A 2.4GHz “spread spectrum” radio band used for modern R/C systems. It operates at higher frequencies than most sources of interference and is more resistant to noise than older 27/72MHz systems. Related technologies include FHSS and DMSS.

A transmitter feature that lets you preset how far a servo can move from center in each direction. Used to fine-tune control sensitivity and prevent over-driving linkages.

A circuit (built into many ESCs) that powers the receiver and servos from the main drive battery. This “eliminates” the need for a separate receiver battery pack.

A radio feature that allows you to connect the transmitter directly to the receiver by cable so you can test servo operation on the bench without transmitting a radio signal.

A 2.4GHz radio system type that locks onto one (or two) “clean” frequencies and transmits on them. Like FHSS systems, DMSS is designed to resist interference and electrical noise.

A 2.4GHz radio system that constantly jumps between different available frequencies. Because it doesn’t stay on any single frequency very long, it is highly resistant to interference.

A precise voltmeter designed to check receiver and transmitter battery packs. Often plugs into the charge jack so you can check voltage between flights without removing the wing.

A fast charger that runs from a 12-volt source (car battery or field battery). Used to recharge flight packs and transmitter packs at the flying field.

The system of managing which radio channel you use so you don’t interfere with others. Traditionally used on the 72MHz band, which is divided into many channels. Pilots at a field coordinate which channel each person is on to avoid “hits.”

A removable module that plugs into some transmitters to change the operating channel or band. Common on older 72MHz radios so you could swap crystals or modules instead of buying a new radio.

A brief radio problem or momentary loss of control. Often shows up “only over those trees” or “only over the swamp.” With modern 2.4GHz systems, glitches are rarer but still possible from interference or bad installations.

A sudden burst of radio interference that makes your model behave unpredictably. Often caused by someone turning on a transmitter on your channel or by distant strong radio sources.

Refers to how the sticks are assigned on the transmitter. Mode 2 (common in the Americas) has elevator/aileron on the right stick and throttle/rudder on the left. Mode 1 swaps throttle and elevator between sticks. Europe and Asia often use Mode 1.

A transmitter feature that electronically links two control channels so they move together. Common uses include aileron-rudder mixing for large models or the special “V-tail” mixes for ruddervators.

Higher-end radios with digital menus and model memory. They offer features like dual rates, exponential, mixing, multiple model setups, flight modes, and more advanced programming.

The onboard radio unit that receives signals from your transmitter and sends commands to the servos and ESC. It is powered by the receiver battery or BEC.

A small electro-mechanical device that converts the receiver’s commands into movement of control surfaces (elevator, ailerons, rudder) or throttles and other functions.

The plastic arm or wheel attached to the servo’s output shaft. Pushrods or linkages connect here to move control surfaces.

A transmitter function that reverses a servo’s direction electronically. Lets you install servos in the most convenient orientation and then correct direction with a switch.

The hand-held radio controller you use to send commands to the model. Contains gimbals (sticks), switches, programming, batteries, and the RF module/antenna.

A wiring harness shaped like the letter “Y” that allows two servos to plug into a single receiver channel. Common for dual aileron or flap servos on the same channel.

Two compatible transmitters linked with a trainer cord (or wirelessly) so an instructor can take control at any time. The student flies until the instructor presses the trainer switch.

The setup that uses a buddy box (two transmitters connected) so a student can learn to fly under supervision. The instructor can instantly override if the student gets into trouble.

Refers to glow engine construction using Aluminum, Brass, and Chrome (or nickel-composite). These engines have an aluminum piston running in a chrome- or composite-plated brass sleeve with no piston ring. They rely on a very tight fit for sealing and must be broken in carefully.

All the radio gear carried in the model: receiver, servos, receiver battery (or BEC), and switch harness. Often also used to refer specifically to the receiver battery pack.

The engine component that controls fuel/air mixture and throttle. The main needle valve sets mixture; a barrel or slide controls how much air‐fuel mixture goes into the engine.

A hand-held 12-volt motor used to spin the prop and start a glow engine. Safer and easier than flipping by hand.

An electronic unit that controls motor speed in electric R/C models. It replaces mechanical speed controls, provides more precise throttle, and often includes a BEC to power the receiver.

A glow engine type that completes a power cycle in four strokes. Compared to two-strokes, they are quieter, more fuel-efficient, and can swing larger props, making them popular for scale and slow-flying models.

The line from the top of the fuel tank that vents the tank to the atmosphere or to the muffler pressure nipple. Fuel flows out this line when the tank is full during fueling.

The fuel line that carries fuel from inside the tank to the carburetor. It typically has a flexible tube with a weighted “clunk” at the end so it stays in the fuel in different attitudes.

The small plug that provides the heat source to ignite the fuel/air mixture in a glow engine. A battery heats the filament for starting; once running, the filament stays hot from combustion.

A 1.2-volt battery with a clip that attaches to the glow plug for starting the engine. Removed once the engine is running steadily.

A glow plug with a small metal bar across the tip. The bar helps shield the element from droplets of raw fuel so the plug stays hot at low idle.

The adjustable needle on the carburetor used to set the fuel/air mixture. Turning it clockwise (in) usually leans the mixture (less fuel); turning it out richens it (more fuel). Some carbs have separate high- and low-speed needles.

Short for nitromethane, a fuel additive in glow fuel. It improves idle and high-speed power. Engines are designed for a certain nitro percentage; always follow the manufacturer’s recommendations.

Nickel-Cadmium rechargeable battery chemistry. Rugged and capable of high current but prone to “memory effect” if not properly cycled. Was common in older radios and receiver packs.

Nickel-Metal Hydride rechargeable battery. Offers higher capacity than NiCd and is more environmentally friendly. Common for receiver and car packs.

A self-contained NiCd-powered unit with a built-in glow plug clip used to power the glow plug during engine starting.

Lithium-Ion battery. Lighter and with a lower self-discharge rate than NiCd or NiMH. Less common than LiPo in R/C but still used in some radio gear and packs.

Lithium-Polymer rechargeable battery. Very light and capable of high power delivery. Must be charged only with a LiPo-compatible balancing charger and handled with care.

A unit of battery capacity. Higher mAh means more energy stored and longer run time for a given load.

A charger that detects when a battery is fully charged and then shuts off or switches to trickle charge. Helps prevent overcharging and damage.

A 12-volt distribution panel mounted on a flight box. It provides controlled power to accessories like glow plug clips, fuel pumps, and electric starters.

The tendency of an airplane to yaw opposite the direction of a roll. Common in trainers with flat-bottom wings, especially at slow speeds. Reduced with differential aileron throw or by coordinating aileron and rudder.

Hinged control surfaces on the trailing edges of the wings. They control roll (banking left or right). For a right roll, the right aileron goes up and the left goes down.

The angle between the wing’s chord line and the relative airflow. Increasing angle of attack increases lift and drag up to the stall point.

The balance point of the model, usually measured along the wing. A nose-heavy model tracks better but lands faster; a tail-heavy model is more responsive but can be unstable and prone to stalls.

Ailerons set to move more up than down. This reduces adverse yaw by reducing drag on the down-going wing.

The upward V-angle of the wings when viewed from the front. More dihedral increases roll stability and allows rudder to also produce some roll, which is why some 3-channel trainers don’t need ailerons.

The engine is mounted slightly angled downward relative to the fuselage centerline. This helps counteract the model’s tendency to climb excessively when power is applied.

The hinged control surface on the horizontal stabilizer that controls pitch. Pulling back on the elevator stick raises the elevator and causes the nose to rise (climb).

Hinged surfaces on the trailing edge of the wing, usually inboard of the ailerons. Dropping flaps increases lift and drag, allowing slower takeoffs and landings.

The maneuver at the end of landing where you gently raise the nose to slow the descent and touch down smoothly on the main wheels.

A dangerous, high-speed oscillation of a control surface (elevator, aileron, rudder) caused by looseness or poor setup. Sounds like a buzz. If you hear it, throttle back and land immediately.

The main body of the airplane. It holds the wings, tail, engine, and radio equipment.

The fixed horizontal tail surface that provides pitch stability. The elevator is hinged to it.

The side-to-side balance of the airplane. A laterally balanced model tracks straighter and performs symmetrical loops better.

The front edge of a wing or stabilizer that first meets the oncoming air.

The axis running wingtip to wingtip. The elevator controls movement around this axis (nose up or nose down).

The axis running from nose to tail. The ailerons control rolling motion around this axis (one wing up, one wing down).

The hinged control surface on the vertical fin that controls yaw. Left rudder yaws the nose left; right rudder yaws it right.

A general-purpose R/C airplane used for everyday flying. Combines some aerobatic capability with durability and easy handling.

When the wing’s angle of attack becomes too great and airflow breaks down, causing a loss of lift. Every airfoil has a maximum angle before it stalls.

When the wing tip stops producing lift before the rest of the wing, causing the airplane to suddenly drop a wing and roll toward the stalled side. Common at low speed in turns.

A beginner-friendly airplane designed to be stable and fly well at low speeds, giving new pilots more time to react and learn.

The rear edge of a wing or tail surface, opposite the leading edge.

The fixed vertical tail surface that provides yaw stability. The rudder is hinged to it.

A twist built into the wing so the wing tips have a lower angle of attack than the wing root. Helps prevent tip stalls by keeping the tips flying longer.

The main lifting surface of an airplane. Its shape, area, and airfoil determine much of the model’s flying characteristics.

The weight of the airplane divided by the wing area (usually in ounces per square foot). Higher wing loading means the plane must fly faster; lower loading means slower, more efficient flight.

The inner end of the wing where the left and right panels meet near the fuselage.

The vertical axis around which the airplane turns left or right (yaw). Controlled by the rudder.

2WD vehicles send power to only two wheels (usually rear). They are simpler, cheaper, and easier to maintain. 4WD vehicles power all four wheels, giving better traction and handling, but with more parts and maintenance.

Cars or trucks that are mostly assembled at the factory. Some components—like radio, battery, or engine—may still need to be added by the customer.

Electric cars use rechargeable packs and are quiet, clean, and beginner-friendly. Gas/nitro cars use small two-stroke engines for more sound, speed, and realism but require more tuning and maintenance.

Large R/C trucks with oversized tires and big suspension travel. Built for rough terrain, crawling, and “car crushing,” focusing more on torque than speed.

R/C cars with full-travel suspension and knobby tires designed for off-road racing and bashing. Excellent for dirt tracks and park running.

Low-ground-clearance R/C cars designed for smooth, paved surfaces. Built for speed and realistic appearance.

R/C trucks inspired by full-size stadium racers. They have durable suspensions and big tires for “bump and jump” action but are also fast and agile.

The national body that standardizes and sanctions R/C car and truck racing in North America.

Indicates a ball-bearing supported crankshaft in an R/C engine. Ball bearings reduce friction, increase smoothness, and can improve engine life.

A fast-setting “super glue” used for building models. Available in thin, medium, thick, and gel. Excellent for wood construction, but most CA formulas will attack regular foam.

A padded stick used to flip the propeller and start an engine safely without risking fingers.

The weighted pickup at the end of the fuel line inside the tank. It stays submerged in fuel even when the aircraft’s attitude changes.

A small dent or damage to the airframe, or a nick in a propeller. Dinged props should be replaced for safety.

A two-part adhesive (resin and hardener) that cures to form a very strong bond. Available in various cure times (e.g., 6-minute, 30-minute). Used where high strength is needed.

A field toolbox used to carry fuel, starter, glow plug driver, tools, batteries, and other gear required for flying sessions.

A model (car, boat, plane, or heli) that requires assembly by the builder. Usually does not include the power system or radio gear, which must be purchased separately.

The second number in a prop size (e.g., 10×6). It represents how far the prop would move forward in one revolution in an ideal medium, measured in inches (a 10×6 prop “screws” 6" forward per revolution under ideal conditions).

A device used to measure engine RPM (revolutions per minute), often by counting light pulses through the spinning propeller.

A small metal ring with a set screw used to keep wheels or axles from sliding off shafts.

A Z-shaped bend in the end of a pushrod wire, used to connect it securely to a servo arm or control horn without additional hardware.

A special plier tool used to form consistent, accurate Z-bends in pushrod wire.

The national organization for model aviation in the United States. It provides safety guidelines, insurance, flying site support, and sanctions competitions.

The governing body for model aviation in Canada. It liaises with government agencies on frequency use, represents competition pilots internationally, and provides insurance and club support.

A prefabricated airplane kit that comes mostly built and covered. The builder typically adds the engine/motor, radio gear, and a few final assembly steps.

An airplane that includes everything needed to fly right out of the box—airplane, radio, power system, and hardware—with only minor assembly required.

A car or truck that comes fully assembled at the factory, often including radio system and power system. Minimal setup is needed before driving.

Informal flying without any particular pattern or maneuvers—just cruising around and having fun.

Flying with the engine off, usually because it quit unexpectedly. The pilot must glide the model in for a landing with no power.

A very smooth, gentle landing with no bounce. The airplane “greases” onto the runway.

A crash, usually nose-first, that turns your model back into a pile of parts. Also called “re-kitting your airplane.”

Humorous phrase for crashing so thoroughly that your finished plane is once again a “kit” of loose parts.

A crash caused by radio interference or a “hit” from another transmitter, rather than pilot error or mechanical failure.

Excess loose movement in the control system—often from oversized holes in servo arms or horns. Slop makes controls feel vague and can lead to flutter.

Your first unassisted flight that ends in a controlled landing. A big milestone in learning to fly R/C.

Landing and then immediately taking off again without stopping. Used to practice approaches and landings.