Flutterby™! : helicopter simulation

Hey, anyone out there have experience with flight simulation? I've been flying the FlightGear helicopter models a bit, and ogling the HeliCycle, and I'm getting the aviation bug again. But in reading through a few references while waiting for some tests to run I'm starting to wonder about how good the helicopter flight model is: It seems a little shy on ground effect, it has no model for feeding blade drag back into the engine, issues like that.

When I was young, probably up to 12 or 13 years old (before I discovered computers), I was totally into aviation, accumulating all the old books on airfoil sections and aeronautics I could, building a wind tunnel and doing a few tests. This weekend I spent some time doing mind experiments on helicopter dynamics and I'm starting to think it'd be fun to at least work through the math of a helicopter simulator, if not actually write the critical bits of code.

But those books are long gone, and those it's been a long time since those neurons were exercised.

So, anyone out there have a line on something like the old NACA lift-drag graphs, especially in numerical form? And an idea of which airfoils are used in helicopter rotors? I'll either have to brush up on my calculus or just do a number of samples to try to catch the issue of different blade speed over a swept area. I don't remember specifically how to deal with swept-wing stuff, but the helicopter has that in spades and solving for a number of samples along the blade and convolving them somehow seems like it might be the easier way to do this.

But I'm also working of the memories of what I could pick up for peanuts at library basement sales, and I'm trying to refresh myself on Reynold's numbers, wing lengths and stall behavior, and wondering if Glauert's model for lift and drag versus speed (N/pow(1-mach*mach, .5)) sufficient? The nice thing about helicopters is that you can pretty much clip when the rotor tip hits Mach 1... I think.

I think the issues of engine simulation are already done, although references to such things would be gratefully received, but any suggestions for good places to start for someone who once knew a little bit would be helpful.