oops..meant to say TAS varies with temp. Mike

This really explains a lot Ron. Thanks!! How easy is it to limit, at least, the YD rudder movement to 5.5 degreees? Is it in the air file or the cfg file? Mike

> This really explains a lot Ron. Thanks!! >> How easy is it to limit, at least, the YD rudder movement>to 5.5 degreees? Is it in the air file or the cfg file?>>> Mike The limit is in both the AIR file (rudder deflection drops above 160 kts or so, and also in the Experimental Yaw Damper I'm testing. While aircraft.cfg sets the maximum Control deflections, which appear to correspond to the K: SET limits. All it takes in the XML file is something like "0.4 max 0.4 min" before the SETRUDDER gain. Whatever values are appropriate to give the desired rudder deflection limits from the YD output. Without the limits, the YD could overcontrol the rudder and create instabilities. Those values could be dynamic, that is, they could be L:Variables that are calculated from something else. This morning I got a new XML 'gauge' file working. I'm testing various PID controllers in it. Which I moved out of a more general XML file. In fact, I already have a pretty good SPD control that is much tigher than the one in FS9. -- And, a couple of the guys in this forum who will likely use and enhance my results. When I get it cleaned up and simplifed to be 'stand alone', I'll likely post at least part of it here. Ron