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A-Main
The final race out of a series of races. How well you do during the heats determines what main you are placed into. The A-Main is the best-of-the-best racing against each other. The B-Main is the second group of racers that did not do as well, and so on.
A-Arm
A suspension arm named for its resemblance to the letter A. Shocks, bulkheads, and hub carriers all connect to an A-Arm.
Acceleration
A quick progression of speed. This is also known as the “low end” of your engine or motor. Dropping your pinion gear a few teeth will give you more acceleration, but at the cost of torque. You can also increase the teeth on your spur gear, but the acceleration increase won’t be as noticeable unless you drastically change the size.
Ackerman
The proportion of the left to right wheel while cornering. During a left turn, the right front wheel has to travel around a radius which is larger than that of the inside wheel. This requires the inside wheel to turn at a sharper angle than the outside in order for both wheels to effectively track. The inside wheel should turn sharper when the wheel is turned as far as it will go. On some cars, this is adjustable by either shimming the steering rack, or by using one of the multiple locations on the steering knuckle or rack.
Ackerman Link
The arm that connects the left and right front tie-rods which are connected to the steering knuckles to allow the servo to move both wheels. Also known as the “steering link”.
Adjustable Travel Volume
A setting on most modern radios which allows fine tuning of the servos’ maximum travel. On cars and trucks this adjusts how tight of a turn you can make. On airplanes this adjusts how much an aileron or rudder moves. Setting this too high on an airplane radio can cause excessive changes in direction while flying. Setting this too low can make it difficult to maneuver properly.
Aft
The aft is the rear portion of a boat or aircraft. Specifically, this refers to the inside rear of the vehicle, whereas the stern refers to the outside rear of the vehicle.
After Run Oil
A protective lubricant used in a nitro engine after being run. After run oil displaces the fuel left in the engine’s chamber, which can corrode parts such as the seals and gaskets. To use after run oil, remove your glow plug or air filter and add 3–4 drops. Then slowly pull the pull starter to move the oil around the engine.
Aileron
The hinged portion of an airplane wing controlled by servos which controls the plane’s rolling and banking movements.
Air Dam
Most touring car bodies have an air dam under the front bumper that is designed to keep air from getting under the car. The benefits of an air dam include enhanced aerodynamics and stability at high speeds.
Air Filter
A foam-like sponge used to remove harmful objects from entering the engine through the carburetor. Some air filters have two different foams—one is thin and catches big objects such as grains of dirt and sand, and the other catches small objects such as dust. Air filters often come pre-oiled, but sometimes need to be manually oiled with air filter oil or WD-40 to further help catch the dust and particles. They need to be cleaned often using motor cleaner or a bowl of water.
Air/Fuel Mixture
The ratio of air to fuel that enters your engine through the carburetor. If your engine is using too much fuel, it is considered “rich”. If it uses too much air, it is considered “lean”.
Allen Wrench
Also called an Allen key, is a small hand tool with a hexagonal cross-section used to tighten or loosen screws and bolts that have a hex socket in the head. It is commonly L-shaped to provide leverage and access in tight spaces and is available in both metric and inch sizes for use in mechanical, automotive, furniture, and hobby applications.
Alligator Clips
Clips from your charger (if it has them) that attach to your full-size 12-volt car battery to charge your batteries. You’ll probably see these at a parking lot race unless power is provided.
AM
A type of radio signal in which the amplitude, or strength, of a radio wave is varied in order to carry information from a transmitter to a receiver. AM radios operate at 27MHz or 75MHz.
Amps
Abbreviation for “Ampere”. A measurement for electric current. Sub-C battery packs are generally charged anywhere from 1–6 amps. Micro 2/3A battery packs are charged at 0.1–2.0 amps. When charging, more amps translates to more punch and acceleration, and fewer amps translates to more runtime. Racers prefer punch over runtime since their heats and mains are only a few minutes long. Bashers usually prefer more runtime.
Angle of Attack
The angle at which an airplane wing penetrates the air. Increased angle of attack will result in added lift and drag.
Anodizing
A process used to protect aluminum from scratches and corrosion. This process also allows aluminum to be dyed a wide range of colors, such as blue and red. Aluminum is covered in aluminum oxide, resulting in dyed aluminum. Titanium and Titanium Nitride (both often used in shock shafts due to their strength) can also be anodized.
Anti-Roll Bar
Also known as “stabilizers”. A thick wire device fitted to the suspension arms which limits the car from traction rolling in high-speed turns and maneuvers.
Anti-Squat
Anti-Squat is the angle of caster on the rear wheels of a vehicle. Raising the front of the hinge pins on the rear arms of a touring car gives a caster angle which helps to transfer the power more evenly and improve steering. This helps keep the front of the vehicle from lifting under acceleration.
Arcing
When voltage jumps from a motor brush to the comm (or from one surface to another) due to poor or corroded contact between the two components. Arcing will cause excessive heat which often causes premature brush and comm wear. This shows it is time to replace the brushes and run your armature on a lathe.
ARF
Abbreviation for “Almost Ready to Fly”. Helicopters and planes that are labeled ARF require minimal work and installation of the electronics and/or engine/motor.
Armature
The spinning part of an electric motor. This is also known as the “arm”, and is home to the comm, windings, and laminations. The armature spins on the motor shaft, which rests on two bushings or bearings.
ATV
Abbreviation for Adjustable Travel Volume.
AWG
Abbreviation for “American Wiring Gauge”. This is the United States measuring standard for wire thickness. Generally, the thicker the wire, the more current that can travel through it and for a longer distance. The larger the number, the thinner the wire. An example is your steering/throttle servo wire. The servo wire is a large number (often 24 AWG), but a small wire.
Axle Pins
Pins that go through the axle and interlock with the hex-hubs or the slot in the wheels. Due to their small size and metal-on-metal contact, it may be a good idea to use a little dab of grease to hold them in. If you lose one, you can use a large paperclip and cut it down to the proper length as a temporary fix.
Backlash
The amount of free movement between gears in a transmission or drivetrain before the gears engage. Too much backlash causes sloppy handling, while too little can bind and wear gears.
Backmarker
A racer who is being lapped on the track.
Ball Cup
A plastic cup that screws onto a tie-rod, shock shaft, or snaps onto a ball stud. Often used in suspension and steering linkages. The cup can pop off rather than break during a crash.
Ball Differential
A differential gear containing small balls that roll smoothly between two metal rings (D-rings). Can be tightened or loosened to adjust handling. Slips under load rather than stripping like a planetary differential.
Ball End
A hex screw with a metal ball on one end. The ball cup attaches over it to provide a pivot point for suspension components.
Ballast
Weight added to a vehicle or boat to maintain proper balance or height. Often made of lead or aluminum.
Ballooned
A LiPo battery that has expanded due to overcharging or gas buildup inside the packaging.
Balsa Wood
Extremely lightweight wood used in RC planes and boats. Highly buoyant, with an average density of 140 kg/m³.
Bashing
Driving your car or truck in extreme or unintended conditions, such as on rooftops, jumps, or irregular terrain.
Battery Jig
A stand that holds batteries or cells during assembly, soldering, or packaging to create level, neat, and professional packs.
BB
Abbreviation for Ball Bearing. See Bearings.
BDC
Abbreviation for Bottom Dead Center. A piston is considered BDC when at the very bottom of its stroke.
Bearings
Stainless steel balls sealed with grease, positioned between two circular walls to reduce friction and support rotating shafts. Often replace bushings.
BEC
Abbreviation for Battery Elimination Circuit. Allows receivers and servos to be powered from the main battery, eliminating the need for a separate pack.
Bevel Gear
A gear with angled teeth, allowing power transfer between shafts at an angle, typically 90 degrees.
Belt Drive
A drivetrain using a belt instead of shafts and gears to transfer power. Can have slop, which a belt tensioner reduces but cannot eliminate.
Belt Tensioner
Keeps a belt tight to prevent slipping and reduce vibration. Typically uses bearings or bushings to roll on the belt’s smooth side.
Belted Tires
Tires reinforced with a non-stretchable band inside to prevent ballooning at high RPMs. Improves predictability and durability.
Bicycling
When a vehicle tips onto two wheels during a sharp turn, usually seen in top-heavy vehicles like monster trucks.
Big Block
A large engine, typically .21cc or greater in RC.
Bipe
Short for biplane, an aircraft with two wings stacked vertically.
BL
Abbreviation for Brushless. A motor without brushes or a commutator, requiring a brushless ESC.
Bled
Refers to the process of removing air bubbles and excess oil from shocks after assembly.
Bleeding
The act of removing excess shock oil by slowly compressing the shock shaft. Can also refer to paint seeping under poorly applied masks.
Blue Groove
A worn line in the dirt track created by repeated tire passes. Tires show a bluish tint over time.
Body
Protects internal components while providing realistic appearance. Often includes aerodynamics, wings, and stickers.
Body Clips
Small clips used to secure the body to the chassis. Available in multiple types and colors.
Body Mounts
Also called body posts. Hold the body above the chassis and moving parts.
Body Posts
See Body Mounts.
Body Reamer
A tool used to create precise body post holes in lexan bodies. Can also cut balsa wood and ABS plastics.
Body Roll
The angle the vehicle leans during a turn due to centrifugal force.
Bog
When a nitro engine stutters or hesitates under acceleration, usually due to incorrect fuel/air mixture.
Booster Pack
An external battery or device used to temporarily increase voltage or current to a motor or ESC.
Booty Roll
Fishtailing movement of the rear end due to uneven terrain.
Bottom Out
When the suspension compresses fully, causing the chassis to slam or scrape the ground.
Brake Check
A tactic to slow or distract a following car by quickly tapping the brakes.
Brake Fade
Loss of braking effectiveness after extended use due to heat buildup.
Braking Zone
Track areas where vehicles slow for sharp turns.
BRCA
British Radio Car Association. Governs RC car racing in the UK.
Break-In
The process of running a new engine or motor for the first time to wear parts in for smooth operation.
Brushless Controller
ESC designed for brushless motors, regulating speed based on receiver input.
Brushless Motor
A highly efficient motor without brushes or a commutator, requiring a brushless controller.
Bubble Fuel
Fuel in the tank forming bubbles due to vibration, potentially causing stalls.
Buddy Box
Training system linking two radios; instructor can control or transfer control to the student.
Bulkhead
Structural part connecting bumpers, suspension arms, and shock towers.
Bulkhead Brace
Reinforcement for a bulkhead to increase rigidity.
Bumper Thumper
A driver who frequently hits the rear of other cars during racing.
Burr
Rough or leftover material from machining or molding. Must be removed to prevent interference.
Bushing
A simple cylinder (brass or bronze) that supports rotating shafts. Less efficient than bearings but inexpensive.
Bump Steer
Unintended wheel turn caused by suspension movement over bumps.
Burn-In
Running a motor or ESC lightly to stabilize performance and detect early issues.
CA Glue
See Cyanoacrylate Glue.
Cable Tie
A strip of nylon with teeth on one side and a flap on the other that interlocks. Used to bundle wires or secure components. Also known as a zip tie.
Calling Traffic
A track policy where the announcer alerts backmarkers that the leader is approaching. The backmarker is expected to yield and avoid disrupting the leader’s line.
Camber
The angle of a wheel relative to a vertical line perpendicular to the ground. Negative camber means wheels tilt inward; positive camber means they tilt outward.
Camber Gauge
Tool for measuring wheel camber. Can be handheld with wheels on or part of a setup board with wheels off.
Camber Link
A rod connecting wheel hubs to bulkheads or shock towers, often threaded with ball cups on each end.
Can Motor
Inexpensive DC motor with fixed endbell, carbon brushes, and ferrite magnets. Not designed for repair; often replaced when faulty.
Capacitor
Electronic component that temporarily stores and releases electrical charge. Often used for smoothing signals in ESCs, motors, or radios.
Carbon Fiber
Lightweight, extremely strong material made from woven carbon filaments. Commonly used in chassis, shock towers, and structural components. Can be black, gray, or other colors.
Carcass
The part of a tire that supports its shape and makes contact with the ground. Wider carcass for monster trucks; thinner for touring cars.
CCPM
Abbreviation for Cyclic Collective Pitch Mixing. Mixes control signals for 3 swashplate servos, reducing helicopter mechanical complexity.
Cell
Individual battery unit. Battery packs are composed of multiple cells soldered together.
Celluloid
Thin, clear plastic film used to cover scratch-built planes. Resistant to water, oils, and dilute acids.
Center of Gravity (CG)
The point where a vehicle balances. Lower CG increases stability and reduces the chance of flipping.
Centerline
Imaginary line down the middle of a chassis or fuselage, front to back.
Charger
Device for charging batteries. Quick chargers stop after a set time; peak chargers continue until full.
Chassis
Main platform where all components (electronics, battery, engine, transmission, etc.) are mounted.
Checked Out
Term used by race directors or announcers to indicate a racer has a significant lead over the field.
Chicken Stick
Small stick used to flip-start airplane engines safely. Alternative to using hands; electric starters are preferred.
Class
Grouping of similar vehicles for racing. Examples: Rookie Stock, 19 Turn Expert, Sportsman Nitro, Factory Modified, Open Stadium Truck Nitro.
Clunk
Weighted fuel line component in aircraft tanks that ensures fuel remains submerged when inverted.
Cogging
When a brushless motor draws more current than the battery/ESC can supply, causing sputtering. Can be caused by thin wires or poor connectors.
Cold Solder Joint
Weak solder connection, dull gray, possibly chunky. Can result from low-wattage irons or poor technique. Proper joints are shiny and smooth.
Collapsed Foam
Foam tire insert that has broken down, leaving gaps under the tire carcass. Can be caused by wear, moisture, or improper installation.
Comm / Commutator
Rotating part of a motor armature that carries voltage through windings. Needs occasional maintenance on modified or stock motors.
Compound
Rubber formulation of a tire, affecting grip and performance. Can be hard, soft, flexible, grippy, or slippery.
Contact Patch
Portion of a tire that contacts the ground. Affected by acceleration, braking, turning, and camber. Soft sidewalls may enlarge the patch.
Control Linkage
Rod connecting a servo horn to a control surface or steering block.
Control Surface
Movable surface (aileron, rudder, or steering surface) controlled by a servo.
Countersunk
Hole with a flared top so a screw sits flush with the surface, often seen in chassis or bumpers.
Crystal (X-Tal)
Small microchip with a specific frequency for radios. Crystals are interchangeable and used for channel assignment.
CVD
Abbreviation for Constant Velocity Drive. Trademarked by MIP, commonly used to describe driveshafts that maintain constant speed through angles.
Cyanoacrylate Glue
Also called CA glue. Fast-setting adhesive used to bond materials like tires to wheels or structural components. Extremely strong; different viscosities exist.
Cycle
To fully discharge and recharge a battery pack or cell. Used to erase memory effect in NiCd cells. NiMH cells typically do not require cycling.
Dampening
The resistance caused by a piston and oil in a shock body. The piston has one or more holes which the oil must pass through so the shock shaft can come in and out of the shock body. The thickness of the oil, thickness of springs, and the amount of holes in the piston can all affect the dampening of a shock. If a shock compresses and uncompresses quickly, it is considered to have fast dampening.
Dead Stick
A term used to describe a stalled plane which is gliding down to the ground. Since the pilot still has control of the ailerons and rudder the plane can usually be safely landed.
Decked Out
A hopped up car or truck. To say “Woah! That truck is decked out with aluminum!” would mean the truck has a lot of aluminum hopups (aftermarket parts).
Dig
A term used in crawling were the rear wheels are disengaged from the drivetrain via an electronic or mechanical device, thus allowing the front wheels to pull while the rear wheels are stationary. The combined effect allows the vehicle to pivot like a tracked vehicle and increases the ability of a crawler to make sharp turns. After the dig is engaged, the front wheels “dig” in for traction.
Direct Servo Control
Some radios can be directly connected to the receiver through a cable to check servo operation without transmitting any radio frequency. This is great for big events where pilots need to make adjustments without turning on their radio and risking a crash of someones plane.
Discharge Tray
A piece of equipment used to discharge each cell of a side-by-side battery pack individually, for the purpose of keeping each cell at a consistent voltage. Some electric racers simply refer to it as a ‘tray’, and placing a battery in one to ‘tray a pack’.
DNF
Abbreviation for “Did Not Finish”. This will often be printed next to a racers name if their car crossed the starting line but was unable to complete the race.
Dogbone
Named due to its similarity to a dog bone. A dogbone is a long shaft with two pins on both ends that run perpendicular to the shaft. It is used to transfer power from the differential outdrives to the axles.
DQ
Abbreviation for disqualified. Often shown on race results when someone is found to have cheated or broken the rules of the track or club.
Draft
The area directly behind the car in front of you where there is very little wind. This effect is much more noticeable in full scale racing, but does still exist in radio controlled cars. However, the effectiveness of tailing the car in front of you is very slim as it would be smarter to just pass it. Next time your driving your full scale car or truck, roll down your window and put your hand behind the mirror. Then move it above the mirror. The area behind the mirror is considered the draft.
Drag Link
The arm that connects the left and right front tie-rods which are connected to the steering knuckles to allow the servo to move both wheels. Also known as the “steering link”.
Drifting
A driving technique where the rear wheels intentionally lose traction while cornering, allowing the vehicle to slide sideways through a turn. Often used in RC car racing for style, control practice, or tight cornering.
DSM
Abbreviation for “Digital Spread Modulation”. Spektrum RC, a division of Horizon Hobby, created this term to set their radios apart from others. 2.4GHz radios that use DSM technology (Spektrum), are really using a technology called DSS (Digital Spread Spectrum), which is used by companies such as Spektrum and Nomadio. Cell phones and pagers also use this technology.
DSS
Abbreviation for “Digital Spread Spectrum”. Spektrum RC and Nomadio make use of this technology in their radio systems, as do cell phones and pagers. If a radio operates at 2.4GHz, it is considered to be a DSS radio.
Duct Tape
A water resistant tape made of small threads and adhesive surface which is very strong and sticky. One of the fix-all products used to repair anything from bodies to suspension arms. Most often seen when bashing around, and very rarely seen at a track.
Dump
When a battery pack’s charge is quickly running out. Often said during the end of a race when the battery is beginning to lose its charge. This quickly slows the car or truck down and is a very unfavorable affect in the racing scene.
E-Clip
A small steel ring named for its resemblance to the letter E, which are used to hold hinge pins and shock shafts in place.
Endbell
The endbell is the part of an electric motor where the brushes travel inward toward the armature and the commutator. Electricity is applied to this area for the motor to properly rotate. Many motors have adjustable endbells, which allow for different timing. Stock “silver can” motors usually have “closed” endbells, meaning they are not adjustable, and the brushes and springs cannot be changed. Modified motors usually have what is known as an “open” endbell, where springs and brushes are able to be changed.
ESC
Abbreviation for “Electronic Speed Control”. An electrical unit which controls how much voltage to supply to the motor according to the receiver. An ESC uses a circuit board along with transistors, capacitors, diodes, and other circuitry to create smooth and efficient acceleration.
Factory Driver
A racer who is sponsored by a large RC manufacturer (such as Associated, Losi, Tamiya, Xray) and has all the latest cars and equipment. These drivers are usually covered in company logos and have hopped up cars with top of the line parts.
Failsafe
An electronic device that returns the servos to neutral, applies the brakes, or cuts power to the speed control in the event of signal loss, low battery, or interference.
Fixed Link
A non-adjustable turnbuckle or tie-rod, often solid plastic and included in lower-end or RTR vehicles. Most companies offer adjustable turnbuckles as a hop-up for those seeking more adjustability.
Flange Nut
A locknut with an edge at the bottom for extra grip. See “locknut”.
Flat-Spotting
Similar to a collapsed foam but instead of affecting the entire insert, only one patch or “spot” is compressed. This can be caused by improper installation (a fold or a bunch in the foam), but more often comes as a result of the vehicle being parked in one place for an extended period of time, with the tires bearing the weight of the vehicle instead of freely suspended with the chassis on a stand.
Flooded
When you have too much fuel in your engine. This can sometimes lock the piston in place. To fix a flooded engine, simply take the glow plug out and drain the fuel. Then replace the glow plug and start up your engine.
Flux
Used when soldering. Flux removes oxidation from the surface it is applied to when heated with a soldering iron, and helps improve the bond of the solder. Some brands of solder already contain flux. Using solder that contains flux while using a separate application of flux is a generally good idea to prevent cold solder joints.
Frankentire
A combination of different tires assembled together to create a new tire with characteristics of both tires. Commonly seen in the rock crawling aspect of the hobby.
Frequency
The number of oscillations (vibrations) in one second. Frequency is measured in Hertz. Radio control vehicles commonly run on 75MHz, 72MHz, 50MHz, and 27MHz. 2.4GHz is currently new to world of radio control cars, but is increasing in popularity and convenience.
Fuel Gun
A handheld fuel bottle with a trigger and handle designed for rapid release of fuel in to the fuel tank during nitro races. Most racers who need to come in to the pit for fuel have a fuel gun because their pit guy can shave off several seconds compared to a fuel bottle.
Fuel Tubing
Flexible silicone tubing that transfers fuel from the fuel tank to the carburetor. Fuel tubing is also used to transfer pressure created by the exhaust pipe into the fuel tank.
Fuselage
The main body of an aircraft from the nose to the tail boom which everything connects to. The fuselage contains most if-not all of the electronics. On fuel-powered planes, the engine is mounted in the nose of the fuselage.
Gauge
A standard unit of measurement to determine the thickness of a wire. See “AWG”.
Gear Mesh
The space between two gears. Usually used to describe the space between the spur gear and the pinion or clutch. If the gears are too tightly meshed (too close together), they will slow your car or truck down. If the gears are too loosely meshed (too far apart) they will strip easily. To achieve a proper mesh, put a piece paper between the two gears and move the gears together. Secure the gears in that position and remove the paper. After time, you’ll learn how to do this without a piece of paper.
Gearing
The size of the pinion and spur gear. The spur gear is the first number, and the pinion in the second. For example, if asked what the stock gearing of the Team Associated RC18T, you would say 55T / 14T.
Ghost Rider
A car or truck with a clear or partially painted body. A car or truck with clear windows is not considered a ghost rider.
Ghost Tail
An unpainted wing on a car or truck.
Gigahertz
Commonly expressed as GHz. A unit of frequency that is equal to one billion hertz per second. Now becoming available to hobbyists. In the past, hobbyists have had to run on 75MHz, 72MHz, 50MHz, and 27MHz, which are more prone to interference and transmit at slower speeds.
Glitch
A short moment in time when your vehicle is unresponsive to your radio due to radio interference.
Grub Screw
A small screw with no face. A threaded shaft (screw) with an allen-key hex socket on one end. Often used to secure pinion gears to motor shafts, among other things.
Gyro Effect
An off road term used to describe the effects of manipulating the throttle, brake, and steering while in midair. Accelerating increases the inertia in the chassis and causes it to climb up. Similarly, tapping the brake will cause the car to dive forward. In the same way a gyroscope resists movement, steering in midair will twist the car one way or the other. By using the gyro effect, off road drivers can guide their cars to a smooth landing.
Hacker
One who intentionally (a rude racer) or unintentionally (an inexperienced driver) crashes (“hacks”) into other vehicles on the track. A hacker can be easily spotted and sometimes disqualified at the race directors discretion. If you’re having radio problems, pull yourself off the track so others don’t leave disappointed because your car kept hitting them. If your just not experienced enough, get some practice before entering a race.
Hacker is also a company, Hacker Brushless USA, who manufacture brushless motors and speed controls.
Hairpin Turn
A sharp, 180 degree turn. When viewed from above, it resembles a hair pin.
Hard-Wire
To solder a battery directly to a speed control, or a speed control to a motor. This is often done by racers because of the undesirable resistance battery and motor plugs have. Hard-wiring can result in a slightly faster car or truck while having longer runtimes and less heat buildup. The only downside is convenience, as you have to heat your soldering iron up to remove your motor, speed control, or battery pack.
Header
A bent aluminum pipe connected between the engines exhaust port and muffler. Usually bent in a 90 degree angle, but can come in any shape or size. Also known as a “manifold”.
Heat
Also known as “qualifier”. You race several heats to determine the ranking for the mains.
Heat Gun
An electronic device that resembles a hair dryer, but is much more powerful. A heat gun draws air into it’s body and passes it over heating coils, then blows the hot air out. This is ideal for shrink wrap and heat shrink, as heat makes them contract around the object/wire.
Heat Shrink
Shrinkable rubber tubing used to insulate wires. Often used on battery plugs to prevent the battery pack from shorting out. Also used to encase entire battery packs and single battery cells.
Heat Sink
A piece of aluminum with fins for maximum surface area and to channel airflow. Heat sinks are often used in speed controls, motors (clip-on), servos, batteries, and chargers. The goal of a heat sink is to dissipate heat. The heat sink heats up, and cool air blows over it which helps cool the heat sink down. Without a heat sink, some electronics would get too hot and burn up.
Hex Driver
A tool with an ergonomic handle and long shaft used to fasten a screw or bolt with a hex-shaped head. These tools are often made with lightweight aluminum handles and replaceable steel shafts. Most kits include hex wrenches, but these can be cumbersome to use and wear out quickly. Most sponsored racers and seasoned racers will have a set of hex drivers in their toolbox.
Hex Wrench
Also known as an “allen wrench”. These are often small L-shaped tools used to fasten a screw or bolt with a hex-shaped head. Hex wrenches are commonly included with rc kits, but can be cumbersome to use and wear out quickly. Most sponsored racers and seasoned racers will instead have a set of hex drivers in their toolbox.
Hobby Grade
A vehicle is able to be hopped up with aftermarket parts, repaired, and is generally made of higher grade material.
Hobby Knife
A small knife blade with a pencil-like handle used for cutting in detail. Often used for cutting stickers, wires, servo tape, and other thin objects. Also known as an “X-Acto Knife”.
Hop Up
An aftermarket upgrade. Can be for appearance, performance, or durability. For example, buying new wheels which are different from what came with your car or truck.
Hot Wire
The hot wire is the positive power lead coming from the battery or power source. It is always energized when the battery is connected and is the wire that delivers voltage to the ESC, receiver, or other electronics.
Hot wire (foam cutting):
A hot wire is a resistive metal wire that is heated by electric current and used to melt through foam for clean, precise cuts. Common materials: nichrome or stainless steel.
Idle
The lowest engine or motor speed where it continues to run without throttle input.
IFMAR
Abbreviation for “International Federation of Model Auto Racing”. IFMAR is the world sanctioning body of radio controlled vehicles. The objective of IFMAR is to provide uniformal rules and regulations and coordinate international races and competitions.
For more information, visit ifmar.org.
Inrunner
A type of brushless motor where the rotor spins inside the stator, typically higher rpm and used in cars and boats.
Interference
Unwanted electrical noise that disrupts radio signals, causing glitches or loss of control.
Input voltage
The voltage supplied to an esc, receiver, or other rc electronics from the battery or power source.
Integrated bec
A battery eliminator circuit built into an esc that provides regulated power to the receiver and servos.
Inertial stabilization
A system using gyros or accelerometers to help keep a model stable during movement or flight.
Internal Combustion Engine
Fuel gases are ignited in a chamber which causes an increase in pressure and moves a component of the engine. This component is connected to a shaft that can be connected to a transmission or drivetrain to provide mechanical power.
Internal resistance
The resistance inside a battery that limits current flow and causes voltage drop under load.
Inverted flight
Flying an aircraft upside down while maintaining controlled flight.
Isr
Interrupt service routine used in flight controllers or receivers to handle time critical signal processing.
Jig
A tool or fixture used to hold parts in place during assembly, alignment, or repair.
Joystick
A control stick on a transmitter or controller that directs movement of the RC vehicle or aircraft.
Jump
A ramp or obstacle designed for RC cars, trucks, or buggies to launch off the ground.
Jitter
Rapid, small, unintended movements of servos or motors, often caused by signal noise or interference.
J-B Weld
A popular alternative to welding and brazing. It comes in a package of two tubes, which are mixed equally to form the final product. After mixing, the compound is applied to the two objects you’re joining together. J-B Weld sets in 4-6 hours and is completely cured in 15-24 hours.
Jumper wire
A short wire used to connect two points in a circuit, often for testing or temporary connections.
Jump start
The act of quickly powering up an RC vehicle, often after battery installation, to get it running immediately.
KPH
Abbreviation for “Kilometers Per Hour”. This is the ratio of distance traveled in kilometers to the time spent traveling in hours. This is used to express speed. A kilometer is equal to 0.6214 miles.
Kickup
The upward motion of a car’s front wheels after hitting a ramp or obstacle.
Kicker
A small ramp or obstacle used in RC car racing to launch the vehicle into the air.
Kingpin
The pivot pin in a steering mechanism that allows the wheels to turn; common term in trucks and buggies.
Kit
A kit is a vehicle which needs to be assembled. Kits include most of the necessary pieces to build a working RC, aside from the electronics. Electric kits usually require a speed control, motor, radio system, servo(s), battery, and a charger. Nitro kits will usually require fuel, a radio system, servo(s), and a glow-starter. Some nitro kits do not come with an engine. All kits require special tools such as hex drivers, phillips screwdriver, hobby knife, needle-nose pliers, curved scissors, and a Dremel or other cutting tool. Paint must be purchased separately according to the customer’s preference.
Knife Edge
A maneuver where a plane rotates 90 degrees from horizontal to vertical with the wings pointing up and down.
Knockdown
When a component or part of a model is damaged or dislodged during a crash or hard landing.
Kill switch
A safety switch that immediately cuts power to the motor or engine to prevent damage or accidents.
LCD
Abbreviation for “Liquid Crystal Display”. A small screen used to display information in high-end radios and chargers. Outside of the RC scene, LCDs are used in electronics such as clocks, watches, cellphones, computer screens, and microwaves.
LED
Abbreviation for “Light Emitting Diode”. Used in electronics such as ESCs and radios. Also used in household items such as computers, TV remotes, clocks, and video game systems. LEDs can last for more than 50,000 hours without burning out.
Landing
The act of safely bringing your aircraft back to the ground while still in one piece. Otherwise, it would be considered a crash. How an RC car makes contact with the ground or ramp on a jump.
Lateral Balance
When a plane weighs the same on both sides from its centerline with the wings attached. Incorrect lateral balance is caused by one side weighing more than the other and results in the heavier wing dipping down. This is similar to the steering trim on a land vehicle—you always have to fight it if you don’t fix it. To achieve lateral balance, weight may be added or removed from the wings.
Lathe
A small tabletop machine used to shave off about 100 micrometers (1/10th of a millimeter) of copper from an armature’s comm, depending on what the user specifies. A lathe consists of a motor that spins an armature and uses a carbide or diamond bit. This process makes the surface of the comm like new, as if it just came from the factory. Also see “comm”.
Lawn Darting
When a truck or buggy comes down from a jump nose-first and digs a hole into the dirt with its front bumper. This is also used to describe a plane crashing nose-first into the ground.
Leading Edge
The front curved part of any wing, propeller, stabilizer, or rotor blade.
Lexan
Similar to Plexiglas, this is the clear polycarbonate material used to produce RC car bodies. Pronounced lecks-ann but commonly mispronounced as lecks-on.
LHS
Abbreviation for “Local Hobby Shop”. This should be pretty self-explanatory now that you know what LHS stands for.
LHWS
Abbreviation for “Local Hardware Store”. Hardware stores often carry similar products to what we use every day in the hobby, but much cheaper.
Lid Skid
To flip your car or truck over on its roof and skid down the track or road.
Linkage
A thick gauge wire used to connect servo horns to the carburetor intake valve and brake pads. Linkages are often spring-loaded to return to a neutral setting.
LiPo
Abbreviation for “Lithium Polymer”. A rechargeable battery technology that has evolved from Lithium Ion. Lithium Polymer batteries do not require a steel can like AA and Sub-C batteries, so they can be manufactured in a flexible casing. However, this flexibility comes at a cost. Lithium Polymer batteries have a smaller charge-per-pound ratio than Lithium Ion batteries. The main improvements are that they can hold a greater charge-per-pound than NiMH batteries and don’t have the memory effect that Nickel Metal Hydride (NiMH) and Nickel Cadmium (NiCD) batteries do. If overcharged, the battery may explode into a large fireball.
Lithium Ion
Also called Li-Ion. A rechargeable battery technology that is similar to Lithium Polymer. Lithium Ion batteries have a greater charge-per-pound ratio than Lithium Polymer batteries, but are not as flexible. Both Lithium Polymer and Lithium Ion batteries have a greater charge-per-pound ratio than Nickel Metal Hydride (NiMH) and Nickel Cadmium (NiCD) batteries.
Lithium Polymer
Also called Li-Poly or LiPo. A rechargeable battery technology that has evolved from Lithium Ion. Lithium Polymer batteries do not require a steel can like AA and Sub-C batteries, so they can be manufactured in a flexible casing. However, this flexibility comes at a cost. Lithium Polymer batteries have a smaller charge-per-pound ratio than Lithium Ion batteries. The main improvements are that they can hold a greater charge-per-pound than NiMH batteries and don’t have the memory effect that Nickel Metal Hydride (NiMH) and Nickel Cadmium (NiCD) batteries do. If overcharged, the battery may explode into a large fireball.
Locknut
A self-locking hexagon nut with threads coated in nylon. The nylon creates a tight fit to prevent the nut from loosening. A non-locking hexagon nut requires thread lock to prevent it from loosening.
Loctite
A name-brand for thread lock. A compound used to temporarily or permanently glue a screw to a nut or its encasing, such as a molded chassis. Most commonly used for metal-on-metal contact such as an aluminum chassis. There are many different strengths and types of Loctite: heat-resistant, oil-resistant, permanent, removable, and more. For more information, visit loctite.com.
Loose
The effect of having the rear end of your car swinging around. This is a result of poor traction, which can be caused by old or insufficient tires, poor downforce, or incorrect shock settings.
mAH
Abbreviation for “MilliAmp-Hour”. A common measurement of how long a battery can supply power. A milliamp is one thousandth of an ampere. A 3300mAH battery cell is 3.3 ampere-hour, which will provide 3.3 amperes for 1 hour. A 650mAH battery cell will provide 0.6 amperes for 1 hour. Then multiply by the number of cells. A 6-cell 3300mAH battery pack will provide 19.8 amperes for 1 hour, or 3.3 amperes for 6 hours. Generally, the higher milliamp rating, the longer runtime you will receive.
Machine Screw
A screw with very thin threads that are narrowly spaced apart. A machine screw has a flat end, and does not make its own threads (unless the material is soft enough) or drill its own hole like a self-tapping screw. Often used in metal objects that have threads machined into the screw holes.
Manifold
A bent aluminum pipe connected between the engine’s exhaust port and muffler. Usually bent in a 90-degree angle, but can come in any shape or size. Also known as a “header”.
Marker (Track Marker)
An object used to mark the track, course boundaries, or obstacles for RC racing or practice.
Megahertz
Commonly expressed as MHz. A unit of frequency that is equal to one million hertz per second. Chances are this is the frequency your radio uses. Frequencies that are allowed for use of radio control vehicles are 75MHz, 72MHz, 50MHz, and 27MHz.
Metallic Brake Pads
Brake pads made from metal or metal composites for better heat resistance and braking performance, usually found in larger scale RC vehicles.
Mixing (Controls)
A setting on a transmitter that allows two or more channels to work together, such as aileron and rudder mixing for coordinated turns.
MOSFET
Abbreviation for “Metal-Oxide Semiconductor Field-Effect Transistor”. MOSFETs are often used in circuitry where high-speed switching is required.
Motor
The device that provides mechanical power to drive an RC vehicle or aircraft. Electric motors can be brushed or brushless; nitro engines use combustion.
Motor Limit
A guideline for the lowest number of turns a specific speed control can handle. The fewer turns a motor has, the faster it will spin while generating more heat. Some speed controls cannot handle high-voltage or high temperatures. For example, the Associated Quantum Competition 3 speed control can handle motors as low as 6 turns. Running a motor lower than 6 turns could ruin the speed control.
MPH
Abbreviation for “Miles Per Hour”. This is the ratio of distance traveled in miles to the time spent traveling in hours. This is used to express speed. A mile is equal to 1.6093 kilometers.
Muffler
A device that helps reduce the noise produced by a nitro engine. A muffler usually consists of several winding chambers and baffles that bounce the noise off the walls, which cancel each other out and reduce noise output. A muffler also creates pressure for the fuel tank to pump fuel into the carburetor. Also known as a “tuned pipe”.
Monocote
A heat-shrink covering used on model aircraft wings and fuselages to create a smooth, strong, and lightweight surface.
Negative
The electrical terminal or wire that carries the return current back to the battery or power source. Typically black or blue in color.
Nested
Refers to components or parts that fit neatly inside one another for storage, transport, or assembly. In RC, often used for nested frames or stacked electronics.
Neutral
The position of a servo, throttle, or other control when it is centered and not applying motion or power.
Nichrome
A type of high-resistance alloy commonly used in hot wire foam cutters and heating elements.
NiCad
Abbreviation for “Nickel Cadmium”. NiCad is a type of rechargeable battery that is similar to NiMH (Nickel Metal Hydride) batteries, but contains cadmium and mercury, which is expensive and dangerous to the environment. NiCad batteries experience the dreaded “memory effect” or “voltage depression” caused by incorrect charging and have a lower capacity than NiMH batteries.
NiMH
Abbreviation for “Nickel Metal Hydride”. NiMH is a type of rechargeable battery that is similar to NiCad (Nickel Cadmium) batteries, but does not contain cadmium or mercury, which is expensive and dangerous to the environment. NiMH batteries do not experience the “memory effect” or “voltage depression” caused by incorrect charging and have a higher capacity than NiCad’s.
Nickel Cadmium
See NiCad.
Nylon
A strong and durable plastic often used in radio controlled vehicles and equipment. Nylon is very flexible and can be dyed different colors with RIT dye. Nylon was developed in 1935 by Wallace Carothers, a chemist working for DuPont. The first nylon product was a toothbrush with nylon bristles. RPM RC Products, a manufacturer of high-quality aftermarket hop-ups, is known for their patented nylon blends used in their products.
Oil Shock
A shock absorber filled with oil to dampen suspension movement, providing smoother handling and better traction.
Overrun
When a motor continues to spin after the throttle is released, typically due to inertia or improper braking settings.
Overvoltage
A condition where a battery or electronic component receives more voltage than its rated limit, which can cause damage or failure.
Overcurrent
A condition where the current exceeds the safe operating range of an electronic component, often triggering fuses or ESC protection.
Panel
A flat section of a vehicle or aircraft, such as body panels on cars or access panels on planes.
Parasite
The person at your local track who always needs a glow-plug, battery, part, tool, fuel, etc., but never replaces it.
Pass (a Pass) as in Lap Time
The act of overtaking another vehicle or recording a completed lap in racing.
Peak
To fully charge a battery to the point that it no longer accepts a charge. A peak charger will automatically shut itself off when a battery has peaked.
Pickeled
Refers to metal parts that have been treated with a chemical process (like pickling) to remove oxidation or scale before use.
Pin Hole
A tiny hole, usually in a body shell or painted surface, often caused by air bubbles or imperfections during painting.
Pinion Gear
A small metal gear that is tightened down to a motor shaft with a set screw. This gear spins the spur gear, which in turn spins the rest of the drivetrain.
Pits
The area where you work on your cars. Tables, chairs, power, and shade (if outdoors) are usually supplied by the track. You can ask others for help and tips, or borrow tools. As a courtesy to drivers on the track, remember to never turn your radio on in the pits during a race.
Pneumatic
Relating to air pressure or air-driven systems. Often used in reference to tires or suspension systems that use compressed air.
Pole Position
The very front of the starting grid. This is often desirable because other cars must pass you to take the lead, but can also be undesired if racing with hackers or inexperienced drivers who may rear-end you or cause you to crash.
Polycarbonate
A family of thermoplastics characterized by high-impact strength, light weight, and flexibility. Bodies and wings are made of lexan, which is a member of the polycarbonate group.
Polycarbonate-Safe Paint
Paint formulated to adhere to and flex with lexan or other polycarbonate materials without cracking or peeling.
Power
The electrical energy supplied to a motor or electronic device, usually from a battery, to make the vehicle or aircraft move.
Pull Start
A cord used to start an engine. When pulled, it rotates the crankshaft which moves the piston and initiates the combustion process. This starts the engine.
Punch
Also known as “acceleration”. A quick progression of speed. This is also known as the “low end” of your engine or motor. Dropping your pinion gear a few teeth will give you more acceleration, but at the cost of torque. You can also increase the teeth on your spur gear, but the acceleration increase won’t be as noticeable unless you drastically change the size.
Punkd
Passing, lapping, or beating the big shot at your local track. Originated from the MTV television show called Punk’d which features Ashton Kutcher playing pranks on popular celebrities.
Parked
When a vehicle is broken and not active, not going to be fixed that day.
Partition
A divider or section within a pit area, carrying case, or body compartment, often used for organization or structural support.
Qualifier
Also known as “heat”. You race several qualifying rounds to determine the ranking for the mains.
Quick Charger
A charger that charges a battery for a specific amount of time, but stops after that time has elapsed even if the battery is not fully charged.
Quad
Short for quadcopter, an RC aircraft with four rotors.
Quick Connect
A type of connector that allows fast attachment or removal of batteries, motors, or other components without tools.
Quick Release
A mechanism that allows wheels, body shells, or other parts to be removed or installed rapidly.
Ramp Up
The process of gradually increasing throttle, power, or input to avoid sudden stress on the motor, ESC, or drivetrain.
Rally
A class of off-road RC cars which look like sedans with off-road tires. Rally cars often feature slightly extended shocks and protection for the drivetrain.
Ratchet
A mechanical device that allows rotation in one direction while preventing motion in the opposite direction, often used in tools or drivetrain components.
Razor Edge
A very sharp edge on a component, tool, or body part. Often used to describe cutting tools or aerodynamic surfaces.
RC
Abbreviation for “Radio Control”. Often confused with “Remote Control”, which is what a TV, VCR, and DVD player uses.
Reamer
A tool with a multi-flute tapered blade used to create perfect body post holes in lexan bodies. It can also be used to cut balsa wood and ABS plastics.
RF
Abbreviation for “Radio Frequency”.
Rich/Lean
The ratio of air to fuel that enters into your engine through the carburetor. If your engine is using too much fuel, it is considered “rich”. If your engine uses too much air, it is considered “lean”. Running your engine lean improves fuel efficiency but can cause overheating and engine damage.
Riding On Rails
A car or truck that is so correctly set up that it handles as if it were on a railed pathway similar to a train or trolley.
ROAR
Abbreviation for “Remotely Operated Auto Racers”. The official U.S./Canadian sanctioning body for racing radio-controlled vehicles. ROAR produces and maintains rules, organizes race teams, and oversees IFMAR World Championship participation.
Roll Out
The distance a car moves per revolution of the motor. Calculated using tire circumference divided by the gear ratio: Tire Height × 3.14 = Tire Circumference, then Tire Circumference ÷ Gear Ratio = Roll Out.
Rooster Tail
Fine debris or particles (such as sand, dirt, gravel, water, snow) projected in an arc by quickly accelerating. Common with 2WD buggies and boats.
RPM
Abbreviation for “Revolutions Per Minute”. The number of times an object (such as a motor armature) completes a full rotation in one minute.
Rivet
A permanent mechanical fastener used to join two pieces of material together, often found in chassis or body components.
Roller
A cylindrical component used to guide, reduce friction, or transfer motion in a mechanism.
RTR
Abbreviation for “Ready to Run”. Cars and trucks available pre-built and usually only require batteries and a charger to operate. Nitro models may also require fuel and a glow starter.
Run Away
If a receiver loses the signal from the radio, it may continue to send the last command. This can cause a car to move in a circle or continue at speed. Fail-safes prevent or reduce this risk by returning servos or speed control to neutral or braking.
Run In
The process of gradually breaking in a new engine or motor to ensure proper wear and longevity.
Rx
Abbreviation for “Receiver”.
Screamer
A nitro vehicle with a disconnected pipe (muffler). If an engine operates without the muffler, it results in the typical engine sound, but amplified several times to be very loud.
Schottky Diode
Pronounced “Shot-Key Die-Ohd.” A high-speed diode with a very low forward-voltage drop, offering minimal resistance to current flow in one direction.
Self-Tapping Screw
A screw that drills a hole and creates threads in the material it is penetrating.
Servo
A small electronic device that moves servo linkages. Used to steer front wheels, raise/lower airplane wings, shift gears, control nitro carburetors, or regulate speed of a mechanical speed control.
Setup Board
A flat board with precise markings used for fine-tuning touring cars. Helps adjust camber, toe in/out, ride height, droop, and linkages.
Shell
Also known as the “body.” Protects internal components and moving parts while providing a realistic appearance. RC shells feature aerodynamics, wings, and stickers.
Shoe Goo
A rubbery adhesive/sealant used for waterproofing electronics, gluing SxS cells, or repairing cracked lexan bodies. Very potent; use in a ventilated area.
Silicone
A flexible, heat-resistant material used for gaskets, O-rings, and shock components.
Silent Motor Check-In
When all cars in a race are manually checked in at the starting line instead of driving over it. Cars are turned off at this point.
Slipper Clutch
A device combined with the spur gear that allows controlled slipping to prevent wheel spin, improve traction, and reduce drivetrain stress.
Solder
A fusible alloy, typically tin and lead, melted to join two wires or a wire to a conductive surface.
Solder Posts
Small metal posts where wires can be soldered, used in speed controls, motors, and battery packs.
Soldering
The process of joining wires or wires to conductive metals by melting solder. Requires a soldering iron, typically 60W or higher.
Soldering Jig
A tool that holds battery cells and bars for easy soldering to create professional battery packs.
Squirt Gun
A poorly tuned engine which “squirts” fuel from the pipe due to running too rich.
Starting Grid
The lineup of cars at the start of a race, often marked by symbols on the track. Cars must remain in position until the race starts.
Steering Link
The arm connecting left and right front tie-rods to allow the servo to move both wheels. Also known as the Ackerman link.
Stock
The default or standard parts and accessories included with a vehicle. Opposite of a hop-up.
Stoppie
Similar to a wheelie, but involves lifting the rear wheels by a quick stop rather than raising the front.
Straightaway
The longest, straightest section of a track, often containing the start/finish line, lap counter, and starting grid.
Strap Tie
A strip of nylon with interlocking teeth, used to bundle wires. Also called a zip tie.
Suspension Arm
A part of the suspension system connecting shocks, bulkheads, and hub carriers. Also called an A-Arm.
Swapping
A racing term describing extreme oversteer down a straightaway, requiring repeated left/right corrections to prevent spinning.
SxS (Side by Side)
A battery pack configuration where cells are arranged side by side rather than in rows (shotgun) or sticks.
Synthesized Receiver
A receiver capable of operating on multiple frequencies, allowing dial selection to avoid interference with other racers.
Tail Boom
A long arm or pole extending from the main structure of a helicopter that holds the tail rotor.
Tail Dragger
An airplane with two front wheels and a single wheel in the back. Often seen with older-style aircraft.
Tail Rotor
Controls the yaw motion of a helicopter and counterbalances the torque created by the main rotor. Without a tail rotor, the helicopter would spin uncontrollably.
Tamiya Plug
A white connector used to link battery packs and speed controls. Often included with pre-built land vehicles; prone to melting and high resistance.
TDC (Top Dead Center)
A piston is considered at TDC when it is at the very top of its stroke.
Tap
A tool used to cut threads inside a hole.
Thread Lock
A compound used to temporarily or permanently secure screws to nuts or threaded inserts, preventing loosening. Commonly used for metal-on-metal contact, such as aluminum chassis.
Throttle
Controls engine or motor speed.
Throttle Return Spring
A spring on a carburetor linkage that returns the throttle to idle.
Timing
Adjustment of ignition or motor advance to optimize performance.
Tic-Toc Maneuver
A helicopter maneuver where the aircraft rocks side to side or back and forth, typically ±45°.
Tire Bead
The portion of a tire that sits on the wheel, often in a small channel where glue is applied.
Tire Inserts
Foam or rubber padding inside a tire to prevent flat spots and improve traction.
Tire Wall
The side portion of a tire. Taller walls increase hook-up during turns and absorb bumps better.
Top Qualifier (TQ)
The racer who achieves the most laps in the shortest time during qualifying rounds.
Torque
Rotational force applied by the motor or engine.
Torque Roll
A maneuver where a plane hovers vertically and rotates clockwise due to motor/engine torque and aileron control.
Torque Wrench
A wrench used to apply a precise torque to a fastener, ensuring proper tightness.
Trail Braking
Technique of braking while entering a turn to maintain control.
Traction Compound
A chemical applied to tires to enhance grip and traction on the track.
Traction Roll
When a car flips sideways due to excessive traction on a turn; countered by stiffer springs, thicker shock oil, or lowered ride height.
Transponder
A device mounted in a race vehicle that wirelessly transmits lap and position data to the timing system.
Tricycle Gear
An airplane landing gear configuration with one nose wheel and two rear wheels.
Third Member
The central part of a differential containing the gears that transfer power to the axles.
Tricycling
Driving on only three wheels due to a wheel coming off. Easy on flat surfaces but challenging on uneven terrain.
Trimming
Fine-tuning a radio’s trim knobs to adjust steering or throttle. Also refers to cutting lexan body edges for proper fit.
True
To true a tire means to shave uneven portions for a perfectly round and balanced tire. Also called truing.
Truggy
A mix between a monster truck and a stadium truck, with a low chassis and large tires.
Tread
The patterned surface of a tire affecting grip and handling.
Tuned Pipe
A multi-chambered exhaust that reduces nitro engine noise and creates fuel pressure for carburetor feed; also called a muffler.
Turn Marshal
A track official positioned at turns to assist flipped or stuck vehicles and maintain race flow.
Turnbuckle
An adjustable link with threads on both ends, used in steering (toe adjustments) or suspension (camber adjustments).
Turns (T)
Refers to motor winding count. Fewer turns = faster motor; more turns = slower motor.
Turtle
A car or truck flipped on its roof, awaiting assistance from a turn marshal.
TVP (Twin Vertical Plates)
Refers to a chassis design, commonly seen in HPI Savage vehicles.
Two Gallon Expert
A novice nitro/fuel vehicle driver who acts overly confident.
Two Speed
A transmission with two gear ratios, often allowing selection between speed and torque modes.
Tx (Transmitter)
The radio controller that sends signals to a receiver in the vehicle.
Turnigy
A popular RC electronics brand.
Undercarriage
The landing gear or supporting structure of an airplane or RC car chassis.
Understeer
When a vehicle turns less sharply than intended due to front tires losing traction. Opposite of oversteer.
Unilateral Steering
A steering setup where only one side of the front wheels is independently controlled or adjusted. Rare, but sometimes used in experimental vehicles or modified RC setups.
Upper Wing
On biplanes or triplanes, the topmost wing of the aircraft. Provides lift and affects stability.
Upthrust
The upward force experienced by boats or planes; in RC aircraft, excessive upthrust on motors can tilt the aircraft nose up.
Uprights
The vertical parts of the suspension that hold the wheel hubs and connect to the arms.
Unibody
A chassis design where the body and frame are integrated into a single structure.
Universal Joint (U-Joint)
A flexible joint connecting drive shafts to allow torque transfer at angles.
U-turn
A complete 180-degree turn of a car or truck, often used to describe maneuvers on a track.
Ultralight
A very small, lightweight RC airplane designed for slow, stable flight.
Unloading
Releasing tension on a suspension, motor, or drivetrain component to reduce stress or wear.
V-tail
A tail configuration with two surfaces in a “V” shape replacing the traditional horizontal and vertical stabilizers.
Vapor Lock
When fuel in the carburetor boils due to excessive heat, forming vapor that prevents proper fuel flow to the engine.
Variable Propeller
A propeller with adjustable blade angles, allowing control over thrust and efficiency.
Variable Pitch Rotor
A helicopter rotor system that allows changing the blade pitch to control lift, thrust, and maneuverability.
Vectored Thrust
The ability to direct engine or propeller thrust in a direction other than straight back, used for enhanced maneuverability or vertical flight.
Vertical Fin
See Vertical Stabilizer.
Vertical Stabilizer
The non-moving portion of the tail boom which provides stability to the yaw axis. Also known as the vertical fin.
V-Belt
A type of belt with a V-shaped cross-section used in belt-driven drivetrains.
Velcro Straps
Fastening straps used to secure batteries, receivers, or components inside vehicles.
Vibration Damper
A device or material used to reduce unwanted vibrations in motors, engines, or airframes.
Vibration Dampening
Materials or techniques used to reduce vibration transmitted to electronics, servos, or chassis for improved performance and component longevity.
Velocity
The speed and direction of a moving object. Often referenced for projectiles or RC aircraft.
Venturi
A narrowed section of a carburetor or intake that increases air velocity and improves fuel atomization.
Voltage
The electrical potential difference between two points. In RC vehicles, voltage is commonly measured across battery packs and is critical for performance and runtime.
Voltage Drop
A reduction in voltage along a circuit due to resistance in wires, connectors, or components. Excessive voltage drop can reduce motor performance.
Voltage Regulator
A device that maintains a constant voltage to electronics or motors despite changes in load or battery voltage.
Vortex
A swirling flow of air created by wings, propellers, or rotor blades; affects lift and stability.
Wet Start
When fuel has pooled or flooded a turbine engine during startup, flames may shoot from the rear of the engine or exhaust.
Wheel Offset
Any additional horizontal distance from the center of the wheel. A positive 6mm offset moves the wheel 6mm farther from the vehicle’s centerline, increasing overall width. Some
manufacturers offer wheel offset spacers for fine adjustments.
Wheel Spin
When a differential unloads all the power from the motor or engine onto a single wheel. Common during sharp turns on off-road vehicles with soft suspension, causing one tire to lift off
the ground. Locked or spool differentials prevent wheel spin.
Wheelbase
The distance between the front and rear axles. Longer wheelbase improves stability; shorter wheelbase allows sharper turns and faster acceleration.
Wind Sock
A tube-like flag used to indicate wind speed and direction. Named for its resemblance to an open-ended sock.
Wing Root
The innermost portion of an airplane wing where it attaches to the fuselage.
Wishbone
Synonymous with a suspension arm. Named for its resemblance to a turkey or chicken wishbone.
Wonder Woman
A car or truck with a completely clear body, similar to Wonder Woman’s invisible jet.
WOT (Wide Open Throttle)
A term describing a car or truck running at full throttle, as fast as it can go.
Winding
The coiled wire inside a motor or generator that produces magnetic fields to generate motion.
Wing
A lifting surface on an airplane, helicopter, or drone that generates lift. Can also refer to body panels on RC cars shaped to improve aerodynamics.
Washer
A small, flat ring used to distribute the load of a screw, bolt, or nut, often placed under a fastener head.
Washout
The slight twist of an airplane wing from root to tip to improve stability and prevent tip stalls.
Wrapper
The outer covering of a battery pack or wire bundle, often for insulation and protection.
Wringer
A device or tool used to squeeze or remove excess material, e.g., liquid from a sponge or oil from a component. Rarely used in RC-specific context.
Wiper
A component that clears debris or fuel from a surface, such as the wiper on a nitro engine carburetor needle.
Wafer
Thin components or shims used to adjust spacing, commonly in transmissions or suspension setups.
Wrenching
Slang for working on or tuning vehicles, often in a pit or garage.
Washed (Flooded Motor)
A motor that is soaked in fuel or oil, often leading to poor performance or difficulty starting.
Walking
When a car moves slowly forward due to minimal throttle input or engine idle, often during setup or check-ins.
X-Acto Knife
A small knife blade with a pencil-like handle used for cutting in detail. Often used for cutting stickers, wires, servo tape, and other thin objects.
X-Tal
A small microchip with a specific frequency to be used in radio systems. X-tals (also known as crystals) are interchangeable and are easy to remember. For example, a channel 73 crystal is
75.650 MHz. Obviously remembering “channel 73” is much easier.
X-Acto Knife
A small knife blade with a pencil-like handle used for cutting in detail. Often used for cutting stickers, wires, servo tape, and other thin objects.
X-Tal
A small microchip with a specific frequency to be used in radio systems. X-tals (also known as crystals) are interchangeable and are easy to remember. For example, a channel 73 crystal is 75.650 MHz.
X-Brace
A structural support shaped like an “X” used to stiffen frames, chassis, or wings.
X-Cut
A cutting technique or type of blade used to make cross or angled cuts, often in balsa wood, foam, or lexan.
X-Axis
The horizontal axis in a coordinate system, often referenced in quadcopters, planes, or CNC setups to describe movement or orientation.
X-Mount
A mounting plate or bracket shaped like an “X” used to attach motors, servos, or other components securely.
X-Frame
A frame design, commonly seen in quadcopters, where the arms form an “X” shape when viewed from above.
Y-Harness
A plug that uses one channel on your transmitter, and sends the signal to two devices such as servos. This can also be two male/female battery plugs combining into 1 battery plug. For
example, two batteries used on 1 speed control.
Yard Sale
When your vehicle is involved in a bad crash resulting in parts being spread all over the ground.
Yaw
The rotation of an airplane around it’s centerpoint, as if a long pin was stuck in the middle.
Y-Harness
A plug that uses one channel on your transmitter and sends the signal to two devices such as servos. This can also refer to two male/female battery plugs combining into one battery
plug. For example, two batteries used on one speed control.
Yard Sale
When your vehicle is involved in a bad crash, causing parts to be scattered all over the ground.
Yaw
The rotation of an airplane or helicopter around its vertical axis, as if a pin were stuck in the middle. Controls the left and right turning motion.
Yoke
The control device on an airplane or helicopter used to operate the ailerons and elevator.
Yaw Rate
The speed at which an aircraft rotates around its yaw axis.
Yaw Control
Mechanisms or adjustments that manage an aircraft’s yaw movement, such as rudder input or tail rotor adjustment.
Z-Bend
A type of wire or linkage bent in a “Z” shape used in throttle linkages, steering linkages, or other RC control rods to provide adjustment or clearance.
Zero Turn
A maneuver or capability of RC vehicles, where the vehicle can rotate in place with minimal turning radius.
Zig-Zag Track
A section of a racing track or course that alternates left and right turns in quick succession, designed to test handling and driver skill.
Zinc Plating
A corrosion-resistant coating applied to metal parts such as screws, nuts, or chassis components to prevent rust.
Zoom Launch
A technique or feature where an RC plane, helicopter, or drone is launched with maximum initial speed or thrust to quickly gain altitude or distance. Often used in gliders, fixed-wing aircraft, or racing drones.
Zipper Clip
Another term sometimes used for body clips or pins that secure a lexan body or shell to the chassis.