Re: [Flightgear-devel] flight data playback

[Hal V. E. <hv...@gm...>]

On Wednesday, December 08, 2010 12:32:53 am Erik Hofman wrote:
> On Tue, 2010-12-07 at 15:49 -0800, Hal V. Engel wrote:
> > I was asked to record some flight data that is to be used for an
> > aeronautical engineering class.  I used the instructions located here
> > 
> > http://wiki.flightgear.org/index.php/Suggested_Prerecorded_Flights
> > 
> > to do the recording and to test the playback.  I used this same basic
> > technique to record and playback flights in the past but must admit that
> > it was a long time ago.
> > 
> > The recording process seemed fine but playback has a number of issues.
> > 
> > 1. The playback does not seem to manipulate anything other than basic
> > controls.  For example it does not change the position of the fuel cutoff
> > value or the primer switch.  This results in the aircraft not starting
> > at the beginning of the flight.  Yet it will start the take off roll
> > with the engine not running?
> 
> The playback configuration file is just what it says, playback the
> flight with a limited number of options. It records the lat/lon/height
> of the plane and when playing back puts the plane at the recored
> locations. Nothing fancy, really.
> 
> If you want to playback flight where the controls are recorded then
> you'll need to create a new configuration file for it. (In that case you
> shouldn't play back with --fdm=external).
> 
> Erik

Yes I want to record and playback the controls using the native FDM of the 
aircraft.  I do not care at all about the lat/lon/height of the plane.  I want 
to be able to feed my control inputs into the playback and have the FDM 
process this information like normal real time input.  This is what is needed 
for the demo since they want to be able to analyze what is happening during 
the flight and they need control inputs and FDM data (fdm/jsbsim/aero/*) for 
this.   

Where is recording/playback of the controls documented?  What protocol type do 
I specify on the --generic line?  Googling has not provided any links to 
anything other than the generic recording and playback and looking through the 
documentation didn't provide much help but I may have missed the document that 
has this info.  

For playback I tried specifying the fdm

--fdm=jsb

But the engine will not start and it refused to take off since it never reaches 
rotation speed and it crashed when the gear is raised.  Also it only runs a 2 
to 3 FPS.

Hal