RealFlight Glossary


3D Acceleration

3D operations require huge amounts of calculations. Modern video cards offload many of these calculations to the card, rather than performing the calculations directly on your computer's CPU. This speeds up the simulation and allows for faster frame rates, thereby increasing the realism of the simulation.



Amount of servo travel. For instance, 50% ATV would mean the servo's maximum travel is 50% of its physical limit.

Active View

The Active View is the view that all commands in the View menu act on. Only one view at a time is active. You can make a view active by clicking on it with the mouse. When you want to control a view's properties, you must first make it the Active View

Advanced NavGuides

A gadget that displays continuously updated information about your aircraft. The Advanced NavGuides gadget is more customizable than the NavGuides gadget.

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.


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.


This is the cross-section shape of a surface (e.g., wing) that produces lift. Airfoils usually have some sort of a "tear drop" shape.

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.


This is defined as the distance from the point of attachment to the weight.


A prefabricated model - Almost Ready to Fly.


Automatically detects when a CD-ROM is inserted and runs the specific program on the CD-ROM.


A maneuver in which the heli is landed without power. The momentum of the blades is enough to slow the heli prior to landing.


An event where players attempt to autorotate into a target (similar to Spot Landing). Each player takes a turn. Players collect different point amounts based on landing location. The Autorotation Event (also called a Deadstick Landing event) works for helicopters only.


Bilinear Textures

Smoothes textured pixels together. This can cause a blurry appearance but can also improve the overall appearance.

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.


CG - Center Of Gravity

This is the point at which the airplane balances fore to aft, and side-to-side. The location of this point is crucial to how the airplane reacts in the air. A tail-heavy plane will be very snappy, but generally unstable and susceptible to more frequent stalls. Conversely, a nose-heavy airplane 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.


Camber refers to the angle of a wheel in relation to the vertical (perpendicular). 'Negative' camber means that the top of the wheel leans in towards the center of the car, whilst 'Positive' camber refers to the situation when the top of the wheel leans out - away from the center of the car.


Caster refers to the angle of the front king pin in relation to the vertical. The king pin may be either a solid pin, or imaginary line through the center of the steering block. Castor is measured in degrees and generally refers to the angle which the king pin leans back from the front of the car. A typical castor angle for a two-wheel drive buggy or truck is 25 degrees. A four-wheel drive buggy may vary from 5 to 20 degrees.


A mechanism on a helicopter that changes the pitch of the main blades, thereby allowing the helicopter to ascend or descend accordingly. This is the control that adjusts the pitch of the rotor blades.

Collision Detection

RealFlight allows the pilot to activate Collision Detection for all of the objects. If activated, collision detection senses when an aircraft "bumps" into an object, and causes a crash.


When a helicopter hovers, the blades form a slight "cone" when viewed from the side. The Coning effect is caused by the balance between lift and centrifugal forces on the blades.

Control Panel

The Control Panel is useful for many aspects of the program, including installing and uninstalling the simulator, running the simulator, online updates, and technical support.

Control Surface

Generally defined as the portion of the wing that moves. This is usually the ailerons, elevator, rudder, flaps or spoilers.


A device used to control an aircraft in RealFlight. Currently, all new versions of RealFlight ship with Great Planes's USB InterLink Controller by Futaba. This device can either be used as a standalone controller, or as an interface to use your own R/C transmitter to control RealFlight. Previous versions of RealFlight shipped with either a Futaba game port controller, or a Transmitter Adapter Interface. For information on the latter two controllers, please see the manuals that came on the program CD with those versions of RealFlight.

RealRace includes a genuine Futaba pistol-grip controller to add to the Realism.


Refers to the changing of a main rotor blade's pitch as the rotor head rotates. Pitch is added while the blade is pointing in one direction (e.g. while the blade is over the canopy), and removed while the blade is pointing the the opposite direction (e.g. while the blade is over the tail boom). This causes the helicopter to pitch and roll.


Dead Stick

A term used to describe non-powered flight (glide) when the engine quits running.

Deadstick Landing Event

See Autorotation Event.

Differential Throw

Ailerons that are set up to deflect more in the upward direction than downward are said to have Differential Throw. The purpose is to counteract Adverse Yaw.


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., have no ailerons).

Direct Control Interface

This is using your own radio to completely control the aircraft. This usually means you have a separate radio program on your radio for each aircraft that you want to fly with this method. All mixing and radio functions are performed on your radio and RealFlight simply passes the values directly to the aircraft servos. This is in contrast to the Joystick Emulation Interface.

DSC - Direct Servo Control

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 checks.

Direct3D Technology

Used to render the 3D image when you have an accelerated graphics card. It works best on faster computers.


A technology created by Microsoft that controls graphics and sound operations.


Blends the pixels together to produce a smoother image. This can also simulate colors that may not be available to you.

Down Thrust

This is the downward angle of the engine in relationship to the centerline of the airplane. Down Thrust helps overcome the normal climbing tendency of flat bottom wings.


A software program that controls a card (e.g., video or sound card) in your computer. The card's manufacturer usually provides its Driver as well. Manufacturers frequently update their Drivers to fix bugs, or make their cards compatible with new software and hardware. You can often find an updated driver for your video or sound card by visiting the web site of the card's manufacturer, and following links to "Drivers," "Support," "Downloads", or "Upgrades."


Drop refers to the amount your suspension arms hang down.


ESC - Electronic Speed Control

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.


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 the problem.


An organized flying contest with a set of rules. RealFlight Generation 2 currently supports five types of Events: Limbo, Spot Landing, Pylon Racing, Autorotation/Deadstick and Freestyle. You can play Events by yourself or with other RealFlight users over the Internet. You can start an Event using the "Event" menu.


A feature commonly found on computer radios that desensitizes the servo when the sticks are close to the neutral position. The further the stick movement, the faster the controls.



For Airplanes:
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.

For Helicopters:
Flapping is an up-and-down motion of the main rotor blade's tip. With a "dual-damped" head (as used in the Kyosho Concept helicopters, for example) both blades are able to Flap independently. With "solid axle" heads (as used in the Hirobo Shuttle helicopters, among others), moving one blade up causes the other to move down.

Flapping Head

This describes a type of rotor head in which the two blades are not connected directly. Each blade is independent of the other, usually resulting in a helicopter with smoother performance.


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 Playback Gadget

A gadget that lets you control playback of flight recordings using mouse actions.

Flight Recording Gadget

A gadget that lets you make flight recordings using mouse actions.


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.

Flybar Paddles

These are the short blades on the end of the flybar. Available in a variety of weights and airfoils, these paddles assist the main blades.

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.

Frame Rate

Frame Rate is the number of times per second that RealFlight creates a different picture to display on your monitor. Frame rate is determined by the speed of your CPU and graphics card, and how many RealFlight options you turn on. This is not the same as refresh rate, which is the number of times per second that your monitor retraces an image on its screen.

Freestyle Event

An event where players decide on the rules. RealFlight sees that each player gets a turn; it is the players' responsibility to judge the competition. Use this event when you have devised a group activity that requires every player to take a turn.

Full Edit

Allows you to edit every single parameter about the car. This is for advanced users or adventurous novices. You will not be able to race a "Full Edited" car in a "spec race."

This prevents racers from putting a .21 engine in a .10 truck race. If the Race Manager allows unlimited racing, then you can race a car that has been modified using the Full Edit feature.


This is the main part of the airplane that holds the wings and engine. Often thought of as the "body" of the airplane. This term is also used to refer to a "body" that might be used on helicopters.



An onscreen display that shows you continuously updated information about your aircraft, or lets you control RealFlight features using mouse clicks.


Momentary radio problem that never happens unless you are over trees or a swamp.

Gouraud Shading

Smooths the intensity from one corner of a polygon to another corner. Causing objects to look "smooth."


This is a device that is used to maintain a constant RPM (head speed). Generally used in helicopters rather than airplanes.


A collection of scenery objects or foliage objects in your airport. Every object in the airfield must belong to one Group. You can place all your airport's scenery objects in a single Group, or create multiple Groups to place objects in categories with related objects.


A device, most commonly used in helicopters, that aids in controlling the yawing action of the helicopter by automatically adjusting the deflection of the tail rotor blades.


HAL Device

A hardware-accelerated 3D video card driver. "HAL" is an abbreviation for the phrase "Hardware Abstraction Layer" that uses software drivers to communicate between RealFlight's software and the hardware of the PC. 

Horizontal Stabilizer

The horizontal tail surface at the back of the fuselage which provides aerodynamic pitch stability to the airplane.


In RealFlight, every multiplayer session requires one player to serve as Host. The Host starts the session, and then the other players join. Other players can leave the session whenever they want, but only the host can terminate the entire session. The host must start any multiplayer event (Limbo, Spot Landing, Pylon Racing, Autorotation, Freestyle).

Hot Pluggable/Hot Swappable

A device is said to be Hot Pluggable or Hot Swappable when you can safely connect or disconnect it without turning off your computer or rebooting.


The centralized mechanical device used to attach the main rotor blades and paddles.


Interface Mode

With RealFlight set to Interface Mode, you are using the InterLink controller as an interface to your own R/C radio. In Interface Mode your own radio controls RealFlight. Conversely, in Joystick Mode RealFlight is controlled by the InterLink Controller used as a mockup of a R/C transmitter.

Great Planes's USB InterLink Controller by Futaba is a USB device shipped with all new versions of RealFlight. The InterLink Controller can either be used as a standalone "mockup" R/C controller, or as an interface for using your own R/C transmitter to control RealFlight.

IP Address

Whenever your computer is connected to the Internet, it has an IP address. This number is a string of digits and periods, and looks something like "". The IP address is like an Internet "zip code" that tells other computers where to look for your computer. Depending on your Internet connection, your IP address may always be the same, or may change each time you connect to the Internet. For other RealFlight users to join your Multiplayer session, they must obtain your IP address. You can either provide it to them directly, or post it through the RealFlight list server.



A device that connects to your computer, and is used to control the simulated aircraft. The InterLink Controller that comes with RealFlight is considered a Joystick.


There are no terms beginning with the letter K.



Local Area Network. This is usually a network where the computers are connected with high speed network cards.

Lead Lag

The hinge point where the blade attaches to the hub. This allows the blade to move forward and backward at certain times during the blades rotation.


An event (flying competition) in which pilots take turns flying their aircraft under a Limbo bar.

List Server

1) A publicly available list of open RealFlight multiplayer sessions. We currently offer a free, public list server for use by RealFlight owners. This service may be modified or discontinued without notice.

2) RealFlight's Multiplayer function lets you publicly "post" your session, so that any RealFlight user, anywhere in the world, can find out about your session and join you (assuming you have not reached the enrollment limit of your session). The place where you post is called a List Server. Use of the List Server is completely optional. You can preserve privacy by not posting your session, and privately communicating your IP address to your selected multiplayer partners.

Low Rates

A switch on the radio that causes the servos move to much smaller extremes, thus making the model respond more slowly.



Also known as Flight Mode or Stick Mode, this refers to the transmitter's gimbal stick assignments (locations) which determine the flight mode of your controller. There are two main modes of control, Mode 1- mostly used in Europe and Mode 2 which is the predominant method of controlling aircraft commonly used in the United States.

Mode 1

A controller which is designated as Mode 1 means that it contains the throttle and aileron on the right stick (gimbal). The left stick will, therefore, control the elevator and rudder.

left stick moves up and down


left stick moves left and right


right stick moves up and down


right stick moves left and right


Mode 2

A controller which is designated as Mode 2 will have the left stick, or gimbal, controlling the throttle and the rudder. Conversely, the right stick will control the elevator and the ailerons.

left stick moves up and down


left stick moves left and right


right stick moves up and down


right stick moves left and right


Mode 3

A controller which is designated as Mode 3 might also be known as a 'left-handed' Mode 2. The gimbal stick assignments are the same as a Mode 2 transmitter, however, they are on the opposite sides. That is, the left stick will control the elevator and the ailerons. The right stick is used for the throttle and the rudder.

left stick moves up and down


left stick moves left and right


right stick moves up and down


right stick moves left and right


Mode 4

A controller which is designated as Mode 4 might also be known as a 'left-handed' Mode 1. The gimbal stick assignments are the same as a Mode 1 transmitter, however, they are on the opposite sides. That is, the right stick will control the elevator and rudder. The left stick, the throttle and the aileron input.

left stick moves up and down


left stick moves left and right


right stick moves up and down


right stick moves left and right



A feature of Microsoft's DirectX technology that allows you to connect with other RealFlight users over a network. 

Multiplayer Session

A network connection between RealFlight users that allows each user to fly in the same "virtual world," and allows all participants to see and interact with each other's aircraft.


A gadget that displays basic, continuously updated, information about your aircraft.


There are no terms beginning with the letter O.



A technology that creates a flying field by using a panoramic photograph as a background for a flat terrain. RealFlight offers you a choice of two display styles for airports: Photofield or 3D Terrains. 3D Terrains are more realistic, but Photofield may render more quickly if you have an older, slower computer or graphics card.


The yawing action of a helicopter that looks much like an ice skater. One Pirouette is equal to one 360-degree rotation.


A piston is a crucial part of the internal mechanism of a shock absorber. The piston is mounted on the end of the 'shock shaft' and is typically a thin plastic disc with a number of holes drilled in it. Changing the piston for one with either larger, or smaller holes or a different number of holes can have a dramatic effect on the performance of the shock absorber.

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.

Plumb String

When you measure your aircraft for RealFlight, some measurements require that you have a reference line running straight up and down. To make such a line, we tie a weight to the free end of a string, and let the weight dangle. Because the string is then "plumb" (oriented straight up and down), we call it a "Plumb String". A Plumb String is particularly useful in measuring an aircraft's center of gravity.

Private Session

A multiplayer session that is not published on our list server. For a private session, the host must distribute his/her IP address to each participant, who must manually enter this information to join.


Props are generally designated by two numbers (for instance, "10 - 6"). The first number is the prop's length (10" in the example). The second number is the pitch or angle of the blades. (In the example, "6" represents the distance the Propeller will move forward in one revolution, in this case 6".)

Public Session

A multiplayer session that is published on a list server.

Pylon Racing

An event (flying competition) in which pilots take turns flying their aircraft around a closed course. Pylons mark the course perimeter. The pilot that finishes the course first wins.


Quick Edit

Only allows select parameters to be edited. These are parameters that are likely to be changed on a car by a racer. This is for Novice and Advanced users. Vehicles that have been modified using the Quick Edit feature may be utilized in either a "spec" Race or an Unlimited Race.



Random Access Memory


This is RealFlight's exclusive physics modeling technology. RealPhysics authentically replicates the actual physics of model aircraft by calculating hundreds of thousands of floating point operations each second while delivering sizzling real time performance.

Refresh Rate

The number of times per second that your monitor retraces an image on its screen. This is different from the Frame Rate.


When used in the context of screen Resolution, this term describes the picture quality of the screen. Lower Resolutions will produce an image that is not as sharp as higher Resolutions.

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. Roll is used to bank or turn the airplane. In most airplanes, the ailerons control roll. However, when the main wing has dihedral, the plane can be banked using the rudder only. Consequently, many planes with wing dihedral do not have ailerons, and the rudder controls both roll and yaw. This is one reason why most trainer aircraft have a large amount of dihedral-a plane with large dihedral can be controlled using fewer input channels.


Hinged control surface located at the trailing edge of the vertical stabilizer, which provides control of the airplane about the Yaw axis (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.



The electromechanical device that moves the control surfaces or throttle of the airplane according to commands from the receiver. This device does the physical work inside the aircraft.


See Multiplayer Session.

Simulator Settings

Defines all the graphics, sound, and input preferences for RealFlight Classic/Deluxe and RealRace. Accessible by clicking "Simulator Settings" on the main screen.

Sound Card

A card inside your computer that controls audio (what you hear over your computer speakers). Most sound cards plug into your computer's motherboard. You can upgrade your sound card (or the software driver that controls it) without getting a new computer.

Spot Landing

An event (flying competition) in which pilots take turns trying to touch their aircraft down within a small, marked landing area. Each pilot receives a score based on touch down location. The pilot with the highest score wins the event.


This is what happens when an airplane's angle of attack is too great to generate lift, regardless of airspeed. During a Stall, the plane will dive and rapidly lose altitude. Every airfoil has an angle of attack at which it generates maximum lift. The airfoil will Stall beyond this angle.

Swash Plate

The mechanism in a helicopter rotor that turns non-rotating control movements into rotating control movements.


Throttle Hold

This is used to keep the throttle at a set position, yet allows input to the collective of the helicopter. Generally it is used to practice autorotation.


Toe is the angle of the wheels in relation to the centerline of the chassis. Toe-in refers to the setting when the wheels point 'inward' whilst Toe-out refers to the setting when the wheels point 'outward'. You can check 'Toe' by placing a ruler against each wheel — if the ruler points inward — that's Toe-In.


Some elements of a RealFlight landscape are inserted and removed using the Tree editor page of the Advanced Terrain Editor. These include trees, bushes, people and animals.


USB - Universal Serial Bus

USB is a connection protocol for computer peripheral devices (like Great Planes's USB InterLink Controller by Futaba). USB technology allows you to connect multiple devices to your computer, and supports high data transfer rates and hot swappable. USB devices have a special connector that only fits into a USB port. Most modern personal computers have USB ports, which are usually clearly labeled.


Video Card

A card inside your computer that produces the images on your video monitor. Most modern 3D video cards have accelerated 3D operations-that is, they perform numerical calculations for rendering a 3D scene, to free up your computer's CPU to perform other tasks. The video card plugs into your computer's motherboard. You can upgrade your video card (or the software driver that controls it) without replacing your computer.


A picture-in-picture display inset within the RealFlight main display. Each Viewport is independently adjustable and serves as its own unique "window on the world". The number of Viewports that may be created are totally dependent upon the power of your processor.

VFI - Virtual Flight Instructor

This RealFlight feature lets you choose from a variety of prerecorded maneuver training lessons. The maneuver is then demonstrated on screen, along with the instructor's voice and control stick movements. You can speed up, slow down and even loop the maneuver playback for training purposes. 



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.


Wheelbase is the distance between the front and rear axles of your car

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.


There are no terms beginning with the letter X.


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.


There are no terms beginning with the letter Z.