<!-- There weren't many YF23s - just the two prototypes - and I
     couldn't find much 'hard' information so a lot of this fdm is
     guess work (GW).
-->
<!-- Max take off wieght is 64000lb but I imagine that this
     includes some weapons so I'm allocating 8000lb to his and
     subtracting it from the max wieght.

     I got a figure of 24000lb for the fuel load from a web site.
     this seems rather high to me but until I can get a better
     figure it'll have to do.
-->
<airplane mass="32000">

<!-- Approach configuration -->
<!-- From GW & photos -->
 <approach speed="130" aoa="5">
  <control-setting axis="/controls/engines/engine[0]/throttle" value="0.15"/>
  <control-setting axis="/controls/engines/engine[1]/throttle" value="0.15"/>
  <control-setting axis="/controls/engines/engine[0]/afterburner" value="0"/>
  <control-setting axis="/controls/engines/engine[1]/afterburner" value="0"/>
  <control-setting axis="/controls/flight/flaps" value="1"/>
  <control-setting axis="/controls/flight/slats" value="0"/>
  <control-setting axis="/controls/gear/gear-down" value="1"/>
 </approach>

<!-- Cruise configuration -->
 <cruise speed="600" alt="55000">
  <control-setting axis="/controls/engines/engine[0]/throttle" value="0.9"/>
  <control-setting axis="/controls/engines/engine[1]/throttle" value="0.9"/>
  <control-setting axis="/controls/engines/engine[0]/afterburner" value="0"/>
  <control-setting axis="/controls/engines/engine[1]/afterburner" value="0"/>
  <control-setting axis="/controls/flight/flaps" value="0.0"/>
  <control-setting axis="/controls/flight/slats" value="0"/>
  <control-setting axis="/controls/gear/gear-down" value="0"/>
 </cruise>

 <cockpit x="5.70" y="0.00" z="1.26"/>

<!-- Fuselage entries for the fuselage proper and the two
     engine housings.
-->
<!-- Fuselage -->
 <fuselage ax="10.00" ay="0.00" az="0.00"
          bx="-2.00" by="0.00" bz="0.00"
          width="1.6" taper="0.5" midpoint="0.5"/>

<!-- Left engine housing -->
 <fuselage ax="-2.00" ay="1.80" az="0.00"
          bx="-8.00" by="1.20" bz="0.60"
          width="1.2" taper="0" midpoint="0.3"/>

<!-- Right engine housing -->
 <fuselage ax="-2.00" ay="-1.80" az="0.00"
          bx="-8.00" by="-1.20" bz="0.60"
          width="1.2" taper="0" midpoint="0.3"/>

<!-- Lots of guesswork here -->
 <wing x="-2.00" y="0.00" z="0.25" length="6.66" chord="12.00" taper="0.08"
       sweep="0" dihedral="0" camber="0.001" incidence="0.0" idrag="1.6">
  <stall aoa="25" width="3" peak="1.3"/>
  <flap0 start="0.36" end="0.63" lift="1.3" drag="1.8"/>
  <flap1 start="0.63" end="0.89" lift="1.2" drag="1.8"/>
  <slat start="0.36" end="0.89" aoa="6" drag="1.3"/>

<!-- Shortened wing that starts outboard of the engine intakes.
 <wing x="-2.00" y="2.40" z="0.25" length="4.2" chord="8.1"
      taper="0.19" sweep="0" dihedral="0" camber="0.0" incidence="0.0">
  <stall aoa="35" width="2" peak="1.3"/>
  <flap0 start="0.0" end="0.42" lift="1.5" drag="1.6"/>
  <flap1 start="0.42" end="0.833" lift="1.05" drag="1.3"/>
-->
  <control-input axis="/controls/flight/flaps" control="FLAP0"/>
  <control-input axis="/controls/flight/aileron" control="FLAP1" split="true"/>
  <control-input axis="/controls/flight/aileron-trim" control="FLAP1" split="true"/>

  <control-input axis="/controls/flight/slats" control="SLAT"/>

  <control-input axis="/controls/flight/rudder" control="FLAP1" split="true" invert="true"/>

  <control-input axis="/controls/flight/spoilers" control="FLAP0"/>
  <control-input axis="/controls/flight/spoilers" control="FLAP1" invert="true"/>

  <control-output control="FLAP0" prop="/surface-positions/left-flap-pos-norm"/>
  <control-output control="FLAP0" prop="/surface-positions/right-flap-pos-norm"/>

  <control-output control="FLAP1" side="left" prop="/surface-positions/left-aileron-pos-norm"/>
  <control-output control="FLAP1" side="right" prop="/surface-positions/right-aileron-pos-norm"/>

  <control-output control="SLAT" side="left" prop="/surface-positions/left-slat-pos-norm"/>
  <control-output control="SLAT" side="right" prop="/surface-positions/right-slat-pos-norm"/>

  <control-speed control="FLAP0" transition-time="2"/>
  <control-speed control="FLAP1" transition-time="0.5"/>
  <control-speed control="SLAT" transition-time="0.5"/>
 </wing>

 <hstab x="-8.70" y="2.40" z="0.36" length="3.30" chord="5.10"
       taper="0.11" sweep="0" dihedral="40" camber="0.01" effectiveness="2">
  <stall aoa="24" width="2" peak="1.3"/>
  <flap0 start="0" end="1" lift="1.25" drag="1.4"/>

  <control-input axis="/controls/flight/elevator" control="FLAP0"/>
  <control-input axis="/controls/flight/elevator-trim" control="FLAP0"/>

  <control-input axis="/controls/flight/rudder" control="FLAP0" split="true" square="false" invert="true"/>

  <control-output control="FLAP0" side="left" prop="/surface-positions/left-elevator-pos-norm"/>
  <control-output control="FLAP0" side="right" prop="/surface-positions/right-elevator-pos-norm"/>

  <control-speed control="FLAP0" transition-time="0.5"/>
 </hstab>

<!-- I couldn't find a figure for the mass so it's guess work.
-->
 <jet x="-6.26" y="1.20" z="0.60" mass="3000" thrust="24500" afterburner="35000">
  <control-input axis="/controls/engines/engine[0]/throttle" control="THROTTLE"/>
  <control-input axis="/controls/engines/engine[0]/afterburner" control="REHEAT"/>
 </jet>

 <jet x="-6.26" y="-1.20" z="0.60" mass="3000" thrust="24500" afterburner="35000">
  <control-input axis="/controls/engines/engine[1]/throttle" control="THROTTLE"/>
  <control-input axis="/controls/engines/engine[1]/afterburner" control="REHEAT"/>
 </jet>

<!-- Front -->
 <gear x="5.25" y="0.00" z="-2.25" compression="0.65" spring="2.5">
  <control-input axis="/controls/flight/rudder" control="STEER" square="true"/>
  <control-input axis="/controls/gear/gear-down" control="EXTEND"/>
  <control-input axis="/controls/gear/gear[0]/wheel[0]/brake" control="BRAKE"/>
  <control-output control="EXTEND" prop="/gear/gear[0]/position-norm"/>
  <control-output control="STEER" prop="/gear/gear[0]/steering-norm"/>
  <control-speed control="EXTEND" transition-time="4"/>
 </gear>

<!-- Left main -->
 <gear x="-2.20" y="1.92" z="-2.9" compression="2.0" spring="2.5">
  <control-input axis="/controls/gear/gear-down" control="EXTEND"/>
  <control-input axis="/controls/gear/gear[1]/wheel[0]/brake" control="BRAKE"/>
  <control-output control="EXTEND" prop="/gear/gear[1]/position-norm"/>
  <control-speed control="EXTEND" transition-time="4"/>
 </gear>

<!-- Right main -->
 <gear x="-2.20" y="-1.92" z="-2.9" compression="2.0" spring="2.5">
  <control-input axis="/controls/gear/gear-down" control="EXTEND"/>
  <control-input axis="/controls/gear/gear[2]/wheel[0]/brake" control="BRAKE"/>
  <control-output control="EXTEND" prop="/gear/gear[2]/position-norm"/>
  <control-speed control="EXTEND" transition-time="4"/>
 </gear>

<!-- Canopy -->
 <gear x="4.1" y="0.0" z="1.05" retract-time="7" compression="0.6">
  <control-input axis="/controls/gear/parking-brake" control="EXTEND"/>
  <control-speed control="EXTEND" transition-time="10"/>
  <control-output control="EXTEND" prop="/canopy/position-norm"/>
 </gear>

<!-- The locations and capcities are guesswork. -->
<!-- Fuselage tank -->
 <tank x="1.5" y="0" z="0.68" jet="true" capacity="8000"/>
<!-- Left wing tank -->
 <tank x="-1.40" y="2" z="0.0" jet="true" capacity="8000"/>
<!-- Right wing tank -->
 <tank x="-1.40" y="-2" z="0.0" jet="true" capacity="8000"/>

<!-- Avionics -->
 <ballast x="4" y="0" z="0.6" mass="3000"/>

<!-- Cockpit and radar -->
 <ballast x="7" y="0" z="0.2" mass="1500"/>

<!-- Pilot -->
 <ballast x="5.8" y="0" z="0.6" mass="200"/>

<!-- Trim ballast -->
 <ballast x="6" y="0" z="0.0" mass="2000"/>

</airplane>