Andy Ross > Vivian Meazza wrote: > > Meanwhile, you are distracting Andy from updating the awaited > > supercharger code. > > Heh, fair enough. This is checked in now, with a general rewrite > to clarify things and fix the bug where MP was reported "before" > the wastegate application. > > The only new property is "boost-gauge-inhg", which represents the > delta between the actual MP and ambient pressure (not strictly > correct, of course, but good enough for a first cut). > > I ran the solver over a bunch of piston planes, and didn't see > much change, so I think this should be OK. If everyone could fly > a circuit or two in their favorite piston-engined plane and > report success, that would be helpful. >
Back from a holiday in France. The modified software tests OK here. One small snag: the MP is not ambient when the engine is not running. Strictly, this should be turning, I suppose, because a wind-milling supercharger will produce some pressure. Near enough though. I've wasted a couple of days coming to the conclusion that the published graphs for the Merlin show the so-called "boost pressure" in psi absolute, with zero at 1 atmosphere. Illogical, but by making that assumption, I can readily adjust the turbo-mul parameter to make the full-throttle height accord with the published figures. Once this is adjusted, the rest of the simulation seems very close. Overall, most satisfying. Moving on, the Boost Control/Boost Control Cutout has been written in Nasal. This works well, but YASim needs to be told to ignore the wastegate. I tried setting an improbable value for the wastegate, but of course, YASim uses the wastegate value when solving, so this doesn't work. I attach a patch which addresses both issues. This adds a Boolean parameter "supercharger" to the config file. If this is true, the wastegate function is skipped over, so that the supercharger output can be controlled by the Boost Controller via the throttle. Vivian
yasim4.diff
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