Marc's Glossary

A

• acceleration due to gravity - 32 feet per second per second.
• Ackerman - a steering technique such that tires scrub less by steering them the correct directions. Named after the person who first thought of doing it.
• airing tires - relieving any chance of air pressure in the tires.
• alignment - how the tire directions compare to each other.
• anti-squat - suspension geometry which limits body roll from front to back.
• armature - the rotating portion of the motor.
• asphalt tire - a tire used on a asphalt tires. usually made of a sponge rubber material.

B

• bearing - mechanical devices used to interface between objects, one of which is rotating.
• blocking - a driving style of moving back and forth used to keep the competition from passing.
• breaking in the motor - running the motor to ware the brushes into a shape that fits the commutators.
• brushes - the part of the motor that transfers current into the internal wire of the motor.

C

• Camber, negative - leaning the tops of the tires in, is negative camber
• Camber, positive - leaning the tops of the tires out, is positive camber
• Coast time- is the time it takes the wheels to stop spinning, after spinning them by hand with the motor removed.
• cps - cycles per second. This the frequency unit. A cycle is one up and down bounce of the car.
• Chassis/body - is the combination of the car chassis (frame) and the body. They normal move together, hence the word chassis/body.
• Coefficient - is defined as a number that serves as a measure of some property or characteristic, or relative to, or involving joint action in producing a result.
• commutators - are the motor's wire interface with its brushes. They are the shiny copper partial rings on the armature.
• Cushion - is the mound of dirt that forms just outside of the racing groove on dirt track.

D

• differential - a mechanical that distributes power equally to its outputs.
• dirt tire - a tire used on dirt tracks, usually rubber.
• dirt track conditions - a soft dirt track, as opposed to a hard asphalt type dirt track.
• drag - aerodynamic property that slow a car's progress through the air.
• dump - RC car talk, it means the battery did not last the entire race time.
• dynamometer - test equipment that characterizes a motor.

E

• emf - abbreviation for electromotive force.

F

• form donuts - sponge tires material cut into a donut shape. They can be trued to make tires.
• frequency - repetitive motion measured in cycles per second.
• front lift - the front of the car getting lighter on its tires.
• frontal area - aerodynamic property showing the area of the front view of the car.

G

• Groove - the fast line of the racing surface.
• Gs - Force equated to the force of gravity.

I

• instantaneous roll centers - the full name for roll centers.

L

• left side bias - a shift in static weight of a car to the left.
• lift - aerodynamics property that causes the lift.
• loose - an oversteer condition. The opposite of understeer.
• loosen, loosen up - to remove some understeer from a car's handling characteristics

M

• More steering - means that handling characteristics are such that car would tend to turn .
• mAh - stands for milli amp hour. A current rating for batteries.

O

• oversteer - means that handling characteristics are such that car would want to turn or spin-out. Understeer is the opposite of oversteer.

P

• Pan Car - A class of RC car which is very simple and light.
• Percentage - the first number divided by the second times 100. It expresses a ratio of two items in a universal format.

• peak efficiency - a power range of the motor where the efficiency of the motor peaks.

• peak power - a power range of the motor where the power of the motor peaks.
• pi - a mathematical constant, 3.14159
• pre-load - to load the tires unequally before the car is put into motion.

R

• radio equipment - the transmitter, receiver, servo, and speed control of an RC car.
• resistance - a component of Ohm's law that limit electrical current.
• roll axis - the axis which the car rolls on when the body leans.
• roll center - the chassis roll on this point.
• roll couple distribution - expresses which tires absorb the cornering load.
• rolling resistance - a tire resists rolling.
• rpm - abbv. revolution per minute.

S

• safety - staying toward the sane side of life.
• shock absorb mounting - usually a shock tower.
• shock absorber - a device to dampen motion.
• shock absorber collar - the little band on the shock absorber which supports the springs.
• shock oil, wheel rate - the effect the shock has on wheel rate.
• slipper clutch - simple clutch design to slip under high loads.
• sprung weight - the weight of the car minus the unsprung weight.
• stagger - different size of tires from side to side.
• steering - a handling characteristic that indicates the car will turn well.
• sway bars - tension devices added to a car to change roll couple distribution or limit wheel travel during cornering.

T

• tire, diameter - 2 times the radius of the tire.
• tweak - to load the tires unequally before the car is put into motion.
• Traction Circle - A visual aid to used to show the tire contact force. A circle is used to help you visualize two smaller forces (braking and lateral force) being summed into a one larger force
• Truing - a process to make sponge tires round

U

• Understeer - means that handling characteristics are such that car would want to go straight or push. Oversteer is the opposite of understeer.

V

• voltage - unit of electrical potential

W

• watt - unit of electrical power.
• weight jacking - the process which causes traction rolls.
• weight transfer - weight that is shifted from one tire to another
• wheel base - the length of the car front to back measure at the wheel axles.
• wheel rate - the spring rate encompasses the motion ration of the suspension arm.
• wheel travel - the amount the tire moves up and down relative to the chassis.
• wings - aerodynamic devices attached to cars to cause negative lift.