A new version of FlightGear was released last week, and an IRIX tardist of the core package is available for download.
From the 0.9.2 press release:
"The Flight Gear Flight Simulator project is a free, open-source, multi-platform, cooperative flight sim development project. Source code for the entire project is available and licensed under the GPL. The Flight Gear project is working to create a sophisticated flight simulator framework for the development and pursuit of interesting flight simulator ideas. We are developing a good basic sim that can be expanded and improved upon by anyone interested in contributing.
FlightGear can be found at:
New in this release:
o New aircraft available: P51-D (w/ full 3d cockpit), Sea Hawk (WV908), a research ornithopter (propelled by actual flapping wings), A10, B-52, F-104, F-15, F-16, OV10, PA28-161, T-6A Texan II, T-38, British TSR2, YF-23, 737
o Added some early multiplayer features.
o Much improved sky and coloring as well as more realistic coloring of the sunset and sunrise.
o Clouds are drawn on a surface that better matches the underlying curve of the earth.
o A few updated terrain textures, better variety of random ground cover objects.
o Most weather options can now be set via the GUI. Added an option to randomize the weather.
o Various instruments and systems can now be failed/unfailed via the GUI.
For a complete list of changes, please visit:
Some of my observations while setting up the sim under IRIX:
1. Make sure to install the base package -- for some reason it isn't included in the FlightGear tardist. Currently the download link for the 0.9.2 base package on the IRIX download page doesn't work. Get it here instead:
Extract this file into /opt/lib32 (you'll need to create the lib32 directory first) and rename the resulting FlightGear-0.9.2 directory to FlightGear.
2. There are additional IRIX specific notes on the IRIX download page (tips for increasing framerates, etc):