GLOSSARY A to Z
ATL = Adjustable Throttle Limiter
High-end feature which adjusts to bring
full servo potential within the limits of bind-free servo travel.
Ideal for throttle control, or for more effective braking in gas
ATV/EPA = Adjustable Travel
Volume/End Point Adjustment
Allows separate adjustments of maximum
servo travel to both sides of neutral. Helps tailor outputs for
different control styles. Please refer to this FAQ for more
Creating larger upward aileron travel
than downward aileron travel to help minimize the model dragging the
drooped aileron which causes a model to yaw with aileron input.
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.
Twin elevator servos plugged into
separate channels used to control elevator with the option to also
have the 2 elevator servos act as ailerons in conjunction with the
The shape of the wing when looking at
its profile. Usually a raindrop type shape.
For helis : The rotor disk is the
effective wing, and airfoil refers to the shape of the blades.
Angle of Attack
The angle that the wing penetrates the
air. As the angle of attack increases so does lift, up to a point
The number of square inches (or feet) of
the wing. It is the wingspan multiplied by the wings chord. The area
of a tapered wing is the wingspan multiplied by the average chord.
The wingspan divided by the chord.
Aspect ratio is important where a wings efficiency is concerned. A
short aspect ratio (short wings) is better for maneuvering, since it
allows a high roll rate. Short wings are also stronger than long
wings. Gliders use high-aspect ratio wings (long, skinny wings)
because they are more efficient for soaring flight. Example: 10 ft.
wingspan with a 1 ft. chord has an aspect ratio of 10.
The ability of a rotary wing aircraft to
land safely without engine power. This maneuver uses the stored
energy in the rotor blades to produce lift at the end of decent,
allowing the model to land safely.
The line around which a body rotates.
BEC = Battery Eliminator Circuitry
Allows receiver to draw power from a
main battery pack, eliminating the need for (and weight of) a
Connection using a ball, and a link
which rotates on the ball. Used to connect the servo to a control
surface or lever.
Term describing the amount of play
between gears, or gear mesh. If too loose, the gear can slip, or
strip the teeth. Too tight and excessive wear is caused.
Base Load Antenna
A rigid, short antenna mounted to the
model. Used to replace the longer receiver antenna.
Bell and Hiller
Control system used in helicopters.
Changes pitch of blades in relation to their position via a swash
plate. A flybar with paddles is used to gain responsiveness. The two
systems are linked with Control Levers.
What occurs when the friction at a joint
is stronger than the linkage.
Buddy or Trainer Box
Two similar transmitters that are wired
together with a trainer cord. This is most useful when learning to
fly. It is the same as having dual controls. The instructor can take
control by using the trainer switch on his transmitter.
Also known as crow. A mix which
activates up flaperons and down inner-most flaps for gliding speed
control without spoilers or airbrakes.
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
Cyclic-Collective-Pitch-Mixing. Type of
swash plate mixing which requires a radio with CCPM mixing
functions. This uses three servos to control the cyclic, while all
three work together to raise and lower the swash plate for
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.
If you draw a line through the center of
the airfoil that is exactly half-way between the top and bottom
surface, you get the mean airfoil line. Depending upon the airfoil,
it can be straight or curved. This curve is called the camber of the
airfoil. If it has a lot of curve, the airfoil is said to be
The horizontal surface forward of the
wing used to control pitch. It is found on very few aircraft. Also
the word used to describe aircraft that have a main wing and a
horizontal control surface in the nose...also called, tail first
The part of the engine which controls
the speed or throttle setting and lean/rich mixture via setting of
the needle valve.
A very steep climbing turn where the
airplane makes a 180 degree change of direction.
The frequency number used by the
transmitter to send signals to the receiver. If radios transmit on
the same frequency, or channel, glitching will occur in the active
receiver on that channel. This is due to conflicting signals sent by
the two radios. Flying sites should have a frequency control system
to ensure that only one radio operates on any given channel at one
time. This is usually a board with some type of marker for each
channel. If the marker is not available, someone else is using that
channel. Do not use your radio unless you are sure you are the only
one on the frequency.
The number of functions your radio can
control. Ex: an 8 channel radio has 8 available servo slots used for
separate control surfaces or switches. These channels can also be
mixed on many radios, for such functions as collective, which
increases pitch when throttle is increased.
The depth of the wing, its distance from
leading edge to trailing edge. One of the components used to
determine wing area. May vary from root to tip.
Any one of the various moveable portions
of the wings, tail surfaces, or canard.
In a conventional servo, the motor has a
steel core armature wrapped in wire that spins inside the magnets.
In a coreless design, the armature uses a thin wire mesh that forms
a cup that spins around the outside of the magnet eliminating the
heavy steel core. A coreless motor does not have magnets as standard
servo motors do, so they have a smoother, more constant, and
stronger action. Regular servo motors have either 3 or 5 magnets
(poles) which when the armature is between these, the servo motor is
at its weakest.
The large molded fairing around an
engine. It serves two purposes when done right: It helps the airflow
go smoothly around the front of the airplane, and also provides a
proper path for cooling air around the engine.
Term used for the horizontal controls
used to determine the attitude of the helicopter. Also known as
elevator and aileron.
DSC = Direct Servo Control
High-end convenience feature which
allows control/adjustment of servo function without sending signal
through receiver. Requires optional DSC cord (FUTM4250) and
DSC-compatible receiver such as R149DP and R113IP.
Slang term for a landing without engine
power. An example: I ran out of fuel at 50 feet and had to dead
Slang term for the condition in which
the model is set up to fly smoothly and predictably. This is the
state where the mechanics and electronics work together to produce
the best performance.
Uneven movement in each direction of a
control surface. Usually used when discussing ailerons or when
describing an undesired unevenness in movement of other controls.
An extension of the vertical fin forward
of the main part of the fin, and against the fuselage. On the top,
or dorsal side of the aircraft.
The air resistance to forward motion.
Drag can be increased with the use of certain types of devices
installed on the aircraft, such as spoilers, airbrakes, or flaps.
Old-style aircraft with lots of supporting wires had very large
amounts of drag, while modern aircraft such as military jets, have
very low drag.
A type of receiver that converts the
incoming frequency through two intermediate stages. This tends to
eliminate the type of interference known as image. With
high-precision components, it also allows the receiver to be much
more precise in selecting the incoming channel it accepts. This is
what helps the receiver to be very narrow-band.
A switch that can make controls more or
less sensitive. Lower rates are better for beginners, who tend to
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.
Used to apply flaps along with elevators
to increase lift, allowing modeler to fly at slower speeds, make
tighter loops or turns, etc.
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.
Offers servo travel that is not directly
proportional to stick travel. Control response is milder below
half-stick, but becomes increasing stronger as stick travel
approaches 100%. Great for aerobatics and trouble situations.
Frequency Modulation. This describes the
mode of transmission of radio signal from transmitter to receiver.
A safety feature which turns a servo to
a preset position if the signal is lost or interrupted.
Additionally, battery failsafe is a safety feature which brings the
throttle servo down to idle as a warning that the receiver battery
voltage is getting dangerously low.
A shaped area used to smooth out,
streamline, or fair, the joint between two members of an airplane. A
wing fairing joins the wing and fuselage. A landing gear fairing
streamlines the landing gear struts, and wheel fairings (wheel
pants) streamline the bulky shape of the wheels.
The movement of two aileron servos, both
in the same direction at the same time, acting as 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.
The point during the landing approach in
which the pilot gives an increased amount of up elevator to smooth
the touchdown of the airplane.
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.
Long, canoe-shaped structures that allow
an airplane to land on water. They are not a part of the aircraft
structure, but suspended below the fuselage on struts. Also called
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.
Decrease in angle held by a servo which
is being commanded by an AVCS gyro when the input is released. For
example, a rudder servo might be at full deflection when rudder
input is held. When the rudder stick is released but the model has
not yet turned as far as the AVCS gyro has read your input to tell
it to move, the servo will continue to hold input. However, it may
flyback or decreases the angle at which it is holding slightly. This
is perfectly normal.
The type of aircraft where the fuselage
has the lower portion shaped like a power boat. The plane lands on
water directly onto the fuselage. There may be small floats
suspended from the wings to keep the plane level when it is in the
The FCC has allowed the 72MHz (72.010 -
72.990) 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.
The FCC has allowed band 75MHz (75.410 through 75.990) for ground
model use only (robots, cars, boats), 50MHz (50.800 - 50.980) is
allocated only to Amateur HAM license holders for R/C use (and only
at 1W maximum power output.)
The body of an airplane.
Gyro sensitivity. When too low, the tail
will not hold position well. When too high, the surface being
dampened by the gyro will tend to wag, or hunt for center.
Momentary radio problem that never
happens unless you are over trees or a swamp.
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 cylinder. See next heading and
Idle Bar plug.
A very smooth, gentle landing without a
hint of a bounce.
A gyro is an electro-mechanical, or
electronic device which aids in the control of an R/C model. The
gyro senses motion in one axis, and directs the servo to counter
that motion. The sensor, which can be a mechanical gyroscope, or an
electronic piezo crystal, detects unwanted movement. The gyro then
instructs the servo to counter for that motion. At all times, the
radio commands will override the gyro command. The level of control
the gyro had is adjusted by the GAIN setting.
Mechanical Gyro: uses a mechanical
gyroscope to sense movement.
Piezo Gyro: uses a piezo crystal to
Non-Heading-hold vs. heading hold: A
standard (nonHH) gyro senses movement and makes an effort to counter
that movement as long as it feels it. Therefore, it is NOT going to
return the model to the exact heading prior to the movement. Heading
Hold (or AVCS) gyros will lock the model into one position, and
accurately correct for movement by sensing rate of change and
returning at that same rate.
SMM technology: utilizes a microchip to
sense movement and provide all readings. Experiences minimal effect
from temperature change, commonly known as temperature drift which
affects piezo and some mechanical gyros.
This describes a type of Gyro which
senses rotation, and maintains direction. This is accomplished by
sensing the rate of motion, and the time of motion, then
compensating for the distance. While this sounds complicated, the
effects is that if you have the model dialed in, and point the nose
north, with a heading hold gyro on the yaw axis the model will
continue to face north until you command it to yaw. See also Heading
Lock. This is not recommended for aircraft use while in flight due
to the requirement to use YAW (rudder) command to turn the model.
Often used for ground use only for perfect take off and landing
Slang term for Heading Hold Gyro.
A remote control radio system designed
specifically for use with helicopter models. The helicopter radio
differs from an aircraft radio in a few ways. First, the heli radio
needs mixing functions specific to helicopters, and usually a
minimum of five channels. Collective mixing for collective pitch
helicopters is a necessity. Second is the throttle stick, which is
ratcheted in airplane transmitters, will not have the clicking feel
on the heli version. This is due to the precise control needed on
the heli collective stick to achieve and sustain a controlled hover.
The specific radio requirements will vary from user to user, and the
parameters used will vary from helicopter to helicopter. Note that
many radios produced have both airplane and helicopter programming
in a single radio.
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.
The horizontal tail surface at the back
of the fuselage which provides aerodynamic pitch stability to the
This is a setting on the transmitter
which limits the throttle minimum. Particularly useful for FFF and
3D stunt flying.
A maneuver originally used to reverse
direction in combat. The airplane noses up and over onto its back.
It then rolls upright and continues in the direction opposite to the
original direction. It was invented by the World War I German pilot
Max Immelmann, whose airplane could perform the maneuver, and others
could not. It got him out of a lot of trouble in combat until the
Allied aircraft designs caught-up and allowed their planes to
perform the maneuver, too.
An air inlet on an aircraft. You can
have a carburetor intake, cooling intake, air conditioning intake
(on full-size aircraft), and so on. Named because it takes in air,
and because intake is a better-sounding word than takes in.
To fly a model upside-down.
Inverted Flight Control
Activates inverted flight programming
for helis, which reverses the direction of the rudder, pitch and
elevator servos, and sets up inverted flight pitch high-side and
low-side. Inverted programming is used to allow the radio inputs to
be identical to upright flight while the model is inverted. Note:
this approach to hovering is seldom used. Instead, idle-ups are used
and the modeler learns to understand and respond to the controls
reversal in inverted flight.
The assemblies that include the wheels
and the wheel struts. The word gear is used in the sense of
equipment, as opposed to the toothed wheel meaning of gear. The
British call the landing gear the undercarriage.
The left-right or side-to-side balance
of an airplane. An airplane that is laterally balanced will track
better through loops and other maneuvers.
Leading Edge (LE)
The very front edge of the wing or
stabilizer. This is the edge that hits the air first.
A vertical circle in the air. The plane
noses up, keeps rotating until it is on its back, and then comes
down and around to describe a vertical circle in the air.
MHz = Megahertz
The unit of radio frequency. 75 MHz are
surface frequencies; 72 MHz are air frequencies; 27 MHz and 50 MHz
can be used for either ground or air applications. Note: Use of the
50 MHz (ham radio) band requires an FCC license.
Also Main Landing Gear. The large,
heavy-duty landing gear struts and wheels that support most of the
weight of the airplane. They are usually under the wing or under the
fuselage near the center of the aircraft. Any other landing gear
struts and wheels are noticeably smaller.
Drive gears within a servo which is made
of one or multiple metal types. Metal gears tend to wear more
rapidly than nylon gears when in the same installation, and so
require more frequent service to maintain optimum accuracy; however,
metal gears are more durable in the case of severe vibration,
flutter, or physical shock.
Allows a single input to control the
operation of two or more servos. Simplifies routine flying and
allows more involved maneuvers—great for intermediate-advanced
fliers. For example, Flap-to-elevator mixing: Most models will
change pitch upon deploying flaps (some will climb; others dive).
After test flying the model and determining the direction and amount
of elevator throw required to correct for this change, a pilot may
set a flap-to-elevator mix to compensate. Once the mix is operating
properly, when the modeler gives flap control, the radio
automatically also gives the proportional amount of elevator throw,
keeping the model flat and straight.
A specialized lever which has three or
more pivots. The length between pivots will determine the proportion
of the mix between two or more linkages.
A removable/replaceable plug in unit
used in most complex computer radios, containing all frequency
control equipment, including the crystal and all tuned components.
Changing channels or bands on a modular radio requires only changing
module. Changing crystals WITHIN a module to change the channel of
the module itself is against FCC regulation and is not recommended.
To use your transmitter on a different channel you simply purchase
another module on that other channel and the radio is now fully
properly tuned and safe and easy to use on that other channel as
Futaba module models include TP, TK, TJ,
TL, and TK-FSS. For information on which module to use, see 9Z/8U
modules, TF modules and aftermarket modules.
A radio with a 20 KHz band width. All
Futaba radios produced 1992 or later and all Futaba FM and PCM
radios ever produced are narrow band.
NiCad (or NiCd) = Nickel Cadmium
Rechargeable batteries which are
typically used as power for radio transmitters and receivers.
Nitro = Nitromethane
A fuel additive which increases a model
engines ability to idle low and improves high speed performance.
Ideal nitro content varies from engine to engine. Refer to the
engine manufacturers instructions for best results. Nitro content in
fuel is indicated by the percent of the fuel.
The strut and wheel that is under the
nose of some aircraft.
Drive gears within a servo are made of
nylon. Nylon gears show slower wear than metal gears, but are more
prone to failure due to severe vibration, flutter, or physical shock
to the servo.
PCM = Pulse Code Modulation
PCM systems use digitally encoded
signals to minimize interference and provide todays most advanced
R/C control. Please refer to the PCM 1024 info page and the FAQ for
Pulse Position Modulation. Another term
This is the point at which a battery
will no longer accept a charge, and converts the energy to heat.
This is damaging to the battery pack, and potentially hazardous.
This type of charger will eliminate the
guesswork. When the battery has reached peak, the charger reverts to
a maintenance charge rate, which will not damage the pack.
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.
The programming function of the radio
which aids in setting the hover point, and end points of the blade
pitch in the collective mix.
Offsets the entire heli pitch curve,
increasing or decreasing responsiveness proportionally at all
A linkage set up using two rods or
wires. One is pulled for one direction and the other is pulled for
A linkage set up using two rods. One rod
pushes, while the other pulls.
How fast something turns. It means
Revolutions Per Minute. It is both singular and plural.
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.
If a wing has an airfoil that curves
down from the high point, and then curves back up, it is said to be
reflexed. Reflex is the size of that reverse curve.
This is the increased vibration (or
amplitude of oscillation) of system when acted upon by a force whose
frequency is close to or equal to the normal frequency of the
system. When the resonances of many parts of a machine are in synch,
the whole machine will vibrate at a greater rate and can be damaged.
Resonance can cause difficulties in an aircraft, particularly when
using a vibration mount with an improperly balanced
For helis: Keep in mind that a
helicopter has many rotating parts, and they all cause resonance.
The helicopter will need to be tuned to reduce the amount of
Specifically used for mechanical
retracts. It is a non-proportional servo which only moves 180
degrees. That is to say this servo is either off (gear up and fully
locked) or on (gear down and fully locked). No ATV, EPA, or AST
adjustments can be made on these servos because they are not
proportional. The linkage must be set up properly to allow this
servo to operate at its full range and do its job—securing your
models landing gear in a gear-up or gear-down position.
Short for retractable landing gear.
Wheels and struts that fold up into the airplane to get them out of
the air stream and present less resistance to the airflow.
The function of the radio which mixes
throttle to rudder, preventing the rotation of the helicopter during
throttle increase or decrease.
The airplane keeps the nose pointed in
one direction while it rolls over on its back and then upright
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
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.
In radios with idle up functions, this
specifies the amount of tail rotor pitch in the different idle up
Mix used to counteract undesirable roll
which often happens with rudder input, especially in knife edge,
also called roll coupling.
This heli mix adds a small amount of
throttle to counter the added load on the main gear from increasing
the pitch of the tail blades, helping to maintain a constant head
speed during rudder application. (This is a minor effect and is not
a critical mix for most helicopters.)
Ruddervators are on a v-tail. Both of
the ruddervators move up and down for pitch control and both move
left or right for yaw control.
Abbreviation for receiver.
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.
Reverses the rotation of a servo with
the flip of a switch. Adds ease and flexilibility during
Servo Output Arm
The removable arm or wheel which bolts
to the output shaft of a servo and connects to the pushrod.
Used to reverse the direction of a servo
to ease installation and set up.
Moveable surfaces on the leading edge of
the wing that helps airflow in low-speed flight. They enable the
wing to fly at lower airspeeds than without them by directing the
airflow over the wing and preventing separation of the airflow.
Basically, they are retractable slots. All modern jetliners have
slats, which open when landing flaps are lowered. Some aircraft
intended for very short takeoff and landing have slats that open and
close automatically, depending upon airspeed and angle of attack.
A maneuver where the airplanes controls
are used to make the fuselage fly at an angle to the line of flight.
This causes a tremendous increase in drag, and allows an airplane
without landing flaps to increase its angle of descent without
picking up a lot of speed.
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. Also, see flutter.
A specially-shaped slot in the wing just
behind the leading edge. This directs airflow from below to the top
of the wing, and helps low-speed flight by delaying the stall.
Because they are permanently-mounted, they do add drag. See also
A very slow version of the roll.
A type of rolling maneuver that is very
quick and violent. It is basically a spin where the flight path is
in any direction chosen by the pilot. Improper speed control during
a landing approach can also make the model snap over on one wing and
enter a spin. Since it is close to the ground, there is not enough
room to recover, and a crash results.
Snap Roll Switch
Combines rudder, elevator and aileron
movement to cause the aircraft to snap or spin on the flip of a
Your first totally unassisted flight
that results in a controlled landing.
Span also Wingspan
The widest straight-line distance
between the two wingtips.
Large panels that fold out of the
aircraft structure to provide a lot of extra drag to the air. They
are not part of the wing structure, but are usually mounted on the
fuselage. Military jets most often have speed brakes, which fold out
of the fuselage. Some airliners use spoilers as speed brakes when at
The middle control surface on a
6-trailing-edge-surface glider or the inboard control surface on a
A maneuver where at least one wing is
stalled and the two wings are operating at very different angles of
attack. This causes the airplane to rotate around its middle while
it descends at a high rate of speed. When it is done on purpose, it
is a precision maneuver, with the pilot trying to get the airplane
to rotate an exact number of turns from entry to exit. When it is
done accidentally, it can easily result in a crash. Many models
crash when the pilot enters an accidental spin too close to the
ground. This is caused by improper speed control during the landing
The bullet-shaped fairing on the nose of
the airplane around the propeller. This smooths the airflow around
the propeller hub and also makes the airplane looks much better.
Basically a reverse Immelmann. The
airplane rolls onto its back, and then the nose comes down to finish
a 1/2-loop. The direction of flight is changed 180 degree.
Control surfaces on the wing that
destroy lift. They spoil it. They are used on sailplanes because
they can steepen the very flat glide of the aircraft, which makes
landings much easier. On full-size aircraft, spoilers are also used
to kill lift on landing to make sure the airplane is firmly on the
ground. They also add a lot of drag to help with aerodynamic
Stabilizer and elevator also called
full-flying tail. Stabilizer incidence controlled by pilot in lieu
of an elevator.
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).
Basically this is a supporting member. A
wing strut supports the wing, and goes from the fuselage to the
wing. Cabane struts are on biplanes, and support the upper wing over
the fuselage. A landing gear strut is the portion that holds the
wheel assembly to the airplane, and away from the wing or fuselage.
This is a trim function on many computer
radios, allowing trim function during set-up, and still allowing the
full trim function in flight.
An optical sensor designed specifically
to count light impulses through a turning propeller and read out the
The nickname of an airplane that sits on
its tail with the two main wheels in front and a tailwheel in the
Stabilator with collective and
The small wheel at the tail of the
airplane. This is found on the type of airplane that have the two
large wheels in the front, and the small one in the rear. The
airplane sits on its tail.
The control that allows the pilot to
change the speed of the engine. In a car, the gas pedal is actually
the throttle control for the car.
The programming function of the radio
which allows throttle operation to be adjusted to meet the modelers
specific needs at various points along the throttle movement.
Particularly useful with 2-stroke engines in providing linear
throttle response at the various points of throttle application.
For helis: Aids in setting the hover
point, and end points of the throttle in the collective mix.
A radio function which locks the
throttle at a fixed point while a switch is activated. This function
is used to hold the throttle in an idle. Useful when starting, as
well as for auto rotations.
The forward force provided by the
airplanes engine. This is the force that drives the airplane
The force which tends to cause rotation.
Trailing Edge (TE)
The rearmost edge of the wing or
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.
Allows trainer to link radios with a
student via a cord, and to instantly take control of students craft
in-flight. The 8U system has special training features available.
The hand-held radio controller. This is
the unit that sends out the commands that you input.
Abbreviation for transmitter.
This means that the lower surface of the
wing has a hollow curve when observed from front to back. A thin
wing with a high camber will be undercambered.
V-tail Model Mixing
Used on a V-tail model to have two
servos operate two control surfaces as both rudder and elevator.
The non-moving surface that is
perpendicular to the horizontal stabilizer and provides yaw
stability. This is the surface to which the rudder attaches.
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, and helps
the PT family of trainers recover, hands-off, from unwanted spiral
The large fairings used to streamline
the wheels of an aircraft that has non-retracting or fixed landing
gear (so-called because it is fixed in place).
The main lifting surface of an airplane.
A small vertical surface at the tips of
the wings. They help direct the turbulent airflow that all wings
have at the tips. They make the wings more efficient.
The nose-left and nose-right movement of
the airplane. This is controlled by the rudder.
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.