Questions about real two-axis autopilots

[Guest]

I'm trying to recreate a King/Bendix type of autopilot for my homecockpit. I thought I knew how these things worked but now I'm not so sure. The way I have it programmed now, when I hit the "altitude" button the AP captures the current altitude, not the one I had dialed in at the onset. I then need to reset the altitude bug to the desired flightlevel. It will default to the VS that is in the plane cfg but I can change that up or down too. This is different from the way the AP usually works in FS. It used to be that hitting the ALT button would just set the VS and the plane would climb until reaching the preselected altitude. Which is more correct? And what about on APs that also have a VS button? How is that used?Thanks!David

[Geofa 108]

It really can be different depending on make/model even within a particular manufacture which is why I am always puzzled when fs's autopilot is addressed. As far as I know we don't really know what make or model fs's is and therefore what to really expect it to be capable of (it does appear to me to be based on a king Ga autopilot-maybe a 150 (I can't remeber how it is depicted on the screen?)).I would suggest going looking online at manuals for different autopilots-Here is the king 225 for instance:http://www.bendixking.com/static/productbrochures/kfc225.pdfHere is stec which alone has 6 or so different types with different features ( I have the stec-50):http://www.s-tec.com/manuals.htmlOn my aircrafts' autopilot for instance when hitting "alt" the plane will hold at whatever altitude you are at if the plane is trimmed reasonably-if not lights will tell which direction to trim. There is no altitude preset on my model. Hope that helps.http://members.telocity.com/~geof43/Geofdog2.gif

[Guest tallpilot]

Hi David,I have a King KFC200 two axis autopilot in my Baron. It has an altitude preselect. (which also functions as an altitude alerter)With this installation the ALT button acts as an altitude capture mode. when the autopilot is engaged initially it will maintain the current pitch attitude (and rate of clinb). If the desired level off altitude is selected in the altitude preselect window and the arm button is pushed the autopilot will automatically level when that altitude is reached and go into "Altitude hold mode" If you want to change the pitch attitude/rate of climb or descent before reaching the preselected altitude you use the UP/DN rocker type switch on the mode controller/autopilot panel.If the arm button on the altitude preselect panel is NOT pressed even thought the altitude is dialed in, the autopilot will not level off at that altitude. Pressing the ALT button will cause the autopilot to level at the altitude you are passing through any time.I hope this information helps. If you have any questions you can e-mail me at flyers@citlink.netRegards,Ed Weber a.k.a tallpilot

[Guest]

Thanks for the input guys! I guess autopilots do vary quite a bit. I usually fly FLight1's Cessna 421 and it has an altitude preselect but I'm not sure it functions quite like Ed describes. Guess I'll have to take a closer look at it and maybe read the manual again. I suspect some of the functionality is probably not possible within MSFS yet. Thanks again!David

[Guest]

In something like 2,500 hours of flying singles, most of them had "no" autopilot. Most of the others had no altitude hold, just heading hold. The ones that did have altitude hold, you had to level the plane, and turn AH on when you were ready to have the current altitude held. Some had funny eccentricities, such as having to turn AH on 20 to 40 feet below, then the plane would "drift" up to the held altitude. Only one (P210) had preselect and autolevel.So, I'd say your observed behavior was correct! --BeachComer Stephen "Beach" Comer Real World Pile-it Commercial ASMEL, Instrument Airplane 4500 TT, 2500 BE20 & BE10