> It's the ground reaction code. :) > > JSBSim and YASim do things pretty much the same way, using a > coefficient of friction for gear as they slide over the ground. This > integration works fine for a moving aircraft, but it's really not > right for a stopped one. An aircraft with exactly zero speed would > produce exactly zero force, and thus be "moved" by a wind gust, and > then feel a very strong force in the opposite direction. > > An ideal mechanism would keep track of how much force each wheel > "could" apply in the ground plane, and then calculate the right amount > to apply to keep the aircraft from moving. This basically comes down > to solving a bunch of simultaneous equations for each FDM iteration. > It's a big mess; I'd be really scared of making this work.
Oh, God. Yes, I went through the mental gyrations for that one a year or two ago. It's a "story problem nightmare" when considering how to implement with multiple and variable numbers of gear bogeys. What if you run into ice on one gear? What if one gear shows slippage should be occuring? etc. I don't think the "Big Boy" sims even do that. LaSRS++ purports to do something that sounds clever enough, and I may head that direction for JSBSim. Jon _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
