Duncan Greer wrote: > I'll probably be shot for saying this on this list, but if you are building > an entirely new aircraft from scratch you may find X-plane far more useful > in this respect - not open source or free I know - but it does offer the > capability to design and test fly completely new aircraft without needing to > be an aero engineer. >
X-Plane is a neat tool and you are right, you can get an airplane up to speed really quickly with X-Plane. But with YASim (part of FlightGear), you can get FlightGear aircraft up and flying quite quickly too, with about the same information that you need for X-Plane. YASim has a neat feature where you specific your target cruise speed/altitude and target approach speed and angle of attack and it has a built in solver that nails those numbers dead on. In X-Plane you specify an airfoil instead and hope it gets close enough. That's a bit of an overly simplistic comparison, but if you aren't an aerospace engineer, that's all you need to know. :-) People talk about 1% models in the world of X-Plane meaning they manage to hit all the performance data within that percentage tolerance, but with YASim's solver, you hit the numbers exactly. And if you aren't an aero-person, that's all you need to know. :-) :-) :-) X-Plane is a great tool as far as it takes you. The downside is you are stuck with the aerodynamic solution the code spits out. If you need to do something different with the dynamics, or the solution it gives you isn't as close to reality as you'd like, you are stuck in a process where you may have to make non-intuitive changes to your model to get it to fly better. X-Plane is just a tool. It's good at doing some things and not so good at doing other things. People get a lot of mileage out of it and have a lot of fun with it and even do some real engineering and flight training work with it. But if you are serious about high fidelity dynamics simulation, there's nothing like being able to tweak the stability derivatives and tables of data so that you can represent the aircraft in as much detail as you have data for. And also so that you can include all the effects you have data for. This is where JSBSim (also included with FlightGear) *really* shines. You do have to dip your toes in the world of aerospace engineering to use JSBSim effectively, but hey there are worse places to waste your brain cells. :-) And before anyone makes any smart comments, I've been WWF free for at least 3 weeks. And besides, X-Plane doesn't do proper aircraft shadows based on sun position. And X-Plane aircraft can't self shade themselves like in FlightGear (i.e the tail can't cast it's shadow properly on the wing, etc.) :-) Curt. -- Curtis Olson http://www.flightgear.org/~curt HumanFIRST Program http://www.humanfirst.umn.edu/ FlightGear Project http://www.flightgear.org Unique text: 2f585eeea02e2c79d7b1d8c4963bae2d _______________________________________________ Flightgear-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/flightgear-users
