This dictionary is organized by alphabetical order, and all terms that are in here are linked. Also, if you have a term you need defined, email me and I'll add it in.
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Acceleration: When a car is picking up speed or going faster, it is accelerating. Better acceleration means that a car can get up to speed sooner than another. See gearing.
Ackerman: A term describing how much more the inside wheel turns than the outside wheel. It is measured in degrees. If a car has 2 degrees of ackerman, and you turn the wheels full left
(say 45 degrees), the inside wheel will be at 47 degrees. Negative ackerman means that the inside wheel is trying to push the car straighter than the outside wheel is doing, which decreases
handling.
AE: See Associated Electrics
Aerodynamics: The way air flows over something. Have you ever held your hand out of a moving car? Did you notice that when you held it parallel (flat) with the ground, it was easier to
keep there than when you held it at an angle or straight up? That's aerodynamics. Air can provide a considerable amount of force when it's moving. So, car bodies are designed to
cut through the air for maximum speed. They also can act to provide downforce.
Armature: The part inside of a motor that is actually doing the spinning. An armature, or arm for short, is where the biggest tuning can be made, when using
modefied motors, but not stock motors. A mod motor can be tuned by changing the wind of a motor, though
that means having to buy a new armature. The armature also contains the commutator.
Associated Electrics: Commonly known as Team Associated, or abbreviated to AE, they are one of the oldest R/C car manufacturers. They date back to the '70s with
cars like the RC100 and RC12e, and currently make the B3, T3, TC3, RC10L3, and RC12L3 cars.
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Ball Diff: A form of a differential that uses two plates and a gear with balls in it. See this picture for a diagram. Ball diffs are
generally smoother than gear diffs, but are sometimes heavier. In pan cars, the ball diff is generally the only kind of differential used.
Bearing: Normally means a small, donut-like piece of metal with small, smooth balls in it. Click here to see a diagram. What it does is reduce friction
drastically between two moving surfaces. The inner ring turns with the shaft, and the ring runs against the balls. The balls, enclosed in the oil-filled bearing, roll smoothly against the inner
ring and the outer ring, making it very easy to turn.
Body: The lexan covering on top of a car. It not only serves to look cool, but provides aerodynamics and protection to the insides of the car.
Body Clips: The little clips that hold the body onto the car. You will lose these if you race. They normally do a good job of staying in, but since crashes are inevitiable, especially
with other cars, these get bent or lost, necessitating frequent trips to get another 75 cent bag....
Brushes: The brushes are the path for the electricity into the commutator. Brushes come in two types, arranged by how they rest on the endbell. Laydown
brushes are wider than they are tall, standup brushes are taller than they are wide. They also come in different compounds, somewhat like tires. Hard, 'silver' brushes give more power, but wear
the comm down faster. Softer, 'copper' brushes give longer comm life, but shorter brush life and less power.
Brushless Motors: A special, new type of motor that has only recently begun to gather momentum in R/C land vehicles. It's been in use in airplanes for a while, but for various reasons has
been slow to move to cars. First is the up-front cost. Whereas a brushed mod and an ESC will run about $150 up front, a brushless is about $300 (including specialized ESC). Second is the
sanctioning bodies - it's not ROAR legal yet. Third is that the ESCs are still somewhat plane oriented. Only Aveox has a brushless ESC that has braking, and
none have reverse (which will probably not be offered for a long time). However, they have their advantages. First is performance and efficiency - they are about the equivalent of a 14 or 15 turn
motor, but use less electricity, giving the runtime of a 17 or 18 turn, or even more. Second is life. Though they cost more up front, you won't spend much more. Brushed motors require new
brushes, a comm lathe for semi-serious racing, new armatures after a while, and some other stuff. They're also more maintenance intensive. After a year of use, both types are roughly equal in
cost.
Bushings: Bushings are small, donut-shaped pieces made of either bronze or plastic which are designed to reduce friction between a shaft passing through something. However, since the
inside of the bushing does not rotate with the shaft, there is much more friction than with a bearing. See below.
Bearings vs. Bushings: Bearings and bushings do the exact same thing - reduce friction between a rotating shaft passing through something (i.e. an axle through a wheel). However, bearings
do it much more efficiently. They reduce the friction to almost nothing. However, bearings cost more than bushings, and must be maintained more often (cleaning and oiling) than bushings. Also,
bearings can 'lock up' if they get too dirty or just plain fail, making it worse than a bushing. But the difference can be very visible in performance.
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Camber: The wheels on any car are very rarely installed so that they are perpendicular, or straight up from the ground. When you turn, the car puts more of its weight on the outside
wheels (i.e. in a left turn, the right tires are the 'outside', in a right turn, the left tires are on the 'outside'). This causes them to tilt ever so slightly. Since we get the most traction
when the wheel is perpendicular to the racing surface, we put in a little camber. Camber is a measure of how many degrees a tire has been tilted. It is expressed in either positive or negative
degrees. Negative camber is where the bottom of the tire sticks out more than the top. Positive camber is where the top of the tire sticks out a little more. Using camber, we can counter-act the
tires being titlted, and also increase tire life.
Can: The can is most often used to refer to the outside of a motor. The can is, well, a can-shaped metal piece where the armature sits in and the endbell
sits on top of. The can contains magnets which help the armature spin around.
Cells: R/C cars use battery packs made up of, on average, 6 individual batteries, or cells. We often refer to a pack of 6 cells as a single battery. The standard R/C cell is a 'sub-C'
size, roughly the same as a C cell but a little smaller. They are durable and fit better than the amount of AA batteries that you would need to produce the same current and capacity.
Channel: The frequency that a car and its radio are operating on. Only one car can be on a channel at a time.
Commutator: The part on a motor that makes contact with the brushes and makes the power. A commutator must be kept both clean and true, or straight. As a commutator
wears, it gets curved and dirty. Cleaning it after every three runs with a 'comm stick', a two-ended stick with one end that cleans the comm and one that cleans the brushes, and motor spray is a
good idea. However, trueing the comm - removing the curve - needs to be done also, though not nearly as often.
Comm Drops: Comm drops are drops of a special combination of chemicals (nobody but the manufacturers knows exactly what) that are dropped onto the commutator. They help seat the brushes and increase power.
Compounds: Tires are made out of either foam or rubber. But not all tires of the same type (foam or rubber) are the same. Tires can be made with a different blend of chemicals to provide
different amounts of traction and life. 'Softer' tires are made with soft, sticky foam or rubber. They provide a lot of grip, but since they are very soft, they wear down rapidly. 'Hard' tires
may still seem soft or sticky, but provide less traction at the benefit of longer life. They are better for the person who just plays around.
Crystal: The crystal is the device in the radio that determines the channel of the radio. There is a crystal in the reciever (called the Rx crystal) and a crystal in the transmitter (the
Tx crystal). Crystal is often abbreviated to x-tal. CVDs: In a vehicle with independent suspension at the drive wheels, the power needs to be routed to the wheels in such a way that it can
get to them no matter what angle the suspension is at, and not shorten the suspension's travel (movement up and down). Most cars come with 'dogbones', which are dogbone- shaped metal pieces that
can be tilted at almost any angle and still transfer power. However, they can be a little wanting for smoothness. CVDs are basically a lot smoother and longer-lasting than dogbones. Most often,
they are a hop-up part for a car.
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Differential: The differential is something in the drive wheels that allows them to still be driven and yet turn at different speeds. In a turn, the outside tire turns faster than the
inside. If there was no differential, the turning ability would be greatly reduced, since the inside wheel would be turning too fast to make the turn.
Discharge rate: The discharge rate is a rating of how fast packs are discharged. It is rated in amps, a rating of electrical current (or flow - i.e. 1 amp is a slow river, 30 amps is a
torrential current). When matched packs are being matched, they are normally discharged at anywhere from 20 to 30 amps, which is similar to that of our cars.
Downforce: The force that can help make a car 'stick' to the ground. If you hold your hand out of a moving car at a downward angle (so that the part of your hand that's facing the
direction the car is going is pointing somewhat down) you will notice that it will get pushed down a little. Wings on car bodies can take advantage of this and use the wind to produce downforce,
and make the car effectively weigh more at speed. The downside is that it produces drag.
Drag: The force of air that slows a car down. When you hold your hand out of a car window so that it is straight up and down, it gets pushed back a lot. But if you hold it flat, it gets
pushed back very little. The hand, when held up, produces a lot of drag. The air going around it is slowed down trying to get out of the way. Wings take advantage of this and use it to push the
car down for better grip. However, the more downforce there is, the less top speed there is.
Dumping: Dumping refers to when a battery pack in a car starts losing all of its power. They don't drop off gradually. They drop off some at the beginning, then stay relatively level,
then drop sharply at the end. A good matched pack will dump all at once, sometimes in as little as 30 feet. Non-matched packs may start dumping but last for another lap or more. NiMh packs, even when matched, are slow dumpers, but should never be completely discharged.
Dyno: A dyno, or dynamometer, is a device that is used to determine how much power a motor puts out. It is used almost exclusively on electric motors, because two identical electric
motors vary in power much more than two identical nitro engines. It can determine as little as the power and RPMs (revolutions per minute), or include the efficiency (how well it uses the
electricity it is given), torque (turning force), and amp draw (how much power it is really drawing). A good stock motor will put out 125 watts or more, and pull more than 25,000 RPM. Modefieds
put out much more.
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Electronics: A general name for all of the electronic devices in a car - the reciever, servos, and speed control.
Electronic Speed Control: The device that routes electricity from 1) the battery to the motor, and 2) the battery to the
reciever. It is an electronic speed control if it is all in one unit; it is a mechanical speed control if you need a servo
to control it. Mechanical speed controls can not put power to the reciever. Aside from that, both forms of speed controls are basically your throttle, or exactly as they sound, your speed
control. Nitro cars do not use any speed control.
Endbell: The endbell is a slightly bell-shaped piece that goes on the end of a motor. It houses the brushes and holds them to the comm with springs. It
also provides cooling, helps hold the armature, and is where the electricity is hooked up to the motor. Rotating it in relation to the can can also adjust timing in a modefied motor.
ESC: See Electronic Speed Control
