Dave Martin said: > On Thursday 20 Jan 2005 16:13, Jim Wilson wrote: > > Dave Martin said: > > > On Thursday 20 Jan 2005 14:42, Jim Wilson wrote: > > > getting an aircraft working > > > > > > > is about 2 parts theory and 1 part voodoo (the part that the basic > > > > formulas don't cover). > > > > > > "Any sufficiently advanced technology is indistinguishable from magic" - > > > Sir Arthur C Clarke. > > > > Ok wrong word. Let me just say that it seems to lack some magic. Setting > > up the p51d in Yasim was not my original intention as Jon S. Berdnt was > > claiming at the time I started the 3D that he had a nearly working JSBSim > > model. Doing the yasim model was a juggling act that started with > > geometric specifications, a couple software patch submissions, and then an > > endless number of tweaks. The "tweaks" were really comprimises that ended > > up producing something that was sort of close to performance > > specifications, but not really accurate in any respect. > > > > Best, > > > > Jim > > Thats litterally what I've just been doing with the B1900D FDM. > > The numbers in the FDM file don't all match up to the numbers in the POH but > the FDM does now match with the *performance* figures in the POH - Which I > hope is the right thing to aim for. >
The biggest tradeoffs seemed to be in trying to balance high end performance, (e.g. altitude, speed) against having enough drag to get reasonable behavior at lower power settings. It seems pretty common for yasim models to glide too much (excessive lift/insufficient drag) when cutting the power. Best, Jim _______________________________________________ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
