I'll jump in with some quick background. Originally I developed a system where you defined your electrical system components and all the connections in a complex xml file. Then a C++ module loaded this configuration at run time and used a simplistic approach to propagate the "juice" through the system. (IANAEE) :-)
I developed a sample configuration file for the C172 which worked pretty well, even to the point of working for an FAA certified trainer where all the backend stuff and circuit breakers needed to always do the right thing. Then I needed to model the electrical system for a light twin. I discovered that the electrical system on a typical light twin is much more complex than a single engine plane. You have two generators, two batteries, systems are often fed by default from one side or the other to balance the load, but if one side fails the other side can feed the whole system. I found I needed to extend some of the simple assumptions that worked ok for the single engine case and create new parts and had to totally rewrite the "juice" propagation system. But then I found that my requirements weren't just to figure out what parts were powered, I also needed to model current load as different systems were powered on and off to support an ammeter gauge and a volt meter gauge. At that point my C++ scheme was really creaking under the load. The xml file was exploding into a huge monstrosity, and it started to look like I was going to need a full circuit simulation system to proceed. I basically crushed myself under the complexity of the system I built and couldn't reach the finish line. In the mean time I was trying to field questions about this system from other aircraft developers and it quickly became clear as soon as other people tried to use it that it was an overwhelming beast to try to figure out, not to mention test and debug. So instead I abandoned that approach and created a procedural based electrical system model written in nasal. This turned out to be sooo much cleaner, so much easier, so much quicker, so much more understandable, so much more maintainable, and probably ran a heck of a lot faster because it wasn't iterating over hundreds of components every frame. I made the decision to keep the xml/C++ based electrical system in place for compatibility and because by then I wasn't just the only one using it. But my recommendation for most people is to strongly consider writing their electrical system model in nasal. I think most people will be much happier with a nasal based electrical system. Now if we have people who still want to build an electrical system using a circuit simulation based approach, that's great, this is exactly what FlightGear is for ... an open-source sand box. Go for it! Scratch that itch! Best regards, Curt. On Wed, Feb 23, 2011 at 3:39 PM, Heiko Schulz wrote: > Hi, > > > A few months ago I created a > > nasal-based generic electrical system > > modeled after the built-in Flightgear system. I thought I'd > > offer it > > up here for those who might be interested: > > > > http://ltts.crlt.indiana.edu/grn/flightgear/electrical_1.html > > > I must admit, I'm a bit confused now about the electrical systems in > FlightGear. > > I know the one used in the c172p, the ones created by Syd Adams which I use > by myself in my projects (Ec130) and now this one. > > What are the advantages, where are the issues? > I must admit creating the different systems in FlightGear (electrical, > hydraulic, pneumatic, etc...) is quite difficult for those who aren't that > into programming and scripting... > > Cheers > Heiko > > > > > ------------------------------------------------------------------------------ > Free Software Download: Index, Search & Analyze Logs and other IT data in > Real-Time with Splunk. Collect, index and harness all the fast moving IT > data > generated by your applications, servers and devices whether physical, > virtual > or in the cloud. Deliver compliance at lower cost and gain new business > insights. http://p.sf.net/sfu/splunk-dev2dev > _______________________________________________ > Flightgear-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/flightgear-devel > -- Curtis Olson: http://www.atiak.com - http://aem.umn.edu/~uav/ http://www.flightgear.org - http://www.flightgear.org/blogs/category/curt/<http://www.flightgear.org/blogs/category/personal/curt/>
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