Major A writes: > Just another question: I noticed that the different places in which > heading plays a role (the different indicators as well as the > autopilot) use magnetic and geographic heading at will. Are there any > plans to unify them and/or come up with a convention of what heading > is magnetic and what isn't?
Are you sure? Here's what you should find in the 172: - The magnetic compass displays magnetic heading, but it is strongly affected by acceleration and turning errors: it will be accurate only in straight-and-level steady flight (or sitting flat on the ground). - The directional gyro is purely relative and doesn't care what it displays: you can set it to true, magnetic, or anything in-between. It will drift during flight, however, so you have to reset it from time to time. Its starting point is fairly arbitrary -- make sure you adjust it to what you want before you take off. - The autopilot in the 172 tries to keep the orange heading bug at the top of the directional gyro, period. If you set the DG to the true heading (as you would in the Arctic), then the autopilot uses true heading; if the DG has drifted, the AP will be off by the amount of the drift. Bigger planes have more sophisticated flight-management systems, but we're not modelling those properly yet. - The ADF needle simply points to the ADF station (in real life, +/-10 degrees -- it's not all that accurate). - The VOR indicators show (roughly) what radial the plane is on. That's not necessarily the direction you're flying, or even exactly the direction to the VOR. The only place you can get the true heading directly is the HUD, which isn't really meant to simulate anything you'll find in a small plane -- it's just a (useful) developer's tool or a user's toy. Usually it should be turned off. All the best, David -- David Megginson, [EMAIL PROTECTED], http://www.megginson.com/ _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
