RE: Fixed wing > rc heli > full size heli
If your checkbook can swing the Phoenix or the RealFlight simulators, either one would be great for the muscle memory required to fly these things. For learning purposes either one will do. Once you get into the aerobastics and what we call 3D maneuvers, then Phoenix has a slight advantage. The downside to Phoenix, is that depending on which version you get, you might end up using your real radio and put unnecessary wear into the components. The RealFlight, and newer versions of Phoenix already come with a "radio" in the box thus limiting wear on the one you will be using in the field.
As far as learning to fly the real thing by flying the rc one... Well, yes and no. I was already an avid RCer when I got my first chance to climb in a Cessna 172. I did have the smoothness at the control required for pleasant flight, but of course did not have the rest of the skill required pertinent to a craft carrying humans. G forces, bank angles, and a myriad of other concepts need to be learned.
I was also able to utilize a UH-60 simulator. The UH-60 actually has a gyro-stabilized tail, very similar to our rc machines, but to a point. You have to keep torque within certain limits. The rudder pedals have switches in them that as soon as you place your feet on them, the gyro is disabled, and now you have to fly the machine. Also the UH-60 has a governor that keeps the engine power in the green while the torque on the system varies as you change collective pitch. I was able to hover, and do a couple of laps around the simulated airstrip.
As far as I know, the UH-60 is the only helicopter that is gyro stabilized. There might be others out there, but they will be in the millions of $$$ range, doubtful that you would be learning in one of those.
So, yes, learning in the RC world, could be applied to the real thing. But only applied with some forethought on your part.
Rafael