Andy Ross wrote > Vivian Meazza wrote: > > How do we set the reduction gearing ratio? > > Set the "gear-ratio" attribute of the propeller tag. This is the > reduction ratio, so typical values will be less than 1.0. > > > Can we do a constant speed propeller? > > The min-rpm and max-rpm attributes define the range of the blue lever. > These are the speeds to which the propeller will seek; it may not be > able to achieve them in practice. The documentation for these was, > er, wrong. I'll fix that. > > > And can we set the handedness of the propeller to RH? > > Sure thing. Use a negative moment value. :) No joke: that will have > exactly the effect of a counter-rotating engine. The DC-3 uses this > trick for the starboard engine, for example. I'll add some > documentation for that as well. > > Andy >
I have almost finished the Spitfire model. Texturing, animation and a 3d cockpit remain to do. However, I am having some difficulty with the engine reduction gear ratio. I've used using the following numbers which give a reasonable solution in YASim. <propeller x="-1.10" y="0" z="0" radius="1.638" moment="37.15" mass="2000" eng-power="1140" eng-rpm="2850" turbo-mul="4.0" wastegate-mp="18.32" cruise-alt="17500" cruise-power="1100" cruise-speed="308" cruise-rpm="2850" takeoff-power="1100" takeoff-rpm="2850" manual-pitch="true"> <actionpt x="-0.75" y="0" z="0"/> <control-input axis="/controls/engines/engine[0]/propeller-pitch" control="PROPPITCH" src0="0" src1="1" dst0="0.1" dst1="0.6"/> </propeller> The model flies reasonably well, with the following output data when throttle = 1: max-hp = 1140.491452 mp-osi = 26.050 - does the "wastegate" work? - is this psi? power-pct = 105.863353 prop-thrust = 1314.603118 rpm = 3014.603118 I've kept to manual pitch control for now. I've tried this, although I would think, incorrectly: <propeller x="-1.10" y="0" z="0" radius="1.638" moment="37.15" mass="2000" eng-power="1140" eng-rpm="2850" turbo-mul="4.0" wastegate-mp="18.32" cruise-alt="17500" cruise-power="1100" cruise-speed="308" cruise-rpm="2850" takeoff-power="1100" takeoff-rpm="2850" manual-pitch="true" gear-ratio = "0.477"> <actionpt x="-0.75" y="0" z="0"/> <control-input axis="/controls/engines/engine[0]/propeller-pitch" control="PROPPITCH" src0="0" src1="1" dst0="0.1" dst1="0.6"/> </propeller> The model still flies reasonably well, with the following output data when throttle = 1: max-hp = 1140.491452 mp-osi = 29.729 - does the "wastegate" work? - is this psi? power-pct = 222.856 prop-thrust = 1375.645173 rpm = 6176.318088 - this is wrong Finally, I tried this: <propeller x="-1.10" y="0" z="0" radius="1.638" moment="37.15" mass="2000" eng-power="1140" eng-rpm="2850" turbo-mul="4.0" wastegate-mp="18.32" cruise-alt="17500" cruise-power="1100" cruise-speed="308" cruise-rpm="1360" takeoff-power="1100" takeoff-rpm="2850" manual-pitch="true" gear-ratio = "0.477"> <control-input axis="/controls/engines/engine[0]/propeller-pitch" control="PROPPITCH" src0="0" src1="1" dst0="0.1" dst1="0.6"/> </propeller> The model does not fly, failing to accelerate (insufficient prop thrust), with the following output data when throttle = 1: max-hp = 1140.491452 mp-osi = 29.729 power-pct = 225.856 - wrong prop-thrust = 659.082929 - wrong rpm = 6232.318088 - even more wrong I've tried increasing pitch, to no avail. I've tried <takeoff-power="1100" takeoff-rpm="1360" - then YASim crashes What is the obvious mistake that I am making? Regards Vivian Meazza _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel