You can always try RC Desk Pilot:
http://rcdeskpilot.com/
It's not exactly RealFlight, but it's free - and one of our own forum members has built several of the FT models for it, and they work really well. I have RealFlight 7.5 too, and I love it... but I occasionally fire up RC Desk Pilot just to play with the FT planes. And while we're discussing sims, ClearView is also really good. There's a cost, but it's a very nicely-done sim, and it's a good deal less expensive than RealFlight, etc.
Gryf