On Fri, 2008-12-19 at 23:28 -0700, John Denker wrote: > An alternative approach is diagrammed at > http://www.av8n.com/fly/throttle.htm#fig-x1xt > > This is more plausible in terms of the physics of the situation, and > more consistent with everyday Real World pilot experience.
Here is a dynamometer test report of an engine intended for use in an aircraft: http://members.cox.net/alg3/Dynamometer%20test%20report.htm Please note especially the RPM v. Manifold Pressure chart at the end: http://members.cox.net/alg3/Dynamometer%20test%20report_files/image005.jpg The shape of this curve is the reverse of the curves you've postulated in your figure 3. It also remains above 28 inHg to nearly 5000 RPM. Your proposed model appears unable to duplicate this feat, as your full throttle line is below 0.94 (28 inHg / 29.92 inHg) MAP by 0.07 RPM. While we're at it, please consider this dyno picture http://aagearinc.com/supercharged_na.gif Yes, its a motorcycle engine not an aircraft engine, but both function according to the same principles and studying one will lead to understanding of both. The red line is a normally aspirated engine. You can clearly see the power peak and fall off. The blue line is the same engine with boost. It produces linear power to the top of the RPM run because it can breathe. Thanks, Ron ------------------------------------------------------------------------------ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
