Did you ever want to fly a plane yourself, but lacked the money or ability to do so? Are you a certificated pilot looking to improve your skills without having to incur the high expense associated with aviation? Do you want to try some dangerous maneuvers without the stress and inherent risks? Or do you just want to have fun with a more serious game without any violence? If any of these questions apply to you, flight simulators are just for you.
You may already have some experience using Microsoft’s Flight Simulator or any other of the commercially available flight simulators targeted at the home consumer. As the price tag of those is usually within the $50 range, buying one of them should not be a serious problem given that running any serious flight simulator requires computer hardware within the $1500 range.
With so many commercially available flight simulators, why would we spend thousands of hours of programming and design work to build a free flight simulator? Well, there are many reasons, but here are the major ones:
The points mentioned above form the basis of why we created FlightGear. With those motivations in mind, we have set out to create a high-quality flight simulator that aims to be a civilian, multi-platform, open, user-supported, and user-extensible platform. Let us examine each of these characteristics:
Multi-platform: The developers are attempting to keep the source code as platform-independent as possible. This is based on their observation that people interested in flight simulation utilize a wide variety of computer hardware and operating systems. The present code supports the following Operating Systems:
For optimum performance, it is recommended that you use a recent OS with a minimum of 4 GiB of system memory, current graphic drivers, and a GPU containing at least 1 GiB of memory.
Open: The project is not restricted to a static or elite cadre of developers. Anyone who feels they are able to contribute is most welcome. The code (including documentation) is copyrighted under the terms of the GNU General Public License (GPL).
The GPL is often misunderstood. In simple terms, it states that you can copy and freely distribute the program(s) so licensed. You can modify them if you like and even charge as much money as you want for the distribution of the modified or original program. However, when distributing the software, you must make it available to the recipients in source code as well and it must retain the original copyright notices. In short:
“You can do anything with the software except make it non-free.”
The full text of the GPL can be obtained from the FlightGear source code or from:
Without a doubt, the success of the Linux project, initiated by Linus Torvalds, inspired several of the developers. Not only has Linux shown that distributed development of highly sophisticated software projects over the Internet is possible, it has also proven that such an effort can surpass the level of quality of competing commercial products.
In comparison to other recent flight simulators, FlightGear’s system requirements are not extravagant. A medium-speed AMD or Intel 64 bit processor should be sufficient to handle FlightGear pretty well, given that you have a proper 3D graphics card.
One important prerequisite for running FlightGear is a graphics card whose driver supports OpenGL. If you don’t know what OpenGL is, the Khronos web site1 says it best:
“OpenGL® is the most widely adopted 2D and 3D graphics API in the industry…”
FlightGear does not run on a graphics board which only supports Direct3D/DirectX. Contrary to OpenGL, Direct3D is a proprietary interface, being restricted to the Windows operating system.
You may be able to run FlightGear on a computer that features a 3D video card not supporting hardware accelerated OpenGL – and even on systems lacking any 3D graphics hardware. However, the absence of hardware accelerated OpenGL support can bring even the fastest machine to its knees. The typical indication of lacking hardware acceleration are frame rates below 1 frame per second.
Any modern 3D graphics card featuring OpenGL support will do. Windows video card drivers that support OpenGL can be found by visit the home page of your video card manufacturer. You should note that sometimes OpenGL drivers are provided by the manufacturers of the graphics chip instead of by the makers of the board. If you are going to buy a graphics card for running FlightGear, a NVIDIA GeForce card is recommended, as these tend to have better OpenGL support than AMD/ATI Radeon. 1 GiB of dedicated graphics memory will be more than adequate – many people run FlightGear happily on less.
For the sound effects, any capable sound card should suffice. Due to its flexible design, FlightGear supports a wide range of joysticks and yokes as well as rudder pedals under Linux and Windows. FlightGear can also provide interfaces to full-motion flight chairs.
FlightGear is being developed primarily under Linux, a free UNIX clone (together with lots of GNU utilities) developed cooperatively over the Internet in much the same spirit as FlightGear itself. FlightGear also runs and is partly developed under several flavors of Windows. Building FlightGear is also possible on a macOS and several different UNIX/X11 workstations. Given you have a proper compiler installed, FlightGear can be built under all of these platforms. The primary compiler for all platforms is the free GNU C++ compiler (the Cygnus Cygwin compiler under Win32).
If you want to run FlightGear under macOS, you need to have macOS 10.9 or higher. All recent Apple hardware should run FlightGear, but discrete (as opposed to integrated) graphics will give much better performance (frame-rate). Note that FlightGear is not yet built for Apple Silicon machines, but will run on them using the automatic translation.
It is recommended that you run the latest official release, which is typically produced annually and is available from:
https://www.flightgear.org/download/
If you really want to get the most recent (and, at times, buggiest) code, you can clone the sources at:
https://sourceforge.net/p/flightgear/flightgear/ci/next/tree/
A detailed description of how to set this up for FlightGear can be found at:
https://wiki.flightgear.org/Git
Historically, FlightGear was based on a flight model it inherited (together with the Navion airplane) from LaRCsim. As this had several limitations (most importantly, many characteristics were hard wired in contrast to using configuration files), there were several attempts to develop or include alternative flight models. As a result, FlightGear supports several different flight models, to be chosen from at runtime.
Possibly the most important one is the JSB flight model developed by Jon Berndt. The JSB flight model is part of a stand-alone project called JSBSim:
Finally, there is the UIUC flight model, developed by a team at the University of Illinois at Urbana-Champaign. This work was initially geared toward modeling aircraft in icing conditions, but now encompasses “nonlinear” aerodynamics, which result in more realism in extreme attitudes, such as stall and high angle of attack flight. Two good examples that illustrate this capability are the Airwave Xtreme 150 hang glider and the 1903 Wright Flyer. More details of the UIUC flight model can be found at:
It is even possible to drive FlightGear’s scene display using an external FDM running on a different computer or via named pipe on the local machine – although this might not be a setup recommended to people just getting in touch with FlightGear.
There is little, if any, material within this guide that is presented here exclusively. You could even say with Montaigne that we “merely gathered here a big bunch of other men’s flowers, having furnished nothing of my own but the string to hold them together”. Most (but fortunately not all) of the information herein can also be obtained from the FlightGear web site located at:
The FlightGear Manual is intended to be a first step towards a complete FlightGear documentation. The target audience is the end-user who is not interested in the internal workings of OpenGL or in building his or her own scenery. It is our hope that someday there will be an accompanying FlightGear Programmer’s Guide a FlightGear Scenery Design Guide, describing the Scenery tools now packaged as TerraGear; and a FlightGear Flight School package.
We kindly ask you to help us refine this document by submitting corrections, improvements, suggestions and translations. All users are invited to contribute descriptions of alternative setups (graphics cards, operating systems etc.). We will be more than happy to include those in future versions of The FlightGear Manual (of course not without giving credit to the authors).