On Saturday 18 June 2011 21:00:41 Jon S. Berndt wrote: > Here's an example from Hal's P-51D Mustang. This is from an old version, so > it may have changed by now, but it illustrates the approach. In the > <aerodynamics> section of the config file - but outside of any <axis> > element - is this definition of qbar due to propwash: > > [Note: <v> is shorthand for "value", and <p> is shorthand for "property".] > > <function name="aero/thrust-qbar_psf"> > <product> > <v> 0.5 </v> > <p> atmosphere/rho-slugs_ft3 </p> > <pow> > <sum> > <p> velocities/u-aero-fps </p> > <product> > <p> propulsion/engine/prop-induced-velocity_fps </p> > <v> 2.0 </v> > </product> > </sum> > <v> 2.0 </v> > </pow> > </product> > </function>
I recently added this function to the A6M2 Zero. I placed it on CYdr (rudder yaw) and dCLdf (flap lift delta) as well as CMde. It makes the plane fly much, much better during the initial takeoff roll. It probably should be used with CMdf (pitch due to flaps) as well. But why are you multiplying propulsion/engine/prop-induced-velocity_fps by 2? > [Note that while this function definition is named "aero/coefficient/Cmde" > it is not really a coefficient, but an actual moment in units of foot > pounds. The "coefficient" part of the name is a holdout from years past.] I prefer to read this as "The reconstituted coefficient" or "The formula containing the coefficient" :) Seriously, I was never confused by the function naming. It helped me along when I was first learning JSBSim, because those are the terms all the textbooks use. Look at FDMs like the c182rg that have had everything renamed to the marginally pendantically correct "FLDe" instead of "CLDe" and "MmDe" instead of "CmDe". I find it ugly and potentially confusing to new users. Thanks, Ron ------------------------------------------------------------------------------ EditLive Enterprise is the world's most technically advanced content authoring tool. Experience the power of Track Changes, Inline Image Editing and ensure content is compliant with Accessibility Checking. http://p.sf.net/sfu/ephox-dev2dev _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
