Georg Vollnhals writes: > If I understand the right way what he tries to do is calculating the > forces and effects of the rotor by calculating it for every blade in > discrete time-steps and from this calculation the resulting forces on > the helicopter.
I haven't downloaded the code yet, my day job is currently funded out of my pocket and I'd rather do something that takes different neurons at the end of the day, but it sounds like this is the way that X-Plane does it, and on modern hardware it doesn't seem that unreasonable. It's also going to be very useful to be calculting lift-drag information for varying sections when we start to get a realistic engine model, when we start to model flapping, and when we model mast tilt and the effects of forward motion. So I'm not going to call this "too complex" immediately. However, next up on my technical reading list is NACA Technical Note 4357, "Lift and Profile-Dra Characteristics of an NACA 0012 Airfoil section as Derived From Measured Helicopter Rotor Hovering Performance", which seems to reduce a lot of stuff down to a simple table that could be interpolated on. I think the other "must-read" is NASA Contractor Report 177476, aka "Minimum Complexity Helicopter Simulation Math Model". Both of these are freely distributed PDFs that I eventually tracked down on the net, but they were hard to find so if you don't have them I'll see about putting them somewhere that people can get to them. As I've said before, last time I looked seriously at aerodynamics modeling was two and a half decades ago when I was 12 years old, but a lot of it, especially when dummied up from tables for a simulator, isn't that complex. What's hard is that we're trying to approximate realism, and as such are more interested in a "feel". I've sat in the middle back seat of an A*Star once, with a pilot who probably had a thousand hours under his belt. No matter what I code up, even if it's a full on fluid dynamics simulation of what's going on, I'm not going to know if it's right or wrong because right or wrong isn't whether it models the physics correctly, it's whether it feels like flying a real helicopter. Dan _______________________________________________ Flightgear-users mailing list [email protected] http://mail.flightgear.org/mailman/listinfo/flightgear-users 2f585eeea02e2c79d7b1d8c4963bae2d
