On 12/04/2007 11:26 PM, Syd&Sandy wrote: > Hi all , I've added the elevator, aileron and rudder trim to the > control-centering function - keypad ( 5 ). Should this be added > before the release ? Or is there a particular reason that the trims > aren't reset ?
There is _some_ merit to this idea, but it needs refinement; see below for details. > developed the habit of hitting the 5 key before releasing the brakes As Curt pointed out, simply zeroing the trims is a Bad Idea. In most airplanes -- simulated and real-life -- zeroing the trim is not the right answer. In the C182 for instance -- FG and RL -- you would be well advised to apply significantly nonzero elevator and rudder trim before takeoff. A certain nonpilot on this list dismissed this as "probably not that much help" but every RL pilot I know does it anyway. The general problem of setting the trim to the "desired" value is ESP-complete; that is, it requires reading the pilot's mind to ascertain his intentions. As an extreme example of this, suppose I am buzzing along upside down in my Decathlon, trimmed for straight-and-level inverted flight. If I push "5" to center the primary flight controls, I definitely do not want the trim set to zero, nor set to the level-flight values. So, all evidence suggests that there is a need for a "5" command that does /not/ mess with the trim. You could *also* implement something that does set the trim automagically. I know a simple way to do this, if anybody is interested. However, I don't recommend it, because it is both unnecessary and unrealistic. This sort of automation appeals to people who drive cars, and expect to be able to jump in and drive away. It is, alas, highly unrealistic in present-day general-aviation aircraft, where the pilot expects to spend quite a long time running the preflight checklists, including setting the trim. One problem is that many aircraft in the FG fleet lack usable trim-position indicators. That is why the Sport Model contains a popup that provides the necessary information. (The popup is only a workaround, it is not meant as a long-term replacement for a proper realistic trim-position indicator.) http://www.av8n.com/fly/fgfs/README.sport.model http://www.av8n.com/fly/fgfs/git-overview ------------------------------------------------------------------------- SF.Net email is sponsored by: The Future of Linux Business White Paper from Novell. From the desktop to the data center, Linux is going mainstream. Let it simplify your IT future. http://altfarm.mediaplex.com/ad/ck/8857-50307-18918-4 _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
