Re: [Jsbsim-devel] Position/orientation-hold

[David C. <dav...@co...>]

On Saturday 29 December 2007 08:25, Jon S Berndt wrote:
> This sounds like a good idea. Could be that if the hold-position flag
> was set, then the final position and/or orientation of the aircraft
> would be set to its previous value, overriding any newly calculated
> value. The new "previous value" would then be set (to what it already
> is), and the position/orientation would hold.

Yes, that should do the trick.  Actually there are three types of position 
freeze that I can think of:

1)  Lat/Lon Freeze:  the orientation and altitude can change, but not lat/lon.

2)  Position Freeze:  the orientation can change, but not lat/lon/altitude.

3)  Full Freeze:  the orientation and position freeze.

The first one is the kind of freeze I see used in the high-end sims I deal 
with.  This allows one to manually trim up for a given configuration prior to 
being "cut loose".  In this case the airplane feels like it's flying because 
the altitude is allowed to change.

The second one I've not seen before.  Off-hand I can't think of a benefit.

The third one would give a useful wind tunnel effect for data collection and 
testing.

Dave