Can you check the centre of gravity and the aerodynamic reference point that are used in your FDM and the various data sources.
Also is the pitch moment that you are using wing only, or is it wing+tail+fuselage?
Alan
dany93 wrote in Mon Aug 07, 2017 10:42 am:The empty CG location seems correct relative to the FDM axes (reference for seats, loads,.. locations) because the limits with loads (at least those that I tested) are correct, inside the weight and balance graphs.
Moving the AERORP forwards from initially 18.90" (which seems correct IMO) to 15.67" helps, with keeping your (= Du Y) initial Cm_alpha and Cm_elevator values. But it becomes located before the most aft CG (19" or 20"). Usually considered as bad for stability IRL.
Notice that these limits should be different for the J3Cub -34 to +29 deg) and the PA18 (-25 to +15 deg).
<aerosurface_scale name="Elevator Control J3Cub">
<input>fcs/pitch-trim-sum</input>
<range>
<min> -0.51 </min>
<max> 0.34 </max>
</range>
<output>fcs/elevator-pos-rad-j3cub</output>
</aerosurface_scale>
<aerosurface_scale name="Elevator Control PA-18">
<input>fcs/pitch-trim-sum</input>
<range>
<min> -0.44 </min>
<max> 0.26 </max>
</range>
<output>fcs/elevator-pos-rad-pa18</output>
</aerosurface_scale>
<fcs_function name="fcs/elevator-pos-rad">
<function>
<sum>
<product>
<eq>
<property>/sim/model/j3cub/pa-18</property>
<value>0</value>
</eq>
<property>fcs/elevator-pos-rad-j3cub</property>
</product>
<product>
<eq>
<property>/sim/model/j3cub/pa-18</property>
<value>1</value>
</eq>
<property>fcs/elevator-pos-rad-pa18</property>
</product>
</sum>
</function>
<output>fcs/elevator-pos-rad</output>
</fcs_function>
<function name="aero/force/LIFT">
<sum>
<property>aero/force/Lift_propwash</property>
<property>aero/force/Lift_alpha</property>
<property>aero/coefficient/CLDf</property>
<property>aero/force/Lift_pitch_rate</property>
<property>aero/force/Lift_alpha_rate</property>
<property>aero/force/Lift_elevator</property>
</sum>
</function>
<function name="aero/force/PITCH">
<sum>
<property>aero/moment/Pitch_propwash</property>
<property>aero/moment/Pitch_alpha</property>
<property>aero/moment/Pitch_elevator</property>
<property>aero/moment/Pitch_damp</property>
<property>aero/moment/Pitch_alphadot</property>
<property>aero/coefficient/Cmdf</property>
</sum>
</function>
Alant wrote in Wed Aug 09, 2017 7:52 pm:The aerodynamic moments are not measured about the CG, they are measured about some reference point. Oftehn the 1/4 chord point is used, but it can be any arbitrary point. This is not necessarily the same as the CG. The FDM must use the same one that was used in the dataset.
<megginson/>
(linear aerodynamic coefficients)
These coefficients [...] use stability axes.
var saveSettings = func {
aircraft.data.add("/first-property", "/second-property");
aircraft.data.save();
}
saveSettings();
Solution to this is to run a aircraftdata save via nasal when then setting is toggled, see here example in my A320.
Thorsten, I think what Josh posted is less about saving all settings upon a forced exit, but saving the setting the second it is selected.
wlbragg wrote in Wed Aug 09, 2017 7:51 pm:J3Cub (-34 to +29 deg)
PA18 (-25 to +15 deg)
EDIT: If you happen to notice other differences along the way, ie: aileron, rudder, etc., let me know and I can plug those in also.
<min> -0.59 </min>
<max> 0.51 </max>
it0uchpods wrote in Thu Aug 10, 2017 6:01 am:Wayne,
Yes, I always quit via the "X" on my operating system.
Solution to this is to run a aircraftdata save via nasal when then setting is toggled, see here example in my A320.
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