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.
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 style.
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.
APM - ArduPilot Mega combines sophisticated IMU-based autopilot electronics
with free Arduino-based autopilot software that can turn any RC vehicle into a
fully-autonomous UAV. APM is a trademark of 3DRobotics. The open
source is referred to Ardupilot, Arduplane, or Arducopter and later DroneCode.
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
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 ("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.
DMSS (Direct Sequence Spread Spectrum) - A 2.4GHz radio system which selects
one (or two) of the available "free" frequencies and transmits only on the one(s)
chosen. Like FHSS (Frequency Hopping Spread Spectrum) systems, it is resistant
to electrical noise. See also: FHSS.
Dead Stick - A term used to describe unpowered flight (glide) when the engine
quits running. Differential Throw - Ailerons that are set up to deflect more in
the upward direction than downward are said to have
Deans Connector or Deans Ultra-Plug is a low-resistance, high-quality,
polarized electrical connector specifically designed for radio control use. This
red color connector and its variants get their widely accepted nickname because
of the name of their manufacturer, W.S. Deans of Los Alamitos, California USA.
Differential Throw. The purpose is to counteract Adverse Yaw.
Dihedral - The V-shaped bend in the wing. Typically, more dihedral causes
more aerodynamic stability in an airplane, and causes the rudder to control both
the roll and yaw axis. This is why some trainers and sailplanes require only 3
channels of radio control--i.e., having no ailerons.
Direct Servo Control (DSC) - This radio feature permits you to check servo
operation without broadcasting a radio signal. A cable connects the transmitter
to the receiver. Direct servo control is very useful for on-the-ground control
Ding - Minor dent or damage to the structure. Also, a nick in a prop. Dinged
props must be replaced.
DM - Drone Mission, aka DroneMission.com Search and Rescue
Down Thrust - Downward angle of the engine relative to the centerline of the
airplane. Down thrust helps overcome the normal climbing tendency of flat bottom
DroneCode - Open Source projects managed by the Linux Foundation launched
October 2014, that sets a new standard of Unmanned Aircraft System development.
Electric vs. Gas Cars - Electric vehicles are the most popular choice in R/C
car racing. They are quick, quiet, easy to build and comfortable for the
beginning R/Cer to drive. The electric cars are powered with a rechargeable nicd
battery that can be charged in as little as 15-20 minutes. A vehicle with a
stock motor will provide about 6-8 minutes of run time; with a couple of
batteries and a 15 minute charger, an electric car or truck is ready for hours
of use. The popularity of Gas vehicles has increased tremendously over the last
few years. The explosive power and acceleration of a gas powered car or truck is
exciting to watch. Gas vehicles are powered by a small two-cycle engine burning
glow fuel (not gasoline!), and many modelers enjoy the realistic sound and smell
that goes along with gas powered racing. Some gas models can reach speeds over
50mph! The wider availability of pull-start engines and the new wave of 1/10
scale vehicles has made it much more affordable for the beginner to enter
Electric Starter - A hand-held electric motor used for starting a model
airplane engine. Usually powered by a 12-volt battery.
Electronic Speed Control (ESC) - Electronic speed controls replace the
mechanical speed control and servo providing enhanced power efficiency and
precision in an electric R/C car or boat. In addition, they are lighter which
improves the performance of some electric models.
Elevator - Hinged control surface located at the trailing edge of the
horizontal stabilizer, which provides control of the airplane about the pitch
axis and causes the airplane to climb or dive. The correct direction of control
is to pull the transmitter elevator control stick back, toward the bottom of the
transmitter, to move the elevator upward, which causes the airplane to climb,
and vice versa to dive.
Endpoint Adjustment - This radio feature adjusts the length of servo travel
in one direction (a single channel will have adjustments for two endpoints). If
your plane rolls faster one way than the other, endpoint adjustments can correct
Epoxy - A two-part resin/hardener glue that is extremely strong. It is
generally available in 6 and 30-minute formulas. Used for critical points in the
aircraft where high strength is necessary.
Expanded Scale Voltmeter (ESV) - Device used to read the battery voltage of
the on-board battery pack or transmitter battery pack.
FHSS (Frequency Hopping Spread Spectrum) - — A 2.4GHz radio system which
switches from one "free" frequency to another every few milliseconds. While
jumping from one to the other frequency, you are not spending much time on that
frequency and this keeps out interference. See also: DMSS.
Field Charger - A fast battery charger designed to work from a 12-volt power
source, such as a car battery.
Flaps - Hinged control surface located at the trailing edge of the wing
inboard of the ailerons. The flaps are lowered to produce more aerodynamic lift
from the wing, allowing a slower takeoff and landing speed. Flaps are often
found on scale models, but usually not on basic trainers.
Flare - The point during the landing approach in which the pilot gives an
increased amount of up elevator to smooth the touchdown of the airplane.
Flight Box - A special box used to hold and transport all equipment used at
the flying field.
Flight Pack (or Airborne pack) - All of the radio equipment installed in the
airplane, i.e., Receiver, Servos, Battery, Switch Harness.
Flutter - A phenomenon whereby the elevator or aileron control surface begins
to oscillate violently in flight. This can sometimes cause the surface to break
away from the aircraft and cause a crash. There are many reasons for this, but
the most common are excessive hinge gap or excessive "slop" in the pushrod
connections and control horns. If you ever hear a low-pitched buzzing sound,
reduce throttle and land immediately.
Four Stroke (Four Cycle) - Although a 4-stroke engine has less power than a
2-stroke engine of comparable size, there are advantages to 4-stroke engines.
They do not require a muffler and are often quieter than most 2-strokes are with
a muffler. They can swing a bigger prop than the same size 2-stroke engine. This
is an asset in the large, slow-flying aerobatic and scale models where 4-stroke
engines are usually mounted. Lastly, the fuel economy is better.
FPV - First person view, also known as remote-person view (RPV), or
simply video piloting, is a method used to control a radio-controlled vehicle
from the driver or pilot's view point.
Frequency Control - The FCC has allowed the 72MHz band to be used for R/C
aircraft operations. This band is divided up into many different channels in
which you can choose a radio system. You should be aware that certain areas have
frequencies in which there is pager interference. This is why it is always a
wise move to check with your local hobby shop to find out any channels that may
be troublesome in the area you wish to fly.
Frequency Module - A frequency module plugs into the transmitter and enables
you to change the channel number your radio broadcasts on.
Fuel Overflow Line (Vent) - The fuel line is either open to atmospheric
pressure or attaches to the muffler pressure nipple to pressurize the fuel tank
for better fuel flow to the engine. This is the line through which the fuel will
overflow when the tank is full.
Fuel Pick Up-Line - The fuel line in the fuel tank through which fuel travels
to the carburetor. Typically a flexible tube with a weight or "Clunk" on the end
which allows it to follow the fuel with changes in aircraft attitude. This is
the line through which the tank is filled.
Fuselage - The body of an airplane.
Gimbal - A gimbal is a pivoted support that allows the rotation of an object
about a single axis. It is commonly used these days to stabilize a camera,
giving you a smooth cinematic recording of a video.
Glitch - Momentary radio problem that never happens unless you are over trees
or a swamp.
Glow Plug - The heat source for igniting the fuel/air mixture in the engine.
When starting the engine a battery is used to heat the filament. After the
engine is running, the battery can be removed. The wire filament inside the plug
is kept hot by the "explosions" in the engine's cylinder. (See next heading and
"Idle Bar" Plug.)
Glow Plug Clip/Battery - A 1.2-volt battery, which is connected to the glow
plug on a model airplane engine for starting. The battery is removed once the
engine is running steadily.
GoPro - a popular high-definition action sports camera used on model aircraft
Grease-In - A very smooth, gentle landing without a hint of a bounce.
Hit (or to be hit) - Sudden radio interference which causes your model to fly
in an erratic manner. Most often caused by someone turning on a radio that is on
your frequency, but can be caused by other radio sources miles away.
Horizontal Stabilizer - The horizontal tail surface at the back of the
fuselage which provides aerodynamic pitch stability to the airplane.
Idle Bar Plug - This type of glow plug has a "bar" across the tip to help
prevent raw fuel from being splashed onto the glow element. Too much raw fuel
will cool the plug and prevent it from igniting the fuel/air mixture. An idle
bar is a help in obtaining a low idle speed.
iLook+ a all-in-one FPV camera with built-in video transmitter made by
Walkera, sometimes refer to as a FPV pack.
IOC (intelligent orientation control) flying regardless of aircraft
heading using GPS, it is relative to where you are standing. Forward is
forward, backward is pulling back, regardless of which direction the model is
Kit - A car, truck, boat, airplane, multirotors or heli that requires the
modeler to do most/all of the building and finishing work. Modelers are likely
required to add their own power plant, radio system or both.
Lateral Balance - The left-right or side-to-side balance of an airplane. An
airplane that is laterally balanced will track better through loops and other
Leading Edge (LE) - The very front edge of the wing or stabilizer. This is
the edge that hits the air first.
LiIon Battery - Lithium Ion Battery. They are lighter in weight and have a
much lower (5%) discharge rate than NiCds or NiMHs (30%).
LiPo Battery - Lithium Polymer Battery. Derived from Lithium Ion batteries,
they're compact and light, with the ability to offer 30% more power in less
space than comparable NiCds and NiMHs. Must be used with a LiPo-compatible
M.A.A.C. - 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
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 unstoppable.
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 xceptions--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 Clip.)
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
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
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. It translate the radio
signals which tells the RC vehicle what to do, such as what direction and speed
to move. The transmitter and receiver must operate on the same frequency. 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
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.
RTL - Return To Launch or Return To Home, an autopilot mode where a model
aircraft uses GPS to find it ways back home to launch point.
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
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
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 input.
Touch-And-Go - Landing and taking off without a pause. Often confused with a
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
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
Worm Servo - Gear for servo motor products such as
retractable landing skid, made popular by iUAS
XT60 - These yellow connectors are made from high-temp nylon
with gold-plated spring pins or sockets molded originating from a Chinese
company called Changzhou Amass Electronics Co., Ltd. which holds the original
patent on them. The shape of this XT60 prevents reverse polarity, and when
plugged in the connection is super-solid. Perfect for applications up to 65A
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 adequate.
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