FlightGear

Infobox Software
name = FlightGear



caption = Boeing 787 with Continental Airlines livery in version 1.0.0
collapsible =
author =
developer = FlightGear Developers & Contributors
released = July 17, 1997
latest release version = 1.0.0
latest release date = release date and age|2007|12|17
latest preview version =
latest preview date =
frequently updated =
programming language = C++ [ [http://sourceforge.net/projects/flightgear/ SourceForge.net: FlightGear - Flight Simulator ] ]
operating system = 32-bit Windows, Linux, Mac OS X, FreeBSD, Solaris or IRIX
platform = Cross-platform
language =
status = Active (1996-)
genre = Flight simulator
license = GNU General Public License
website = http://www.flightgear.org/

FlightGear is a free open-source multi-platform flight simulator developed by the FlightGear project since 1997. [cite web | title = FlightGear takes off | first = Joe | last = Barr | date = 4 December 2006 | url = http://www.linux.com/articles/58579 | accessdate = 2007-06-25 ]

The project had its first release in 1997 and continued in development, culminating in the latest major release of 1.0.0 in December 2007, with specific builds for a variety of operating systems including Microsoft Windows (Win 32), Mac OS X, Linux, IRIX, and Solaris, although hardware requirements, especially OpenGL hardware graphics acceleration constrict systems capable of running Version 1.0.

FlightGear code is released under the terms of the GNU General Public License, and it is free software.

History

Early Development (1996, 1997-2001)

Development formally started in the late-1990s with an online proposal and code being written in 1996, but using custom 3D graphics code. Development of an OpenGL based version was spearheaded by Curtis Olsen starting in 1997, after the initial start in 1996. A large community response lead to many contributing to the project from its start in late '90s up to the present. [ "The Flight Gear Manual" Version .9, April 2006 ] [ "Flight Gear Flight Simulator" Proposal http://www.flightgear.org/proposal-3.0.1 checked June 26, 2007]

Rather than start entirely from scratch, FlightGear developers made use of the LaRCsim flight model from NASA, with OpenGL for 3D graphic code, and freely available elevation data. First working binaries came out in 1997, with an intense updating of newer versions for several years resulting in progressively more stable and advanced programs.

Version 0.7-0.9 (2001-2003)

By 2001, the team was releasing new beta versions regularly (0.7.x, 0.8.x over 2001-2003). Later in the decade, the rate of final public releases slowed, but had larger amounts of content (0.9.8, 0.9.10, etc.). The maturity of software by 2005 lead to more widespread reviews, and increased popularity. The use of version numbers slowed dramatically after the late 2002 release of version 0.9.0. Versions 0.9.9 (2005) and 0.9.10 (2006) had about 8 all-new or redone aircraft adding to a total of 70-90 aircraft, while 0.9.11 has about 33 new or redone designs.

Version 0.9.0-1.0.0 (2003-2007)

FlightGear graphics are outdated in many respects compared to flight simulators such as "X-Plane" of the same period, but can compare well to older versions and to open source contemporaries such as "ACM Flight Simulator" or "Vertigo". Also, the whole world is well represented using the freely available SRTM elevation data, and a number of special features are available, such as sloped runways. Over 20,000 runways, 3d clouds, multi-platform support, multiple open flight data model (FDM) choices, roughly 100 aircraft choices by version 0.9.10 provide a well-rounded feature set.

FlightGear requires OpenGL and 3D hardware acceleration, with NVIDIA hardware and binary drivers having better support. Early versions had support for 3dfx cards, though this was dropped as hardware requirements increased.

FlightGear has been used in a range of projects in academia and industry. [cite web|url=http://www.usenix.org/events/usenix04/tech/sigs/full_papers/perry/perry_html/Applications_Simulator.html|title=Applications for the Simulator|accessdate=2007-09-03]

oftware

The simulation engine in FlightGear is called SimGear. It is used both as an end-user application and in academic and research environments, for the development and pursuit of flight simulation ideas.

This customizability of FlightGear is illustrated by the wide range of aircraft models that are available in FlightGear, from gliders to helicopters, and from airliners to fighter jets. These aircraft models have been contributed by many different people.

The FlightGear aircraft use one of three main data models JSBSim, YAsim, or UIUC as of version 0.9.10. Currently only one terrain engine is used, TerraGear. Weather effects include 3D clouds, lighting effects, and time of day.

Flight Dynamics Models

Flight Dynamics Models (FDM) are how the flight for an aircraft is simulated in the program. FlightGear uses a variety of internally written and imported flight model projects. Any aircraft must be programmed to use one of these models. Currently FlightGear is the only graphical flight simulator for which all the FDM are used, and UIUC and YASim were developed specifically for FlightGear.

Early version used an FDM based on LaRCsim by NASA, which was replaced with more flexible FDM.

*JSBSim - the default flight dynamics model software since 2000. Started by Jon Berndt. [ cite web | title = Flying the Open Skies with FlightGear| first = Howard | last = Wen | date = 11 December 2003 | publisher = O'Reilly Network | url = http://www.linuxdevcenter.com/pub/a/linux/2003/12/11/flightgear.html | accessdate = 2008-03-04 ]
*YASim - another FDM using different calculation method. Introduced starting in 0.7.9 in 2002. Developed by Andy Ross [ [http://www.linuxdevcenter.com/pub/a/linux/2003/12/11/flightgear.html LinuxDevCenter.com - Flying the Open Skies with FlightGear ] ]
*UIUC - another included FDM, developed by the UIUC Applied Aerodynamics Group at University of Illinois at Urbana-Champaign, also made use of LaRCsim. [ cite web | title = Aircraft Dynamics Models for Use with FlightGear | publisher = UIUC Applied Aerodynamics Group at University of Illinois at Urbana-Champaign | url = http://www.ae.uiuc.edu/m-selig/apasim/Aircraft-uiuc.html | accessdate = 2007-06-26 ]
*Flight Gear can also be setup to render using inputs from an external FDM source, such as from Matlab.
*Other custom FDM for a specific aircraft type have been written, such as for lighter than air aircraft.

FlightGear dependencies

Unlike commercial software titles, the main output of the project is simply the release of a collection of code. To turn it into a usable program it must be compiled for a given platform. The software libraries used to create FlightGear have varied over time. The main one is SimGear, which is the underlying sim engine for FlightGear. TerraGear is not a dependency, but simply a name for the default terrain data program in FlightGear. OpenAL is used for sound/audio software, including support for SDL (since 0.9.5). [ cite web | title = FlightGear v0.95 Released | publisher = LockerGnome | url = http://www.lockergnome.com/nexus/news/2004/08/03/flightgear-v095-released/ | accessdate = 2007-06-24 ] PLIB is used for hardware support routines, formerly used for sound support also which was taken over by OpenAL. OpenGL is used for its integrated 3D graphics routines, and other hardware acceleration (namely DirectX) is not supported. OpenSceneGraph is also integrated into FlightGear. Finally, Simple DirectMedia Layer is a software library which is also used. Some of the dependencies vary depending on which platform the code is being compiled for. FlightGear users must either compile the code themselves, or find a third party to release a binary, if it is not among the ones available from the project.

Networking and multi-display

Several networking options allow FlightGear to communicate with other instances of FlightGear. A multiplayer protocol is available for using FlightGear on a local network in a multi aircraft environment. This could be used for formation flight or control tower simulation. Multiplayer was soon expanded to allow playing over the internet. Other features include a Google maps based moving map that allows users to observe where other players are. [ [http://www.freesoftwaremagazine.com/articles/flightgear Flying high with FlightGear ] ]

Several instances of FlightGear can be synchronized to allow for a multi-monitor environment. If all instances are running at the same frame rate consistently, it is possible to get good and tight synchronization between displays.

Additional software

There are programs that are either integrated into FlightGear (dependencies) or perform a function with it. Some of these are included in the release of FlightGear for a specific platform but made by the project, while others are independently distributed but are hosted by the FlightGear project.

One major additional software is the actual interface for launching an executable of FlightGear. For most of its early life FlightGear was only run through command line interfaces. However, the FlightGear Launch Control has been included with the "FG launcher" front-end since 0.9.3 in 2003. "KFreeFlight" is a launcher/front-end for KDE. "FGTools" is an alternative windows launcher front-end. "FGKicker" is a GTK+ based front-end.

Other significant programs include editors and projects for Terrain Data. "Atlas" is a chart/map support for FlightGear; "Kelpie Flight Planner" is a Java based flight planner for FlightGear. "FlightGear Scenery Designer" is a FlightGear scenery editor for working with terrain data. The "World Custom Scenery Project" is a project coordinating custom scenery efforts. Finally, "Taxidraw" is an editor for airport runways and taxiways.

FlightGear code vs. binaries

Unlike most commercial software, the project is totally open and the current CVS build is always available. The actualy release dates apply to standardized and stable release of code, which is then compiled into a executable program. Both the the development, the code releases, and the binaries are all created by those who volunteer their time to FlightGear. To create a runnable program the code must be compiled, which requires several specific libraries (see section of #FlightGear dependencies), including some general ones and, in some cases some platform specific ones. However, since this too difficult for most mainstream users, other contributors will work to make binaries available for a specific platform and operating system. These packages vary in their stability, performance, dependencies, and how up to date they are with the code base. For example, some older binaries work on Mac OS 9 but newer releases require specific Mac OS X versions.

For example, by late 2007 the latest code release was 0.9.11-pre1 (pre-release) and 0.9.10 (final). However, the actual binaries available vary significantly. Examples of actual binaries available a year after the release of the 0.9.10 code release:

*Win-32 has ~138 Mb package (v0.9.10) (For Windows 98, 2000, ME, 32-bit XP)
*Linux- pre-built packages for specific Linux distributions
**Slackware package (v0.9.10), Fedora Core [2,3,4] packages (v0.9.10), Pardus (v0.9.10), Debian (v0.9.9)
*Solaris packages either for it running on either SPARC or x86 processors.
** SPARC (v0.9.8), x86 (v0.9.9)
*Silicon Graphics IRIX;at the time had SGI binaries for (v0.9.9)
*Mac OS X has a version for Mac OS 10.4 (v0.9.10) and for Mac OS 10.3 (v0.9.9)
*FreeBSD has a package for(v0.9.10)By early 2008, many versions for 1.0.0 became available although older releases remained for several aforementioned platforms. Increased hardware requirements for 1.0.0 reduced performance on older systems.
*Win-32 has a ~172 Mb package (v1.0.00) (For Windows 98, 2000, ME, XP, Vista)
*Linux- pre-built packages for specific Linux distributions included (v1.0.00) for Slackware and Debian
*Macintosh OS 10.4 (v1.0.00)

Reviews of FlightGear

Although not developed or typically analyzed solely as a game in the traditional sense, FlightGear has nevertheless undergone reviews in a number of online and offline publications, and received postived reviews as a flight simulator game. [ http://www.flightsim.com/cgi/kds?$=main/review/fltgear.htm ] FlightGear 1.0.0 was noted as being impressive for game over a decade in the making, with a wide variety of aircraft and features. [ http://techwoo.com/flightgear-100-released/ ]

"FlightGear" 0.9.10 received many reviews, being highlighted as an accurate simulation but requiring patience and some pre-game work. [ cite web | url = http://www.freesoftwaremagazine.com/articles/flightgear | title = Flying high with FlightGear | publisher = Free Software Magazine | issue = 14 | year = 2006 ] PC Magazine noted how it is designed to be easy to add new aircraft and scenery. [ cite web | title = FlightGear 0.9.10 | first = Tim | last = Smith | date = 1 September 2006 | publisher = PC Magazine (UK) | url = http://www.pcmag.co.uk/computeractive/downloads/2163376/flightgear | accessdate = 2007-06-29 ]

In contrast, an older review some years early, a June 2002 review by FlightXPress, had been more critical, noting a lack of functions and the scenery (this would be for version 0.7.10 of FlightGear). [FlightGear, Marc Stoering, Issue June 2002 FlightXPress magazine.]

Release timeline

Final build code release dates by year. [ http://www.flightgear.org/index.shtml (checked June 24 , 2007) ] Prototype code using LaRCsim, OpenGL, USGS DEM data, and VRML were tested by July 3, 1997 by C. Olson. [ http://web.archive.org/web/19990209201526/www.flightgear.org/News/ (checked March 4, 2008)]

FlightGear visual development 2004-2008

FlightGear has undergone many major and minor graphical improvements during its roadmap to release in 2008. FlightGear uses OpenGL and requires a 3D graphics card.

0.9.4 (2004)

0.9.9 (2005)

0.9.10 (2006)

1.0.0

ee also

*Microsoft Flight Simulator
*YS Flight Simulation System 2000
*X-Plane (simulator)

References

External links

* [http://www.flightgear.org FlightGear's official homepage] - [http://web.archive.org/web/*/http://www.flightgear.org Archive] - [http://wiki.flightgear.org/flightgear_wiki/index.php?title=Main_Page FlightGear Wiki] - [http://fgfs.i-net.hu/ FlightGear Community Site] - [http://macflightgear.sourceforge.net/home/ FlightGear for Mac]
* [http://sourceforge.net/projects/flightgear/ sourceforge.net FlightGear]
* [http://cvs.flightgear.org/viewvc/data/ Official Flightgear CVS aircraft]