On Tue 7 August 2007 18:20, gh.robin wrote: > On Tue 7 August 2007 17:57, Torsten Dreyer wrote: > > There is a bug in JSBSim causing multiengine aircraft with > > counterrotating props suffer from excessive yaw when engines are running. > > Significant aileron deflection is required to fly straight and level. > > > > I tracked down that issue and finally came to FGPropeller.cpp line 198: > > > > vH(eX) = Ixx*omega*Sense; > > > > If I understand correctly, this is some kind of force along the rotating > > axis of the propeller and it should not be multiplied with Sense (unless > > someone mounts a wrong propeller...) > > > > Making the line > > > > vH(eX) = Ixx*omega; > > > > removes the unwanted yaw and creates symmetrical forces and moments. > > > > The only aircrafts using counterrotating props are the P-38L and the > > SenecaII. All others should not be affected by this patch. > > > > Greetings, Torsten > > May be i don't understand your remark, and i could be wrong, > > but all aircraft propeller have not the same rotation direction , > some are CCW on the same aircraft > some are CW on others aircraft. > > Sure there is no problem with P-38L one propeller is given > <sense> -1 </sense> > The other is given > <sense> 1 </sense> > > so, Sense could be -1 or 1 which is significant for the propeller effect. > > it is very important to keep in that calculation the Sense. > > > Regards
In addition to, if these effect seems to be more than you espect it is possible to reduce the value with <p_factor> </p_factor> with zero there is no effect. -- Gérard ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
