On Samstag, 31. Januar 2004 17:42, Jon Berndt wrote:
> > That's right it isn't necessary. We are able to configure that
> > dynamically in
> > the viewer through properties, which is a good thing. If you look in the
> > /sim/view property paths you'll see x,y,z offsets that express the camera
> > position. These are offsets in meters from the lat,lon,alt
> > position that is passed from JSBSim.
>
> OK. Now, since we will be passing in the lat/lon/alt of the VRP - rather
> than the CG - will those points (the offsets you describe) need to be
> changed once the VRP is used?
That depends on where the VRP is.
I would expect that most models assumed that the static center of gravity was
reported by JSBSim. This one is identical to the dynamic center of gravity if
fuel tanks were modeled to be at the center of gravity (the f16 model uses
this location of the fuel tanks for example). But the reported position
varies around the static center of gravity if mass points which change their
mass dynamicaly, like fuel tanks do, if you burn fuel, are located somewhere
else.
So, I guess that there are models which 'fixed' this more or less
unpredictable offset to the static center of gravity by some try and error
method. This needs to be corrected I think. For a first cut the static center
of gravity will be a good approximation for the visual reference point.
Also, I think that, the dynamic center of gravity quite past model
initialization will give you most likely the best approach for computing the
VRP for existing models. Just because it maches the reported position at
model initialization time before the visual reference point was introduced.
Then everything will work as expected.
I think that further cleanup of this shifts could be left to the owner(?) of
the specific aircraft model ...
Greetings
Mathias
--
Mathias Fröhlich, email: [EMAIL PROTECTED]
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