On Sat, 2002-02-16 at 16:06, Alex Perry wrote: > > > > > Please note that there is a difference between fgfs's internal > > > > > representation of wind, and the way it is set by the user. As an > > > > > engineer, I am partial to using 'to' vectors internally. > > > > Yup, that is more mathematically correct. > > There is nothing mathematical about the wind vector convention; > it's not as if we're actually modelling the wind as a particle field. > > A pressure sensor that is exposed to the "wind" and pointed in the > direction specified as the "wind direction" will indicate a pressure > above ambient. When pointed in the opposite direction, i.e. the > direction that the air is travelling towards, the sensor will report > the same as for the directions at right angles, namely no increase. > Therefore, I could argue that the "pilot viewpoint" makes a whole > lot more sense, for use in the context of aerodynamic modelling.
One could apply a similar argument to a vane; it doesn't change the fact that the air is flowing the other way ( and that may well be why the aviation convention is "from" ) > > Trying to standardize here is about as pointless as making the > whole simulator use SI units exclusively for _every_ numeric value. > > > > IMHO, I think the way JSBSim does it is more consistent from an > > > EOM/weather/smulation POV. However, perhaps we can account for the > > > difference in the FGInterface-derived class for the specific FDM? > > Purely on principle, I think it is more important to let each FDM > subsystem use whatever conventions that its authors believe will make > for a consistent and easy to maintain codebase. We want them to work! > Any sign (or axis) mismatches can be dealt with in the interface class. > > > I'd be happier if we kept it as is. Wouldn't be the first time > > engineers have traded correctness for pragmatism. > > Yes. > That's been suggested as the differentiator between engineers and scientists > and formed the basis for many many jokes at each others' expense. > > _______________________________________________ > Flightgear-devel mailing list > [EMAIL PROTECTED] > http://mail.flightgear.org/mailman/listinfo/flightgear-devel > -- Tony Peden [EMAIL PROTECTED] We all know Linux is great ... it does infinite loops in 5 seconds. -- attributed to Linus Torvalds _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
