re: [Flightgear-devel] more on JSBSim init probs

[David M. <da...@me...>]

Cameron Moore writes:

 > Well, the saga continues.  Try this on for size...start fgfs with:
 > 
 >   runfgfs --fdm=jsb --aircraft=c172 --altitude=100
 > 
 > and let yourself freefall and bounce around.  At some point you should
 > start getting NaNs or have FG lockup on you.

This is a problem with the gear code, I think.  The wingtips are
defined as gear/contact points (good), but under unpredictable
circumstances, contact between the wingtips and the ground sends
JSBSim into NAN-land.  Here's another way to invoke the bug:

1. Start on the runway (on a near-sea-level runway, like KSFO).

2. Accelerate to about 80 kt.

3. Throw hard rudder left or right.

This will bring one of the wingtips into hard contact with the ground,
and will usually trigger the bug.


All the best,


David

-- 
David Megginson
da...@me...