On Monday 23 August 2010 21:37:06 Ampere K. wrote: > Thank you very much Jon and Ron. That certainly cleared things up for me.
You're welcome > I only have one question left, which is my original question regarding > turbofan in JSBsim. How does JSBsim simulates a turbofan engine? I am far from an expert on turbine engines, or the JSBSim turbine model, but here it goes: (I'll use the f16 engine file, F100-PW-229.xml, as an example) Idle thrust is the factor from the IdleThrust table multiplied by the value in the <milthrust> tag. So, at Mach 0 at Sea Level, the running engine produces 0.0488 * 17800.0 lbs = 869 lbs idle thrust and 1.0000 * (17800.0 - 869 idle thrust) lbs = 16931 lbs mil thrust N2norm is derived from the throttle position. It is essentially just a lag filtered throttle command. We square the N2norm value, which is between 0.0 and 1.0, multiply that by the mil thrust value, which is reduced from the configured value by the amount of idle thrust (previous equation), then add the idle thrust back in thrust = idlethrust + (milthrust * N2norm^2); so the engine varies between 869 lbs + ( 16931 lbs * 0.0^2) = 869 lbs thrust and 869 lbs + ( 16931 lbs * 1.0^2) = 17800 lbs thrust If the afterburner is on (a.k.a, augmentation or reheat) the AugThrust table is used in conjunction with the MaxThrust tag to increase the thrust available using throttle position (we are in augmeathod = 2). Augmethod =1 simply replaces the above thrust calculation with the prodoct of the AugThrust table value and the MaxThrust tag with no control available. Hope that wasn't too unclear? Questions? Ron ------------------------------------------------------------------------------ Sell apps to millions through the Intel(R) Atom(Tm) Developer Program Be part of this innovative community and reach millions of netbook users worldwide. Take advantage of special opportunities to increase revenue and speed time-to-market. Join now, and jumpstart your future. http://p.sf.net/sfu/intel-atom-d2d _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
