I noticed that all of the YASim models tended to nose down with
neutral elevator. I assumed that it was a WB problem and tried
shifting weight all over the place in the J3 cub (and even moved the
wings around), but nothing fixed the problem.
In the end, I figured out that the YASim solver simply
David Megginson wrote:
I noticed that all of the YASim models tended to nose down with
neutral elevator. I assumed that it was a WB problem and tried
shifting weight all over the place in the J3 cub (and even moved the
wings around), but nothing fixed the problem.
Right. The solver just
Andy Ross writes:
This came up a while back. Apparently I didn't put it in the docs. A
slightly terser explanation is this:
YASim trims the aircraft (with tail incidence, not control input) so
that the elevator value is exactly zero in the specified cruise
configuration. It
David Megginson wrote:
That was not happening, however; instead, with 0 elevator and 0
elevator trim, all aircraft would continue pitching downwards and
accelerating past Vne. Setting the elevator property solved the
problem. I don't know why it wasn't trimming for 0
elevator/elevator trim.
Andy Ross writes:
And it *was* trimming for zero /controls/elevator{-trim}. That's the
whole point: It's not a bug in the solver. The pitching moment* at
the specified cruise conditions is very near zero; that's what the
solver does. The problem is that a real aircraft under those
