differential equation sense). Fixing *this* by interpolating the
force function over small velocities leads to a stable but
non-physical solution that exhibits the drift problem that was
talked about.
Ah, OK. So did I get this right, here's a tradeoff between the
``physically correct''
be skidding at any given moment. The notion of holding forces at
zero makes intuitive sense, but underneath that it has very little
physical meaning.
On the contrary. I haven't followed this discussion too closely and I'm
no physicist either, but this sounds to me exactly like static vs.
Hi,
I'm no math or phisics genius but I was wondering if anyone has
tried making the friction logarithmic. As in high friction at slow
speeds and quickly dropping to normal friction.
This is just a suggestion. :-)
Stephen
___
Flightgear-devel
Hi,
I'm no math or phisics genius but I was wondering if anyone has
tried making the friction logarithmic. As in high friction at slow
speeds and quickly dropping to normal friction.
This is just a suggestion. :-)
Stephen
Actually, there is some truth in this. To show yourself, try
Gerhard Wesp wrote:
On the contrary. I haven't followed this discussion too closely and
I'm no physicist either, but this sounds to me exactly like static vs.
gliding friction.
Yes, there are separate coefficients of friction for the static
vs. dynamic case. But these are only different
Jon Berndt writes:
In the end, it could turn out that a physics-based approach is not
worth the effort, and we should simply make the aircraft do what
experience tells us a real aircraft would do.
As either you or Andy mentioned before, the problem is the
transition. Improving the
Jon Berndt [EMAIL PROTECTED] said:
If there were no winds at all, that might help. Otherwise, it doesn't work
at all.
Jon
Let me expand on that. If you do come to a stop, and there are no winds at
the moment, then the winds come up after you have stopped, then having
reduced the
Jim Wilson writes:
So then what would happen if you artificially introduced resistance at the
same time (near zero velocity) in a manner similar to a partially applied
parking brake?
The problem is that if the landing gear produces opposing forces or
moments that are too great, the plane
David Megginson [EMAIL PROTECTED] said:
Jim Wilson writes:
So then what would happen if you artificially introduced resistance at the
same time (near zero velocity) in a manner similar to a partially applied
parking brake?
The problem is that if the landing gear produces opposing
Jim Wilson wrote:
Can't we bring in some sort of damping factor that would just render the
aircraft stuck at very small velocities, but would still allow it to become
unstuck if a great enough force was applied? A sort of automatic parking
break that gets applied gradually starting at 0.01 fps
David Megginson wrote:
I was amazed at how tricky this got a year or so ago when I was
experimenting with it. I agree that we need some kind of damping at
slow speed. Essentially, the gear forces have to become a special
case, reducing forces and moments towards zero but never beyond into
David M. wrote:
Unfortunately, not -- when the JSBSim and YASim aircraft are rolling,
they are still far too much affected by the wind. In real life, even
with 30 kt gusts, you can usually taxi a 172 or Cherokee around as if
it were a car. Personally, I do set the controls appropriately
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