You can do that by remarking out a line in the Viewporthandling.lua
Found here X:\DCS World OpenBeta\Scripts\Aircrafts\_Common\Cockpit\ViewportHandling.lua
Line 81, purposes = {render_purpose.GENERAL,
Change to, purposes = {--render_purpose.GENERAL,
It does save some FPS I think, the only problem with this is it will not pass the IC if you fly online.
If anyone knows how to implement this and be able to pass the IC that would be awesome.