Short report of testing DCS P-51D on Windows 8 64bit with OpenTrack and Nthusim HMD (http://forums.nthusim.com/viewforum.php?f=4)
The setup was very quick. Below the main steps.
separation (70,0) - did not feel any difference for any setting between [0,100]. May be it is only for actual SBS 3D.
Zoom: (100,200) - otherwise wrong aspect ration
Desktop Correction, Look Around, Mouse - all not selected
OpenTrack download from: http://ananke.laggy.pk/opentrack/
Important to start OpenTrack before Nthusim HMD otherwise it can not receive tracking information. However then "Look around" feature will not work either.
Settings: Tracker Source: Rift, GameProtocol: FreeTrack 2.0, all curves on 1-1 relation with movement (straight line from 0,0 - 180,180)
Display Configuration: NVIDIA GTX680, "Duplicate" mode with 1280x800 resolution. I have tried to use "Extend" mode with Rift as Primary display however it was not usable: I could not select any menu options in DCS UI while looking via Rift. "Look around" feature was not available because of OpenTrack. May be when Nthusim HMD will support head tracking, the problem will be solved. It is important because using "Duplicate" mode is not recommended for Rift because of additional lag.
In DCS I have setup 45 degrees FOV in SnapView.Lua for P-51D however it was too zoomed in so I have changed it in game with "/" and "*".
Instrument readability was much better than in WarThunder or IRacing. I dont know how to explain it, but i was able to read all main instruments: AIS, ALT, V/S. Manifold, RPM etc. Even for different zoom levels. However in order to be able to read instruments, it was required to keep head steady, without any movement.
Outside view also was very reasonable, no problem to spot airports, hours, trains, cars. Did not try to spot other plans.
Head movement was not very smooth (comparing to IRacing and Warthunder with native head tracking support) with detectable lag that immediately caused me very light nausea (did not have any problems in iR and WT). Framerate around 120 FPS.
In general, I still had a strong feeling looking via binocular and not feeling like in IRacing of actually being there. May be because of not optimal zoom level and lack of SBS 3D.
However , it is way better than playing with displays (i have cockpit with 3x32in LCD displays and motion seat).
Did not try with motion enabled yet, will update
Did also quick test with X-Plane, without flying or head tracking, worked great. Will do more detailed test tonight.