I too use Realflight 3.5, It is neat sim, clarity and accuracy is awesome, uploaded the Axe cp, Electric Dominion, which I think is the most stable heli available for download from Knife Edge swap pages forum. The Trex's does not fly too well, lol, I actually am doing real well with 3D with this sim. You may also want to checkout FS One, awesome looking graphics
Electric Dominion 3D
Axe cp