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A-arm:
The lower arm of a suspension assembly, 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.
Ackerman: The degree of difference in the steering
angle between the inside and outside wheel when
a vehicle is turning.
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 driving style.
Anti-Squat: The angle, from horizontal, of the inner
rear hinge pin in relationship to the chassis. Anti-squat
helps to keep the rear suspension from squatting
(compressing) under acceleration.
Armature: Is the spinning part of an electric motor.
Also known as the arm.
ARR: Some cars and trucks are available virtually
pre-built 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.
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.
Battery Eliminator Circuitry: (BEC): A circuit that
eliminates the need for a receiver battery, usually
in electric R/C cars and boats.
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.
BEC: (Battery Eliminating Circuitry): 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.
Body Roll: The changing of the chassis' angle in
relation to the ground when going through turns
or corners.
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.
Brush: A small rectangular piece of conductive metal
that makes contact with the commutator inside an
electric motor.
Bump-Steer: The changing of steering angles while
the suspension is moved through its range of travel.
Generally, not a desired action.
CA: (Abbreviation for "Cyanoacrylate"):
An instant type glue that is available in various
viscosities (Thin, Medium, Thick, and Gel). These
glues are ideal for gluing R/C car or truck Tires
and Wheels together. Note: Most CA glues will attack
Styrofoam.
Camber: The angle, from vertical, of the wheels.
Negative camber is when the top of the tire is closer
to the center of the vehicle than the bottom of
the tire. Negative camber is commonly used to add
stability in bumps. Positive camber is when the
bottom of the tire is closer to the center of the
vehicle than the top of the tire. Positive camber
is not commonly used.
Camber Link: The rod assembly used to connect the
rear hub to the rear bulkhead and the front spindle
carrier to the front shock tower. These are often
adjustable, but sometimes fixed.
Capacitor: A small electronic component used as
a filter to reduce radio noise generated by an electric
motor.
Carburetor: The part of the engine which controls
the speed or throttle setting and lean/rich mixture
via setting of the needle valve.
Carcass: The main "body" of a tire.
Caster: The angle, from vertical, of the kingpin
in relation to the ground. Caster can have a great
effect on how a vehicle enters and exits turns and
corners. Increasing positive caster, so that the
kingpin is angled back, will generally increase
steering going into a corner and a slight decrease
in steering coming out. Less positive caster will
decrease the amount of steering going into a corner,
but will increase the amount of steering in the
middle and while exiting that corner.
Center of Gravity (C.G.): The point on the chassis
at which the vehicle balances with all components
installed. C.G. is the three-dimensional balance
point of the car. That is, there is a vertical C.G.
as well as a horizontal C.G. All forces acting on
the chassis can be considered to act through the
chassis' center of gravity. Ideally, a vehicle's
center of gravity should be as low as possible.
Charger: Device used to recharge batteries, usually
supplied with the radio if NiCd batteries are included.
Cold Solder Joint: A solder joint with poor electrical
integrity. It is not mechanically, or electrically
solid, and has a rough or grainy look. Cold joints
can cause radio interference.
Commutator: The top part of the armature. Typically
referred to as the Comm. The comm takes the current
the brushes.
Compound (Tire): The type of rubber that a tire
is made of. A softer compound will usually have
more traction than a harder compound, while often
wearing quicker.
Compression: The pressure that builds in a glow
engine as the piston moves through the up-stroke.
Concourse: A contest at racing events where vehicles
are judged on their appearance.
Connecting Rod: The rod that connects the piston
to the crankshaft in a glow engine.
Contact Patch: The "footprint" of a tire;
the part of a tire which comes in contact with the
road surface which is elliptical in shape.
Countersunk: A (flathead) screw with a tapered head;
A hole with an angle that accepts a flathead screw.
(countersunk chassis)
Crystals: Crystals are tuned to resonate at an exact
frequency so that the transmitter (Tx) and receiver
(Rx) operate on the same frequency. Crystals may
be purchased separately and in many different channels.
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.
Dampening: The resistance caused by fluid in a shock
body when the piston moves through it.
Diff (Differential): The part of the drive train
which allows powered wheels (front or rear) to rotate
at different speeds. This is important since, when
turning, the outside wheel travels farther and faster
than the inside wheel.
Diff Balls: In a ball differential , the balls float
within the diff gear and cause the opposite side
to rotate in the opposite direction when the diff
gear is held and one outdrive is turned.
Diff Rings: The metal rings that the diff balls
run against.
Discharge: The act of draining a battery of its
stored energy, either by running a vehicle or connecting
the battery pack to discharge device.
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.
Drag: Resistance encountered that impedes motion
or movement
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.
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 beginner to drive. The electric cars are powered
with a rechargeable NiCad or Nickel Metal Hydride
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. In 2001 an electric
modified car reached 111 mph. 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 80mph....one was actually clocked with
a Police Radar Gun at 102mph. 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 Control (ESC): Electronic speed
controls replace the mechanical speed control and
servo, providing enhanced power efficiency and precision
in an electric R/C car, truck or boat. In addition,
they are lighter which improves the performance
of most electric models.
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.
Expanded Scale Voltmeter (ESV): Device used to read
the battery voltage of the on-board battery pack
or transmitter battery pack.
Flux: Actually rosin, but often referred to as "flux";
helps the flow of solder.
Foam Insert: A foam ring or donut that is used in
soft compound tires for support.
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.
Gauge: A standard of measure used to determine the
thickness of wire.
Glitch: Momentary radio problem that can cause your
car or truck to go out of control. This is more
common with Nitro cars and trucks. To prevent your
car or truck from going out of control if your radio
does glitch, put a return spring on the Servo that
controls the throttle and brake. The return spring
will close down the throttle and apply the brake,
if the onboard receiver losses contact with the
radio, because of a glitch.
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.
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: A stiff, lightweight, space age composite
material commonly used for chassis, suspension arms,
shock towers, and other parts of a vehicle's chassis.
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.
Heat Sink: Made of a heat conductive material, a
heat sink is used to dissipate heat over an increased
surface area.
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.
"Hydra-Drive": A fluid slipper clutch,
manufactured by Team Losi, that increases rear traction.
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. This type of glow plug is not
often used on R/C cars or trucks.
Kick Up: The angle of the entire front suspension,
from horizontal, in relationship to the rest of
the chassis.
Kingpin: The pin in the steering assembly on which
the steering spindles rotate.
Lean: A term used to describe the way an engine
is running when it is not drawing enough fuel compared
to the amount of air. This will cause the engine
to run hot and if run in this condition too long,
will cause engine damage.
LED (Light-Emitting Diode): Those little red lights
you see on everything from speed controllers to
chargers-even tail lights!
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.
Longitudinal Flex: The flex of a chassis when both
ends are being forced toward each other.
mAh (Milliamp Hour): A measure of a battery's total
capacity. 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.
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.
Muffler: A device attached to the exhaust outlet
of the engine to reduce noise and increase back
pressure which helps low speed performance.
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.
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.
NiCad: Nickel Cadmium battery. Rechargeable batteries
which are typically used as power for radio transmitters
and receivers.
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 in
fuel is indicated by the percent of the fuel.
Ni-Starter: A self-contained battery and glow plug
clip, used when starting the engine.
Off-Road car: Off-road buggies and trucks are the
most popular land vehicles. These cars sport full-travel
suspensions, and high ground clearance. Their knobby
rubber tires give them the ability to tackle any
dirt terrain. These cars are available in gas or
electric, 1/10, 1/12 and 1/8th scale. On a dirt
track or at the park, these off-road are great fun.
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 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.
Outdrives: The piece that mount on either end of
the diff gear and transfer power out of the transmission.
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
Over steer: 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.)
PCM (Pulse Code Modulation): A transmission system
that uses digitally encoded signals. A PCM radio
is less likely to glitch than an AM or FM radio.
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.
Pinion Gear: The gear that attaches to you motor.
Pitch: The number of teeth per inch on the gear.
The higher the number, the smaller the teeth.
Planetary Gear Diff: A type of differential that
has small gears rotating around the center drive
gear.
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.
Punch: R/C racers' term used to describe the amount
of acceleration a car or truck possesses.
Push: A term used to describe a vehicle with oversteer.
(see oversteer above)
Reamer: An angled tool with a rough surface used
to enlarge holes...to mount a Body to the chassis
for example.
Receiver (Rx): An electronic device that receives
the signal from the transmitter.
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 term used to describe the way an engine
is running when it is drawing too much fuel compared
to the amount of air.
Ride Height: The point at which the vehicle naturally
rides when fully loaded with the necessary equipment.
Roll Center: A point about which the sprung mass
of the vehicle will roll under influence of centrifugal
force.
RPM (Revolutions Per Minute): Just that! The number
of times an object completely rotates (360 degrees)
in one minute.
RTR: 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.
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.
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
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), that 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 tie-rod.
Servo Saver: Usually a servo horn that uses a spring
to absorb sudden shock or impact coming from the
servo linkage.
Servo Output Arm: The removable arm or wheel which
bolts to the output shaft of a servo and connects
to the pushrod.
Servo Reversing: This radio 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 radio and check each channel. If a
channel operates opposite of its intended direction,
a simple flick of a switch corrects the problem.
Sidewall: The side of the tire that extends from
the wheel up to the top of the carcass.
Slop: Unwanted, excessive free movement in a control
system. Often caused by a hole in a servo arm or
control horn that is too big for the pushrod wire
or clevis pin. This condition allows the control
surface to move without transmitter stick movement.
Spoiler: Often referred to as a wing, a spoiler
disturbs the air flowing over the body to create
down force on the car.
Spur Gear: The gear that is attached to the differential
or gear box.
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.
Stadium Truck: Designed for backyard fun, or all
out racing, R/C stadium trucks are the masters of
"bump and jump" excitement. Like full-size
stadium trucks they are built to take punishment.
They have heavy-duty suspensions, oversized shocks
and large tires which enable them to survive the
roughest terrain. Yet, when tuned correctly, they
also display speed and agility equal to the off-road
cars.
Tie-Rod: The rod assembly used to connect the steering
bell- cranks or servo saver to the spindles.
Titanium: A metal alloy used to manufacturer parts,
such as tie-rods 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 often times make a car more
stable under acceleration and 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
for an off-road vehicle.
Top End: A vehicle's final acceleration rate, or
the amount rpm's available from a motor depending
on type of motor and gearing.
"Torquey": A. term used to describe a
motor's brute strength during acceleration.
Transponder: A small device, that when installed
in a vehicle will count your car's laps as it goes
by a radio pick-up device.
Traction Roll: If a vehicle has too much traction,
it may roll over during a high-speed turn.
Traction Compound: Used to soften foam or rubber
tires; used in on-road and off-road racing; a mixture
of different chemicals that usually have a strong,
unpleasant odor.
Trickle: A low-rate charge, usually below 0.5 amp.
Transmitter (Tx): The hand-held radio controller.
This is the unit that sends out the commands that
you input.
Turn Marshal: Persons assigned to correct- ing vehicles
that are upside down or stuck on the race track.
Racers are usually expected to turn marshal immediately
following their race.
Tweak: A condition in which more pressure is applied
to one side of the chassis. A vehicle that has a
tweak will pull to one side under acceleration and
braking.
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.
Under steer: A situation in which the rear tires
have more traction than the front tires. This causes
the vehicle to have inadequate steering.
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).
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.
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.
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