New to RC Flight? Lots of the language confusing? Well, check our remote control airplanes glossary. It isn’t complete, but hopefully, it’s useful.
AET – Abbreviation for Aileron Elevator Throttle (a 3 channel aircraft)
Alpha – see Angle of Attack
Ailerons – The hinged control surfaces attached to trailing edge of the wing which allow an aircraft to rotate around the length of the fuselage. (see Wikipedia for more).
Airfoil – The shape of the wing which causes it to generate lift. There are many different types of an airfoil (see symmetric and semi-symmetric below).
Amps – Unit for measure electrical current. See our primer on electrics to understand how amps, volts and power interrelate for electric flight.
Angle of Attack – the angle between the wing and the airstream moving over it.
AOA – see Angle of Attack
Attitude – Nose up Nose down (see Pitch).
AUW – All Up Weight – the total takeoff weight of an aircraft including batteries/fuel/cargo/everything that leaves the ground.
Base – the second part of a three-leg landing approach where the model flies across the wind and finalizes the position from which it turns to make the “Final” approach into the wind.
BEC – Battery Eliminator Circuit – for electric powered models rather than having a flight pack (see below) the power to drive the receiver and the servos are taken from the same battery that runs the main engine. Often built into the ESC.
Brushed – the traditional type of electric motor where brushes make contact between the rotor and the stator. The touching of the brushes essentially creates the timing and current to make the motor spin correctly.
Brushless – the more modern type of electric motor where there is no contact between the rotor and the stator. A more complicated speed controller is required to carefully feed current in sequence to the magnets to make the motor spin with the correct timing. Brushless motors are much more efficient than brushed motors.
Cavitating – What occurs when a prop spins to fast for the airflow around it and is no longer “gripping” the air as it spins. Typically you need to slow the engine to get a grip, and then increase it again later.
CoG – Centre of Gravity – the balancing point for the plane where the “weight” (physics teachers forgive me) of the tail perfectly balances the “weight” of the nose. Planes with CoG too far back tend to snap roll. Planes with CoG too far forward tend to be sluggish in the air.
Control Horn – The small part that connects to a control surface (ruder, elevator, aileron) with holes in it and allows that surface to be moved via linkage from a servo.
Critical Angle of Attack – the point at which the wing stalls due to having too high an angle of attack to the airstream
Cuban Eight – A type of aerobatic maneuver where a plane traces a figure eight in the sky. The sequence of maneuvers is as follows. From level flight, up elevator, half roll, three quarter inside a loop, half roll, three quarter inside loop – complete.
Current – the flow rate of electrical energy. Measured in amps – see our primer on electrics.
Cyclic – The control on a helicopter that deflects the main rotor to control the pitch (“cyclic pitch”) and roll (“cyclic roll”) of the helicopter. Because they make similar orientation changes to a fixed-wing aircraft they are sometimes also called elevator and aileron respectively.
Dead stick – no motor power. Often means landing with no motor power.
Delta – aircraft with swept-back wings and low profile – built for high speed. Although they often glide well trying to turn at low speed will cause the inner wing to stall and tuck in.
Downwind – The first part of three leg landing approach (see Three Leg Approach below) where the model flies with the wind before turning onto “Base”
Dual rates – A transmitter option that allows servos to be set up to allow for more or less travel depending on whether the TX is in low or high rates. A typical use would be to use low rates for landing, and high rates for extreme maneuvering once at a safe altitude.
Elevons – A type of setup typically used for Deltas (such as Styker, Zagi, Elebee etc) where each aileron is served by a separate servo, and mixing is done so that the ailerons also act as an elevator (for example – to climb both ailerons are pulled up simultaneously).
ESC – Electronic Speed Controller – the thing that controls how much current is given to the engine and hence how fast the engine runs, and the plane flies. Often has a BEC (see above) built in. Note – two main types – brushless and brushed.
Exponential – A configuration option on computer radios which allows the relationship between stick deflection (on the TX) and servo deflection to be made nonlinear. This allows more delicate control when sticks are closer to the center position but still allows full deflection near the extremes of the stick travel.
EXP – see exponential
Final – The final approach for a landing – ideally made into the wind, or across the wind if necessary. Only made downwind in emergencies.
Flaperon – a type of flap setup where if the ailerons are controlled by separate servos on separate radio channels then a computer radio can be programmed to make them behave as flaps as well as ailerons.
Flaps – control surfaces which increase the amount of lift and drag created by the wing for the purpose of landing or taking off.
Flare – The maneuver just before landing where the nose is brought up to extract the maximum lift, and wash off any extra airspeed.
Flight pack – a battery pack which is carried by your plane purely for the purpose of powering the receiver and servos. Typically a high capacity 5-volt type arrangement.
Full Noise – WOT – Wide Open Throttle.
Glitch – radio interference or other electronic control problem making your model not behave according to input.
Go around – going around for another landing attempt.
Ground – something you should aim for your model to reach very gently at the end of a flight, not violently halfway through.
Ground Effect – the extra lift that an aircraft gets as it comes into close proximity of the ground (normally around one wing span for fixed-wing aircraft). For helicopters, ground effect is especially challenging as the lift tends to unsettle the copter making it unstable.
Hammerhead – an aerobatic maneuver where the plane is pulled perpendicular to the ground, and then using the rudder made to fall to the side rather than forwards or backwards when it stalls.
Hand Launch – taking off by throwing the model from the hand.
Heading Hold – a type of gyro for a helicopter designed to control the tail rotor so that it holds the tail of the helicopter steady by varying the speed or pitch of the tail rotor.
Head speed – a helicopter term which describes the speed and momentum of the main rotors.
Hit – radio interference – a “glitch” (see glitch above).
Horizontal Stabilizer – the horizontal fin which the elevator hinges off.
Hovering – something helis do, and some model planes can also do. Exactly what it sounds like.
Inside Loop – A loop that starts from level flight, involves using up the elevator to loop and returning to level flight. The upper part of the aircraft is on the inside of the loop.
Inverted – just like you would expect. Upside down (so the plane’s canopy is pointed at the ground).
Kick Point – when flying a hammerhead stall (sometimes called a stall turn) the kick point is the place where the full rudder is applied to make the aircraft nose fall to one side.
Knife Edge – a type of aerobatic maneuver where the aircraft is held with its wings perpendicular to the ground, and it’s nose pointing up making the aircraft appear to be balanced on a wing tip.
KV – rating for brushless engines – 1000s of RPM per volt. So a 5KV engine would spin at 55,000rpm approximately if you applied 11.1 volts (3s).
Landing AOA – The nose up position that aircraft with undercarriage need to achieve before touching down for a good landing. Also see Flare above.
Leading Edge – The front of the wing. The part that first comes into contact with new air as the plane flys through the sky, hence the term leading edge.
LiIon – Lithium Ion battery. First generation of Lithium Polymer. More stable, can have quite high capacities, but can’t produce current as LiPos can. See Wikipedia for more info.
Linkage – The “system” of wire that connects servos to control horns.
LiPo – Lithium Polymer battery. A type of battery chemistry that can support extremely high discharge rates. Battery can be dangerous and need to be handled carefully. See Wikipedia for more.
Maiden – an aircraft’s first flight.
NiCad – Nickel Cadmium Battery – a type of cell chemistry. Must be recycled when disposing as Cadmium is an environmental pollutant.
NiMH – Nickel Metal-Hydride Battery – a type of cell chemistry.
Outside Loop – the type of loop performed starting from level flight and using down elevator until the plane is returned to level flight. The top of the aircraft is on the “Outside” of the loop whilst performing the maneuver.
Piano Keys – refers to the black/white strips which appear at the start of real runways. Aiming at the piano keys means aiming just to a touchdown just after the start of the runway.
Pitch (prop) – the distance (normally expressed in inches) that the propellor “cuts” through the air in a single rotation assuming no slippage.
Pitch (attitude) – rotation of the plane through the axis of the wings (so nose up, nose down).
Pitch speed – The speed at which the propeller pulls through the air. It is calculated by looking at the pitch of the propeller, and the number of revolutions it performs in a unit of time. Pitch speed does not consider slippage, drag and other forces that may affect the aircraft.
Power – For electric models, this is a product of voltage and amps and is measured in watts. See our electrical primer for a better understanding of the relationships between volts, amp and watts.
Propellor – the thing that spins. Two ratings on model aircraft. The first number is the diameter (normally in inches) of the propeller, the second is the pitch (see above). So a 7×5 propellor has a diameter of 7 inches, and a pitch of 5 inches.
Pusher – an aircraft where the propeller sits behind the wing. Pushes are often good for beginners as the motor/propeller are not normally damaged on poor landings.
Push Rod – another term for linkage (see above).
Receiver – see RX below.
Retracts – Retractable Landing Gear.
RET – Abbreviation for Rudder Elevator Throttle (3 channel aircraft)
REAT – Abbreviation for Rudder Aileron Elevator Throttle (4 channel aircraft)
RoG – Rolling over Ground – taking off using undercarriage.
Roll – the rotation of the model through the axis of the fuselage (so left wing tip up/right wing tip down and vice versa).
Roll rate – how quickly the model can perform a roll by using ailerons, or aileron and rudder.
Rotate – lift off, pull back on the elevator, get off the ground already.
RX – Receiver – that thing in the plane that means it will actually do things when you tell it to with the transmitter (TX)
Semi-symmetric airfoil – a type of airfoil which generates almost as much lift when the plane is inverted as when it is flying normally.
Servo – the small motor with control arms that responds to input from the receiver to actually do the mechanical work of moving a control surface or throttle.
Speedie – Slang for the Electronic Speed Controller (ESC) – see above.
Spin – a maneuver (often entered involuntarily due to a stall exaggerated by a yawing force) where the aircraft is rolling with its nose down rapidly losing altitude. Spins are recovered by closing the throttle, and if necessary adding opposite rudder. Once the spin is correct power can be reapplied.
Stall – The point at which the wing no longer produces lift and the model’s nose falls.
Stall Speed – the speed at which the air stream passes the critical angle of attack and the wing stalls.
Symmetric airfoil – a type of airfoil which generates the same amount of lift when the plane is inverted.
Tip stall – a stall where a wing tip is dropped rather than a straight through stall where the nose drops. Tip stalls are harder to recover from than straight through stalls.
Three-legged approach – an approach for landing with three distinct phases – Downwind (see above), which turns onto Base (see above), before turning into the wind for Final (see above).
Thrust – the force produced by the propeller, ducted fan, turbine, whatever. Is measured in grams (at earth standard gravity of course) or ounces (for imperial measures).
Trailing Edge – The edge of the wing that is last in contact with air as the plane flies. Hence the term Trailing edge.
Transmitter – see TX below.
TX – Transmitter – that box with the sticks on it that allows you to control your plane.
Unlimited Vertical – a state of model aviation nirvana where a model has enough power to fly perpendicular to the ground (vertically) forever (excepting battery/fuel/radio range limits) without stalling. This is significant because the wings are generating no lift to fight gravity when the aircraft is perpendicular meaning the engine alone is creating enough thrust to overcome gravity.
Vertical Stabilizer – the upright fin which the rudder hinges off.
Voltage – electrical pressure – measured in volts – see our electrical primer for a better understanding of the relationships between volts, amp, and watts.
Washout – a design feature of many wings where the wing tips have a lower angle of attack than the wing root, causing the wing root to stall before the tips leading to a gentle straight through a stall.
Watts – a measure of power. Is the product of volts and amps – see our electrical primer for a better understanding of the relationships between volts, amp, and watts.
Wing Loading – the all up weight (AUW) of the aircraft divided by the surface area of the wings. Lighter wing loading generally means the aircraft will get more lift with less speed.
WOT – Wide Open Throttle .
Yaw – rotation around the vertical axis of the aircraft (that is perpendicular to the wings and the fuselage – so nose left, nose right).
Y lead – a cable that allows two servos to be controlled from a single channel. Used when you have an aileron plane which takes separate servos on each wing.