On 12/16/2008 09:54 PM, Ron Jensen wrote: > Lets see. Ignoring the manifold pressure and just looking at the > assertion that an increase in RPM always leads to an increase in > HORSEPOWER, I did a google image search for RPM vs HORSEPOWER.
OK. >> This one is particularly interesting, as it shows exactly what you >> described as an "error" in the model. That is the horsepower decreasing >> with increasing RPM below the red-line when throttled: >> http://reveg-catalog.tamu.edu/images/Appendix/Engine%20Speed%20Graph-2.jpg I don't know what that is. There's not enough context. It comes from a "revegetation" site. Maybe it's some kind of farm tractor. I would not be at all surprised to find a _governor_ on such a tractor. What's true for tractors is not necessarily true for airplanes. > Just a few random hits that disprove your assertion: > http://myzx5.virtualdojo.net/images/dyno/Stock-vs-Volant%5BHP-AFR%5D(RPM%20Base).jpg That's from a Ford Focus. It has a rev limiter built into the electronic ignition. In that respect it is very unlike the real O-320 as installed in a real Cessna 172P. In other respects, notably the very large range over which the power at first increases and then levels off as a function of rotation rate, it behaves as expected. In other words, it in some ways confirms what I said, and in no way "disproves" anything I said. > I will grant the current model produces too much power at lower manifold > pressures. I will look into that. Yes, that's the right place to start. I reckon some impedance in the intake would be a step in the right direction. ------------------------------------------------------------------------------ SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. The future of the web can't happen without you. Join us at MIX09 to help pave the way to the Next Web now. Learn more and register at http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ _______________________________________________ Flightgear-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/flightgear-devel
