fgdata/Aircraft/Generic/JSBSim/Systems/hydrodynamic-planing-floats.xml

<?xml version="1.0"?>
<!--

  Model of hydrodynamic planing based on [Wagner:1933:POW] for JSBSim.

    Copyright (C) 2015 - 2017  Anders Gidenstam  (anders(at)gidenstam.org)

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

-->
<system name="hydrodynamic planing of floats">

 <documentation>

  This system depends on the generic hydrodynamics.xml system for JSBSim.

  <reference refID="Wagner:1933:POW"
             author="Herbert Wagner"
             title="Planing of Watercraft  Translated as NACA-TM-1139"
             date="1933/1948"/>

 </documentation>

 <!-- Model parameters -->

 <!-- Parameters defining the planing surfaces of the floats. -->
 <!-- NOTE: Coordinates in the frame with
            origin at hydro RP and x/y/z = aft/right/up
 -->
 <property>hydro/planing-floats/forebody-length-ft[0]</property>
 <property>hydro/planing-floats/forebody-beam-ft[0]</property>
 <property>hydro/planing-floats/forebody-keel-y-ft[0]</property>
 <property>hydro/planing-floats/forebody-keel-z-ft[0]</property>
 <property>hydro/planing-floats/forebody-end-x-ft[0]</property>
 <property>hydro/planing-floats/afterbody-length-ft[0]</property>
 <property>hydro/planing-floats/afterbody-beam-ft[0]</property>
 <property>hydro/planing-floats/afterbody-keel-y-ft[0]</property>
 <property>hydro/planing-floats/afterbody-keel-z-ft[0]</property>
 <property>hydro/planing-floats/afterbody-end-x-ft[0]</property>

 <property>hydro/planing-floats/forebody-length-ft[1]</property>
 <property>hydro/planing-floats/forebody-beam-ft[1]</property>
 <property>hydro/planing-floats/forebody-keel-y-ft[1]</property>
 <property>hydro/planing-floats/forebody-keel-z-ft[1]</property>
 <property>hydro/planing-floats/forebody-end-x-ft[1]</property>
 <property>hydro/planing-floats/afterbody-length-ft[1]</property>
 <property>hydro/planing-floats/afterbody-beam-ft[1]</property>
 <property>hydro/planing-floats/afterbody-keel-y-ft[1]</property>
 <property>hydro/planing-floats/afterbody-keel-z-ft[1]</property>
 <property>hydro/planing-floats/afterbody-end-x-ft[1]</property>

 <!-- Other parameters. -->
 <property value="1.0">hydro/planing-floats/forebody-normal-force-factor[0]</property>
 <property value="1.0">hydro/planing-floats/afterbody-normal-force-factor[0]</property>
 <property>hydro/planing-floats/forebody-skin-friction-coefficient[0]</property>
 <property>hydro/planing-floats/afterbody-skin-friction-coefficient[0]</property>

 <property value="1.0">hydro/planing-floats/forebody-normal-force-factor[1]</property>
 <property value="1.0">hydro/planing-floats/afterbody-normal-force-factor[1]</property>
 <property>hydro/planing-floats/forebody-skin-friction-coefficient[1]</property>
 <property>hydro/planing-floats/afterbody-skin-friction-coefficient[1]</property>

 <channel name="Planing dynamics based on [Wagner:1933:POW]">

  <fcs_function name="hydro/planing-floats/forebody-entry-point-x-ft[0]">
   <function>
    <description>The intersection point with the water surface.</description>
    <quotient>
     <sum>
      <quotient>
       <property>hydro/floats/height-agl-ft[0]</property>
       <cos><property>hydro/floats/pitch-rad[0]</property></cos>
      </quotient>
      <property>hydro/planing-floats/forebody-keel-z-ft[0]</property>
     </sum>
     <tan><property>hydro/floats/pitch-rad[0]</property></tan>
    </quotient>
   </function>
   <clipto> <!-- We don't want to get +/-inf out of this function. -->
    <min>-10000.0</min>
    <max>10000.0</max>
   </clipto>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-entry-point-x-ft[0]">
   <function>
    <description>The intersection point with the water surface.</description>
    <quotient>
     <sum>
      <quotient>
       <property>hydro/floats/height-agl-ft[0]</property>
       <cos><property>hydro/floats/pitch-rad[0]</property></cos>
      </quotient>
      <property>hydro/planing-floats/afterbody-keel-z-ft[0]</property>
     </sum>
     <tan><property>hydro/floats/pitch-rad[0]</property></tan>
    </quotient>
   </function>
   <clipto> <!-- We don't want to get +/-inf out of this function. -->
    <min>-10000.0</min>
    <max>10000.0</max>
   </clipto>
  </fcs_function>

  <fcs_function name="hydro/planing-floats/forebody-entry-point-x-ft[1]">
   <function>
    <description>The intersection point with the water surface.</description>
    <quotient>
     <sum>
      <quotient>
       <property>hydro/floats/height-agl-ft[1]</property>
       <cos><property>hydro/floats/pitch-rad[1]</property></cos>
      </quotient>
      <property>hydro/planing-floats/forebody-keel-z-ft[1]</property>
     </sum>
     <tan><property>hydro/floats/pitch-rad[1]</property></tan>
    </quotient>
   </function>
   <clipto> <!-- We don't want to get +/-inf out of this function. -->
    <min>-10000.0</min>
    <max>10000.0</max>
   </clipto>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-entry-point-x-ft[1]">
   <function>
    <description>The intersection point with the water surface.</description>
    <quotient>
     <sum>
      <quotient>
       <property>hydro/floats/height-agl-ft[1]</property>
       <cos><property>hydro/floats/pitch-rad[1]</property></cos>
      </quotient>
      <property>hydro/planing-floats/afterbody-keel-z-ft[1]</property>
     </sum>
     <tan><property>hydro/floats/pitch-rad[1]</property></tan>
    </quotient>
   </function>
   <clipto> <!-- We don't want to get +/-inf out of this function. -->
    <min>-10000.0</min>
    <max>10000.0</max>
   </clipto>
  </fcs_function>

  <fcs_function name="hydro/planing-floats/forebody-wetted-keel-ft[0]">
   <function>
    <description>The length of keel below the free water surface.</description>
    <max>
     <value>0.0</value>
     <min>
      <property>hydro/planing-floats/forebody-length-ft[0]</property>
      <sum>
       <product>
        <ge>
         <property>hydro/floats/pitch-rad[0]</property>
         <value>0.0</value>
        </ge>
        <difference>
         <property>hydro/planing-floats/forebody-end-x-ft[0]</property>
         <property>hydro/planing-floats/forebody-entry-point-x-ft[0]</property>
        </difference>
       </product>
       <product>
        <lt>
         <property>hydro/floats/pitch-rad[0]</property>
         <value>0.0</value>
        </lt>
        <difference>
         <property>hydro/planing-floats/forebody-entry-point-x-ft[0]</property>
         <difference>
          <property>hydro/planing-floats/forebody-end-x-ft[0]</property>
          <property>hydro/planing-floats/forebody-length-ft[0]</property>
         </difference>
        </difference>
       </product>
      </sum>
     </min>
    </max>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-wetted-keel-ft[0]">
   <function>
    <description>The length of keel below the free water surface.</description>
    <max>
     <value>0.0</value>
     <min>
      <property>hydro/planing-floats/afterbody-length-ft[0]</property>
      <sum>
       <product>
        <ge>
         <property>hydro/floats/pitch-rad[0]</property>
         <value>0.0</value>
        </ge>
        <difference>
         <property>hydro/planing-floats/afterbody-end-x-ft[0]</property>
         <property>hydro/planing-floats/afterbody-entry-point-x-ft[0]</property>
        </difference>
       </product>
       <product>
        <lt>
         <property>hydro/floats/pitch-rad[0]</property>
         <value>0.0</value>
        </lt>
        <difference>
         <property>hydro/planing-floats/afterbody-entry-point-x-ft[0]</property>
         <difference>
          <property>hydro/planing-floats/afterbody-end-x-ft[0]</property>
          <property>hydro/planing-floats/afterbody-length-ft[0]</property>
         </difference>
        </difference>
       </product>
      </sum>
     </min>
    </max>
   </function>
  </fcs_function>

  <fcs_function name="hydro/planing-floats/forebody-wetted-keel-ft[1]">
   <function>
    <description>The length of keel below the free water surface.</description>
    <max>
     <value>0.0</value>
     <min>
      <property>hydro/planing-floats/forebody-length-ft[1]</property>
      <sum>
       <product>
        <ge>
         <property>hydro/floats/pitch-rad[1]</property>
         <value>0.0</value>
        </ge>
        <difference>
         <property>hydro/planing-floats/forebody-end-x-ft[1]</property>
         <property>hydro/planing-floats/forebody-entry-point-x-ft[1]</property>
        </difference>
       </product>
       <product>
        <lt>
         <property>hydro/floats/pitch-rad[1]</property>
         <value>0.0</value>
        </lt>
        <difference>
         <property>hydro/planing-floats/forebody-entry-point-x-ft[1]</property>
         <difference>
          <property>hydro/planing-floats/forebody-end-x-ft[1]</property>
          <property>hydro/planing-floats/forebody-length-ft[1]</property>
         </difference>
        </difference>
       </product>
      </sum>
     </min>
    </max>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-wetted-keel-ft[1]">
   <function>
    <description>The length of keel below the free water surface.</description>
    <max>
     <value>0.0</value>
     <min>
      <property>hydro/planing-floats/afterbody-length-ft[1]</property>
      <sum>
       <product>
        <ge>
         <property>hydro/floats/pitch-rad[1]</property>
         <value>0.0</value>
        </ge>
        <difference>
         <property>hydro/planing-floats/afterbody-end-x-ft[1]</property>
         <property>hydro/planing-floats/afterbody-entry-point-x-ft[1]</property>
        </difference>
       </product>
       <product>
        <lt>
         <property>hydro/floats/pitch-rad[1]</property>
         <value>0.0</value>
        </lt>
        <difference>
         <property>hydro/planing-floats/afterbody-entry-point-x-ft[1]</property>
         <difference>
          <property>hydro/planing-floats/afterbody-end-x-ft[1]</property>
          <property>hydro/planing-floats/afterbody-length-ft[1]</property>
         </difference>
        </difference>
       </product>
      </sum>
     </min>
    </max>
   </function>
  </fcs_function>

  <fcs_function name="hydro/planing-floats/forebody-normal-force-lbs[0]">
   <function>
    <description>
     The normal force produced by the planing surface.
     NOTE: The formulation is only valid for very small pitch angles and
           the pitch angle should also be adjusted for down-wash.
           See [Wagner:1933:POW].
    </description>
    <max>
     <value>0.0</value>
     <product>
      <property>hydro/planing-floats/forebody-normal-force-factor[0]</property>
      <value>3.1415927</value>
      <property>hydro/qbar-u-psf</property>
      <property>hydro/planing-floats/forebody-beam-ft[0]</property>
      <property>hydro/planing-floats/forebody-wetted-keel-ft[0]</property>
      <sin><property>hydro/floats/pitch-rad[0]</property></sin>
     </product>
    </max>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-normal-force-lbs[0]">
   <function>
    <description>
     The normal force produced by the planing surface.
     NOTE: The formulation is only valid for very small pitch angles and
           the pitch angle should also be adjusted for down-wash.
           See [Wagner:1933:POW].
    </description>
    <max>
     <value>0.0</value>
     <product>
      <property>hydro/planing-floats/afterbody-normal-force-factor[0]</property>
      <value>3.1415927</value>
      <property>hydro/qbar-u-psf</property>
      <property>hydro/planing-floats/afterbody-beam-ft[0]</property>
      <property>hydro/planing-floats/afterbody-wetted-keel-ft[0]</property>
      <sin><property>hydro/floats/pitch-rad[0]</property></sin>
     </product>
    </max>
   </function>
  </fcs_function>

  <fcs_function name="hydro/planing-floats/forebody-normal-force-lbs[1]">
   <function>
    <description>
     The normal force produced by the planing surface.
     NOTE: The formulation is only valid for very small pitch angles and
           the pitch angle should also be adjusted for down-wash.
           See [Wagner:1933:POW].
    </description>
    <max>
     <value>0.0</value>
     <product>
      <property>hydro/planing-floats/forebody-normal-force-factor[1]</property>
      <value>3.1415927</value>
      <property>hydro/qbar-u-psf</property>
      <property>hydro/planing-floats/forebody-beam-ft[1]</property>
      <property>hydro/planing-floats/forebody-wetted-keel-ft[1]</property>
      <sin><property>hydro/floats/pitch-rad[1]</property></sin>
     </product>
    </max>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-normal-force-lbs[1]">
   <function>
    <description>
     The normal force produced by the planing surface.
     NOTE: The formulation is only valid for very small pitch angles and
           the pitch angle should also be adjusted for down-wash.
           See [Wagner:1933:POW].
    </description>
    <max>
     <value>0.0</value>
     <product>
      <property>hydro/planing-floats/afterbody-normal-force-factor[1]</property>
      <value>3.1415927</value>
      <property>hydro/qbar-u-psf</property>
      <property>hydro/planing-floats/afterbody-beam-ft[1]</property>
      <property>hydro/planing-floats/afterbody-wetted-keel-ft[1]</property>
      <sin><property>hydro/floats/pitch-rad[1]</property></sin>
     </product>
    </max>
   </function>
  </fcs_function>

 </channel>

 <channel name="Fbx">

  <fcs_function name="hydro/planing-floats/forebody-induced-fbx-force-lbs[0]">
   <function>
    <description>Drag (induced) due to planing. FIXME: direction/frame?</description>
    <product>
     <value>-1.0</value>
     <max>
      <value>0.0</value>
      <product>
       <property>hydro/planing-floats/forebody-normal-force-lbs[0]</property>
       <sin><property>hydro/floats/pitch-rad[0]</property></sin>
      </product>
     </max>
    </product>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-induced-fbx-force-lbs[0]">
   <function>
    <description>Drag (induced) due to planing. FIXME: direction/frame?</description>
    <product>
     <value>-1.0</value>
     <max>
      <value>0.0</value>
      <product>
       <property>hydro/planing-floats/afterbody-normal-force-lbs[0]</property>
       <sin><property>hydro/floats/pitch-rad[0]</property></sin>
      </product>
     </max>
    </product>
   </function>
  </fcs_function>

  <fcs_function name="hydro/planing-floats/forebody-induced-fbx-force-lbs[1]">
   <function>
    <description>Drag (induced) due to planing. FIXME: direction/frame?</description>
    <product>
     <value>-1.0</value>
     <max>
      <value>0.0</value>
      <product>
       <property>hydro/planing-floats/forebody-normal-force-lbs[1]</property>
       <sin><property>hydro/floats/pitch-rad[1]</property></sin>
      </product>
     </max>
    </product>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-induced-fbx-force-lbs[1]">
   <function>
    <description>Drag (induced) due to planing. FIXME: direction/frame?</description>
    <product>
     <value>-1.0</value>
     <max>
      <value>0.0</value>
      <product>
       <property>hydro/planing-floats/afterbody-normal-force-lbs[1]</property>
       <sin><property>hydro/floats/pitch-rad[1]</property></sin>
      </product>
     </max>
    </product>
   </function>
  </fcs_function>

  <fcs_function name="hydro/planing-floats/forebody-friction-fbx-force-lbs[0]">
   <function>
    <description>Drag due to skin friction.</description>
    <product>
     <value>-1.0</value>
     <property>hydro/planing-floats/forebody-skin-friction-coefficient[0]</property>
     <property>hydro/qbar-u-psf</property>
     <property>hydro/planing-floats/forebody-beam-ft[0]</property>
     <property>hydro/planing-floats/forebody-wetted-keel-ft[0]</property>
    </product>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-friction-fbx-force-lbs[0]">
   <function>
    <description>Drag due to skin friction.</description>
    <product>
     <value>-1.0</value>
     <property>hydro/planing-floats/afterbody-skin-friction-coefficient[0]</property>
     <property>hydro/qbar-u-psf</property>
     <property>hydro/planing-floats/afterbody-beam-ft[0]</property>
     <property>hydro/planing-floats/afterbody-wetted-keel-ft[0]</property>
    </product>
   </function>
  </fcs_function>

  <fcs_function name="hydro/planing-floats/forebody-friction-fbx-force-lbs[1]">
   <function>
    <description>Drag due to skin friction.</description>
    <product>
     <value>-1.0</value>
     <property>hydro/planing-floats/forebody-skin-friction-coefficient[1]</property>
     <property>hydro/qbar-u-psf</property>
     <property>hydro/planing-floats/forebody-beam-ft[1]</property>
     <property>hydro/planing-floats/forebody-wetted-keel-ft[1]</property>
    </product>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-friction-fbx-force-lbs[1]">
   <function>
    <description>Drag due to skin friction.</description>
    <product>
     <value>-1.0</value>
     <property>hydro/planing-floats/afterbody-skin-friction-coefficient[1]</property>
     <property>hydro/qbar-u-psf</property>
     <property>hydro/planing-floats/afterbody-beam-ft[1]</property>
     <property>hydro/planing-floats/afterbody-wetted-keel-ft[1]</property>
    </product>
   </function>
  </fcs_function>

 </channel>

 <channel name="Fby">

  <fcs_function name="hydro/planing-floats/forebody-fby-force-lbs[0]">
   <function>
    <description>
     Fby force due to planing.
     FIXME: model/direction/frame?
    </description>
    <product>
     <property>hydro/planing-floats/forebody-normal-force-lbs[0]</property>
     <cos><property>hydro/floats/pitch-rad[0]</property></cos>
     <sin><property>hydro/floats/roll-rad[0]</property></sin>
    </product>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-fby-force-lbs[0]">
   <function>
    <description>
     Fby force due to planing.
     FIXME: model/direction/frame?
    </description>
    <product>
     <property>hydro/planing-floats/afterbody-normal-force-lbs[0]</property>
     <cos><property>hydro/floats/pitch-rad[0]</property></cos>
     <sin><property>hydro/floats/roll-rad[0]</property></sin>
    </product>
   </function>
  </fcs_function>

  <fcs_function name="hydro/planing-floats/forebody-fby-force-lbs[1]">
   <function>
    <description>
     Fby force due to planing.
     FIXME: model/direction/frame?
    </description>
    <product>
     <property>hydro/planing-floats/forebody-normal-force-lbs[1]</property>
     <cos><property>hydro/floats/pitch-rad[1]</property></cos>
     <sin><property>hydro/floats/roll-rad[1]</property></sin>
    </product>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-fby-force-lbs[1]">
   <function>
    <description>
     Fby force due to planing.
     FIXME: model/direction/frame?
    </description>
    <product>
     <property>hydro/planing-floats/afterbody-normal-force-lbs[1]</property>
     <cos><property>hydro/floats/pitch-rad[1]</property></cos>
     <sin><property>hydro/floats/roll-rad[1]</property></sin>
    </product>
   </function>
  </fcs_function>

 </channel>

 <channel name="Lift">

  <fcs_function name="hydro/planing-floats/forebody-lift-force-lbs[0]">
   <function>
    <description>Lift due to planing. FIXME: direction/frame?</description>
    <max>
     <value>0.0</value>
     <product>
      <property>hydro/planing-floats/forebody-normal-force-lbs[0]</property>
      <cos><property>hydro/floats/pitch-rad[0]</property></cos>
      <cos><property>hydro/floats/roll-rad[0]</property></cos>
     </product>
    </max>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-lift-force-lbs[0]">
   <function>
    <description>Lift due to planing. FIXME: direction/frame?</description>
    <max>
     <value>0.0</value>
     <product>
      <property>hydro/planing-floats/afterbody-normal-force-lbs[0]</property>
      <cos><property>hydro/floats/pitch-rad[0]</property></cos>
      <cos><property>hydro/floats/roll-rad[0]</property></cos>
     </product>
    </max>
   </function>
  </fcs_function>

  <fcs_function name="hydro/planing-floats/forebody-lift-force-lbs[1]">
   <function>
    <description>Lift due to planing. FIXME: direction/frame?</description>
    <max>
     <value>0.0</value>
     <product>
      <property>hydro/planing-floats/forebody-normal-force-lbs[1]</property>
      <cos><property>hydro/floats/pitch-rad[1]</property></cos>
      <cos><property>hydro/floats/roll-rad[1]</property></cos>
     </product>
    </max>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-lift-force-lbs[1]">
   <function>
    <description>Lift due to planing. FIXME: direction/frame?</description>
    <max>
     <value>0.0</value>
     <product>
      <property>hydro/planing-floats/afterbody-normal-force-lbs[1]</property>
      <cos><property>hydro/floats/pitch-rad[1]</property></cos>
      <cos><property>hydro/floats/roll-rad[1]</property></cos>
     </product>
    </max>
   </function>
  </fcs_function>

 </channel>

 <channel name="Yaw">

  <fcs_function name="hydro/planing-floats/forebody-yaw-moment-lbsft[0]">
   <description>
    Yaw moment due to planing drag.
    FIXME: direction/frame? Limits on the acting point? Induced drag?
   </description>
   <function>
    <product>
     <value>-1.0</value>
     <property>hydro/planing-floats/forebody-friction-fbx-force-lbs[0]</property>
     <property>hydro/planing-floats/forebody-keel-y-ft[0]</property>
    </product>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-yaw-moment-lbsft[0]">
   <description>
    Yaw moment due to planing drag.
    FIXME: direction/frame? Limits on the acting point? Induced drag?
   </description>
   <function>
    <product>
     <value>-1.0</value>
     <property>hydro/planing-floats/afterbody-friction-fbx-force-lbs[0]</property>
     <property>hydro/planing-floats/afterbody-keel-y-ft[0]</property>
    </product>
   </function>
  </fcs_function>

  <fcs_function name="hydro/planing-floats/forebody-yaw-moment-lbsft[1]">
   <description>
    Yaw moment due to planing drag.
    FIXME: direction/frame? Limits on the acting point? Induced drag?
   </description>
   <function>
    <product>
     <value>-1.0</value>
     <property>hydro/planing-floats/forebody-friction-fbx-force-lbs[1]</property>
     <property>hydro/planing-floats/forebody-keel-y-ft[1]</property>
    </product>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-yaw-moment-lbsft[1]">
   <description>
    Yaw moment due to planing drag.
    FIXME: direction/frame? Limits on the acting point? Induced drag?
   </description>
   <function>
    <product>
     <value>-1.0</value>
     <property>hydro/planing-floats/afterbody-friction-fbx-force-lbs[1]</property>
     <property>hydro/planing-floats/afterbody-keel-y-ft[1]</property>
    </product>
   </function>
  </fcs_function>

 </channel>

 <channel name="Pitch">

  <fcs_function name="hydro/planing-floats/forebody-pitch-moment-lbsft[0]">
   <description>
    Pitch moment due to planing.
    FIXME: direction/frame? Limits on the acting point?
   </description>
   <function>
    <sum>
     <product>
      <value>-1.0</value>
      <property>hydro/planing-floats/forebody-normal-force-lbs[0]</property>
      <difference>
       <property>hydro/planing-floats/forebody-end-x-ft[0]</property>
       <product>
        <value>0.75</value>
        <property>hydro/planing-floats/forebody-wetted-keel-ft[0]</property>
       </product>
      </difference>
     </product>
     <product>
      <value>-1.0</value>
      <property>hydro/planing-floats/forebody-friction-fbx-force-lbs[0]</property>
      <property>hydro/planing-floats/forebody-keel-z-ft[0]</property>
      <cos><property>hydro/floats/pitch-rad[0]</property></cos>
     </product>
    </sum>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-pitch-moment-lbsft[0]">
   <description>
    Pitch moment due to planing.
    FIXME: direction/frame? Limits on the acting point?
   </description>
   <function>
    <sum>
     <product>
      <value>-1.0</value>
      <property>hydro/planing-floats/afterbody-normal-force-lbs[0]</property>
      <difference>
       <property>hydro/planing-floats/afterbody-end-x-ft[0]</property>
       <product>
        <value>0.75</value>
        <property>hydro/planing-floats/afterbody-wetted-keel-ft[0]</property>
       </product>
      </difference>
     </product>
     <product>
      <value>-1.0</value>
      <property>hydro/planing-floats/afterbody-friction-fbx-force-lbs[0]</property>
      <property>hydro/planing-floats/afterbody-keel-z-ft[0]</property>
      <cos><property>hydro/floats/pitch-rad[0]</property></cos>
     </product>
    </sum>
   </function>
  </fcs_function>

  <fcs_function name="hydro/planing-floats/forebody-pitch-moment-lbsft[1]">
   <description>
    Pitch moment due to planing.
    FIXME: direction/frame? Limits on the acting point?
   </description>
   <function>
    <sum>
     <product>
      <value>-1.0</value>
      <property>hydro/planing-floats/forebody-normal-force-lbs[1]</property>
      <difference>
       <property>hydro/planing-floats/forebody-end-x-ft[1]</property>
       <product>
        <value>0.75</value>
        <property>hydro/planing-floats/forebody-wetted-keel-ft[1]</property>
       </product>
      </difference>
     </product>
     <product>
      <value>-1.0</value>
      <property>hydro/planing-floats/forebody-friction-fbx-force-lbs[1]</property>
      <property>hydro/planing-floats/forebody-keel-z-ft[1]</property>
      <cos><property>hydro/floats/pitch-rad[1]</property></cos>
     </product>
    </sum>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-pitch-moment-lbsft[1]">
   <description>
    Pitch moment due to planing.
    FIXME: direction/frame? Limits on the acting point?
   </description>
   <function>
    <sum>
     <product>
      <value>-1.0</value>
      <property>hydro/planing-floats/afterbody-normal-force-lbs[1]</property>
      <difference>
       <property>hydro/planing-floats/afterbody-end-x-ft[1]</property>
       <product>
        <value>0.75</value>
        <property>hydro/planing-floats/afterbody-wetted-keel-ft[1]</property>
       </product>
      </difference>
     </product>
     <product>
      <value>-1.0</value>
      <property>hydro/planing-floats/afterbody-friction-fbx-force-lbs[1]</property>
      <property>hydro/planing-floats/afterbody-keel-z-ft[1]</property>
      <cos><property>hydro/floats/pitch-rad[1]</property></cos>
     </product>
    </sum>
   </function>
  </fcs_function>

 </channel>

 <channel name="Roll">

  <fcs_function name="hydro/planing-floats/forebody-roll-moment-lbsft[0]">
   <description>
    Roll moment due to planing.
    FIXME: direction/frame? Limits on the acting point?
   </description>
   <function>
    <sum>
     <product>
      <value>-1.0</value>
      <property>hydro/planing-floats/forebody-normal-force-lbs[0]</property>
      <property>hydro/planing-floats/forebody-keel-y-ft[0]</property>
     </product>
     <product>
      <property>hydro/planing-floats/forebody-fby-force-lbs[0]</property>
      <!-- FIXME: dependency on pitch? -->
      <property>hydro/planing-floats/forebody-keel-z-ft[0]</property>
     </product>
    </sum>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-roll-moment-lbsft[0]">
   <description>
    Roll moment due to planing.
    FIXME: direction/frame? Limits on the acting point?
   </description>
   <function>
    <sum>
     <product>
      <value>-1.0</value>
      <property>hydro/planing-floats/afterbody-normal-force-lbs[0]</property>
      <property>hydro/planing-floats/afterbody-keel-y-ft[0]</property>
     </product>
     <product>
      <property>hydro/planing-floats/afterbody-fby-force-lbs[0]</property>
      <!-- FIXME: dependency on pitch? -->
      <property>hydro/planing-floats/afterbody-keel-z-ft[0]</property>
     </product>
    </sum>
   </function>
  </fcs_function>

  <fcs_function name="hydro/planing-floats/forebody-roll-moment-lbsft[1]">
   <description>
    Roll moment due to planing.
    FIXME: direction/frame? Limits on the acting point?
   </description>
   <function>
    <sum>
     <product>
      <value>-1.0</value>
      <property>hydro/planing-floats/forebody-normal-force-lbs[1]</property>
      <property>hydro/planing-floats/forebody-keel-y-ft[1]</property>
     </product>
     <product>
      <property>hydro/planing-floats/forebody-fby-force-lbs[1]</property>
      <!-- FIXME: dependency on pitch? -->
      <property>hydro/planing-floats/forebody-keel-z-ft[1]</property>
     </product>
    </sum>
   </function>
  </fcs_function>
  <fcs_function name="hydro/planing-floats/afterbody-roll-moment-lbsft[1]">
   <description>
    Roll moment due to planing.
    FIXME: direction/frame? Limits on the acting point?
   </description>
   <function>
    <sum>
     <product>
      <value>-1.0</value>
      <property>hydro/planing-floats/afterbody-normal-force-lbs[1]</property>
      <property>hydro/planing-floats/afterbody-keel-y-ft[1]</property>
     </product>
     <product>
      <property>hydro/planing-floats/afterbody-fby-force-lbs[1]</property>
      <!-- FIXME: dependency on pitch? -->
      <property>hydro/planing-floats/afterbody-keel-z-ft[1]</property>
     </product>
    </sum>
   </function>
  </fcs_function>

 </channel>

</system>