Glossary

1) Beginner issues

2) Safety 

3) Batteries

  4) Electric motors

  5) Speed controllers (ESC's)

 6) Propellers

7) Chargers

  8) Model info

 9) Electrical formulas

Reference  resources
Mailing lists 
FTP sites 
Web pages 
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Non-electronic Resources 
Magazines 
Books

Contributor Credits

 Glossary

Adverse yaw	When turning an airplane using only ailerons, the drag of the lowered aileron is greater that that of the raised aileron; this extra drag tend to yaw the airplane in a direction that's the opposite of what the pilot intended.
Aerobatics	Maneuvers that involve bank and pitch angles in excess of 60 degrees.
Aerodynamics	The dynamics of bodies relative to gases - especially the interaction of solid  objects moving within the atmosphere.
Aileron	A hinged or movable portion of an airplanes wing, at the trailing edge, primarily used to induce roll.
Airfoil	A part or surface, e.g., wing, prop blade, aileron, or rudder that's designed (shape, orientation etc.) to control the aircraft stability, direction, lift, thrust or propulsion.
AOA (angle of attack)	The acute angle between the wing chord line and the relative airflow.
Auxiliary channel	Any radio channel function other than the four basic primary channels - aileron, rudder, elevator and throttle.
Base leg	The part of the landing pattern that's at 90 degrees to the final approach.
BEC	Battery Eliminator Circuitry. This feature enables a speed controller to operate a receiver from the same battery that the motor uses. BEC saves weight, as it eliminates the receiver battery.
Bulkhead	A solid, vertical piece of wood inside a fuselage which helps to give it shape and rigidity.
C	A charging rate of C is that which will in theory fully charge a cell in 1 hour. It's actually the same number as the cell capacity but expressed in mA not mAH. E.g. for a 2000 mAH cell the C rate is 2000 mA i.e. 2A.
Can Motor	Another name for a FERRITE MOTOR
Capacity	Usually battery or cell capacity. It is measured in Amp Hours (AH) or more commonly milliAmp Hours (mAH). 1 AH = 1000 mAH = the ability to deliver a CURRENT of 1 Amp for 1 Hour, or 10 Amps for 6 minutes (1/10th of an hour), or 30 Amps for 2 minutes etc. Note that this is not related to voltage. It a characteristic of the CELL type. To get greater VOLTAGE you add more CELLS.
Center of gravity (CG)	A model airplanes balance point.
Charger	Device used to recharge Packs, usually from a 12V car/leisure type battery. These come in a wide range of prices and specifications. The main things to look for are the number of cells they will charge and the maximum current they will deliver. You will find a price jump from chargers which charge up to 7 cells and those over. That's because to charge more than 7 cells from a 12V battery requires special circuitry to increase the available voltage.
Climb out	To gain altitude after takeoff.
Cobalt Motor	This term is generally used for brushed (conventional) motors with rare earth magnets. Some of these (Astro) actually use cobalt as the brush material but there are other materials used. Regardless of the precise material these are all commonly, if inaccurately, called cobalt motors.
Control linkage	Metal rods or plastic tubes that connects servos to control horns. Carbon fiber rods are also used in smaller models.
Control surface	A movable airfoil that can be controlled by the pilot to change the aircraft's flight attitude.
Crab	To point the model's nose into a crosswind by using the rudder to move the model sideways and prevent it from being blown off course.
Crosswind	Wind blowing across the takeoff run or a models flight path.
Crosswind leg	Portion of the traffic pattern at 90 degrees to either the upwind or downwind legs; directly opposite the base leg.
Dead-stick landing	A landing without power.
Doubler	A section of balsa or plywood added to the inside of a fuselage to strengthen it.
Drag	Air resistance that slows the airplane.
Elevator	A movable control surface  - usually on the horizontal stabilizer - that's used to control a model's pitch attitude.
Energy Density	Characteristic of a cell. It is basically a measurement of how much CAPACITY you get for each unit weight. Since the cells are usually a high percentage of our total weight the higher this is the better. If you could get a 2000 mAH cell that weighs only half the conventional ones you would save a lot of weigh from the plane.
ESC	Electronic Speed Control. This device is the equivalent of a throttle for electric motors. It controls the power into the motor. Many ESC's are also fitted with other facilities like BEC (see above), a brake (to stop the motor wind milling and allow folding propellers to close properly)
Ferrite Motor	Brushed (conventional) type of motor with low cost ferric oxide magnets.
Final approach	The portion of the landing pattern which starts from the 90 degree turn from the base leg and is followed by the landing.
Flare	A slow, smooth transition from normal approach attitude to a landing attitude.
Folder	Folding propeller. When the motor is not running the prop blades fold alongside the fuselage for lower drag (and you don't break so many blades on landing). Typically used with powered gliders.
hi-rate	A hi-rate speed control switches at a high frequency, usually at around 2 to 3000 times per second.
IC	IC stands for "internal combustion." I use this term to refer to all the various kinds of fuel-driven engines: gas, diesel, glow, etc... (i.e. the "normal" R/C power plant).
Internal Impedance	This is the main characteristic of a CELL which limits the maximum current you can get out of it. So far NiCds have by far the lowest internal impedance available.
Lo-Rate	A lo-rate speed control switches at the same frequency as the servo signal. Roughly 50 times per second.
Opto-coupling	Indicates that the electrical current for the power system is isolated, which makes motor-induced radio interference less likely. The design of opto-coupling makes it impossible to incorporate with BEC.
Soft start	Some electronic switches will ramp the current up over a small time (often less than a second) when you switch on. This greatly helps to reduce wear and tear on motors and particularly gearboxes. Some ESCs also claim this feature though it only really does anything if you slam the throttle wide open from zero.