From: WillyB <[EMAIL PROTECTED]> > Ok, I'm probably confusing the switch then. > I resized and enhanced the photos and have > attached the new one I made from it. > Is that 4 position switch for the C HT or am I totally wrong on that? > Url : http://mail.flightgear.org/pipermail/flightgear-devel/\ > attachments/20030728/02418d4a/chtimg.jpg
Aha! Nicely enhanced; it resolves the confusion. The two switches lower left are the magnetos as you've already figured out. The rotary analog display is labelled "CYL HEAD TEMP" and only has one needle (white) and the redline (which is irrelevant to the discussion). From: Alex Perry <[EMAIL PROTECTED]> > * You normally have one CHT sensor per cylinder (sometimes two), > so you either need to have lots of dials, or a switch to select > among them, or an electronic display to cycle through them, etc. The metal control (without a knob) is shown, in both the drawing and the panel, with four positions and, in the drawing, is labelled "CHT select". I therefore assert that this aircraft has a four cylinder engine and this selects which cylinder measurement is going to be seen on the dial. Individual cylinders have slightly more or less airflow cooling (due to the pattern of baffles in front of the firewall) and receive slightly different richness in the mixture (due to fuel injection differences, or uneven atomization after the carbureter as appropriate). For each engine (and baffle layout), the pattern of differences is generally well known and the behavior is pretty consistent across most of the fleet. After enough experience in an aircraft, many owners know which cylinder is going to be hottest for a given phase of flight and therefore can leave the switch in a single position, just changing it (eg) after climb ends. Periodically, the pilot will cycle through all the cylinders to make sure they all read as expected, as a way of detecting some imminent failures. As far as simulating it is concerned, there are standard models for how CHT changes as a function of operating conditions for a given cylinder. Therefore, we could easily have per-cylinder parametrics for the cooling and for the mixture (in the engine file) that drive a standard CHT model. Those parametric values, plus the broken status of each CHT sensor, would be accessible to the instructor through the property tree. Hope that helps ... _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
