TamiyaUSA.com - R/C Glossary

4 4WD-4 Wheel Drive

All four wheels are powered by the engine/motor through a drive train. The use of four wheel drive allows a buggy, monster truck or car to obtain better traction.

A

ABC

Engine construction that consists of an aluminum piston, & a brass cylinder that has been chrome plated. Very commonly used today on higher performance engines for long wear.

AMPS- Amperage

The strength of a electrical current measured in amperes

Aramid

Commonly known as Kevlar made by Dupont. Aramid is a multifilament processed into fibers that is extremely tough, flame and heat resistant, and outstanding strength to weight ratios.

Armature

The central part of an electric motor, usually carrying the windings and the commutators. The pinion gear) is usually attached to the armature shaft.

ATVor EPA

Adjustable Travel Volume or End Point Adjustment features on more expensive radio transmitters control the maximum travel of Fthe servo on both sides of neutral position.

B

Battery Eliminator Circuitry (BEC)

A circuit that eliminates the need for a separate receiver battery by using the battery pack that powers the vehicle also powers the servos.

BDC

Abbreviation for Bottom Dead Center. When a piston is at the very bottom of it's stroke.

Brushless Motor

A motor that has a rotating center permanent magnet & a fixed outer electromagnet driven by a special ESC that changes AC pulses to DC pulses.

C

CA Glue

CA stands for "Cyanoacrylate" (commonly referred to as "super glue" outside the hobby). This glue is fast drying and works well on wood, most plastics and other building materials. It can destroy foam surfaces.

Camber

Camber is the angle of the wheel relative to vertical, as viewed from the front or the rear of the car. If the wheel leans in towards the chassis, it has negative camber; if it leans away from the car, it has positive camber.

Carbon Fiber

An extremely strong thin fiber made by pyrolyzing synthetic fibers, such as rayon, until charred. Very light and strong.

Carburetor

The carburetor on a glow or gas engine mixes fuel and air into just the right proportions as to cause an efficient "burn" or explosion in the combustion chamber of the engine. To "lean" a mixture means there is insufficient fuel. To "rich" a mixture means there is too much fuel for the motor to efficiently burn.

Caster

Caster is the angle to which the steering pivot axis is tilted forward or rearward from vertical, as viewed from the side. If the pivot axis is tilted backward (that is, the top pivot is positioned farther rearward than the bottom pivot), then the caster is positive; if it's tilted forward, then the caster is negative.

Center of Gravity

This is the point at which the model balances for the best balance of maneuverability and stability.

Choking

The Engine Choking the engine refers to placing an object over the carburetor in order to create suction that will draw fuel from the tank into the combustion cylinder of the engine. This is also known as "priming" the engine. On some older setups, one can squirt fuel directly into the carburetor to accomplish the same result.

D

Damping

Damping describes the lessening of impact on a car through its shock absorbers. Damping can be accomplished by changing the stiffness of a shock absorber. A "soft" damping shock can provide more traction in a turn but limits responsiveness because the car must "recover" after the turn. On the other hand, "stiff" damping increases responsiveness, but compromises traction in severe turns.

Differential

A differential is a gearing mechanism that permits the drive wheels (powered wheels) to spin at different rates while turning. Since wheels on the outside diameter of the turn must travel a greater distance than those on the inside, the differential eliminates slippage on the turn.

Direct Drive

The pinion and motor drive the wheels directly on the vehicle.

Dogbone

A part of the drivetrain connecting the out-drive to the axle. This allows the differential to transfer power from the engine out to the axle and tires of the car or truck.

Drafting

Drafting is the action of following a vehicle closely enough to shield your vehicle from the wind that would normally cause drag on your vehicle.

Drag

The force that resists movement of any object through the air. Can apply to surface or air vehicles.

Droop

Droop is the distance the wheel drops from normal ride height when the car is lifted off the ground. Adjustment is either via droop screws in the wishbones that rest on the chassis; or spacers under the shock piston inside the shocks. Droop is another tuning aid and can have a dramatic effect on handling.

Dual Rates

Dual rates are simply transmitter switch inputs that allow the user to program two sets of control parameters that the user can switch to instantly.

E

ESC

Electronic Speed Control. This device controls the throttle function on electric surface vehicles. Some ESC's come with an automatic shut-off feature that simply shuts the motor down if the voltage in the battery becomes too low. This is done to conserve power for servos that operate the control surfaces.

F

Fail Safe

A separate device that communicates pre-set "safe" transmitter positions to the receiver in case communication between receiver and transmitter is interrupted for a specified period of time (usually a short period).

Fish Tail

When your car fish tails, it can be because of a sudden weight transfer, and a lot of other things but the tail end slides out and it can get hard to control or it can roll over.

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.

Frequency Board

A system used for multiple Drivers to determine what Frequencies are in use within his or her driving area. Each Drivers Radio frequency will be announced or posted in a designated area to let other Drivers know what frequencies are in use to prevent Radio interference between Radio systems.

FRP (fiber reinforced plastic)

Plastic that is molded with synthetic fibers to add rigidity and strength into existing shapes and parts

FWD (front wheel drive)

Only the two front wheels are powered by the engine/motor through the drivetrain

G

Gearing

A car's gearing is the relationship between the spur gear and the pinion gear as compared to the transmission drive ratio of the vehicle. Use our gearing calculator.

Glitch

Sometimes called a "hit", a glitch is a temporary interruption in the radio signal being transmitted from your transmitter to your receiver. With the advent of PCM transmission standards and synthesized modes of transmission, glitches are becoming more rare.

Glow Ignitor

A device that attaches to a "Glow Plug" in order to heat the plug to a sufficient temperature to cause combustion to begin in the cylinder of a glow engine. A glow ignitor is powered by a 1.5 volt battery in most instances.

Glow Plug

Similar to a spark plug in a car's internal combustion engine, the glow plug is a filament that literally glows in order to ignite the fuel inside the engine cylinder. When a glow engine is first started, a "Glow Ignitor" is attached to give the filament a very high temperature. Once the engine is running, the combustion keeps the temperature of the filament high enough to sustain the engine.

H

HSN

High speed needle. This needle found on nitro engines controls the maximum amount of fuel that can enter the engine at ANY throttle opening. It also serves to adjust the fuel/air mixture from part throttle to full throttle. In vehicles, proper adjustment of this needle will allow an engine to attain maximum rpm and horsepower without causing a lean condition. Adjustment of this needle should be done BEFORE adjusting the low speed needle.

Hub Carrier

The parts of the suspension system that hold the axles and bearings on which the whiles of the vehicle rotate. Also called "uprights".

Hydro Lock

Phenomenon common to internal combustion engines, where the Air/Fuel mixture is too rich (e.g. too much fuel) and the unburned fuel is trapped between the cylinder head and the piston, causing the engine mechanism to lock due to excessive hydrolic pressure. Common fix: remove glow plug, disconnect fuel line and crank engine using a starter or ratchet. Trying to run or start a flooded engine may cause permanent damage.

I

Inserts

Rather than inflating tires with air, many R/C tires use foam inserts that give cushion to the tire.

K

KPH-Kilometers Per Hour

A unit of speed

L

Lean Mixture

This refers to the air/fuel mixture on an internal combustion engine. A "lean" mixture means that there is not enough fuel compared to the amount of air entering the combustion chamber.

LHS

LHS Local Hobby Shop

Low End 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 transition 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.

M

mAh-Milliamp Hour

This is a measure of a battery's total capacity. The larger the number of milliamps, the more power the battery can store. Batteries for today's electric Cars typically run 3,300 mAh packs. Do not confuse milliamps with volts!

Marshal

A person who fixes cars due to a crash or pile-up during the race.

MPH-Miles Per Hour

A unit of speed.

N

Needle Valve

A needle valve is a threaded screw with a finger grip that permits the user to regulate the flow of fuel into the carburetor of a motor. Many larger glow motors have two needle valves to control flow rates at different motor speeds (e.g. medium and high range valves).

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 lap!) or sarcastically (What are you, a newbie???).

Nitro Fuel

The fuel ran in all nitro engine applications can contain 5-50% nitro methane

O

One-Way Bearing

A type of bearing that allows a shaft to turn in only one direction.

Oversteer

Oversteer is a condition that results when the rear wheels lose traction faster than the front wheels, causing the car to fishtail.

P

PCM "Pulse Code Modulation"

PCM stands for Pulse Code Modulation. PCM in R/C is actually no closer to an accurate description than PPM! PCM is another encoding scheme, not a modulation scheme.

Peak Battery Charger

A peak charger automatically ceases charging when your battery is fully charged.

Pinion Gear

A gear that fits over the drive shaft of a motor. By adjusting the number of "teeth" in the pinion gear, you can increase the torque or overall drive speed of the output device (be it a propeller or wheels). An increase in torque will result in a decrease in speed and visa versa.

Polycarbonate (PS)

A type of glass reinforced plastic used in R/C car bodies and various applications due to its high performance use and tough design- Flexible.

PPM "Pulse Position Modulation"

PPM stands for Pulse Position Modulation and is a term describing the concept for encoding using the scheme that came into being in the early 1960's.

Pre Load

Is the distance a spring is compressed from its free length at full extension. This is usually done with different sized pre load clips inserted between the spring and shock.

R

Receiver

An electronic device designed to receive radio transmissions from the transmitter and translate the commands into servo movements or electronic signals for electronic speed controls, gyros and other electronic equipment connected to the receiver.

Rich Mixture

This refers to the air/fuel mixture on an internal combustion engine. A "rich" mixture means that there is not enough air compared to the amount of fuel entering the combustion chamber. This condition can lead to hydro lock.

Roll Center

is the virtual pivot point in space that a car rotates around when subjected to cornering forces.

RPM "Revolutions Per Minute"

The number of times a wheel, motor shaft or other rotating part will turn in one minute.

RTR "Ready to Run"

These vehicles come ready to go out of the box. Most only require the installation of batteries.

RWD (rear wheel drive)

Only the two rear wheels are powered by the engine/motor through the drivetrain

S

Servo

A small electrically powered motor encased in plastic or metal (typically plastic) with an arm protruding from the side or top. The servo takes control input from the receiver and is used to translate transmitter control changes into movement of control rods, levers or other mechanical linkages on the radio controlled vehicle.

Servo Reverse Switch

Most transmitters have switches that permit the user to reverse the direction of the servo controlled by the applicable channel reversing switch.

Shock Absorber

A device that softens the shock that occurs when a car wheel runs over an obstacle, turns sharply or drops sharply into a rut in the road. Shock absorbers can be made using a coiled spring assembly or by using a piston and oil setup that uses the viscosity of the shock oil to regulate the stiffness of the shock absorber.

Slipper Clutch

Typically found on monster trucks and other off-road vehicles, the slipper clutch regulates how much engine power is transmitted from the drive gears to the wheels. The device is used to maximize a vehicle's traction.

Speed Controller/Electronic Speed Control

This device controls the throttle function on electric vehicles and aircraft. Some ESC's come with an automatic shut-off feature that simply shuts the motor down if the voltage in the battery becomes too low. This is done to conserve power for servos that operate the control surfaces.

Spring rate

The stiffness of a spring measured by a unit of length over weight or by overall rigidity. This determines how much a spring compresses under load

T

TDC

Abbreviation for Top Dead Center. When a piston is at the very top of it's stroke.

Toe Angle

The toe angle of a car is the angle of the tires from 0 degrees when viewing the car or truck from above. A "toe in" refers to wheels that are angled slightly in when the steering mechanism is neutral. Slight toe angles provide stability, but too much creates friction and is inefficient. Toe-out on front wheels provides more responsive steering but less stability. Toe-in on rear wheels provide stability and most cars are manufactured that way.

Touring Car

Touring cars are standard street cars that are modified for racing (e.g. Skyline). There are hundreds of R/C touring cars available on the market. Most R/C versions are all-wheel drive.

Track Width

The distance between the midline of each tire measured on either the front or the rear set of wheels.

U

Understeer

The opposite of oversteer, this condition results when the car or truck's front tires have less grip than the rear, causing it to "push" through turns.

V

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 carburetor, boiling fuel before it enters the combustion chamber

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)

W

Wheel Offset

Wheel offset is the additional distance from the center of the wheel to the inside part of the wheel that attaches to the axel. If a vehicle has a 2mm wheel offset, the axel will meet the wheel hub before it gets to the midline of the wheel, effectively lengthening the track width of the vehicle.

Wishbone

An outdated term synonymous with "suspension arm". The term was coined because suspension arms resembled chicken or turkey wishbones.

WOT

A abbreviation for Wide Open Throttle