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R/c Dictionary

By Tony, Feb 14, 2017 | | |
  1. Tony
    Every day in the RC world, we use different terms that you may or may not know. We are working on helping you better understand these terms by providing you with a dictionary will all of the terms that we use. If there is something missing, just let us know and we will add it. Just click on the Contact Us link at the bottom of every page and send us an email. When you send your email, please include your definition of the word or abbreviation.

    2.4GHz - a.k.a. Spread Spectrum. The newest radio band available for R/C use. Operates at higher frequencies than noise. See also: FHSS and DMSS.

    2-Wheel-Drive vs. 4-Wheel Drive - As in full-scale cars, there are two main drive types:
    two-wheel drive (2WD) where power is supplied to the two rear wheels, and
    four-wheel drive (4WD) where power is supplied to all four wheels. The 2WD
    vehicles are less expensive and require less overall assembly and
    maintenance than 4WD vehicles. Assembly and maintenance for 4WD vehicles
    tends to be more involved, though not necessarily more difficult; the
    trade-off is that 4WD vehicles offer better steering through turns.

    ABC / Non-Ringed - These letters stand for aluminum, brass and chrome or a
    composite such as nickel. These engines have an aluminum piston and a
    chrome or composite coated brass cylinder sleeve which allows them to be
    more efficient for higher performance. They have no piston ring and rely
    on a very tight piston/cylinder fit to obtain a piston/cylinder seal. New
    ABC engines are normally hard to turn over by hand. Because of the tight
    fit, it is very important that the engine is broken in properly.

    Adjustable Travel Volume (ATV) - ATV allows you to preset the maximum
    travel of a servo to either side from its neutral position. Such
    settings help tailor control action to suit your flying or driving

    Adverse Yaw - The tendency of an airplane to yaw in the opposite direction of the roll. For instance, when
    right aileron is applied, the airplane yaws to the left, thus opposing the turn. Adverse yaw is common in
    trainer type airplanes having flat bottom wings. It is most noticeable at slow speeds and high angles of
    attack, such as during takeoffs and when stretching a landing approach. Caused by the unequal drag of the
    upward and downward deflection of the ailerons, this undesirable trait can be minimized by setting up the
    ailerons with Differential Throw or by coordinating the turns, using the aileron and rudder controls
    simultaneously. (See Differential Throw.)

    Ailerons - Hinged control surfaces located on the trailing edge of the wing, one on each side, which provide
    control of the airplane about the roll axis. The control direction is often confusing to first time modelers. For
    a right roll or turn, the right hand aileron is moved upward and the left hand aileron downward, and vice
    versa for a left roll or turn.

    AMA - The Academy Of Model Aeronautics. The official national body for model
    aviation in the United States. AMA sanctions more than a thousand
    model competitions throughout the country each year, and certifies
    official model flying records on a national and international level.

    Angle of Attack - The angle that the wing penetrates the air. As the angle of attack increases so does lift
    and drag, up to a point.

    ARF - A prefabricated model - Almost Ready to Fly.

    ARR - Some cars and trucks are available virtually prebuilt and will be
    indicated by the terms ARR (Almost-Ready-To-Run) or RTR (Ready-To-Run).
    The ARR/RTR vehicles cost a little more, but if you're just not
    interested in building your car, this is an option for you. Most vehicles,
    however, come in kit form and require you to do the building. This may
    require a few evenings, but the familiarity you gain from assembly will
    make repairs, adjustments and modifications easier to make down the road.

    AUW All Up Weight. This is the weight of the aircraft when ready
    to be put into the air, battery and all.

    Battery Eliminator Circuitry (BEC) - A circuit that eliminates the
    need for a receiver battery, usually in electric R/C cars and boats.

    BB - These letters usually designate a ball-bearing supported
    crankshaft in an R/C engine. This makes the engine run smoother and last longer.

    Buddy Box - Two similar transmitters that are wired together with a "trainer cord." This is most useful when
    learning to fly -- it's the same as having dual controls. The instructor can take control by using the "trainer
    switch" on his transmitter.

    Boring Holes in the Sky - Having fun flying an R/C airplane, without any predetermined flight pattern.

    CA (Abbreviation for "Cyanoacrylate") - An instant type glue that is available in various viscosities (Thin,
    Medium, Thick, and Gel). These glues are ideal for the assembly of wood airplanes and other materials.
    Note: Most CA glues will attack Styrofoam.

    Carburetor - The part of the engine which controls the speed or throttle setting and lean/rich mixture via
    setting of the needle valve.

    CG or CoG ("Center of Gravity") - For modeling purposes, this is usually considered -- the point at which the
    airplane balances fore to aft. This point is critical in regards to how the airplane reacts in the air. A tail-heavy
    plane will be very snappy but generally very unstable and susceptible to more frequent stalls. If the airplane
    is nose heavy, it will tend to track better and be less sensitive to control inputs, but, will generally drop its
    nose when the throttle is reduced to idle. This makes the plane more difficult to land since it takes more
    effort to hold the nose up. A nose heavy airplane will have to come in faster to land safely.

    Charge Jack - The plug receptacle of the switch harness into which the charger is plugged to charge the
    airborne battery. An expanded scale voltmeter (ESV) can also be plugged into it to check battery voltage
    between flights. It is advisable to mount the charge jack in an accessible area of the fuselage so an ESV can
    be used without removing the wing.

    Charger - Device used to recharge batteries, usually supplied with the radio if NiCd batteries are included.

    Chicken Stick - A hand-held stick used to "flip start" a model airplane engine.

    Clunk - A weighted fuel pick-up used in a fuel tank to assure the intake line is always in fuel.

    Model Aircraft Association of Canada. The official governing body for model aviation in Canada
    acting as a liason to government agencies, such as Industry Canada (formerly Department of Communications)
    with regard to radio frequencies and their use in R/C models, as well as representing internationally
    competitve modelers to the Fédération Aéronautique International (FAI) through the Aero Club of Canada. M.A.A.C.
    also provides liability insurance to its members and chartered clubs, among many other membership benefits.

    mAh (Milliamp Hour) - A measure of a battery's total capacity. The higher the number (ex. 600 mAh,
    1,500 mAh) the more charge a battery can hold and usually, the longer a battery will last under a certain
    load. Typical rechargeable receiver battery packs are in the 500-600 mAh range. Typical R/C car motor
    batteries are in the 1,200 - 1,500 mAh range.

    Mixing (Coupling) - Two radio control channels can be coupled together so
    that they move together when only one control channel is activated.
    Many 1/4 scale models require a combination of aileron and rudder to
    turn. Mixing does this electronically at the transmitter. V-tailed
    models, where the two halves of the V-tail must move not only
    together but independently, are
    another use of control mixing.

    Mode 1 / Mode 2 - Refers to the stick configuration of an aircraft transmitter's control
    sticks. Mode 1 has the aileron/throttle on the right stick and the rudder/elevator on the left.
    Mode 1 is popular in Europe and Asia. Mode 2 is the USA standard and has the elevator/aileron
    on the right stick and the rudder/throttle on the left. Almost all radios used in the USA, Canada,
    Central and South America are Mode 2. All 4-channel and above aircraft radios sold by Tower Hobbies
    are Mode 2 unless otherwise noted.

    Monster Truck - Monster trucks are gigantic! They are the king of the hill
    in any group of R/C vehicles. Designed for torque instead of speed, these
    car crushers can move up hills, down slopes and over unsuspecting cars by
    virtue of sheer, brute power. The gas powered monster trucks are nearly

    Muffler - A device attached to the exhaust stack of the engine to reduce noise and increase back pressure
    which helps low speed performance. Note: Most R/C Clubs require the use of mufflers.

    Muffler Baffle - A restrictor plate inside the muffler which reduces engine noise. This plate can be removed
    to increase power, but only if there are no noise restrictions where you fly.

    Needle Valve - Adjustment on a carburetor used to set proper fuel/air mixture. Some carburetors have
    separate needle adjustments for low and high throttle. Typically, turning the needle clockwise (screwing in)
    leans the mixture (less fuel), and vice versa. However, there are a few exceptions--refer to the engine
    manufacturer's instructions.

    NiCd - Nickel Cadmium battery. Rechargeable batteries which are typically used as power for radio
    transmitters and receivers.

    Nitro - Nitromethane, a fuel additive which increases a model engine's ability to idle low and improves high
    speed performance. Ideal nitro content varies from engine to engine. Refer to the engine manufacturer's
    instructions for best results. Nitro content in fuel is indicated by the percent of the fuel.

    NiCd Starter - A self-contained battery and glow plug clip, used when starting the engine. (See Glow Plug

    NiMH Battery - Nickel Metal Hydride Battery. Rechargeable batteries which are typically used as power sources for cars, trucks and boats as well as receiver packs. They’re offer longer run times and are more environmentally friendly than NiCds.

    Off-Road Buggy - Off-road buggies are the most popular R/C
    land vehicles. Available in gas or electric, these cars sport full-travel
    suspensions, and high ground clearance. Their knobby rubber tires
    give them the ability to tackle any dirt terrain. On a dirt track or
    at the park, these off-road buggies are great fun.

    One-Point Landing (or a figure 9) - Synonymous with "stuffing it in." Something we hope you never do.

    On-Road Car - On-road cars don't have the beefy suspension that the
    off-road cars have, but they are impressive in their authentic looks
    and all out speed. Built for racing on smooth, paved surfaces, they
    are available in gas or electric, 1/10,1/12 and 1/8 scale. It's easy
    to get involved. On-road cars are burning up the tracks of organized
    parking lot racing courses everywhere.

    Peak Charger - A peak charger automatically shuts off when your
    battery is fully charged. This means longer run times for your
    vehicle. Peak chargers are nearly foolproof, if you forget to turn
    it off, the charger does it for you. No more overcharged batteries.

    Pitch Axis - The airplane axis controlled by the elevator. Pitch is illustrated by holding the airplane at each
    wingtip. Raising or lowering the nose is the pitch movement. This is how the climb or dive is controlled.

    Power Panel - 12-volt distribution panel that provides correct voltage for accessories like glow-plug clips,
    fuel pumps and electric starters. Usually mounted on a field box and connected to a 12-volt battery.

    Programmable or Computer Radios - These high-tech radios are not
    inexpensive but allow a full set of programmable transmitter features like
    multiple plane memory, preprogrammed maneuvers (rolls, loops, etc. at the
    touch of one button) and much more.

    Prop Pitch - Props are designated by these two numbers, for instance 10 - 6. The first number is the prop's
    length, 10". The second number is the pitch or angle of the blades. The 6 represents the distance the
    propeller will move forward in one revolution, in this case 6".

    Re-Kitting Your Airplane - Changing your finished model back into a kit, as a result of "stuffing it in."

    Receiver (Rx) - The radio unit in the airplane which receives the transmitter signal and relays the control
    to the servos. This is somewhat similar to the radio you may have in your family automobile, except the
    radio in the airplane perceives commands from the transmitter, while the radio in your car perceives music
    from the radio station.

    Roll Axis - The airplane axis controlled by the ailerons. Roll is illustrated by holding the airplane by the nose
    and tail. Dropping either wingtip is the roll movement. This is used to bank or turn the airplane. Many aircraft
    are not equipped with ailerons and the Roll and Yaw motions are controlled by the rudder. This is one reason
    why most trainer aircraft have a larger amount of dihedral.

    ROAR - Radio Operated Auto Racing. National body to standardize and sanction R/C car and truck racing.

    RTF - Ready-to-Fly. Some newer airplanes are now available as RTF models. These planes usually come with
    everything needed for flight--plane, radio system, engine and all hardware. The really nice thing about an RTF is that it
    will almost always be completely pre-built with only a few minor construction steps left for the modeler. If you want to
    fly and want to fly now, RTF is the way to go.

    RTR - Some cars and trucks are available virtually prebuilt and will be
    indicated by the terms ARR (Almost-Ready-To-Run) or RTR (Ready-To-Run).
    The ARR/RTR vehicles cost a little more, but if you're just not
    interested in building your car, this is an option for you. Most vehicles,
    however, come in kit form and require you to do the building. This may
    require a few evenings, but the familiarity you gain from assembly will
    make repairs, adjustments and modifications easier to make down the road.

    Rudder - Hinged control surface located at the trailing edge of the vertical stabilizer, which provides control
    of the airplane about the Yaw axis and causes the airplane to Yaw left or right. Left rudder movement causes
    the airplane to Yaw left, and right rudder movement causes it to Yaw right.

    Servo - The electro-mechanical device which moves the control surfaces or throttle of the airplane according
    to commands from the receiver. The radio device which does the physical work inside the airplane.

    Servo Output Arm - The removable arm or wheel which bolts to the output shaft of a servo and connects
    to the pushrod.

    Servo Reversing - This radio feature allows you to install the servos where
    they can give the best pushrod routing without concern about the
    direction of servo rotation. When your installation is complete, turn on
    your radio and check each channel. If a channel operates opposite of its
    intended direction, a simple flick of a switch corrects the problem.

    Shot Down - A "hit" that results in a crash landing. Sometimes caused by radios miles away.

    Slop - Unwanted, excessive free movement in a control system. Often caused by a hole in a servo arm or
    control horn that is too big for the pushrod wire or clevis pin. This condition allows the control surface to
    move without transmitter stick movement. (See Flutter.)

    Solo - Your first totally unassisted flight that results in a controlled landing.

    Spinner - The nose cone which covers the hub of the propeller.

    Sport Airplane - A model which possesses some attributes of many of the specialty airplanes and are best
    for general flying as they are the most versatile and durable.

    Stadium Truck - Designed for backyard fun, or all out racing, R/C
    stadium trucks are the masters of "bump and jump" excitement. Like
    full-size stadium trucks they are built to take punishment. They have
    heavy-duty suspensions, oversized shocks and large tires which enable them
    to survive the roughest terrain. Yet, when tuned correctly, they also
    display speed and agility equal to the off-road buggies.

    Stall - What happens when the angle of attack is too great to generate lift regardless of airspeed. (Every
    airfoil has an angle of attack at which it generates maximum lift -- the airfoil will stall beyond this angle).

    Tachometer - An optical sensor designed specifically to count light impulses through a turning propeller
    and read out the engine RPM.

    Tip Stall - The outboard end of one wing (the tip) stops developing lift, causing the plane to roll suddenly
    in the direction of the stalled wing. This situation is not fun when you are only a few feet off the runway
    trying to land.

    Trainer Airplane - A model designed to be inherently stable and fly at low speeds, to give first-time
    modelers time to think and react as they learn to fly.

    Trainer System - This effective method of training allows two
    transmitters to be connected by means of a trainer cord. The
    instructor can pass control over to the student's transmitter so that he
    can fly. If the student gets into trouble, the instructor can regain
    control instantly.

    Trailing Edge (TE) - The rearmost edge of the wing or stabilizer.

    Transmitter (Tx) - The hand-held radio controller. This is the unit that sends out the commands that you

    Touch-And-Go - Landing and taking off without a pause. Often confused with a good bounce.

    Vertical Fin - The non-moving surface that is perpendicular to the horizontal stabilizer and provides yaw
    stability. This is the surface to which the rudder attaches.

    Washout - An intentional twist in the wing, causing the wing tips to have a lower angle of attack than the
    wing root. In other words, the trailing edge is higher than the leading edge at the wing tips. Washout helps
    prevent tip stalls.

    Wheel Collar - A small, round retaining device used to keep wheels from sliding off an axle.

    Wing - The main lifting surface of an airplane.

    Wing Loading - This is the amount of weight per square foot that has to be overcome to provide lift. It is
    normally expressed in ounces per square foot. This specification can be easily calculated as follows: If you
    know the square inches of the wing, simply divide by 144 to obtain square feet. Divide the total weight (in
    ounces) of the airplane by the wing area (in square feet). This information is valuable when deciding on
    which airplane to build next. Planes with high wing loading numbers must fly faster to stay in the air. These
    are generally "performance" airplanes. Conversely, planes with lower numbers do not need as much air
    flowing around the wing to keep it flying. Gliders and trainer airplanes fall into this category because slow,
    efficient flight is desirable.

    Wing Root - The centerline of the wing, where the left and right wing panels are joined.

    Y-Harness - Two servos can be plugged into one channel with a
    Y-harness. The two servos will then operate simultaneously. It is
    most often used in areas where the strength of one servo is not

    Yaw Axis - The airplane axis controlled by the rudder. Yaw is illustrated by hanging the airplane level by
    a wire located at the center of gravity. Left or right movement of the nose is the Yaw movement.

    Z-Bend - A simple Z-shaped bend in the wire end of a pushrod, which is used to attach the pushrod to a
    servo output arm.

    Z-Bend Pliers - An inexpensive plier type tool used for easily making perfect Z-bends.

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  1. Rajat
    Nice one, all acronyms in one place.
    Just saw it today.
    Thanks a lot !!