auto pilots
- Thread starter ScottK
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Sac Arrow
Touchdown! Greaser!
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Snorting his way across the USA
Typically, yes
MAKG1
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MAKG
Depends on the autopilot. Some don't make turns at all.
The autopilot I've used (STEC-50, with retrofitted coupling through an Aspen and Garmin 430) makes turns noticeably slower than standard rate when coupled to GNSS.
The most basic autopilot just holds your current heading.
The autopilot I've used (STEC-50, with retrofitted coupling through an Aspen and Garmin 430) makes turns noticeably slower than standard rate when coupled to GNSS.
The most basic autopilot just holds your current heading.
Inverted
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In theory they should all do standard rate turns under normal modes. More advanced autopilot systems have soft, or 1/2 rate modes that will be easier on the passengers.
poadeleted20
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Do you have an example of a roll autopilot which doesn't make turns? I don't know of one.
That would probably be because the GPS isn't commanding enough of a turn to reach standard rate before it is commanding a rollout. It also might be due to crosswind causing a less-than-standard-rate turn to be necessary to join the desired ground track from where the turn was commenced. Otherwise, it should be commanding standard rate.
The most basic autopilot I know is the Century I, and it doesn't have heading hold at all, but it does have a standard rate turn command.
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Inverted
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There certainly isn't an autopilot on the market now that does not come with turn capability.
oldShar
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He may have been referring to Wing Levelers? Which 1/2 century ago, used to be considered as autopilots (of sorts), FWIW
poadeleted20
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Well, the only "wing leveler" type of autopilot I've seen in 43 years of flying is the Century I, and it has turn command.
wabower
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I have a basic "wing leveler" autopilot. If I turn it on and my head indicator is somewhere other than the heading I'm on it will turn to it at standard rate. No rudder as it's only a 1 axis. It will also make small adjustments to get back on a heading or if it's windy it will turn all over the place to find the heading again. After my steering bungee was replace I flew and couldn't figure out why in the world the airplane wouldn't fly straight. As soon as I came off the right rudder after climb-out it went ridiculously uncoordinated. I flipped the a/p on and off again to see if that was an issue. It wasn't, but the airplane was so uncoordinated that the basic a/p was turning every which way. Turns out my rudder was way out of trim because when they took that panel out it wasn't possible to get totally straight again.
poadeleted20
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Ah, yes -- the "PC" system, right? Positive Control or something like that? I remember now having to fight it while flying a Mooney. Wouldn't call it an autopilot, of course, but yes, it did do its best to keep the wings level despite any pilot desires to the contrary.
wabower
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Yep, and my opinion of the value corresponds with yours. But my thumb strength improved markedly while I owned it.
Ah, yes -- the "PC" system, right? Positive Control or something like that? I remember now having to fight it while flying a Mooney. Wouldn't call it an autopilot, of course, but yes, it did do its best to keep the wings level despite any pilot desires to the contrary.
poadeleted20
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Right -- there was a button on top of the yoke you had to hold down to disable it whenever you wanted anything but wings level flight.
Jaybird180
Final Approach
IIRC, it was an air pressure based system that detected changing AoA over the ailerons?
flyingcheesehead
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Standard rate *or less*. For example, a 20-degree change in heading or less wouldn't make sense to do at standard rate, you'd spend the entire turn rolling in and rolling out.
BillTIZ
Final Approach
Ah, yes -- the "PC" system, right? Positive Control or something like that? I remember now having to fight it while flying a Mooney. Wouldn't call it an autopilot, of course, but yes, it did do its best to keep the wings level despite any pilot desires to the contrary.
We put a heavy rubber band on the yoke to hold the cutoff button down for traffic pattern operations and air work.
Marauder
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LOL! On my Mooney when I had the PC, I called the rubber band the ADM (Autopilot Disconnect Mechanism). Sounded more aviation oriented
The PC was great for straight and level to grab a quick look at a map. But after a while, the ADM was on more than off.
denverpilot
Tied Down
Mine makes S-turns well beyond standard rate, pretty much continuously except in wing leveling mode where it chases the turn coordinator back and forth in a very relaxing rocking motion. Haha.
gismo
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S-Tec autopilots and a few other units (e.g. all Brittain autopilots and the Century I) sense turn rate (actually turn+roll rate but for your question that doesn't really matter) directly with an input from a specially built turn-coordinator. With those autopilots the turn rate will be consistent on any big turn and typically is limited to "standard rate" or 3°/sec with no limits on bank angle. That means the bank angle will be nearly proportional to the airspeed. That's not much of a problem for "slow" airplanes with cruise speeds below 200 KTAS because the max bank angle won't exceed 30°. But at 400 KTAS the bank angle would exceed 45°.
Most other autopilots use bank angle sensing from a "autopilot" artificial horizon or a solid state AHRS. With those the bank angle is limited to something between 20° and 30° and a big turn will produce a constant bank angle regardless of the airspeed (with a correspondingly varying turn rate).
flhrci
Final Approach
Mine makes S-turns well beyond standard rate, pretty much continuously except in wing leveling mode where it chases the turn coordinator back and forth in a very relaxing rocking motion. Haha.
Are the S-turns within PTS standards?
David