FlightGear

FlightGear started as an online proposal in 1996 by David Murr, living in the United States. He was dissatisfied with proprietary, available, simulators like the Microsoft Flight Simulator, citing motivations of companies not aligning with the simulators' players ("simmers"), and proposed a new flight simulator developed by volunteers over the Internet.{{Cite web|last=|first=|date=|title=Archive of rec.aviation.simulators at Google Groups|url=https://groups.google.com/d/msg/rec.aviation.simulators/ny8HFBE5_T8/OdtIiGNGJc8J|url-status=live|archive-url=https://archive.today/20190905071139/https://groups.google.com/forum/%23!msg/rec.aviation.simulators/ny8HFBE5_T8/OdtIiGNGJc8J|archive-date=2019-09-05|access-date=2019-09-05|website=groups.google.com}}{{Cite journal|last=Perry|first=Alexander R.|date=2004-06-27|title=The FlightGear flight simulator|url=https://www.usenix.org/legacy/events/usenix04/tech/sigs/full_papers/perry/perry.pdf|journal=Proceedings of the Annual Conference on USENIX Annual Technical Conference|series=ATEC '04|location=Boston, MA|publisher=USENIX Association|pages=31|archive-url=https://web.archive.org/web/20210316101914/https://www.usenix.org/legacy/events/usenix04/tech/sigs/full_papers/perry/perry.pdf|archive-date=16 March 2021}} The flight simulator was created using custom 3D graphics code. Development of an OpenGL based version was spearheaded by Curtis Olson starting in 1997. FlightGear incorporated other open-source resources, including the LaRCsim flight dynamics engine from NASA, and freely available elevation data. The first working binaries using OpenGL came out in 1997. By 1999 FlightGear had replaced LaRCsim with JSBSim built to the sims' needs, and in 2015 NASA used JSBSim alongside 6 other space industry standards to create a measuring stick to judge future space industry simulation code.{{Citation|last1=Murri|first1=Daniel G.|title=Check-Cases for Verification of 6-DOF Flight Vehicle Simulations - Volume I|date=2015|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150001264.pdf|volume=|pages=|publisher=NASA|language=en|doi=|access-date=2019-09-03|last2=E. Bruce Jackson|last3=Shelton|first3=Robert O.}}

FlightGear reached 1.0 in 2007, 2.0 in 2010, and there were 9 major releases under 2.x and 3.x labels, with the final one under the previous numbering scheme being "3.4", since "3.6" was cancelled. The project moved to a regular release cadence with 2-4 releases per year since 2016, with the first version under the new naming scheme being "2016.1". Around that time, the graphical front end "FlightGear Launch Control", also known as "FGRun", was replaced by a hard-coded Qt launcher.{{Cite web|title=Category:FlightGear changelogs - FlightGear wiki|url=http://wiki.flightgear.org/Category:FlightGear_changelogs|access-date=2021-02-13|website=FlightGear wiki}} FlightGear's source code is released under the terms of the GNU General Public License and is free and open-source software.

The FlightGear project has been nominated by SourceForge, and subsequently chosen as project of the month by the community, in 2015, 2017, and 2019.{{Cite web|last=|first=|date=2015-11-01|title=November 2015, "Community Choice" Project of the Month – FlightGear|url=https://sourceforge.net/blog/november-2015-community-choice-project-of-the-month-flightgear/|url-status=live|archive-url=https://web.archive.org/web/20190904083229/https://sourceforge.net/blog/november-2015-community-choice-project-of-the-month-flightgear/|archive-date=2019-09-04|access-date=2019-09-04|website=SourceForge Community Blog|language=en-US}}{{Cite web|last=|first=|date=2017-09-01|title=September 2017, "Community Choice" Project of the Month – FlightGear|url=https://sourceforge.net/blog/september-2017-community-choice-project-month-flightgear/|url-status=live|archive-url=https://web.archive.org/web/20190904100359/https://sourceforge.net/blog/september-2017-community-choice-project-month-flightgear/|archive-date=2019-09-04|access-date=2019-09-04|website=SourceForge Community Blog|language=en-US}}{{Cite web|last=|first=|date=2019-02-01|title=February 2019, "Community Choice" Project of the Month – FlightGear|url=https://sourceforge.net/blog/february-2019-community-choice-project-month-flightgear/|url-status=live|archive-url=https://web.archive.org/web/20190904083341/https://sourceforge.net/blog/february-2019-community-choice-project-month-flightgear/|archive-date=2019-09-04|access-date=2019-09-04|website=SourceForge Community Blog|language=en-US}}

Forces experienced by a flying aircraft depend on the time-varying state of atmospheric fluid flow along the flight path - the atmosphere being a fluid that can exchange energy, exchange moisture or particles, change phase or other state, and exert force with boundaries formed by surfaces. Fluid behaviour is often characterised by eddies^{(Videos:[https://www.youtube.com/watch?v=-D5N_OnZ_Tg aircraft], [https://www.youtube.com/watch?v=4JNkaVEXKqU terrain])} or vortices on varying scales down to the microscopic, but is harder to observe as the air is clear except for moisture phase changes like condensation trails or clouds. The atmosphere-terrain boundary interaction follows fluid dynamics, just with processes on hugely varying scales and 'weather' is the planetary boundary layer. The aircraft surface interaction works with the same dynamics, but on a limited range of scales. Forces experienced at any point along a flight path, therefore, are the result of complicated atmospheric processes on varying spatial scales, and complex flow along the craft's surface. Craft also experience varying gravitational force based on the 3d shape of the potential well and the non-spherical shape of the Earth.

FlightGear can simulate the atmosphere ranging from energy inputs/outputs to the system, like energy from the Sun or volcanic sources, through to fluid flow on various scales and changes of state. FlightGear is able to model different surface characteristics such as heating or cooling, and the exchange of heat and moisture with the atmosphere depending on factors like windflow or dew point. FlightGear models the continuously evolving life-cycle of phenomena on various scales, driven by interaction of fluid with terrain. They range from turbulence on different scales to, individual thermals, thunderstorms, through to moving air layers, and depicting air-masses on the scale of thousands of kilometers. Atmospheric water is modeled by FlightGear ranging from state changes such as condensing into cloud or haze layers, along with energy provided from latent heat to drive convective fluid flow, through to precipitation as rain droplets, snow, or hail.{{Cite web|last=|first=|date=June 25, 2013|title=The art of cloud and weather rendering – FlightGear Flight Simulator|url=https://www.flightgear.org/tours/the-art-of-cloud-and-weather-rendering/|url-status=live|archive-url=https://web.archive.org/web/20201031172624/https://www.flightgear.org/tours/the-art-of-cloud-and-weather-rendering/|archive-date=31 October 2020|access-date=2019-07-23|website=FlightGear.org|language=en-US}}{{Cite web|last=|first=|date=December 17, 2014|title=The magic of light and haze – FlightGear Flight Simulator|url=https://www.flightgear.org/tours/the-magic-of-light-and-haze/|url-status=live|archive-url=https://web.archive.org/web/20201205092108/https://www.flightgear.org/tours/the-magic-of-light-and-haze/|archive-date=5 December 2020|access-date=2019-08-31|website=FlightGear.org|language=en-US}}{{Cite web|last=|first=|date=November 30, 2014|title=A preview of features for Flightgear 3.4 – FlightGear Flight Simulator|url=https://www.flightgear.org/info/a-preview-of-features-for-flightgear-3-4/|url-status=live|archive-url=https://web.archive.org/web/20210119222757/https://www.flightgear.org/info/a-preview-of-features-for-flightgear-3-4/|archive-date=19 January 2021|access-date=2019-08-31|website=FlightGear.org|language=en-US}}{{Cite web|last=|first=|date=February 24, 2012|title=Advanced Weather v1.4 in Flightgear 2.6+ – FlightGear Flight Simulator|url=https://www.flightgear.org/tours/advanced-weather-v1-4-in-flightgear-2-6/|url-status=live|archive-url=https://web.archive.org/web/20190831105119/https://www.flightgear.org/tours/advanced-weather-v1-4-in-flightgear-2-6/|archive-date=31 August 2019|access-date=2019-08-31|website=FlightGear.org|language=en-US}}

The process of generating lift creates turbulence with vortices, and FlightGear models wake turbulence with shedding of wingtip vortices by flown craft as well as AI craft.{{Cite web|title=AI wake turbulence - FlightGear wiki|url=http://wiki.flightgear.org/AI_wake_turbulence|access-date=2019-09-04|website=FlightGear wiki}}{{Cite web|title=Changelog 2017.3 - FlightGear wiki|url=https://wiki.flightgear.org/Changelog_2017.3#JSBSim|url-status=live|archive-url=https://web.archive.org/web/20200705062057/https://wiki.flightgear.org/Changelog_2017.3#JSBSim|archive-date=5 July 2020|access-date=2021-03-15|website=FlightGear wiki}}

FlightGear also has a less physically accurate model that uses METAR weather updates of differing frequency, designed for safe operation of aerodromes, to dis-continuously force atmosphere based on attempted guesses of processes that are fundamentally constrained by the closeness or density of observation stations, as well as the small-scale, limited, rounded off, non-smoothly varying, and need-to-know precision of information.{{Cite web|title=Weather - FlightGear wiki|url=http://wiki.flightgear.org/Weather#Scenarios_and_METAR|access-date=2019-09-04|website=FlightGear wiki}} Aloft waypoint settings modelling high altitude behaviors of wind can be synced to updates from Jeppeson.{{Cite web|last=|first=|date=|title=Weather - FlightGear wiki|url=http://wiki.flightgear.org/Howto:Fetch_live_aloft_data|url-status=live|archive-url=https://web.archive.org/web/20190904073627/http://wiki.flightgear.org/Howto:Fetch_live_aloft_data|archive-date=2019-09-04|access-date=2019-07-23|website=FlightGear wiki}}

Flightgear has a simulation of planetary bodies in the Solar System which is used for purposes like driving latitude dependent weather from solar radiation, as well as the brightness and position of stars for celestial navigation. There is a model of gravity based on a non-spherical Earth, and craft can even experience differing gravity across their bodies which will exert twisting force.{{Cite web|last=|first=|date=December 18, 2015|title=An experience like no other… – FlightGear Flight Simulator|url=https://www.flightgear.org/tours/an-experience-like-no-other/|url-status=live|archive-url=https://web.archive.org/web/20210315092603/https://www.flightgear.org/tours/an-experience-like-no-other/|archive-date=15 March 2021|access-date=2019-08-31|website=FlightGear.org|language=en-US}} A model of the observed variation in the Earth's complex magnetic field, and the option to simulate, to an extent, the propagation of radio wave signals due to interaction with different types of terrain, also exists in FlightGear.{{Cite web|title=Avionics and instruments - FlightGear wiki|url=http://wiki.flightgear.org/Avionics_and_instruments#Compass|access-date=2019-09-05|website=wiki.flightgear.org}}{{Cite web|title=Radio propagation - FlightGear wiki|url=http://wiki.flightgear.org/Radio_propagation#Rationale|access-date=2019-09-05|website=wiki.flightgear.org}}

FlightGear uses an exact, non-spherical, model of Earth, and is also able to simulate flight in polar regions and airports (arctic or antarctic) without simulator errors due to issues with coordinate systems.

FlightGear supports multiple flight dynamics engines with differing approaches, and external sources such as MATLAB/Simulink, as well as custom flight models for hot air balloons and spacecraft.{{Cite web|title=Flight Dynamics Model - FlightGear wiki|url=http://wiki.flightgear.org/Flight_Dynamics_Model|access-date=2019-07-23|website=wiki.flightgear.org}}{{Cite web|title=Flight Simulator Interface - MATLAB & Simulink|url=https://www.mathworks.com/help/aeroblks/introducing-the-flight-simulator-interface.html|archive-url=https://web.archive.org/web/20130704083155/http://www.mathworks.com/help/aeroblks/introducing-the-flight-simulator-interface.html|archive-date=2013-07-04|url-status=live|access-date=2021-03-15|website=Mathworks - Makers of MATLAB and Simulink - MATLAB & Simulink}}

JSBSim is a data driven flight dynamics engine with a C++ core built to the needs of the FlightGear project from 1996 to replace NASA's LaRCSim, and integrated into FlightGear as the default from 1999.{{Citation|last=Berndt|first=Jon|title=JSBSim: An Open Source Flight Dynamics Model in C++|url=https://arc.aiaa.org/doi/abs/10.2514/6.2004-4923|work=AIAA Modeling and Simulation Technologies Conference and Exhibit|year=2004|publisher=American Institute of Aeronautics and Astronautics|doi=10.2514/6.2004-4923|isbn=978-1-62410-074-1|access-date=2019-09-01|url-access=subscription}} Flight characteristics are preserved despite low frame rate, as JSBSim physics are decoupled from rendering and tick at 120 Hz by default.{{Cite web|last=|first=|date=|title=Howto:Methods to replace the NASAL code with JSBSim code - FlightGear wiki|url=http://wiki.flightgear.org/Howto:Methods_to_replace_the_NASAL_code_with_JSBSim_code#Performance_of_JSBSim_.28or_data-driven_languages.29_in_a_real-time_.28RT.29_context|url-status=live|archive-url=https://web.archive.org/web/20190903092718/http://wiki.flightgear.org/Howto:Methods_to_replace_the_NASAL_code_with_JSBSim_code|archive-date=2019-09-03|access-date=2019-09-03|website=FlightGear wiki}} This also supports high time-acceleration as rendering does not have to be done faster causing the GPU to be a bottleneck.

Mass balance, ground reactions, propulsion, aerodynamics, buoyant forces, external forces, atmospheric forces, and gravitational forces can be utilized by JSBSim, the current default flight dynamics engine supported by FlightGear, to determine flight characteristics.{{Cite web|title=JSBSim - FlightGear wiki|url=http://wiki.flightgear.org/JSBSim|access-date=2019-07-23|website=wiki.flightgear.org}} JSBSim supports non-terrestrial atmospheres and has been used to model unmanned flight in the Martian atmosphere by NASA.{{Cite web|last=|first=|date=|title=JSBSim Open Source Flight Dynamics Model|url=http://jsbsim.sourceforge.net/links.html|url-status=live|archive-url=https://web.archive.org/web/20190901135809/http://jsbsim.sourceforge.net/links.html|archive-date=2019-09-01|access-date=2019-09-01|website=jsbsim.sourceforge.net}}{{Citation|last1=Kenney|first1=P. Sean|title=Simulating The ARES Aircraft In The Mars Environment|url=https://arc.aiaa.org/doi/abs/10.2514/6.2003-6579|work=2nd AIAA "Unmanned Unlimited" Conf. and Workshop & Exhibit|publisher=American Institute of Aeronautics and Astronautics|doi=10.2514/6.2003-6579|access-date=2019-09-01|last2=Croom|first2=Mark|year=2003|isbn=978-1-62410-094-9|hdl=2060/20040034718|s2cid=13269363 |hdl-access=free}}

JSBSim was used by NASA in 2015 with other space industry simulation code, both to establish a ruler to judge future code for the requirements and standards of the space industry, as well as check agreement. The verification tested both atmospheric and orbital flight in 6-degrees-of-freedom for simulations like JSBSim{{Cite web|date=January 2015|title=Check-Cases for Verification of 6-Degree-of-Freedom Flight Vehicle Simulations - Volume II|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150001264.pdf|url-status=live|archive-url=https://web.archive.org/web/20170227123110/https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150001264.pdf|archive-date=2017-02-27|access-date=|website=NASA Technical Reports Server|at=See Section B.6.7 JSBSim|last1=Murri|first1=Daniel G.|last2=Jackson|first2=E. Bruce|last3=Shelton|first3=Robert O.}} that supported both. The results from 6 participants consisting of NASA Ames Research Center (VMSRTE), Armstrong Flight Research Center (Core), Johnson Space Center (JEOD), Langley Research Center (LaSRS++, POST-II), Marshall Space Flight Center (MAVERIC), and JSBSim{{Citation|last1=Murri|first1=Daniel G.|title=Check-Cases for Verification of 6-DOF Flight Vehicle Simulations - Volume I|date=2015|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150001264.pdf|volume=|pages=|publisher=NASA|language=en|doi=|access-date=2019-09-03|last2=E. Bruce Jackson|last3=Shelton|first3=Robert O.}}{{Cite web|last=|first=|date=|title=Check-Cases for Verification of 6-Degree-of-Freedom Flight Vehicle Simulations - Volume I|url=https://nescacademy.nasa.gov/src/flightsim/Reports/NASA-TM-2015-218675-EOM_checkcase_summary.pdf|access-date=|website=NASA Engineering and Safety Center Academy|at=See Section 7.4 - Summary of Comparisons}} were anonymous{{Cite web|last=|first=|date=2015|title=Further Development of Verification Check-cases for Six-Degree-of-Freedom Flight Vehicle Simulations|url=https://nescacademy.nasa.gov/src/flightsim/Reports/aiaa-15-1810-EOM_chkcases-II.pdf|url-status=live|archive-url=https://web.archive.org/web/20210310134926/https://nescacademy.nasa.gov/src/flightsim/Reports/aiaa-15-1810-EOM_chkcases-II.pdf|archive-date=10 March 2021|access-date=|website=NASA Engineering and Safety Center|at=See Section II G}} as NASA wanted to encourage participation. However, the assessment found agreement for all test cases between the majority of participants, with the differences being explainable and reducible for the rest, and with the orbital tests agreeing "quite well" for all participants.

YASim's approach to flight dynamics uses the geometry of the aircraft present in the 3D model at startup, conceptually similar to Blade element theory used by some software, to calculate a rough approximation of fluid dynamics - with the conceptual problems that each "element" is considered in isolation therefore missing affecting fluid flow to other elements, and the approximation breaking down for craft in transonic to hypersonic regimes.{{Cite web|last=Neely|first=Gary|date=|title=What is YASim?|url=http://www.buckarooshangar.com/flightgear/yasimtut_introduction.html|url-status=live|archive-url=https://web.archive.org/web/20190902085249/http://www.buckarooshangar.com/flightgear/yasimtut_introduction.html|archive-date=2019-09-02|access-date=2019-09-02|website=www.buckarooshangar.com}} By contrast, offline approaches like JSBSim can incorporate windtunnel data. They can also incorporate the results of computational fluid dynamics which can reach computable accuracy only limited by the nature of the problem and present day computational resources.

FlightGear also supports LaRCsim and UIUC.{{Cite web|title=Flight Dynamics Model - FlightGear wiki|url=http://wiki.flightgear.org/Flight_Dynamics_Model|access-date=2019-07-23|website=FlightGear wiki}}{{Cite book|last1=Zhang Jingsha|last2=Geng Qingbo|last3=Fei Qing|title=International Conference on Automatic Control and Artificial Intelligence (ACAI 2012) |chapter=UAV Flight Control System Modeling and Simulation Based on FlightGear |date=2012 |url=http://mr.crossref.org/iPage?doi=10.1049/cp.2012.1443 |pages=2231–2234|publisher=Institution of Engineering and Technology|doi=10.1049/cp.2012.1443|isbn=978-1-84919-537-9}}

FlightGear is able to accelerate and decelerate time, speeding up or slowing down the simulation. Time acceleration is a critical feature for simulating longer flights and space missions. For all interactions with the simulator, it allows people to speed up uneventful parts, and gain more experience (decisions and problem solving). It also means automated simulations used for research finish faster - this is helped by FlightGear's headless mode.

FlightGear is able to support high time accelerations by allowing parts of the simulation to run at different rates. This allows saving of CPU and GPU resources by letting unimportant parts of the simulation, like visuals or less time-sensitive aircraft systems, run at slower rates. It also improves performance. Separate clocks are available for JSBSim physics, different parts of aircraft systems, as well as environment simulations at large scale (celestial simulation) and small scale (weather physics).

Flightgear's atmospheric rendering is able to provide constantly changing visual cues of processes affecting atmospheric fluid flow and their likely evolution and history - to make prediction of conditions ahead or when returning at a later time possible. Simulation of directional light scattering by the Advanced Light Scattering framework in the atmosphere shows the 3d distribution, layering, geometry, and even statistical orientation of particles in different scattering regimes like Mie or Rayleigh. This ranges from different moisture droplets, to smog, to ice crystals of different geometry in clouds or halos.{{Cite web|title=FlightSim.Com - FlightGear's Atmospheric Light Scattering Rendering Framework|url=https://www.flightsim.com/vbfs/content.php?16990-FlightGear-s-Atmospheric-Light-Scattering-Rendering-Framework|url-status=live|archive-url=https://web.archive.org/web/20210315105803/https://www.flightsim.com/vbfs/content.php?16990-FlightGear-s-Atmospheric-Light-Scattering-Rendering-Framework|archive-date=15 March 2021|access-date=2021-03-15|website=FlightSim.Com|at=See pages 1 to 6}}{{Cite web|title=FlightSim.Com - Weather in FlightGear--|url=https://www.flightsim.com/vbfs/content.php?18201-Weather-in-FlightGear/view/2|url-status=live|archive-url=https://web.archive.org/web/20210315112815/https://www.flightsim.com/vbfs/content.php?18201-Weather-in-FlightGear|archive-date=15 March 2021|access-date=2021-03-15|website=www.flightsim.com|at=See pages 1 to 3}}

The 3d density distribution of cloud (or condensation trail) moisture rendered by FlightGear acts as a cue to the corresponding 3d structure of fluid flow, such as the up and down draft loop of storm cell, internal gravity waves forming undulating cloud bands signalling a sweeping cold front, or windshear shaping cirrus clouds at higher altitude.

FlightGear is able to render rain falling from specific clouds in rain volumes containing the correct droplet size to determine the properties like thickness and intensity of rainbows. Perceptual phenomena like rain streaks are rendered with streak length shortening as time is slowed. Rain and water spray streaks on canopy glass provides cues to the relative air flow, while frost and fog with correct light scattering provide cues to temperature.{{Cite web|last=|first=|date=December 7, 2015|title=The new Cessna 172p – FlightGear Flight Simulator|url=https://www.flightgear.org/tours/the-new-cessna-172p/|url-status=live|archive-url=https://web.archive.org/web/20201205093411/https://www.flightgear.org/tours/the-new-cessna-172p/|archive-date=5 December 2020|access-date=2019-08-31|website=FlightGear.org|language=en-US}}

FlightGear is able to render specified historical accumulation levels of water and snow accounting for flatness on the surfaces of for both terrain and buildings. This provides cues to surface moisture or friction, and weather driven by surface heating that reduces with snow thickness. FlightGear can render gradual snow and ice cover on inland and ocean water.

Layering of hazes is rendered by FlightGear, such as low lying ground haze with 3d structure, smog related to human activity, and dust. FlightGear renders various halos due to ice crystals in the atmosphere, or due to Mie scattering in fog by artificial lights such as landing lights.

FlightGear is able to render day/night visuals of Earth from orbit at high detail with scattering due to clouds, dust, and moisture, as well as effects such as lightning illuminating storm cells. Orientation cues in cockpit are provided by changing colour of light from Sun, Earth, and Moon for craft such as the Space Shuttle. The gradual transition in lighting for spacecraft, between upper and lower atmosphere regimes, is handled by dedicated rendering code. Auroras are simulated with varying intensity and varying penetration of magnetic flux tubes into the atmosphere. They are visible from both space and ground.{{Cite web|last=|first=|date=August 26, 2018|title=The Grand View – FlightGear Flight Simulator|url=https://www.flightgear.org/tours/the-grand-view/|url-status=live|archive-url=https://web.archive.org/web/20201205091017/https://www.flightgear.org/tours/the-grand-view/|archive-date=5 December 2020|access-date=2019-08-31|website=FlightGear.org|language=en-US}}

Accurate rendering of planets, moons, and stars with correct phases/brightness based on FlightGear's celestial simulation allows cues or data for celestial navigation - without reliance on vulnerable ground aids, including of pre-GPS era craft. The celestial simulation allows craft such as the Space Shuttle{{Cite web|title=FlightSim.Com - FlightGear - Visiting the ISS|url=https://www.flightsim.com/vbfs/content.php?19086-FlightGear-Visiting-the-ISS|access-date=2021-03-15|website=FlightSim.Com}} to use star tracker instruments.

Flightgear's Advanced Light Scattering framework simulates locations in time as well as space. The environment simulation renders seasonal change as leaves of different species of trees, bushes, and grass change colour or fall.{{Cite web|last=|first=|date=February 21, 2015|title=Simulating the ever-changing scenery – FlightGear Flight Simulator|url=https://www.flightgear.org/tours/simulating-the-ever-changing-scenery/|url-status=live|archive-url=https://web.archive.org/web/20201205083451/https://www.flightgear.org/tours/simulating-the-ever-changing-scenery/|archive-date=5 December 2020|access-date=2019-08-31|website=FlightGear.org|language=en-US}} Simulated swaying of grass, trees and windsocks provide cues to processes changing the windfield near the ground, while wave simulation provides cues near water. Cloud shadows and the general state of the atmosphere affect light traveling to each point of the environment and then traveling in the atmosphere to reach the eye - the cloud setup and particle spread in the atmosphere changes the colour of the light cast on the environment. Water colour therefore changes based on atmosphere overhead, and also depends on water impurites in a region. FlightGear is capable of rendering a variety of volcanic activity of different intensity that, from v2019.2, responds to the windfield, as well as smoke.

The combination of rendering of the state of atmospheric processes, Aurora, simulation of celestial bodies, ground accumulation of rain or snow or dust, ice cover of water, and the environment simulation produces visualisations with a vast number of permutations.

Several networking options allow {{em|FlightGear}} to communicate with other instances of {{em|FlightGear}}. A multiplayer protocol is available for using {{em|FlightGear}} on a local network in a multi aircraft environment. This can be used for formation flight or air traffic control simulation. Soon after the original Multiplayer Protocol became available, it was expanded to allow playing over the internet. It is possible to see other players in the simulator if they have the same aircraft models and viewing their flight path is possible with the simulator's online multiplayer map.{{Cite web|url=https://mpmap03.flightgear.org/|title=FlightGear μ - The MultiPlayer Map|website=mpmap03.flightgear.org|access-date=2019-07-23}}

Since {{em|FlightGear}} version 2020.1 it is possible to connect to VATSIM by using the open-source swift pilot client.{{Cite web|url=https://wiki.flightgear.org/Swift|title=swift - FlightGear wiki|website=wiki.flightgear.org|access-date=2022-05-18}}

Several instances of {{em|FlightGear}} can be synchronized to allow for a multi-monitor environment.

File:Fgfs-screen-002.png

{{em|FlightGear}} uses METAR data to produce live weather patterns in real time.{{Cite web|url=http://wiki.flightgear.org/index.php?title=Weather_reports&redirect=no#METAR|title=Weather reports - FlightGear wiki|website=wiki.flightgear.org|access-date=2019-07-23}}{{Dead link|date=April 2024 |bot=InternetArchiveBot |fix-attempted=yes }} Detailed weather settings allow for 3d clouds, a variety of cloud types, and precipitation. Precipitation and terrain affect turbulence and cloud formations.{{Cite web|url=https://www.flightgear.org/tours/the-art-of-cloud-and-weather-rendering/|title=The art of cloud and weather rendering – FlightGear Flight Simulator|date=June 25, 2013 |language=en-US|access-date=2019-07-23}} Aloft waypoint settings allow high altitude behaviors of wind to be modeled from live weather information, and thermals can also be modeled.{{Cite web|url=http://wiki.flightgear.org/Weather#Thermic_and_visibility_settings|title=Weather - FlightGear wiki|website=wiki.flightgear.org|access-date=2019-07-23}}

Although not developed or typically analyzed solely as a game in the traditional sense, {{em|FlightGear}} has nevertheless undergone reviews in a number of online and offline publications, and received positive reviews as a flight simulator game.{{cite web|publisher=Flight Sim|url=http://www.flightsim.com/main/review/fltgear.htm|title=Review|url-status=dead|archive-url=https://web.archive.org/web/20100228145133/http://www.flightsim.com/main/review/fltgear.htm|archive-date=February 28, 2010}} {{em|FlightGear}} 1.0.0 was noted as being impressive for a game over a decade in the making, with a wide variety of aircraft and features.

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=September 1, 2006|work=PC Magazine (UK)|url=http://www.pcmag.co.uk/computeractive/downloads/2163376/flightgear|access-date=June 29, 2007|url-status=dead|archive-url=https://web.archive.org/web/20070927201051/http://www.pcmag.co.uk/computeractive/downloads/2163376/flightgear|archive-date=September 27, 2007}} Linux Format reviewed version 2.0 and rated it 8/10.[https://archive.org/stream/Linux_Format_132_June_2010#page/n25/mode/2up/search/reviews Linux_Format_132_June_2010]

In June 2014 Honda lawyers issued a takedown request in which it was claimed that the HondaJet model in the simulator infringes on Honda's trademarks. Subsequently, HondaJet became the first model removed from the simulator for legal reasons.{{Cite web|author=Ernesto|url=https://torrentfreak.com/honda-takes-copyright-infringing-jet-flightgear-140603/|title=Honda Takes Down "Infringing" Jet From FlightGear|publisher=TorrentFreak|date=June 3, 2014|access-date=June 4, 2014|archive-url=https://web.archive.org/web/20140606112909/http://torrentfreak.com/honda-takes-copyright-infringing-jet-flightgear-140603/|archive-date=June 6, 2014|url-status=live|df=mdy-all}}

Games journalist Tim Stone, in his simulation column The Flare Path, criticized the practice of third-parties attempting to profit from the work of community volunteers to the project, pointing to deceptive practices of stealing media available online from other sims to misrepresent VirtualPilot3d, as well as highlighting allegedly fake customer testimonials.{{Cite web|last=Stone|first=Tim|date=2012-08-24|title=The Flare Path: Don't Buy VirtualPilot3D|url=https://www.rockpapershotgun.com/2012/08/24/the-flare-path-dont-buy-virtualpilot3d/|access-date=2020-08-17|website=Rock, Paper, Shotgun|language=en-US}} Following up in 2018, Tim Stone wrote a second column in which he again criticized the "ethical standards" and "extraordinary willingness to lie in the pursuit of sales" displayed by the advertisements for another game which used screenshots from FlightGear.{{Cite web|last=Stone|first=Tim|date=2018-03-09|title=Don't Buy ProFlightSimulator|url=https://www.rockpapershotgun.com/2018/03/09/dont-buy-proflightsimulator/|access-date=2020-08-17|website=Rock, Paper, Shotgun|language=en-US}}

FlightGear has been used in a range of projects in academia and industry (including NASA).{{cite web|url=http://www.usenix.org/events/usenix04/tech/sigs/full_papers/perry/perry_html/Applications_Simulator.html|title=Applications for the Simulator|access-date=September 3, 2007|work=usenix.org|archive-url=https://web.archive.org/web/20071113211512/http://www.usenix.org/events/usenix04/tech/sigs/full_papers/perry/perry_html/Applications_Simulator.html|archive-date=November 13, 2007|url-status=live|df=mdy-all}} The application has also been used for pilot training and as a research and development platform by various agencies and universities.

The simulator has been used by numerous institutes and companies, such as NASA/Ames Human Centered System Lab.{{Cite web|url=http://www.lfstech.com/|title=LFS Technologies|access-date=February 7, 2019|archive-url=https://web.archive.org/web/20160410085357/http://www.lfstech.com/|archive-date=April 10, 2016|url-status=live|df=mdy-all}}[https://web.archive.org/web/20021115162546/http://human-factors.arc.nasa.gov/ihi/hcsl/publications.html Human Centered System Labs], NASA Pragolet s.r.o.{{cite web|url=http://www.pragolet.cz/clanky/flight_simulator_of_light_and_ultralight_aircraft.html|title=Simulator of a Light and Ultra-Light Sport Aircraft|last=Thöndel|first=Evžen|date=January 29, 2009|publisher=Pragolet|access-date=June 12, 2017|archive-url=https://web.archive.org/web/20110112214516/http://www.pragolet.cz/clanky/flight_simulator_of_light_and_ultralight_aircraft.html|archive-date=January 12, 2011|url-status=dead|df=mdy-all}} and the Endless Runway Project; a consortium of several European aerospace institutes.{{Cite web|url=http://endlessrunway-project.eu/downloads/d3.2-aircraft-aspects.pdf|title=Aircraft aspects of the Endless Runway|date=September 30, 2013|access-date=January 16, 2014|archive-url=https://web.archive.org/web/20140416225634/http://endlessrunway-project.eu/downloads/d3.2-aircraft-aspects.pdf|archive-date=April 16, 2014|url-status=live|df=mdy-all}}{{Cite web|url=http://endlessrunway-project.eu/|title=endlessrunway-project.eu|access-date=June 12, 2017|archive-url=https://web.archive.org/web/20170605085904/http://www.endlessrunway-project.eu/|archive-date=June 5, 2017|url-status=live|df=mdy-all}}

• MathWorks FlightGear to Simulink interface.[http://www.mathworks.com/access/helpdesk/help/toolbox/aeroblks/ Aerospace Blockset] {{Webarchive|url=https://web.archive.org/web/20100616004236/http://www.mathworks.com/access/helpdesk/help/toolbox/aeroblks/|date=June 16, 2010}}
• NASA/Ames Human Centered System Lab - 737NG full scale cockpit simulator.{{Cite web|url=http://www.lfstech.com/|title=LFS Technologies|access-date=February 7, 2019|archive-url=https://web.archive.org/web/20160410085357/http://www.lfstech.com/ |archive-date=April 10, 2016|url-status=live|df=mdy-all}}
• Pragolet s.r.o. for light and ultra-light sports aircraft.{{cite web |url=http://www.pragolet.cz/clanky/flight_simulator_of_light_and_ultralight_aircraft.html |title=Simulator of a Light and Ultra-Light Sport Aircraft |last=Thöndel |first=Evžen |date=January 29, 2009 |publisher=Pragolet |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20110112214516/http://www.pragolet.cz/clanky/flight_simulator_of_light_and_ultralight_aircraft.html |archive-date=January 12, 2011 |url-status=dead |df=mdy-all }}
• PAL-V Europe NV{{cite web |url=http://pal-v.com/licenses/the-pal-v-simulator/ |title=The PAL-V simulator |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20170113024315/http://pal-v.com/licenses/the-pal-v-simulator/ |archive-date=January 13, 2017 |url-status=dead |df=mdy-all }}
• Max Planck Institute for Biological Cybernetics, Germany, HeliLab{{cite web |url=http://www.cyberneum.de/de/forschungseinrichtungen/helilab.html |title=HeliLab (Tiled Display) |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20140416210626/http://www.cyberneum.de/de/forschungseinrichtungen/helilab.html |archive-date=April 16, 2014 |url-status=live |df=mdy-all }} and MPI CyberMotion Simulator{{cite web |url=http://www.cyberneum.de/de/labore-forschung/cmslab.html |title=Der MPI-CyberMotion-Simulator |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20170421093055/http://www.cyberneum.de/de/labore-forschung/cmslab.html |archive-date=April 21, 2017 |url-status=live |df=mdy-all }}
• Institute for Scientific Research{{Cite FTP |url=ftp://ftp.uni-duisburg.de/pub/FlightGear/Docs/AIAA-2005-7083.pdf |title=Simulated Flight Testing of an Autonomous Unmanned Aerial Vehicle Using FlightGear |date=September 2005 |server=FTP server |url-status=dead |author=Eric F. Sorton, Sonny Hammaker }}

Endless Runway Project, consortium of several European aerospace institutes.{{Cite web |url=http://endlessrunway-project.eu/downloads/d3.2-aircraft-aspects.pdf |title=Aircraft aspects of the Endless Runway |date=September 30, 2013 |access-date=January 16, 2014 |archive-url=https://web.archive.org/web/20140416225634/http://endlessrunway-project.eu/downloads/d3.2-aircraft-aspects.pdf |archive-date=April 16, 2014 |url-status=live |df=mdy-all }}{{Cite web |url=http://endlessrunway-project.eu/ |title=endlessrunway-project.eu |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20170605085904/http://www.endlessrunway-project.eu/ |archive-date=June 5, 2017 |url-status=live |df=mdy-all }}

• Minia University, Egypt{{cite web |url=https://www.researchgate.net/publication/236174210 |title=Automatic control education using FlightGear and MATLAB based virtual lab |date=May 2012}}

• The Department of Aircraft and Aeroengine from the Chinese Air Force Engineering University{{Cite journal |url=https://www.sciencedirect.com/science/article/pii/S1000936111604342 |title=Airworthiness Compliance Verification Method Based on Simulation of Complex System |date=January 12, 2012 |last1=X |first1=Haojun |last2=Liu |first2=Dongliang |last3=Xue |first3=Yuan |last4=Zhou |first4=Li |last5=Min |first5=Guilong |journal=Chinese Journal of Aeronautics |volume=25 |issue=5 |pages=681–690 |doi=10.1016/S1000-9361(11)60434-2 |access-date=November 7, 2024|doi-access=free }}
• Nanjing University of Aeronautics and Astronautics, China{{cite journal |url=http://www.joca.cn/EN/abstract/abstract16042.shtml |title=3D simulation of A-SMGCS surface movement based on FlightGear |date=May 16, 2012|doi=10.3724/SP.J.1087.2012.03228 |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20171020003646/http://www.joca.cn/EN/abstract/abstract16042.shtml |archive-date=October 20, 2017 |url-status=live |df=mdy-all |last1=Tang |first1=Yong |last2=Hu |first2=Ming-hua |last3=Wu |first3=Hong-Gang |last4=Huang |first4=Zhong-tao |last5=Xu |first5=Zi-li |last6=He |first6=Dong-lin |journal=Journal of Computer Applications |volume=32 |issue=11 |pages=3228–3231|doi-broken-date=December 7, 2024 |url-access=subscription }}
• Shenyang Institute of Automation, China{{Cite journal |url=http://ojs.unsysdigital.com/index.php/just/article/view/2 |title=LP Based Path Planning for Autonomous Landing of An Unmanned Helicopter on A Moving Platform |last1=Wu |first1=Chong |last2=Qi |first2=Juntong |last3=Song |first3=Dalei |last4=Han |first4=Jianda |date=May 24, 2013 |issue=1 |pages=7–13 |journal=Journal of Unmanned System Technology |volume=1 |access-date=November 7, 2024 |archive-url=https://web.archive.org/web/20140228061835/http://ojs.unsysdigital.com/index.php/just/article/view/2 |archive-date=February 28, 2014 |url-status=live |df=mdy-all }}

• RMIT University, Melbourne, Australia{{cite web |url=https://researchbank.rmit.edu.au/eserv/rmit:160101/Thorpe.pdf |title=Modelling and Control of Tethered Kite Systems for Wind Energy Extraction |last=Thorpe |first=Dylan |date=April 2007 |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20150909150954/https://researchbank.rmit.edu.au/eserv/rmit:160101/Thorpe.pdf |archive-date=September 9, 2015 |url-status=live |df=mdy-all }}

• Institute of Aerospace Engineering at the RWTH Aachen{{Cite web |url=http://www.dynamik.rwth-aachen.de/English/Simulators |title=Simulators < English < TWiki |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20100403095645/http://www.dynamik.rwth-aachen.de/English/Simulators |archive-date=April 3, 2010 |url-status=dead |df=mdy-all }}
• University of Naples, Italy{{cite web |url=http://wpage.unina.it/agodemar/DSV-DQV/AIAA_MST_2007_DeMarco_Coiro_Nicolosi_paper.pdf |title=A 6DOF Flight Simulation Environment for General Aviation Aircraft with Control Loading Reproduction |author1=Domenico P. Coiro |author2=Agostino De Marco |author3=Fabrizio Nicolosi |date=2007 |url-status=live |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20140416220631/http://wpage.unina.it/agodemar/DSV-DQV/AIAA_MST_2007_DeMarco_Coiro_Nicolosi_paper.pdf |archive-date=April 16, 2014 |df=mdy-all }}
• University of Wales Intelligent Robotics Group, Aberystwyth, UK[http://users.aber.ac.uk/dpb/aerobots.html Aerobot Research] {{Webarchive|url=https://web.archive.org/web/20140209124540/http://users.aber.ac.uk/dpb/aerobots.html |date=February 9, 2014 }}, Dave Barne
• Delft University of Technology, the Netherlands{{cite web |url=http://www.kbs.twi.tudelft.nl/Research/Projects/ICE/index.html |title=The Intelligent Cockpit Environment (ICE) Project |last=Ehlert |first=Patrick |date=January 18, 2005 |publisher=TU Delft |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20140416214055/http://www.kbs.twi.tudelft.nl/Research/Projects/ICE/index.html |archive-date=April 16, 2014 |url-status=live |df=mdy-all }}{{cite web |url=http://mmi.tudelft.nl/pub/patrick/Ehlert.P.A.M-GAMEON2002.pdf |title=Recognising situations in a flight simulator environment |date=November 2002 |first1=Patrick A.M. |last1=Ehlert |first2=Quint M. |last2=Mouthaan |first3=Leon J.M. |last3=Rothkrantz |access-date=November 7, 2024 |publisher=SCS Publishing House |archive-url=https://web.archive.org/web/20170705082248/http://mmi.tudelft.nl/pub/patrick/Ehlert.P.A.M-GAMEON2002.pdf |archive-date=July 5, 2017 |url-status=live |df=mdy-all }}{{cite web |url=http://www.kbs.twi.tudelft.nl/People/Students/D.Dragos/back/ice/index.htm |title=The ICE Project |author=Datcu Dragos |date=January 2003 |access-date=May 8, 2012 |archive-url=https://web.archive.org/web/20040908181249/http://www.kbs.twi.tudelft.nl/People/Students/D.Dragos/back/ice/index.htm |archive-date=September 8, 2004 |url-status=live |df=mdy-all }}{{Cite web |url=http://www.lr.tudelft.nl/en/cooperation/facilities/simona/the-simona-research-simulator/ |title=SIMONA |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20170223122044/http://www.lr.tudelft.nl/en/cooperation/facilities/simona/the-simona-research-simulator/ |archive-date=February 23, 2017 |url-status=dead |df=mdy-all }}
• Hamburg University of Applied Sciences, Germany{{cite web |url=http://www.fzt.haw-hamburg.de/pers/Scholz/Airport2030/Airport2030_PUB_DLRK_12-09-10_Caja.pdf |title=Box Wing Flight Dynamics in the Stage of Conceptual Aircraft Design |author=Caja R., Scholz D. |date=November 23, 2012 |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20170809042015/http://www.fzt.haw-hamburg.de/pers/Scholz/Airport2030/Airport2030_PUB_DLRK_12-09-10_Caja.pdf |archive-date=August 9, 2017 |url-status=live |df=mdy-all }}
• Technical University of Munich{{cite web |url=http://www.daedalus.ei.tum.de/index.php/de/mach-mit-mm |title=Mach mit ! - daedalus |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20170606060350/http://www.daedalus.ei.tum.de/index.php/de/mach-mit-mm |archive-date=June 6, 2017 |url-status=dead |df=mdy-all }}
• Czech Technical University in Prague[https://www.youtube.com/watch?v=d8SQa9_el8k&feature=autoshare at YouTube]{{Cite web |url=http://measure.feld.cvut.cz/en/cast |title=Center for Advanced Simulation and Technology | Department of Measurement |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20150919035504/http://measure.feld.cvut.cz/en/cast |archive-date=September 19, 2015 |url-status=dead |df=mdy-all }}
• French Aerospace Lab (ONERA) and University of Toulouse, France{{cite web |url=http://oatao.univ-toulouse.fr/2137/1/Dehais_2137.pdf |title=Modélisation des conflits dans l'activité de pilotage |first=Frédéric |last=Dehais |publisher=University of Toulouse |date=June 21, 2004 |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20120714183648/http://oatao.univ-toulouse.fr/2137/1/Dehais_2137.pdf |archive-date=July 14, 2012 |url-status=live |df=mdy-all |language=fr}}
• Pázmány Péter Catholic University and the Hungarian Academy of Sciences{{cite web |url=http://www.analogic.sztaki.hu/publications/UAV_Collision_avoidance.pdf |title=Collision avoidance for UAV using visual detection |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20140801105008/http://www.analogic.sztaki.hu/publications/UAV_Collision_avoidance.pdf |archive-date=August 1, 2014 |url-status=live |df=mdy-all }}
• University of Sheffield, England{{Cite web |url=http://www.dcs.shef.ac.uk/intranet/teaching/public/projects/archive/msc2006/pdf/acq05taa.pdf |title=Modelling and Autonomous Flight Simulation of a Small Unmanned Aerial Vehicle |date=August 2006 |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20140416234247/http://www.dcs.shef.ac.uk/intranet/teaching/public/projects/archive/msc2006/pdf/acq05taa.pdf |archive-date=April 16, 2014 |url-status=dead |df=mdy-all }}
• Supaéro{{Cite web | url=https://www.france-universite-numerique-mooc.fr/courses/isaesupaero/25001/Trimestre_4_2014/about | title=Aerodynamics MOOC using FlightGear | date=February 2015 | access-date=June 12, 2017 | archive-url=https://web.archive.org/web/20150910044025/https://www.france-universite-numerique-mooc.fr/courses/isaesupaero/25001/Trimestre_4_2014/about | archive-date=September 10, 2015 | url-status=live | df=mdy-all }}
• Durham University, England{{cite journal|url = http://dro.dur.ac.uk/17084/1/17084.pdf|title = FlightGear as a tool for real time fault-injection, detection and self-repair|author1 = Alan Purvis|author2 = Ben Morris|author3 = Richard McWilliam| journal=Procedia Cirp |date = 2015| volume=38 | pages=283–288 |publisher = Durham Research Online| doi=10.1016/j.procir.2015.08.040 |access-date = June 12, 2017|archive-url = https://web.archive.org/web/20180719013648/http://dro.dur.ac.uk/17084/1/17084.pdf|archive-date = July 19, 2018|url-status = live|df = mdy-all}}

• University of Tennessee, Chattanooga, USA{{cite web |url=http://www.flightgear.org/Projects/utc.html |title=University of Tennessee at Chattanooga |publisher=FlightGear |first=Dawn |last=Ellis |access-date=April 18, 2012 |archive-url=https://web.archive.org/web/20120614155715/http://www.flightgear.org/Projects/utc.html |archive-date=June 14, 2012 |url-status=live |df=mdy-all }}
• Northeastern University, Boston, USA{{cite web |url=http://www.northeastern.edu/news/stories/2011/05/braincontrol.html |title=A brainy innovation takes flight |publisher=Northeastern University |date=May 31, 2011 |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20120114014229/http://www.northeastern.edu/news/stories/2011/05/braincontrol.html |archive-date=January 14, 2012 |url-status=live |df=mdy-all }}
• Arizona State University, USA[http://campustechnology.com/Articles/2011/08/23/Arizona-State-Tries-Practice-over-Theory-in-Engineering-Education.aspx Arizona State Tries Practice over Theory in Engineering Education] {{Webarchive|url=https://web.archive.org/web/20150909124719/http://campustechnology.com/Articles/2011/08/23/Arizona-State-Tries-Practice-over-Theory-in-Engineering-Education.aspx |date=September 9, 2015 }}, Campus Technology
• The Center for Coastal & Ocean Mapping/Joint Hydrographic Center at the University of New Hampshire, USA{{cite web |url=http://ccom.unh.edu/vislab/projects/simulator.html |title=Spatially Aware Hand-held Devices and the Boat Simulator |access-date=October 20, 2012 |archive-url=https://web.archive.org/web/20120823051732/http://ccom.unh.edu/vislab/projects/simulator.html |archive-date=August 23, 2012 |url-status=live |df=mdy-all }}
• University of Michigan, USA{{Cite web |url=http://www-personal.umich.edu/~duncanlm/Miller_Duncan_AIAA_RegionIII_2011_Autolab.pdf |title=Autonomous Vehicle Laboratory for Sense and Avoid Research and Hardware-in-the-Loop Simulations |publisher=American Institute of Aeronautics and Astronautics |author=Duncan Miller |date=2011 |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20120128091447/http://www-personal.umich.edu/~duncanlm/Miller_Duncan_AIAA_RegionIII_2011_Autolab.pdf |archive-date=January 28, 2012 |url-status=live |df=mdy-all }}
• University of Toronto Institute for Aerospace Studies, Canada{{Cite web |url=http://www.ornithopter.net/MediaGallery/flightgear_e.html |title=Flying the Ornithopter in FlightGear Flight Simulator |author=Project Ornithopter |date=2006 |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20170428072559/http://www.ornithopter.net/MediaGallery/flightgear_e.html |archive-date=April 28, 2017 |url-status=live |df=mdy-all }}{{Cite web |url=http://media.utoronto.ca/media-releases/new-media-technology/human-powered-ornithopter-becomes-first-ever-to-achieve-sustained-flight/ |title=Human-powered ornithopter becomes first ever to achieve sustained flight |publisher=University of Toronto |date=September 22, 2010 |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20160304090830/http://media.utoronto.ca/media-releases/new-media-technology/human-powered-ornithopter-becomes-first-ever-to-achieve-sustained-flight/ |archive-date=March 4, 2016 |url-status=live |df=mdy-all }}
• Purdue University, Indiana, USA{{cite web |url=http://www.syprisresearch.com/Images/secure-control-systems/AIAA-Infotech_Threats-and-Vulnerabilities-Analysis.pdf |title=Cyber Attack Vulnerabilities Analysis for Unmanned Aerial Vehicles |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20140416230112/http://www.syprisresearch.com/Images/secure-control-systems/AIAA-Infotech_Threats-and-Vulnerabilities-Analysis.pdf |archive-date=April 16, 2014 |url-status=dead |df=mdy-all }}
• University of Arizona, USA{{Cite web |url=http://arizona.openrepository.com/arizona/handle/10150/297776 |title=Thermal Energy Extraction Methods for UAV Gliders |author=Umashankar, Rohit |date=April 30, 2013 |access-date=June 12, 2017 |archive-url=https://web.archive.org/web/20151128042552/http://arizona.openrepository.com/arizona/handle/10150/297776 |archive-date=November 28, 2015 |url-status=live |df=mdy-all }}

• National Technological University, Haedo, Argentina{{Cite web|url=http://gsdv.com.ar/fotos/20110528/index.html|title=GSDV-20110528-Proyeccion exterior|access-date=June 12, 2017|archive-url=https://web.archive.org/web/20130609183020/http://gsdv.com.ar/fotos/20110528/index.html|archive-date=June 9, 2013|url-status=live|df=mdy-all}}
• Universidade Federal de Minas Gerais, Brazil{{cite web|url=http://homepages.dcc.ufmg.br/~chaimo/public/SBAI09-cantoni.pdf|title=Analise Comparativa Entre Microsoft Flight Simulator E Flightgear Flight Simulator Em Testes Hardware-In-The-Loop}}

{{Portal|Aviation|Free and open-source software|Video games}}

• Microsoft Flight Simulator
• List of open source games
• X-Plane (simulator)
• YSFlight
• List of free and open source software packages
• Lockheed Martin Prepar3D

{{Reflist|30em}}

{{Commons category}}

• {{official website}}
• {{Sourceforge|flightgear}}
• [http://www.flightgear.org/flightprosim.html About FlightProSim, Flight Simulator Plus, ProFlightSimulator and EarthFlightSim] {{Webarchive|url=https://web.archive.org/web/20101129012657/http://www.flightgear.org/flightprosim.html |date=November 29, 2010 }}
• {{URL|jsbsim.org}}
• [https://aviator4win.com/ Aviator Game Online]

Category:1997 software

Category:1997 video games

Category:2007 software

Category:Cross-platform software

Category:Flight simulation video games

Category:Free software programmed in C++

Category:General flight simulators

Category:Linux games

Category:Open-source video games