to help prevent raw fuel from being splashed onto the glow element. Too much raw fuel will cool the plug and prevent it from igniting the fuel/air mixture. An idle bar is a help in obtaining a low idle speed.
Inner Foams
Another term for insert.
Inserts
Foam strips or donut-shaped cutouts that support a tire on a wheel. The car can be tuned with inserts, much like full-size race cars are tuned with tire air pressures.
Interference
see glitching
Internal Drive Ratio
A measure of the teeth of a car’s gears and pulleys. For Rc cars, you divide the number of teeth on the ball or gear diff pulley or gear by the number of teeth on the smaller drive pulleys.
Kick-Up
While caster refers to the upward angle at the front wheels of the car, kick-up refers to the upward angle of the front suspension arms. Technically, buggies and off-road trucks have kick-up, not caster, but since they are so similar in description most people use the term caster.
Kingpin
The pin in the steering assembly on which the steering spindles rotate.
Kit
A car, truck, boat, airplane or heli that requires the modeler to do most/all of the building and finishing work. Modelers are likely required to add their own power plant, radio system or both.
Knuckles (Uprights)
All R/C cars have front and rear knuckles. They secure the drive shafts to the wheels. Front knuckles are also used for steering. Use bearings to maximize performance.
Lean
A condition referring to engines where the engine is not getting enough fuel. While running lean can help performance and fuel economy, you run the risk of running the engine too hot and blowing the engine! If your engine runs for a few minutes and shuts off suddenly, it’s probably running too lean.
LED (Light-Emitting Diode)
Those little red lights you see on everything from speed controllers to chargers-even tail lights!
LHS
Local Hobby Shop
LHWS
Local HardWare Store
LiIon Battery
Lithium Ion Battery. They are lighter in weight and have a much lower (5%) discharge rate than NiCds or NiMHs (30%).
LiPo Battery
Lithium Polymer Battery. Derived from Lithium Ion batteries, they’re compact and light, with the ability to offer 30% more power in less space than comparable NiCds and NiMHs. Must be used with a LiPo-compatible balancing charger.
Load Up
A term used to describe a tire that is completely packed with dirt around the lugs or spikes. This usually happens on a wet tracks with loose dirt.
Locknut
A type of nut that features a nylon insert that helps to grab the threads of a shaft or bolt, helping prevent the nut from loosening. Commonly used on axles and other critical areas of Rc cars and trucks.
Longitudinal Flex
The flex of a chassis when both ends are being forced toward each other.
Loose
See Over steer
Low End Needle Valve
A valve for tuning a 2 stroke engine in the lower band of its RPM range. Properly adjusting the low end helps ensure a smooth transistion from low to high speed.
LSN
Low speed needle. This needle found on nitro engines controls the idle and just off idle air/fuel mixture. In vehicles, proper adjustment of this needle will allow a consistent idle as well as immediate and explosive acceleration. Adjustment of this needle should be done after the high speed needle is properly set.
mAh (Milliamp Hour)
A measure of a battery’s total capacity or how long a given power source (like a battery) can give off power. The higher the number (ex. 600 mAh, 1,500 mAh) the more charge a battery can hold and usually, the longer a battery will last under a certain load. Typical rechargeable receiver battery packs are in the 500-600 mAh range. Typical R/C car motor batteries are in the 1,400 : 3000 mAh range
Main, or Main Event
In Rc car and truck racing terms, this refers to the final race of the day in each class you are entered in. See Qualifier, then read the rest of this definition. Right after all the qualifying races are over, the race computer will sort all the racers, with the 10 fastest racers in the A Main, the next 10 fastest in the B Main, and so on. The number of racers in each main may vary, depending on the number of total racers in the class. Each main event is run in order from the highest letter to the lowest. For example, if there are enough racers to make an E Main, the E Main is run first, then the D, the C, the B, the A, etc. The winner of the A Main is the winner for that class. Large events (National and World Championships) will usually have what are called Triple A Mains. This is only for the top ten racers in each class, and they will all run three main events. In this case, your two best finishes count towards the final score, so if you win two races in the Triple A Main, you would be crowned the champion.
Marshal
a person who fixes cars due to a crash or pile-up during the race
Matched batteries
Matched batteries have been paired according to the batteries voltage. A set of matched batteries will usually have a voltage of /- .09 A set of matched batteries will give better performance.
Micro
A small scale rc. 1/16th scale and below is considered micro.
Mid-Narrow
see width, wheel.
Milliamp
A rating given to batteries, generally the higher the milliamp rating, the longer the cell can provide power. Currently, batteries are available for Rc use that range from 1500 to 3800 milliamps.
Mini
From the Morris Mini Cooper, Mini refers to an Rc car that is roughly 1/10 scale but models a very small real-life car like the Mini Cooper, VW Polo or the Daimler/Chrysler A-Class. The general difference between a Mini car and a regular sedan car is that the wheels, tires, body, suspension arms and chassis are smaller. For cost-saving measures the rest of the parts are generally interchangeable, especially the drivetrain, bulkheads and shock towers.
Molded Inner Foam
A form of tire insert that is molded in a special mold instead of cut out of foam sheets. While more expensive, the molded inner foam stays in place on the wheel and does not move side to side as the car goes through cornering forces.
Monocoque
Type of construction having the skin act as the main structural member, with a relatively light internal structure. Wings and fuselages completely covered in sheet balsa are an example of monocoque construction.
Monster Truck
Monster trucks are Big! They are the king of the hill in any group of R/C vehicles. Designed for torque instead of speed, these car crushers can move up hills, down slopes and over unsuspecting cars by virtue of sheer, brute power. The gas powered monster trucks are nearly unstoppable.
MOSFETs
Two acronyms used as one term: MOS-metal-oxide semiconductors, and FET-field-effect transistor. MOSFETs are used as switches in electronic speed controls to control the amount of current passed from the battery pack to the motor.
Motor
In Rc racing this generally refers to an electric motor.
Muffler
Installed on every Nitro-powered car, the muffler system traps exhaust gases from the engine case and provide pressure to the fuel tank while keeping noise levels to a minimum. Tuned pipes are another type of exhaust system that provide more power than a muffler. Note: Most R/C Clubs require the use of mufflers.
Muffler Baffle
A restrictor plate inside the muffler which reduces engine noise. This plate can be removed to increase power, but only if there are no noise restrictions where you drive.
Narrow
See width, wheel or width, chassis
Needle Valve
Adjustment on a carburetor used to set proper fuel/air mixture. Some carburetors have separate needle adjustments for low and high throttle. Typically, turning the needle clockwise (screwing in) leans the mixture (less fuel), and vice versa. However, there are a few exceptions:refer to the engine manufacturer’s instructions.
Newbie
A beginner in the hobby. Can be used as a humble self-description (I'm just a newbie...), affectionately (I just helped a newbie make his first flight!) or sarcastically (What are you, a newbie???).
Ni-Cad
The abbreviation for nickel-cadmium
Ni-MH
The abbreviation for nickel-metal hydride
NiCd Starter
A self-contained battery and glow plug clip, used when starting the engine. (See Glow Plug Clip)
Nickel-Cadmium (NiCd, Ni-Cad or NiCad)
Rechargeable batteries which are typically used as power for radio transmitters and receivers. The most common type of battery in use, although it is being phased out of production because of environmental concerns. Easily rechargeable, the Rc hobbyist must be aware that continued charging of this type of battery when it is still partially charged will lead to cell memory and decreased runtime and performance.
Nickel-Metal Hydride (NiMh)
Rechargeable batteries, which are typically used as power sources for cars, trucks and boats as well as receiver packs. They have no cell memory, but feature slightly less voltage than nickel-cadmium batteries. This means that for racers it is slightly less desirable but for most Rc hobbyists these batteries are better because of less concern for maintenance and offer longer run times and are more environmentally friendly than NiCds.
Nitro
Nitro-methane, a fuel additive which increases a model engine’s ability to idle low and improves high speed performance. Ideal nitro content varies from engine to engine. Refer to the engine manufacturer’s instructions for best results.
Nitro Content
A measure of the amount of nitromethane that is included in a mixture of nitro fuel. The normal amount of nitro content for fuel is 20% (when used in cars). Racers will use 30% or even 40%, but using a higher nitro content will shorten the life of the engine, which makes the high content fuels more suited for serious racers only.
Nylon
A type of plastic used in many Rc kits. There are many types of nylon: High-Impact Nylon is able to flex with crash impacts to resist breaking. Many wheels are made from high-impact nylon, as well as many of our suspension arms and shock towers. Fiber Reinforced Nylon is a plastic that is mixed with fiberglass fibers to produce a stiffer plastic piece. The ratio of fiber to plastic will determine the stiffness of the piece. If it is too stiff, the strength advantage is lost because the piece can break too often. Graphite Reinforced Nylon is another type of fiber reinforced nylon, except that instead of fiberglass fibers, the plastic is mixed with graphite fibers, the same type of fibers that make up the graphite mesh in woven graphite pieces. The ratio of graphite fiber to plastic will determine the stiffness of the piece. If it is too stiff, the strength advantage is lost because the piece can break too often.
O-Ring
A donut-shaped circle of rubber or silicone that seals rotating or sliding shafts, used in areas like shock absorbers and differentials.
Off-Road
Any type of running surface that is not on a paved surface. Off-Road can mean gravel, loose or hard-packed dirt, grass, etc. Racing classes that run on off-road surfaces include buggies, trucks, truggies and usually rally cars.
Off-Road Buggy/Truck
Off-road buggies and trucks are the most popular R/C land vehicles. Available in gas or electric, these cars sport full-travel suspensions, and high ground clearance. Their knobby rubber tires give them the ability to tackle any dirt terrain. On a dirt track or at the park, these off-road buggies are great fun.
Offset
see Wheel Offset
Ohm
A measure of electrical resistance.
On-Resistance
The measure of electrical resistance, at full throttle, of an ESC at a given temperature. As the temperature increases, the on-resistance increases. A lower on-resistance will give you more power. A lower on-resistance also means the ESC will run cooler.
On-Road
Usually refers to running cars on a paved asphalt or tarmac surface. The term could also refer to a class of cars, such as touring cars, pan cars, etc.
On-Road Car
On-road cars don’t have the beefy suspension that the off-road cars have, but they are impressive in their authentic looks and all out speed. Built for racing on smooth, paved surfaces, they are available in gas or electric, 1/10,1/12 and 1/8 scale. It’s easy to get involved. On-road cars are burning up the tracks of organized parking lot racing courses everywhere.
One-Way
A term that refers to either one-way diffs or one-way pulleys..
One-Way Bearing
A special and expensive type of bearing that will only allow a shaft to turn in one direction.
One-Way Diff
At some points on a race track, the inside wheels can lift up because of high cornering forces. This causes a normal ball diff or gear diff to ;unload. A ball diff prevents diff unloading because it does not allow the tire to spin less than the speed of the belt that turns the pulley. One-way diffs do take getting used to, because you must use very light braking power or none at all. When brakes are applied to a car using one-way diffs only the rear wheels will stop, making the car spin out very easily. Most drivers will need practice to get used to one-ways, but for racers on high-grip surfaces they can be a valuable tuning aid.
One-Way Pulley
One-way pulleys operate in the same manner as one-way diffs, except the one-way action takes place on a gear shaft instead of the front axle of the car. One-way diffs and pulleys do take getting used to, because you must use very light braking power or none at all. When brakes are applied to a car using one-way pulleys only the rear wheels will stop, making the car spin out very easily. Most drivers will need practice to get used to one-ways, but for racers on high-grip surfaces they can be a valuable tuning aid.
Outdrive
The part of the differential that outputs power to dogbones or universal dogbones.
Oval
The American-style stock car type of racing, where cars compete on oval tracks of different shapes (true oval, square oval, tri-oval, etc.) and are tuned to only go straight or left. Other types of vehicles not covered in this glossary also compete on ovals, including sprint cars, midgets, motorcycles, snowmobiles, etc. In Rc terms, most oval race cars are pan cars, with all the weight (batteries, electronics, etc.) on the left side so the car is the most stable when turning left.
Over geared
The condition where a gear ratio is too low for the motor. This results in excessive motor heat and causes the motor to draw more amps from the ESC
Oversteer
A situation in which the front tires have more traction than the rear tires. This causes the rear tires to lose traction in comers. (Do not confuse this condition with bad throttle control on behalf of the driver.) You may need stickier (or newer) tires, more rear downforce or there may be other problems. Shock and weight settings may need adjusting too.
Pan Car
In Rc terms, this is a car that is made from a flat pan of graphite or fiberglass, with an independent front suspension and straight-axle rear pod. These cars are rear-wheel drive only and use foam tires. Rc Formula 1 cars fall into this category, although the front suspension uses much longer arms and the chassis is narrower.
PCM (Pulse Code Modulation)
A type of transmitter and receiver that uses digitally encoded signals and is less prone to glitching than FM radio systems. Although more expensive than FM radios, PCM radios were very popular until FM radios got cheaper and almost as glitch-free.
Peak Charger
A peak charger automatically shuts off when your battery is fully charged. This means longer run times for your vehicle. Peak chargers are nearly foolproof, if you forget to turn it off, the charger does it for you. No more overcharged batteries. The recommended type of charger for nickel-cadmium batteries. Although not recommended for nickel metal-hydride batteries, these chargers can charge these types of batteries, but they must be monitored for temperature (so they don’t rise above 110 degrees Fahrenheit) and voltage.
Pinion Gear
In electric Rc cars, this is the gear that is attached to the car’s motor, which in turn spins the spur gear, turning the rest of the drivetrain.
Piston
An internal part of an internal combustion engine that slides back and forth inside a sleeve. If the piston must be replaced, the sleeve must be replaced also.
Pitch
The measure on a pinion gear or spur gear of how many teeth fit per inch. On a 64-pitch gear, 64 teeth will fit within one inch; on a 48-pitch gear, 48 teeth will fit in one inch.
Pivot-Ball Suspension
A type of suspension system brought to scale Touring Cars from 1/8 scale Nitro cars. Instead of the more common lower suspension arm/upper turnbuckle link, the pivot-ball suspension uses inner hinge pins and screws on the outer pivots that adjust camber and track. The caster is adjusted by moving clips on the inner upper hinge pin.
Planetary Gear Diff
A type of differential that has small gears rotating around the center drive gear.
Pole Position
A start position for a race where a car is in the very front of the starting grid. Usually the most desirable position to start from, because other cars must pass you to be in the lead.
Port
An opening in the sleeve of a nitro engine. Modifying the port size and shape can affect the power and fuel consumption of an engine, but the modification is best left to a professional.
Porting
A method of hopefully gaining more power from a nitro engine. If done correctly, you can get more power. If not done correctly, you will have possibly more power but much worse fuel consumption. If done very badly, the engine will not run at all!
Power Panel
12-volt distribution panel that provides correct voltage for accessories like glow-plug clips, fuel pumps and electric starters. Usually mounted on a field box and connected to a 12-volt battery.
Preload
The amount of tension on a spring, via the spring collar, before a shock is compressed.
Programmable or Computer Radios
These high-tech radios are not inexpensive but allow a full set of programmable transmitter features like multiple car memory, preprogrammed commands (throttle sensitivity, braking, etc. at the touch of a button) and much more.
Pullstarter
A mechanism that allows the starting of a Nitro car engine without the need for a separate engine starter box. Because it is permanently attached to the engine, the engine must sit higher in the car, which affects its center of gravity. It also can affect the rotating weight of the engine itself, however this and the center of gravity affect will not concern anyone but the most serious racer.
Punch
In Rc terms, this means the same thing as acceleration. Driving full punch means you are on the throttle all the time!
Push
See Understeer
Qualifier
When you attend an Rc car race, you will normally have two or three qualification races, then you will race in your Main Event. The way racers are sorted varies between different events, but usually you will have your best qualifying time determine what Main you will race in (some racing organizations use FTD, or Fastest Time of the Day, to determine qualifying order). The qualifying time refers to the number of laps you are able to complete during the qualifying race (each qualifier is normally 4 or 5 minutes). If you tie with someone else who has the same number of laps, the lowest elapsed time will win. See the entry for Main Event to see how the rest of a race event is run.
Race Director
The person running and organizing the race. Responsible for calling the drivers to the stand, making sure each car is in the correct spot on the starting grid, calling traffic if necessary, and other duties.
Racing Line
the fastest way around the track. Not always a straight line from corner to corner, the racing line is often flowing and smooth, representing feints into hard corners and drifts coming out of corners.
Radio
Refer to Transmitter
Radio-Controlled
Refers to how Rc vehicles are controlled. By the use of a Transmitter
Rally
A newer class of R/C cars. At first glance appearing to be a touring car with treaded tires, a true rally car will feature slightly longer shocks and some protection for the drivetrain. A rally car is generally able to travel on any on-road surface, as well as gravel and hard-packed or loose dirt.
Rc
An abbreviation of radio-controlled
Ready To Run (RTR)
A term that usually means a kit is at least 95% assembled, with minor finishing work being the only requirements to getting it ready. Some painting, tire mounting and minor assembly (such as attaching body posts and body clips) may be necessary, and a nitro-powered car will require break-in.
Reamer
An angled tool with a rough surface used to enlarge holes…to mount a Body to the chassis for example.
Receiver
The electronic device that receives the radio transmissions from the radio transmitter. Through wire plugs inserted into the receiver case, the receiver passes signals to the steering servo and electronic speed control or throttle servo.
Receiver Cover
A plastic or vinyl cover that protects the receiver from fuel, water, mud, dust and dirt.
Resistance
The resistance of electricity flow through a circuit, or connection. Resistance is measured in units called ohms.
Resistor
An apparatus possessing resistance to electrical current. When attached to a Ni-Cd battery, a resistor will drain the power that is in the battery.
Resistor-Type Speed Control
Mechanical speed controls that possess a wiper arm and resistor. The resistor has different steps that act as different speeds as the wiper moves across the surface of the resistor.
Rich
A condition referring to engines where the engine is getting too much fuel. If you accelerate from a stop and the engine dies, you are probably running too rich and should lean out the engine’s low speed idle adjustment a little (by turning the needle valve or low-end adjustment slightly clockwise).
Ride Height
The space between the lowest part of the chassis and the ground, measured with all of the car’s electronics installed; racers measure the front and the rear ride heights separately. There should be enough ride height so that the suspension can be engaged enough to soak up whatever bumps and dips occur on the track, but the chassis should be low enough to the ground so there isn’t too much chassis roll (related to shock settings).
ROAR
Radio Operated Auto Racing. National body to standardize and sanction R/C car and truck racing.
Rod End
Similar to a ball cup/ball end combination, except that a rod end is a plastic eye that holds a metal or plastic pivot. A screw goes through the pivot and is secured in a bulkhead, suspension arm or other area.
Rollcenter
An imaginary point at the front and rear of the car where the chassis rotates around. Affected by the position of the uprights and rotation points of the suspension arm and upper links, the rollcenter can be changed on an Rc car by adding spacers underneath the rear bulkhead, moving the uprights up or down in relation to the arm, and other methods.
Rotating Mass
Refers to the weight of the rotating parts in any car. For an Rc car, this includes the diffs, wheels, universal dogbones, belts, pulleys, flywheels, crankshafts, spur gears and spur gear hubs. The lighter you can make these parts, the faster the car will accelerate and brake, because less force is needed to get these parts moving. Most people agree that reducing one unit of weight (ounce, gram) equals saving between three to four units of weight that does not rotate.
RPM
Rotations Per Minute. How many times an engine, motor, wheel, gear, etc., will turn in a minute. In Rc racing this is most important for electric motors and nitro engines.
RTR
A term standing for Ready To Run
Runtime
A term that means how long an Rc vehicle will run or last on one battery pack or fuel tank.
Sand Bagger
Term used for a racer running in to low of a main or class. Either because they broke in a qualifier or because they are to chicken to run with people of their same ability level.
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 or 1/8 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, Truggy, Touring Car and more.
Schottky Diode
Helps with more consistent braking, more efficient motor operation and allow cooler operation of electronic speed control. Schottky diode is only recommended on forward only, no reverse electronic speed controls
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 one of the more popular form of on-road Rc racing in the world right now. These kits started out modeling the cars that formed the DTM ra
Self Tapping
A screw that creates threads in the material it is penetrating
Servo
A small device used for steering (and throttle with nitro cars). The servo output shaft rotates proportionately to the input from the transmitter. The servo contains a motor and an electronic controller.
Servo Horn
Attaches to the servo and is the link between the servo and the steering linkage.
Servo Reversing
This transmitter feature allows you to install the servos where they can give the best pushrod routing without concern about the direction of servo rotation. When your installation is complete, turn on your transmitter and check each channel. If a channel operates opposite of its intended direction, a simple flick of a switch corrects the problem.
Servo Saver
Usually a servo horn that uses a spring to absorb sudden shock or impact coming from the servo linkage. This helps prevent breakage of the servo.
SHCS
Acronym for Socket Head Cap Screw
Shock Oil
The silicon-based oil in a shock. Measured by viscosity, the lower the number, the lighter the damping.
Shock Piston
The small plastic (or nylon) disc that travels up and down in the shock body. It uses holes of different sizes to regulate the rate at which the shock compresses and rebounds.
Shock Tower (Damper Plate)
Its primary purpose is to secure the shocks to the main component of the car. Graphite and aluminum are both popular materials for shock towers.
Sidewall
The side of the tire that extends from the wheel up to the top of the carcass.
Skid Plate
A plate, commonly made of plastic, aluminum or titanium, that protects the underside of a vehicle. Typically used in offroad vehicles.
Sleeve
The internal cylindrical part that houses the piston in a nitro engine.
Slide Carburetor
A highly modified, car-specific type of carb that has the barrel of the carb slide along its axis, instead of turning. This provides a quicker response at the expense of a complicated set-up procedure. This type of carb has almost become the industry standard for the RC Hobby. Two or three needle valves control the fuel intake at different RPM ranges.
Slipper Clutch
This device (found primarly in offroad vehicles) allows the spur gear assembly to slip under excessive loads. This protects the drivetrain from sudden jolts and, when set properly, helps control the vehicle on slippery surfaces.
Slop
Excessive free movement in a control system. Often caused by a worn out ballcups. This unwanted condition allows the control surface to move without transmitter input.
Spoiler
Often referred to as a wing, a spoiler disturbs the air flowing over the body to create downforce on the car.
Sponsorship
Any racer that has attained a pretty high level of racing (or, in a lot of cases, can be a VERY good company representative) can gain sponsorship help. Manufacturers typically sponsor drivers in hopes of getting their product into the winners circle, showing that their product can win races.
Sportsman Class
Drivers that have won some races and are pretty quick around the track are considered Sportsman. Sportsman drivers typically do not (or should not) have any sponsorship help (if they do, they should be in the Expert/Pro class).
Spring Rate
The stiffness of the springs. Generally, softer springs add traction, harder springs lessen traction. Springs are ‘rated’ by a number value.
Spur Gear
The gear that is attached to the differential or transmission.
Squirm
The movement of a tire between the ground and the wheel. This can be side-to-side movement, or front-to-rear movement. Softer compounds typically have more squirm. Can be corrected by using a different internal insert.
Starting Grid
The order the cars are lined up at the start of a race.
Steering Knuckle:
The part of the car’s front suspension that steers the wheels. The steering turnbuckles connect the bellcrank and steering knuckles.
Stroke
How far the shock absorber can compress. Can be limited externally by a clips or a threaded nut on the outside of the shock body.
Suspension Arm
See A-Arm.
Sway Bar
See Anti-Roll Bar.
Tamiya plug
A type of white electrical connector usually used to connect a battery to a speed controller. It comes stock on many ESC and batteries.
Throttle
Refers to the trigger on pistol-grip style transmitters, or the right stick on dual-stick transmitters.
Tie-Rod
The rod assembly used to connect the steering bellcranks to the steering knuckles. Also used for camber adjustments. Also known as a turnbuckle.
Tire
All RC cars run on some sort of tire. Tires come in different tread designs (for different surfaces) and different compounds (from hard to soft, again, for different surfaces). Purchased tires also include foam inserts. These help support the tire under loads.
Titanium
A metal alloy used to manufacturer parts, such as turnbuckles and hinge pins, that is extremely light and very strong.
Toe-in
A condition when the front edge of both tires are closer together than the rear edge of both tires. Toe-in will make a car more stable under acceleration but decrease turn-in steering.
Toe-out
A condition when the front edge of both tires are farther apart than the rear edge of both tires. Toe-out increases turn-in steering, yet reduces stability under acceleration and through bumpy sections.
Top Deck
Included on almost every onroad car, the top deck connects the from and rear bulkheads (and sometimes a center bulkhead) together. They can come in plastic, carbon fiber or metal (typically aluminum).
Top End
A vehicle’s final acceleration rate. For nitro engines, top end refers to the high-end needles.
Top Qualifier
The fastest car in qualifying gets the inside front row starting position on the starting grid for the main event. Also known as TQ.
Torquey
A term used to describe a motor’s brute strength during acceleration.
Touring Car
A specific onroad car class of RC. Touring Cars are fast and precise and can hit extremely high speeds in short distances. They are available in either nitro or electric powertrains.
TQ
See Top Qualifier.
Track Width
The width of the car, measured from the center of the front axis wheels and the rear axis wheels. A wider stance is more stable and gives better cornering, but with a wider frontal area the car experiences more drag, slowing it down on long straights.
Traction Compound
Used to soften foam or rubber tires in onroad and offroad racing. A mixture of different chemicals that usually have a strong, unpleasant odor.
Traction Roll
If a vehicle has too much traction, it may roll over during a high-speed turn.
Transmission
The transmission of a car houses a number of different sized gears (including the differential) that allows the RC vehicles drive ratio to be reduced. This helps with gearing while using different sized tires.
Transmitter (Tx):
The hand-held radio controller. This unit sends out the commands, that you input, to the receiver in the vehicle.
Transponder
A small device, that when installed in a vehicle, will count your car’s laps. The signal is picked up when you travel over a ‘transponder loop’.
Trickle
A low-rate charge, usually below 0.5 amp.
Truck
A 2wd or 4wd offroad RC car modeled after CORR style racing trucks.
Tuned Pipe
A highly modified muffler that increases the power from a nitro car’s engine.
Turn Marshal
Persons assigned to correcting vehicles that are upside down or stuck on the race track. Racers are usually expected to turn marshal immediately following their race.
Turnbuckle
A threaded rod that has the screw threads facing opposite directions so adjustments can be made without removing the rod. Also known as a Tie-Rod.
Tweak
An unwanted condition in which more pressure is applied to one side of the chassis than the other. A vehicle that has a tweak will pull to one side under acceleration and braking.
Understeer
A situation in which the rear tires have more traction than the front tires. This causes the vehicle to have inadequate steering.
Unloading
At some points on a race track, the inside wheels can lift up because of high cornering forces. This causes a normal ball differential or gear diff to transfer all the available power to the wheel that is in the air. This is because the differential will put any power at the wheel that is the easiest to turn.
Unsprung Mass
That portion of the total mass of a vehicle which is not supported by the suspension. Unsprung mass is comprised of wheels, tires, hubs, hub carriers, and approximately 50% of the mass of the suspension links, drive shafts and shocks (if mounted outboard).
Upright
See Hub Carrier.
Uprights
See Knuckles.
Vapor lock
This occurs when an engine has been running at an excessive heat, normally for 15 minutes or more and the crankcase heat transfers to the carbueretor, boiling fuel before it enters the combustion chamber.
Venturi
1. A short tube with a constricted throat used to determine fluid pressures and velocities by measurement of differential pressures generated at the throat as a fluid traverses the tube. 2. A constricted throat in the air passage of a carburetor, causing a reduction in pressure that results in fuel vapor being drawn out of the carburetor bowl.
Vertical Load
The amount of force applied to an individual tire in the direction perpendicular to the road surface; the forward driving force of the tire.
Volts
The three most basic units in electricity are voltage (V), current (I) and resistance (r). Voltage is measured in volts, current is measured in amps and resistance is measured in ohms. If we compare an electrical system to a water system, it would shake out like this: The voltage is equivalent to the water pressure, the resistance is equivalent to the pipe size and the current is equivalent to the rate at which the water is flowing. The relationship between these three can be stated as follows: I = V/r (Current in Amps is equal to voltage divided by resistance) So, using our water analogy, let's say you had a power nozzle on your hose. If you open the faucet more, you will increase the pressure in the hose and the water will flow faster. In electrical terms, increasing the pressure is like increasing voltage and the resulting increase in flow is an increase in current.
Wheel
Fits inside the RC car tire. They are available in many different styles and colors.
Wheel Offset
This is in relation to track width, but refers specifically to the wheels of the car. The more offset a pair of wheels has, the wider the track and overall width of the car will be.
Wheel Spin
A term used when a tire loses grip, usually during acceleration because of too much power on a slippery surface.
Wheelbase
The distance between the front and rear axles of a car. A longer wheelbase gives a bit more stability, while a shorter wheelbase gives quicker turning and better acceleration, because the weight of the car is closer to the wheels (in relation to the long axis).
Winding
Used in electric motors to refer to the shellac coated wire that makes up the electromagnetic component. When a current is passed through the winding a magnetic field is created and usually "focused" by wrapping it around an iron metal core to increase its field strength.
Wing
See Spoiler.
Winners Circle
Where you want to be at the end of ANY race! It consists of the top 3 drivers in any race.
WOT
A abbreviation for Wide Open Throttle
Y-Harness
A wire that permits two servos to be plugged into a single channel in a receiver.
Z-Bend
A simple Z-shaped bend in the wire end of a pushrod, which is used to attach the pushrod to a servo output arm.
Z-Bend Pliers
An inexpensive plier type tool used for easily making perfect Z-bends
Zip Tie:
A nylon tie wrap, named ‘zip’ tie because of the sound it makes as you tighten it.
“Hydra-Drive”
A fluid slipper clutch, manufactured by Team Losi, that increases rear traction.
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