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FlightGear Newsletter October 2019: Difference between revisions
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FlightGear Newsletter October 2019 (view source)
Revision as of 10:17, 22 October 2019
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''We would like to emphasize that the monthly newsletter can not live without the contributions of FlightGear users and developers. Everyone with a wiki account (free to register) is welcome to contribute to the newsletter. If you know about any FlightGear related news or projects such as for example updated scenery or aircraft, please do feel invited to add such news to the newsletter.'' | ''We would like to emphasize that the monthly newsletter can not live without the contributions of FlightGear users and developers. Everyone with a wiki account (free to register) is welcome to contribute to the newsletter. If you know about any FlightGear related news or projects such as for example updated scenery or aircraft, please do feel invited to add such news to the newsletter.'' | ||
== FlightGear F-15 selected for DARPA project == | |||
DARPA has selected eight teams to compete in the AlphaDogfight Trials, a virtual competition designed to demonstrate advanced artificial intelligence (AI) algorithms that can perform simulated within-visual-range air combat maneuvering, colloquially known as a dogfight. | |||
All eight teams will compete in each of the three scheduled trials. They will use the JSBSim open-source flight dynamics model for simulation environment and the open-source FlightGear Flight Simulator for the visual system. The simulated aircraft for the Trials is the publically available, unclassified FlightGear version of an F-15C fighter aircraft. | |||
[[File:FlightGear F-15 DARPA Alfa DogFight Trial.jpg|inline|FlightGear F-15 DARPA Alfa DogFight Trial]] | |||
== Development news == | == Development news == | ||
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YASim now has a parameter "flow" which is valid for wing, mstab, vstab and hstab. If set to "TRANSONIC", YASim applies a Prandtl/Glauert compressibility correction for each surface of the wing which results in more lift above mach 0.6 with a peak at Mach 1 (see figure). The default value is "SUBSONIC" which turns the behavior off and computes just like previous YASim versions. Use this parameter for all jets with supercritical airfoils or anything that flies faster than mach 0.6. The result is a more balanced lift/drag result from the solver. Please do not use this parameter for supersonic aircraft! | YASim now has a parameter "flow" which is valid for wing, mstab, vstab and hstab. If set to "TRANSONIC", YASim applies a Prandtl/Glauert compressibility correction for each surface of the wing which results in more lift above mach 0.6 with a peak at Mach 1 (see figure). The default value is "SUBSONIC" which turns the behavior off and computes just like previous YASim versions. Use this parameter for all jets with supercritical airfoils or anything that flies faster than mach 0.6. The result is a more balanced lift/drag result from the solver. Please do not use this parameter for supersonic aircraft! | ||
[[File:Prandtl-glauert-transform.png| | [[File:Prandtl-glauert-transform.png|inline|Plot of the subsonic and supersonic Prandtl/Glauert transformation.]] | ||
Also you can specify a critical mach number for each wing (and mstab, vstab, hstab) using the parameter "mcrit". In aerodynamics the critical mach number is the flight mach number above which drag due to mach (also called wave drag) becomes relevant. If flow="TRANSONIC" is set, YASim looks for mcrit (default is 0.6) and adds exponential mach drag above that mach number. The estimation is done by a method according to Perkins and Hage. Future versions may tune and expand this behavior a bit. | Also you can specify a critical mach number for each wing (and mstab, vstab, hstab) using the parameter "mcrit". In aerodynamics the critical mach number is the flight mach number above which drag due to mach (also called wave drag) becomes relevant. If flow="TRANSONIC" is set, YASim looks for mcrit (default is 0.6) and adds exponential mach drag above that mach number. The estimation is done by a method according to Perkins and Hage. Future versions may tune and expand this behavior a bit. | ||