A/P Radar Altitude Hold - is this possible?

[Guest Dominik Mann]

I was wondering if it might be possible to create an altitude hold function which would have the A/P hold a certain radar altitude above the ground instead of the normal barometric altitude. This might be quite ueful for low-flying military planes such as the Tornado, F-111, or even ekranoplanes :-) .Anybody been trying this, or have any idea of how it might work?Thanks,

[Guest harry3]

Should be possible, but you have o progamm the hole A/P function(RadAlt Hold), because there are no variables given for such a function in the SDK. Seems to me as it would be a difficult thing, but I'm not an expert at gauge-programming, as I just have started a month ago. The experts are: Karl Pettersen, Arne Bartels, and some more ...Just saw that you're from EDDF. So I just wanted to ask you if you're in the FlightXPress Forum too???Best regards and Tsch

[badderjet 181]

Hmmmm well I don't know if it's too useful because the ground altitude changes continously, so the nose would go up and down rapidly, especially in these fast military aircraft.Regards :-wave from EDDFhttp://flightsimmers.net/airport/etti/signature_pro.jpg

[MKaprocki 3]

Have the user set the desired altitude agl in the display. Get the altitude of the tile below the aircraft and add them together. Set the FS AP to this. ;)Matt

[Guest]

>Hmmmm well I don't know if it's too useful because the >ground altitude changes continously, so the nose would go up >and down rapidly, especially in these fast military >aircraft. That would actually seem to be the point of a terrain following radar driven autopilot! :)If it is feasible, then some sort of damping algorithm would need to be formulated, to 'smooth out' the transitions.

[Dark Moment 0]

But will it follow contours on that basis, Matt?Mark "Dark Moment" Beaumonthttp://www.swiremariners.com/cxkaitak.htmlhttp://www.swiremariners.com/cxkaitakv3.jpg

[MKaprocki 3]

I doubt it would work too well with the default AP, especially at high speeds, but that will set the AP to the selected height AGL. Would be interesting to try, though.Matt

[Guest]

I know nothing about guage programming but these guys got it to work in the latest SP for Falcon 4. I would love to have it in some of the nice military iron we fly in FS2K2. The APQ-99/APQ-172 TFR on the RF-4C was one of the systems I really enjoyed working on when I was in the USAF. Good luck to whomever takes on this task.[http://f4ut.frugalsworld.com/previews/Terrain-FollowingRadar.shtml]

[Guest]

Use your radar altitude and altitude, and write the output into altitude hold. I.e. altitude hold=Current altitude - radar altitude + wanted altitude agl.There is the possibility to "smooth" out a series of data inputs gathered, but I think a "limiter" would work just as well. I.e. only write data once every second.But I suspect a real radar like this would gather the data in front of the aircraft, not directly below it. FS2002 doesn't allow you to gather terrain information other than directly below you. A shame really, this could prove very handy in other areas as well.Shouldn't be a problem making it, but due to this rather big limitation, I don't think such a gauge could prove too useful.