> -----Original Message----- > From: "Jon S. Berndt" > > While debugging the 737 I discovered something that I find unsettling. For > the 737-300 model (using a JSBSim flight model) there is a nasal script > called air-ground.nas. This apparently adds some automatic control of the > spoilers while on the ground. Now, understand up front that the discussion > that follows is not about nasal (which is a great feature and a great part > of flightgear) but about compatibility, convention, and communication. > > JSBSim has a powerful flight control capability that is specifically > designed for purposes such as that which the mentioned nasal script > addresses. I'd much prefer that such code be done using that capability, and > for several good reasons. Among them: > > 1) It is desirable for debugging and development purposes that the flight > model operates as closely as possible to the same whether run from > FlightGear or from a standalone version of JSBSim. JSBSim code does not > incorporate nasal in its standalone executable. > 2) Similarly, uses of the flight models by other simulators which use JSBSim > may not incorporate nasal, and thus behavior will differ. > 3) Without knowing about such scripts (which I did not until recently), > similar capabilities may be added to the existing flight control > specification already in JSBSim and may result in a "force fight" or > controls confusion. FlightGear has an autopilot model, now there are nasal > scripts that may perform flight control related tasks, and there is the > flight control specification in JSBSim aircraft. Ideally, some emerging > JSBSim aircraft will model their own autopilot within the JSBSim flight > control model (which has been conceived and designed with an aim towards GNC > analysis from the start). So, there needs to be good communication among > several parties when it comes to adding capabilities to a flight model. > > Jon
Those are valid points from a JSBSim centric perspective, but from FlightGear we have other FDMs that don't support the same features so that fgfs has its own control methods independant of specific FDMs. An argument could be made for having a single control script for flying the same aircraft type developed using JSBSim, YASim and UIUC models. Perhaps the answer in the long run is to detach the JSBSim flight control from JSBSim FDM so that they are configured independantly and communicate to each other through the same type of interface that FlightGear currently uses. Then users can choose that as one available method for flight control. FlightGear is still about creating a set of building blocks, isn't it? Such an approach would probably be valuable to folks wanting to use JSBSim in other projects as well. That said, it is good you brought this up, because obviously there are some folks that don't realize this exists in JSBSim. I just happened to know of the feature because you mentioned it to me and also on the mailing list quite some time ago. Best, Jim -- Jim Wilson Kelco Industries PO Box 160 Milbridge, ME 04658 207-546-7989 ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
