The ultimate RC flying Glossary is here!
This RC flying glossary contains some of the more common words and terms that you'll hear now and again when you're reading about rc airplanes, or you're down at the flying field.
We've kept it as non-technical and lighthearted as possible, and where appropriate there are links to relevant pages within this website where you can get more detailed information.
Use these letter links if you're looking for a particular word:
A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z
- 2.4GHz - the frequency band of the newest, interference-free 'spread spectrum' digital rc systems. More details here.
- 2 stroke - the most common type of glow plug engine for rc airplanes. The fuel/air mixture is drawn in, ignited and spat out with one single revolution of the piston inside the engine. More details here.
- 4 stroke - the 2nd most common type of glow plug engine, much more suitable for larger and scale models, because they sound more realistic. 4 stroke engines take 2 revolutions to do what a 2 stroke does in one, but this doesn't make them twice as lazy. More details here.
- 3D - a complex form of aerobatic flying, usually with more than one maneuver being performed simultaneously. 3D airplanes have over-sized control surfaces, exaggerated control surface deflection and excess power for maximum performance and sensitivity.
- Aerobatic - any maneuver or series of maneuvers that involve stunts of any kind, such as loops, rolls and spins. An airplane that is capable of performing such stunts is said to be "fully aerobatic".
- Aeromodeling - the general term used to describe the hobby of building and flying model airplanes and aircraft. Aeromodelers are the guys and gals that do it.
- Ailerons - the moving section of the trailing edge of the wing, located towards the outer end. Ailerons come in pairs, (left and right) and always work in opposite directions to each other (one up, one down). When used, they cause the airplane to roll to the left or right. More details here.
- Airfoil - the cross-section shape of a wing. Airfoils can be flat-bottomed, semi-symmetrical or symmetrical, depending on the style of airplane and what it needs to do. Also written as aerofoil, depending on which country you are in.
- Altitude - the vertical distance between your rc airplane and the ground, usually expressed in feet (').
- Angle of Attack - the angle of the wing (when viewed from the end) in relation to the horizontal airflow when the airplane is flying. Nothing to do with your incoming trajectory when trying to cut the tail off your friend's model in aerial combat games.
- ARC - Almost Ready to Crash. An rc airplane or helicopter that knows something that the pilot is just about to find out.
- ARF - Almost Ready To Fly. This one's a legitimate abbreviation. An ARF model airplane needs a few small finishing touches and you have to install the engine and radio gear yourself. They vary in degrees of completeness, from manufacturer to manufacturer. More details here.
- Attitude - not the obvious meaning, but in the flying world 'attitude' refers to the angle of the plane in relation to the horizontal eg "My plane had a very nose-down attitude, from which it would not recover..."
Well, in this case you could say that your plane had a 'very bad attitude'!
- Barrel roll - an aerobatic maneuver that involves the airplane following the twist of a large imaginary corkscrew (horizontal) through the air.
- Brushless motor - type of electric motor used in rc electric aircraft. Brushless motors are much more powerful than traditional brushed motors, and are commonly used in electric aerobatic aircraft. They can be inrunner or outrunner motors. More details here.
- Buddy Box - one of the best training aids, where the student's transmitter is attached via cable to the instructor's. The student has complete control over the model, but at the flick of a switch the instructor can take control if the student gets into difficulties. Or just to be mean, funny or annoying.
- Bulkhead - the foremost former of your airplane, on to which the engine is mounted.
- Bungee launch - a method of launching rc gliders. More details here.
- Center of Gravity / CG - the airplane's point of balance. As a general rule of thumb, it's found approximately 1/3 of the way back from the leading edge of the wing. More details here.
- Channel - 2 meanings for this in the rc world. First, it can be the number of channels that the model has, eg a 1 channel model may have just motor or rudder control while a 2 channel model will have motor and rudder, etc etc. Second, the channel number refers to the radio frequency which you're using. More details here.
- Chicken stick - a tough rubber sleeve that you put on your finger if starting the motor by hand to give essential protection from the propeller. It can also be a wooden/plastic stick with a rubber coating on one half that you use to flick over the prop, instead of using your finger.
- Control surface(s) - a collective term for the rudder, elevator and ailerons of an airplane. More details here.
- Control surface mixing - when two control surface operations are performed by one pair of surfaces eg when aileron and elevator movement is combined into elevons. More details here.
- Channel mixing - when two or more channels are made to operate together with one stick movement eg rudder can be mixed with aileron, so that the rudder automatically deflects when the ailerons are moved. More details here.
- Crosswind - when the wind is blowing at, or approximately, 90 degrees to your line of flight, take off or landing.
- Crystal - the small component that determines which channel number you fly on. Both tx and rx need to have an identically matching crystal for the radio set to function. 2.4GHz spread spectrum sets don't require crystals.
- Dead stick - when your airplane's motor cuts out unexpectedly in mid-air. With any luck you'll have enough altitude to glide safely in for a nice landing, otherwise you may need to use your plastic bag.
- Dihedral - the upward angle of the wings when viewed from the front. An airplane with dihedral is more stable in the air than one without.
- Disorientation - when you lose sight of which way up your rc airplane is and what it's doing, either because it's too far away to see properly or because you've just flown it directly over your head and momentarily lost all visual reference to everything.
- Drag - the force that is created by the movement of the airplane through the air, on the air immediately surrounding the plane. High drag means that the model has to work harder to cut through the air. Low drag, oddly enough, means the opposite.
A real drag is the term used to describe your flying day when it's not going to plan. - DSM / DSM2 - a type of technology developed by Spektrum for their spread spectrum 2.4GHz rc systems. Stands for Digital Spectrum Modulation, the '2' just being the newer updated version.
- Dual rates - a feature of many rc systems, whereby the control surface deflection can be reduced while still maintaining full movement of the transmitter sticks. With dual rates enabled, the airplane is less sensitive to control inputs.
- Electric starter - a glorified 12 volt electric motor with a special end cup that you place over the spinner to turn the motor over until it starts, hopefully. You can see one here.
- Elevator - the moving section at the rear of the horizontal stabilizer, or tailplane, that controls the pitch attitude of the airplane.
- Elevons - when elevator and aileron control is made by the same control surface, this surface is called an elevon(s). Only possible with a mixing facility on the rc set.
- ESC - Electronic Speed Control - the small unit that delivers the appropriate amount of power from the motor battery pack to the motor, depending on your input at the transmitter.
- FASST - Futaba's answer to Spektrum's DSM technology. Stands for Futaba Advanced Spread Spectrum Technology and uses warp-speed frequency hopping to ensure no breakdown of signal.
- Field box - a box that you take to the field. It contains all your flying accessories and tools, except the one thing that you need on the day when no-one else is at the field. You can see one here. Also often called a flight box, particularly when it gets kicked through the air just after you've written off your model.
- Field equipment - accessories and equipment that you take to the field in your field box. Apart from that one crucial thing... More details here.
- Fin - also called the vertical stabilizer, it's the vertical surface at the rear of the airplane used to stabilize the plane in flight.
- Flaps - moving sections of the trailing edge of the wing, usually found between the ailerons and fuselage. Used to create more lift at slower flying speeds, flaps are usually only found on rc airplanes with 5 or more channels.
- Flaperons - a single control surface on the trailing edge of each wing that does the job of flaps and ailerons. An rc system with control mixing capability is needed to have flaperons.
- Flare - the action taken a few feet above the ground when landing, to reduce the approach angle and slow the rate of descent. Forgetting this crucial action may result in you needing your plastic bag.
- Frequency - all radio control gear works on frequencies. Best explained here.
- Fuel lock - when your glow engine gets flooded and the excess fuel inside the engine prevents you from being able to flick over the prop. It usually happens if you've over-primed the engine, and if you're starting the engine by hand you really know about it.
- Fuselage - the main body of an airplane, excluding wings, tail and everything else. Flying wings, oddly enough, don't have much in the way of a fuselage.
- Glow plug - sits in the top of the engine's cylinder head and contains an electrical filament that glows red hot to ignite the fuel/air mixture in the combustion chamber. Glow plugs have an uncanny habit of burning out on the one day that you've run out of spare ones, and no-one else is at the flying field. More details here.
- Glow plug igniter / starter - used to ignite the glow plug. Obviously.
- Gravity - the force that every rc airplane is trying to beat. RC pilots are often caught out when gravity decides to have some fun and suddenly increases its strength without warning. This common phenomenon is also known as pilot error or radio failure.
- Hand launch - the way to launch any flying model without an undercarriage. The model must be held level at head-height and launched into wind. A hefty shove is needed, but don't throw the model like a ball.
- Horizontal stabilizer - also called the tailplane. The horizontal surface at the back of the fuselage, to which the elevators are attached.
- Inrunner - a type of brushless motor where only the motor shaft rotates within the motor casing, as in a normal brushed motor. Inrunners don't provide a lot of torque so usually need to be geared.
- Landing - the action of bringing your model safely back down to earth, hopefully keeping it in one piece. A good landing negates the use of the plastic bag.
- Landing gear - also called the undercarriage. Refers to all wheels and associated bits. Landing gear can be fixed or retractable up into the underside of the wing or fuselage (called 'retracts', usually only found on models with 5 channels or more).
- Leading edge - the front edge of the wing, tailplane or rudder.
- Lift - the force created by the forward motion of the airplane's wing or helicopter's rotor blades. Air pressure over the wing is less than the pressure below the wing and so the wing, along with the rest of the model, is pushed upwards.
- Li-Po - stands for lithium ion polymer battery. These are the most modern kind of battery pack being used in electric aircraft. They provide enormous amounts of power for their size, especially when used in conjunction with a brushless motor.
- Loop - an aerobatic maneuver whereby the airplane flies a vertical circle in the air. The easiest stunt of all to pull off, and any airplane with an elevator can do them. Just make sure you're not flying too close to the ground first... More details here.
- Mid-air - term used to describe the unfortunate incident of two or more aircraft making physical contact with each other while in flight. A mid-air collision can be very spectacular given the correct speeds and trajectories of each model, and all models involved in such a crowd-pleasing incident always end up going home in the plastic bag.
- Mixing - the ability to combine two different rc functions into one. See control surface mixing and channel mixing above.
- Mode 1 - refers to the set-up of the transmitter whereby the left stick operates the elevator and rudder, and the right stick operates the throttle and ailerons. Common in the UK. More details here.
- Mode 2 - refers to the set-up of the transmitter whereby the left stick operates the throttle and rudder, and the right stick operates the elevator and ailerons. Common in North America and much of the world. More details here.
- NiCD - abbreviation for nickel cadmium, also written as 'nicads'. They are a form of rechargeable battery cells used in radio control gear as well as motor battery packs. NiCDs are being used less and less these days, as NiMH and Li-Po batteries take over.
- NiMH - abbreviation for nickel metal hydride batteries, they are the successors to NiCDs with much better performance and up to 3 times the capacity for an equally sized battery. Only Li-Pos top NiMHs.
- Nitro - short for nitro methane, or nitromethane, depending on who you believe. It's a principle ingredient of glow fuel and is crucial in keeping the fuel/air mixture burning inside the oxygen-starved combustion chamber of the engine.
- Non-scale - any model that is not modeled from a real-life airplane, helicopter or whatever.
- Outrunner - the other type of brushless motor, where the outer shell, or 'can', of the motor rotates with the shaft. The extra inertia produces more torque, so outrunners are more powerful than inrunners and rarely are geared.
- "Oh nooo" - hearing this term from an rc pilot usually indicates that his/her airplane isn't doing what he/she wants it to do. 'Oh nooo' soon changes into mixed swear words if the airplane's situation deteriorates.
- Park Flyer - the general name given to any electric rc airplane that can be safely flown in a public park / school yard / parking lot / sports field etc.
- Peg board - the most common form of frequency control used at rc flying clubs. Pilots must notify other pilots of which channel they are using by pushing a peg into a hole. Very high-tech. More details here
- Pilot error - any mistake, particularly one that ends in a crash, made by the pilot for whatever reasons. Pilot error is never admitted to by the pilot in question. Instead, the incident is traditionally put down to radio failure, radio interference, unexplained gusts of wind, extra fast-growing trees, the strange phenomenon of the ground suddenly lifting upwards and getting in the way without warning, or gravity having some fun and suddenly increasing its strength.
- Pitch attitude - the upward or downward angle of the airplane in relation to the horizontal, when viewed from the side. Pitch is controlled by the elevators.
- Pitch - the angle of a wing, propeller blade or helicopter rotor in relation to the airflow over it. The pitch angle of a moving wing or blade is known as the Angle of Attack.
- Plastic bag - the thing used to take home the pieces that was once your beloved model aircraft, before you failed to keep it airborne at the wrong moment, or didn't manage to pull off the best of landings, or tried to perform an aerobatic maneuver too close to the ground...
RC pilots who have used plastic bags can be laughed at here. - Plug n' Play (PNP) - Ready To Fly models that are missing the transmitter and receiver, allowing the pilot to use his/her own. More details here.
- Power panel - a small central control box for all your electrical field equipment items, typically powered by a 12V battery. You can see one here.
- Pre-flight checks - essential checks that you need to carry out immediately before flight. More details here.
- Priming - the action of introducing fuel in to the engine prior to starting it. Over-priming often causes fuel lock.
- Propeller - the thing at the front of the airplane. It spins round very fast when the motor is running. Propellers have been known to eat the fingers of careless rc pilots who hand start their motor without the use of a chicken stick. Props will fly off at an alarming speed, if the securing nut hasn't been tightened properly.
- Prop - abbreviation for propeller.
- Radio failure - very occasionally this happens, but the uncontrollable actions of the model are usually down to pilot error, not that they'd ever admit to it.
- Radio interference - when two (or more) identical, or close, frequencies are being used at the same time the radio signals will mix together, so your model's receiver won't know which ones to respond to. Radio interference is also a good cover-up for pilot error. 2.4GHz rc systems pretty much eliminate radio interference altogether.
- Radio signals - the invisible messages that pass from transmitter to receiver, telling the model what to do. OK until someone turns on a transmitter of the same frequency...
- Range check - an essential pre-flight check to test the operation of your rc gear. More details here.
- RC or R/C - abbreviation for Radio Control. Often you'll see 'remote control', but 'radio control' is the technically correct term.
- RC Airplane World - the web's #1 website on how to get started in radio control flying, and you're in it right now!
- RC flight simulator - a home computer based training aid that lets you practice flying radio control from the safety and comfort of your house. Excellent for novice rc pilots, particularly those looking at flying rc helicopters. More details here.
- Receiver - part of the radio control gear that lives inside the model and picks up the radio signals sent out by the transmitter. More details here.
- Retracts - abbreviation for 'retractable undercarriage', which is an undercarriage that folds up into the airplane's wings or fuselage after take off. They work most of the time, but sometimes they decide not to re-appear just when you need them the most.
- Roll - the rotational movement of an airplane about its longitudinal axis. Also an aerobatic maneuver whereby the airplane is rolled about its longitudinal axis through 360 degrees, while trying to keep the thing in a straight line.
- RTC - Ready To Crash. RTC models are in the throws of making unplanned air to ground contact, and nothing can be done to prevent it. Usually a result of pilot error, but never admitted to.
- RTF - Ready To Fly. RTF models can be assembled in minutes, usually it's a case of just strapping on the wing. RTFs are very popular these days. More details here.
- Rudder - the moving section on the back half of the fin. Used to control the airplane's yaw.
- Rx - abbreviation for receiver.
- Scale - any model that has been modeled from a real aircraft, such as a Piper Cub or P-51 Mustang for example.
- Semi-scale - any model that is loosely based on a real aircraft, with maybe a few details left out or proportions changed.
- Servo - the part of the radio control gear that converts the radio signal into movement. More details here.
- Servo reverse - a feature on rc systems whereby the direction of the servo horn movement can be reversed, if the builder has been daft enough to install the servo the wrong way round.
- Slow Flyer - different name for Park Flyer. Or a model that is experiencing engine problems, or a very strong headwind.
- Spin - an aerobatic maneuver whereby the airplane is flown vertically down towards the ground, while being made to roll. Easy to get into one but not always so easy to get out of, especially when the airplane-to-ground distance has been badly judged. In this instance, you will need to use the plastic bag.
- Spinner - the plastic cone-shaped piece that covers the center of the propeller. Planes without spinners never quite look complete...
- Sport airplanes - a general term for model airplanes that can be used for training on but are also capable of aerobatic maneuvers, whether intentional or not.
- Spread spectrum - the latest technology for radio control systems. Based on the 2.4GHz frequency band, spread spectrum radio systems are virtually interference-proof. More details here.
- Stall - any flying model will stall when the flying speed gets too low and the necessary amount of lift needed to hold the model in the air is lost. Getting to know your model's stalling speed by reducing throttle and applying up elevator at the same time is a very good idea, but don't practice too close to the ground if you want to avoid using the plastic bag.
- Stall turn - an aerobatic maneuver whereby the airplane is put into a vertical climb, power is reduced and full rudder is applied. The airplane should stop in mid-air and turn through 180 degrees, thus facing the ground, in the direction that the rudder was applied. And don't forget to pull out of the ensuing dive. More details here.
- Straight and level - when your rc airplane is flying in a straight line, with no fluctuation in altitude. A well trimmed airplane should fly straight and level with the tx sticks in their central positions.
- Take off - the action of accelerating your airplane along the ground until flying speed is reached, and the thing gets airborne. Only suitable for models with an undercarriage, otherwise you're limited to hand launching.
- Taildragger - an airplane that has 2 main wheels and a small tailwheel. Taildraggers have a habit of going round in circles on the ground when you're learning how to take off.
- Tailplane - see horizontal stabilizer.
- Tail wind - when the wind is blowing in the same direction as your plane is flying, taking off or landing. Flying with a tail wind not only increases the plane's airspeed, but also its stalling speed, and that's never good.
- Thrust - the force that is generated by the spinning propeller or fan/turbine of the airplane, and pushes/pulls the model through the air.
- Trailing edge - the rear edge of the wing, tailplane or rudder.
- Trainer - any rc airplane that has been designed for learning to fly on. Usually trainers are high wing, with plenty of dihedral. More details here.
- Transmitter - the main part of the radio control system that you hold in your hands while trying to control your model airplane. More details here.
- Trimming - the action of getting your model to fly straight and level, with the transmitter sticks in their neutral positions and no input from you. More details here.
- Tricycle undercarriage - a fixed undercarriage that consists of 2 main wheels and a nose wheel, which is sometimes connected to the rudder servo for easier ground handling. Often abbreviated to 'trike'.
- Tx - abbreviation for transmitter.
- Vertical stabilizer - see fin.
- Windsock - a large material cone-shaped tube, mounted on a tall pole at the flying field, that indicates the direction of the wind. Important because rc airplanes need to be taken off and landed into wind where possible.
- Wing - come on, seriously??
- Wing loading - a calculation that is useful when determining certain flight performance characteristics of a plane, the figure is obtained by dividing the flying weight of the airplane by the total wing area. A plane with large wings relative to its weight will have a lower wing loading, which means better lifting capacity but not so great high speed performance, and vice versa. Wing loading values are given in oz/sq.ft (ounces per square foot).
- Wingspan - the overall length of the wing, from tip to tip. Wingspan is the primary measurement when referring to an airplane's size, and it's usually stated in inches (").
- Yaw - the rotational movement of an aircraft about its vertical axis, controlled by the rudder.
Related pages
Ground School - a few lessons to learn before getting airborne.
Training methods - the main ways of learning how to fly rc aircraft.
RC flight simulators - the safest way to learn to fly.
Flying model airplanes - tips for flying 1 or 2 channel Park Flyer airplane.
RC airplane controls - the primary ones and what they do.
RC flying do's and don'ts - some basic safety tips.
RC flying FAQ - some common questions about getting in to rc flying.
