A little help

[Leandro Santos de Lima]

Hi, good evening!

I am studing some features of JSBsim and I need to get some flight and
simutation properties. Many of them I have no trouble but some have been
hard to get. They are:


- Drag force;
- Lift force;
- Inside force;
- Traction force;
- Roll moment;
- Yaw moment and
- Pitch moment.

I have used a property-list protocol like this:

<PropertyList>

<generic>
<output>
<binary_mode>false</binary_mode>
<var_separator>\t</var_separator>
<line_separator>\r\n</line_separator>
<preamble>t\t VT\t alfa\t beta\t phi\t theta\t psi\t P\t Q\t R\t H\t
deltaA\t deltaE\t deltaR\t D\t L\t Y\t T\t \bar{L} M\t N\t</preamble>
<postamble></postamble>
<chunk>
<node>/fdm/jsbsim/sim-time-sec</node>
<type>float</type>
<format>%.4f</format>
</chunk>
<chunk>
<node>/velocities/airspeed-kt</node>
<type>float</type>
<format>%.4f</format>
</chunk>

but I have no idea of the property node to get those properties.


Could someone help me?

All the best,
Leandro Lima

[Ron Jensen]

Post by Leandro Santos de Lima
Hi, good evening!
I am studing some features of JSBsim and I need to get some flight and
simutation properties. Many of them I have no trouble but some have been
- Drag force;
- Lift force;
- Inside force;
- Traction force;
- Roll moment;
- Yaw moment and
- Pitch moment.
<PropertyList>

<generic>
<output>
<binary_mode>false</binary_mode>
<var_separator>\t</var_separator>
<line_separator>\r\n</line_separator>
<preamble>t\t VT\t alfa\t beta\t phi\t theta\t psi\t P\t Q\t R\t
H\t deltaA\t deltaE\t deltaR\t D\t L\t Y\t T\t \bar{L} M\t N\t</preamble>
<postamble></postamble>
<chunk>
<node>/fdm/jsbsim/sim-time-sec</node>
<type>float</type>
<format>%.4f</format>
</chunk>
<chunk>
<node>/velocities/airspeed-kt</node>
<type>float</type>
<format>%.4f</format>
</chunk>

but I have no idea of the property node to get those properties.
Could someone help me?
All the best,
Leandro Lima

Assuming you're using FlightGear, look in /fdm/jsbsim, you'll find these
folders:

accelerations - output accelerations
aero - working folder for aerodynamics
atmosphere - output on what the atmosphere is locally
attitude - yaw pitch roll
fcs - working folder for the flight control system
* forces - forces acting on the model in various frames
gear - working folder for contact points
ic - initial conditions
inertia - vehicle mass and cg
inertial - navigation stuff
metrics - data on vehicle lengths and areas
* moments - moments acting on the model in various frames
position - output position
propulsion - working folder for engines and thrusters
simulation - simulation control stuff
systems - model systems, fuel control or other things
velocities - output velocities

It sounds like you're looking for:
(the w in fwx is for wind frame)
forces/fwx-aero-lbs == drag
forces/fwy-aero-lbs == side
forces/fwz-aero-lbs == lift
(the b in fbx is for body frame)
forces/fbx-prop-lbs == thrust (longitudinal)
forces/fby-prop-lbs == side component of thrust
forces/fbz-prop-lbs == vertical component of thrust

moments/l-total-lbsft == roll moment
moments/m-total-lbsft == pitch moment
moments/n-total-lbsft == yaw moment

Hope that helped,

Ron