N
Narrow -- see width, wheel or width, chassis
Needle Valve-- An adjustment on an engine's
carburetor that regulates the amount of fuel that enters the engine.
Ni-Cad -- The
abbreviation for nickel-cadmium
Nickel-Cadmium -- 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 -- A type of battery that has no cell
memory, but features 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.
Nitro-- a general term, it could
mean many things. For most people, it refers to the type of car you have: You have
a nitro car? A car can be nitro-powered, run on nitro fuel, and the term can be used
for many other things.
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.
Ni-MH -- The abbreviation for nickel-metal hydride.
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
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.
Offset - see Wheel
Offset
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.
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.
O-Ring
-- A donut-shaped circle of rubber or silicone that seals rotating or sliding shafts,
used in areas like shock absorbers and differentials.
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.
Oversteer-- (also loose) Your car's
rear end keeps swinging around? Condition: oversteer. The rear tires in an oversteering
('loose') condition lose traction before the front wheels, wasting power as the tires
slip, looking for something to grip to. You may need stickier (or newer) tires, more
rear downforce or there may be other problems. Shock and weight settings may need
adjusting too.
P
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 -- A type of transmitter and receiver that is even 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 --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.
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!
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
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.
Q
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.
R
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-- 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.
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.
Receiver Pack -- The battery pack that provides
power to both the steering and throttle servos in a Nitro car.
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).
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.
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.
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.
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.
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.
