FlightGear is nice & powerful, but actually is too heavy and require modern PC.
BTW, There is Vertigo page on FlightGear Wiki.[0]
JFTR, There is also open-source ACM 6.0[1] (enchanched fork of ACM 5.0[2]) — classic old-school 3D flight simulator.
[0] http://wiki.flightgear.org/images/cache/2/2b/Vertigo_%2528fl...
Not sure if that's a modern PC in your mind, but it's not exactly a speed demon. :-)
Version/Platform?
> on a ThinkPad T420
This is not cheap PC.
Try run FlightGear on cheap laptops produced before 2010.
Edit: 2019.1.1/Linux
As for me, if desktop software can't properly work under Linux on cheap 10-year-old laptop then this is not good enough or not optimized app at all.
> I'm not using the 2D cockpit.
Because it will drop FPS under 30 FPS, right?
Good drama which show deep misinterpretation of GNU GPL terms by official FlightGear team.
Care to elaborate?
I don't know if he was the smartest programmer who ever lived, but he certainly was one of the more dedicated and interesting ones.