[Flightgear-devel] Side-Slipping with YASim

[Dany 2. <da...@nu...>]

Hi, FlightGeardevelopers,

YASim airplanes seem to have in common a non realistic behaviour from my point of view:

At least from my experience on Very Light Airplanes in real life, when you make a skid, or side-slipping (for a rapid loss of altitude without gaining too much speed) you push on the rudder, say, on the left, and move the yoke to the right to compensate for the rotation effect of the rudder, and finally go straight, but "in crab" through (calm) air. Then, your wings are inclined to the right side and the plane glides to the right without turning. Drag increases much. For a landing with wind from the side (from the right in my example above), this is also used to align the aircraft axis (the wheels) with the movement along the runway axis before touch (you touch with one wheel, inclined but aligned with the runway and the movement relative to the ground; against the air, you skid to the right, compensating the wind on the beam).

This is well simulated with jsbsim airplanes.

Differently, with YASim airplanes, you can make a straight side-slipping with the rudder right home (left or right, of course with auto-coordination off) and, after a little stabilization time,  with wings in horizontal position. I think this is not realistic because, for me, with wings in horizontal position and continuously pressing on the rudder, the plane should turn according to the rudder.  Moreover, it does not allow training for landing with wind from the side, which is a difficult and interesting exercise. If I'm right (what do pilots in real life think of it ?) that's a pity because YASIM seems a very interesting FDM. 

Is this a YASim weakness ? If yes, can it be corrected ? (I'm sorry not to be able to participate).

Thank you to those who made an effort to understand that I wrote...

Dany