Andy Ross wrote

> Vivian Meazza wrote:
> > wastegate-mp="18.32"
> > [...]
> > mp-osi = 26.050 - does the "wastegate" work? - is this psi?
> The units are absolute pressure in inches of mercury (I 
> honestly don't know what the "-osi" suffix means).  The 
> wastegate should indeed work. However, it is an overpressure 
> release valve.  It cannot suck a vacuum in the manifold if 
> ambient pressure is already higher than its setting. :)
> Typical values for the wastegate are going to be 
> significantly higher than one atmosphere (== ~28" Hg), but 
> I'm sure that varies with supercharger design.  Probably some 
> aircraft don't have them at all.
> > The model does not fly, failing to accelerate (insufficient prop 
> > thrust), with the following output data when throttle = 1:
> Outside the wastegate setting (which is a noop in this case) 
> nothing looks clearly incorrect.  Can you post the whole file 
> so I can try it?

Here's the whole file as requested:

<?xml version="1.0"?>

YASim aerodynamic model for a Spitfire IIa 

The reference datum for measurements is the nose.

<!-- Weight of everything but fuel  (4873 empty) -->
<airplane mass="5200">

<!-- Approach configuration -->
<approach speed="75" aoa="13">
  <control-setting axis="/controls/engines/engine[0]/throttle" value="0.2"/>
  <control-setting axis="/controls/engines/engine[0]/mixture" value="1.0"/>
  <control-setting axis="/controls/engines/engine[0]/propeller-pitch"
        <control-setting axis="/controls/engines/engine[0]/boost"
  <control-setting axis="/controls/flight/flaps" value="1.0"/>
  <control-setting axis="/controls/gear/gear-down" value="1"/>

<!-- Cruise configuration -->
<cruise speed="308" alt="17500">
  <control-setting axis="/controls/engines/engine[0]/throttle"
  <control-setting axis="/controls/engines/engine[0]/mixture" value="1.00"/>
  <control-setting axis="/controls/engines/engine[0]/propeller-pitch"
  <control-setting axis="/controls/engines/engine[0]/boost" value="1"/>
  <control-setting axis="/controls/flight/flaps" value="0.0"/>
  <control-setting axis="/controls/gear/gear-down" value="0"/>

<!-- pilot's eye point -->
<cockpit x="-3.86" y="0" z="0.55"/>

                                        ax="0.0" ay="0.0" az="0.0" 
          bx="-9.13" by="0.0" bz="0.0"
          width="0.94" taper="0.38" midpoint="0.4"
stall aoa not available
flap drag not available
<wing x="-2.99" y="0.77" z="-0.81" taper="0.3" incidence="2" twist="-2.0"
      length="4.576" chord="2.845" sweep="-3.5" dihedral="6"  >
  <stall aoa="20" width="4" peak="1.5"/>
  <flap0 start="0.00" end="0.437" lift="1.3" drag="1.8"/>
  <flap1 start="0.437" end="0.90" lift="1.2" drag="1.2"/>
  <control-input axis="/controls/flight/flaps" control="FLAP0"/>
  <control-output control="FLAP0" prop="/surface-positions/flap-pos-norm"/>
  <control-speed control="FLAP0" transition-time="5"/>
  <control-input axis="/controls/flight/aileron" control="FLAP1"
  <control-input axis="/controls/flight/aileron-trim" control="FLAP1"

<!-- tailplanee -->
<hstab x="-8.22" y="0.25" z="0.0" taper="0.639" effectiveness="2"
       length="1.215" chord="1.246" sweep="5" >
  <stall aoa="24" width="4" peak="1.5"/>
  <flap0 start="0.0" end="1" lift="1.65" drag="1.5"/>
  <control-input axis="/controls/flight/elevator" control="FLAP0"/>
  <control-input axis="/controls/flight/elevator-trim" control="FLAP0"/>
  <control-output control="FLAP0"

<!-- tail -->
<vstab x="-8.52" y="0" z="-0.29" taper="0.386" effectiveness="2"
       length="1.598" chord="0.994" sweep="5" >
  <stall aoa="15" width="4" peak="1.5"/>
  <flap0 start="0" end="1" lift="1.65" drag="1.5"/>
  <control-input axis="/controls/flight/rudder" square="true"
control="FLAP0" invert="true"/>
  <control-input axis="/controls/flight/rudder-trim" control="FLAP0"
  <control-output control="FLAP0" prop="/surface-positions/rudder-pos-norm"
                  min="1" max="-1"/>

<!-- wastegate setting should not apply.  set here so that calculations
would approximate.
      YASim doesn't model gear supercharger.  Have read various figures
(turbo-mul) 4.0 to 5.8 for 
      running the second stage blower.  Fixing this would probably give more
      performance at lower altitude -->
<!-- moment = radius(m)* propeller mass(kg)/2 - equation provided by Andy
Ross -->
<!--  cruise-rpm documented gear ratio of 0.479  min-rpm="600"
<propeller   x="-1.10" y="0" z="0"
           radius="1.638" moment="37.15" 
           eng-power="1140" eng-rpm="2850"
           turbo-mul="4.0" wastegate-mp="48.2454"
           cruise-alt="17500" cruise-power="1100"
           cruise-speed="308" cruise-rpm="2850"
                                         gear-ratio = "0.477">
  <actionpt x="-0.75" y="0" z="0"/>  <control-input
axis="/controls/engines/engine[0]/throttle" control="THROTTLE"/>
  <control-input axis="/controls/engines/engine[0]/starter"
  <control-input axis="/controls/engines/engine[0]/magnetos"
  <control-input axis="/controls/engines/engine[0]/mixture"
  <control-input axis="/controls/engines/engine[0]/propeller-pitch"
                 src0="0" src1="1" dst0="0.1" dst1="0.8"/>
  <control-input axis="/controls/engines/engine[0]/boost" control="BOOST"/>

<!-- Tail wheel -->
<!-- tail wheel castering(locked to make the aircraft controllable) -->
<gear x="-7.90" y="0" z="-0.96" compression="0.2">
  <control-input axis="/controls/gear/tailwheel-lock" control="CASTERING"/>

 <!-- left main -->
<gear x="-2.10" y="0.86" z="-2.10" compression="0.4" spring="0.7"
  <control-input axis="/controls/gear/brake-left" control="BRAKE"/>
  <control-input axis="/controls/gear/brake-parking" control="BRAKE"
  <control-input axis="/controls/gear/gear-down" control="EXTEND"/>
  <control-speed control="EXTEND" transition-time="6"/>
  <control-output control="EXTEND" prop="/gear/gear[0]/position-norm"/>

 <!-- right main -->
<gear x="-2.10" y="-0.86" z="-2.10" compression="0.4" spring="0.7"
  <control-input axis="/controls/gear/brake-right" control="BRAKE"/>
  <control-input axis="/controls/gear/brake-parking" control="BRAKE"
  <control-input axis="/controls/gear/gear-down" control="EXTEND"/>
  <control-speed control="EXTEND" transition-time="6"/>
  <control-output control="EXTEND" prop="/gear/gear[1]/position-norm"/>

<!-- Fuselage tanks. 
Weight of contents calculated using 100 octane AVGAS density of 695 kg/m3 @
<tank x="-2.80" y="0" z="0.17" capacity="335"/> <!-- upper 48 imp gals -->
<tank x="-2.56" y="0" z="-0.45" capacity="258"/> <!--  lower 37 imp gals -->

<!-- ballast and weights -->
<ballast x="-3.95" y="0" z="-0.1" mass="335"/> <!-- Cockpit, sundries-->

<!-- armament -->
<!--  Had too much weight I think...disable until stall speed fixed
<ballast x="-3.20" y="0.7" z="-0.60" mass="800"/> 
<ballast x="-3.20" y="-0.7" z="-0.60" mass="800"/> 
<!-- pilot -->
<weight x="-3.805" y="0" z="-0.20" mass-prop="/yasim/spitfire/pilot-lb"/>


With these settings the aircraft does not fly, and the rpm value is
ridiculous - 6828. mp-osi = 30.012 

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