Autopilots for the uninitiated

When someone says, or writes, the term "auto pilot" I have no problem understanding what this system does in a general sense. What I dont understand are the finer points of modern systems and what constitutes an AP system. I think I'm looking for Autopilots for Dummies, to borrow a phrase. Is there a good source of information that describes things like:

• Are there different types of AP?
• What components make up an AP system?
• What common options are there in AP systems?
• Pitfalls of AP ownership?
• What makes your plane a good or poor candidate for AP?
• How do I determine my needs for an AP?

Wow Gil,
You live in the backyard of what is arguably the most influential manufacturer of autopilots in the country. Perhaps you can start by going to the Tru Trak website and look around. Then perhaps you can call them and get some first hand information.

Tru Trak is just up the road from you in Springdale, AR. I bet if you call and talk to Andrew or Lucas or anyone else that answers the phone they would be glad to talk with you. Perhaps you could even show up and get some first hand experience behind the stick of their RV12 or RV10 running one of their autopilots.

You're in luck!!!

About 20 or so miles south of you in Springdale is the meca of experimental autopilots. I'm sure if you drop by the office any of the guys at Trutrak will be more than happy to address your questions in person.

Lucas usually visits VAF periodically as well. You can view their web site at: http://trutrakap.com/index.html

bob

very funny how only 3 minutes separates two minds that must think alike!

RVbySDI said:

very funny how only 3 minutes separates two minds that must think alike!

Click to expand...

Yep, only one says TT is south, and the other says it is up (I read as north) the road.

Maybe he needs to put the TT address in his gps, and let the AP do the driving???

Lemmingman said:

When someone says, or writes, the term "auto pilot" I have no problem understanding what this system does in a general sense. What I dont understand are the finer points of modern systems and what constitutes an AP system. I think I'm looking for Autopilots for Dummies, to borrow a phrase. Is there a good source of information that describes things like:

• Are there different types of AP?
• What components make up an AP system?
• What common options are there in AP systems?
• Pitfalls of AP ownership?
• What makes your plane a good or poor candidate for AP?
• How do I determine my needs for an AP?

Click to expand...

Gil,

Prepare to be blown away by the capabilities of the digital autopilots!

To quickly answer a couple of your questions:

*There are no pitfalls to owning an autopilot.

*Your plane is an excellent candidate for an autopilot, I suspect most new RVs are flying with one.

*You need to decide what features you need...well.....want in an autopilot. This decision needs to be made in concert with all the other equipment you will have in your panel. Think in terms of integrated systems.

Here is a brochure for an excellent system and this will explain many of the neat things these devices can do. There are several sources for autopilots and all work as advertised if installed properly.

Here:

Lemmingman said:

........[*]How do I determine my needs for an AP?
[/LIST]

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Gil,
If you'd really rather hand-fly the airplane ALL the time, including long, multi-hour cross-countries, then an autopilot is not for you.

Personally, I file IFR often and I can easily let the airplane fly up or down through cloud layers better than I can, allowing me to copy new clearances and talk with Center.

Even flying VFR, it's just so easy to look out of the window and stay perfectly level and perfectly on course too, letting my TruTrak do the works.

Best,

Quick answers:
TruTrak and Trio are the two "stand alone" auto pilot companies.
AFD, GRT, and Dynon all have EFIS-driven autopilot systems now. (AFD uses a TruTrak clone). Dynon currently is less-capable than the others.
You can get one axis (roll) or two axis (roll and pitch).
You need a "controller" (internal to the EFIS in the EFIS units) and one servo motor for each axis.
They will all track a GPS course, and hold altitude (2 axis). Pay more, and they'll do more, up to GPSS steering and shooting an LPV gps approach. Couple them to an EFIS and some of them can do an ILS.

You need one if you feel fatigued after flying. That's it. It's not the autopilot's job to fly when you cannot. But it will help a lot at reducing fatigue.

Disclaimer: I have a GRT HX driving a Trio Pro. (or the Trio will fly gps courses by itself). It is amazing what it will do. Even flying vfr I feel less tired when I let it do most of the work.

brochure link

Sam Buchanan said:

Gil,

Here is a brochure for an excellent system and this will explain many of the neat things these devices can do. There are several sources for autopilots and all work as advertised if installed properly.

Click to expand...

Sam,

Thanks for the link to this brochure. I am a long ways from picking an autopilot, but my only experience is with a crappy autopilot in a 182 years ago that never worked. It was scary to even try to use it. I am amazed with the capabilities of the new systems at what I consider a reasonable cost.

I downloaded the brochure on my phone and I will study it tonight during the boring planning commission I have to go to!

I was just out in your part of the country 2 weeks ago. We were babysitting our grandson in Millbrook. Our son in law just got back from Afghanistan and my daughter and he went to Cancun for a week. We had a great time getting out of the Colorado cold and playing with our grandson. I almost got the chance to meet up with Dan, but it didn't quite work out. Maybe next time!

Autopilots consist of controllers (which the pilot interacts with), servos (which drive the control surfaces), switches for engaging the autopilot and wires for connecting the whole lot together. Just about all of the differences in autopilot capability come from the 'smarts' contained in the controller and whether the controller can be sent commands from an EFIS or GPS. Good autopilots have a pitot static input also (to avoid stalling the airplane and to figure out how much control to use).

If you have a choice buy a trim sensitive pitch servo, so the autopilot can tell you it is out of trim (and you can re-trim, or you buy an auto trim module).

You will get much greater capability if your EFIS can command the autopilot. If you hook a GPS output to the controller the autopilot will follow a route, waypoint to waypoint. If a compatible EFIS and autopilot are installed the EFIS will be able to command the autopilot to fly much more complex flight paths, including coupled ILSs. Of course the price goes up with increasing connectivity (but not hideously). If you need the autopilot to track a VOR you will have to interface via an EFIS (there is one expensive exception).

Garmin and Advanced Flight Systems both use an autopilot made by Trutrak with a different badge on the front. Grand Rapids interfaces to a TruTrak autopilot to a similar extent, and also now offers their own autopilot. Trio autopilots have a good reputation, but I have no experience of them so don't know how well they interface to various EFISs.

Dynon and MGL make autopilots that are driven directly from the EFIS.

My own view is that it is worth the money to buy a standalone autopilot - complex reasons.

RVs are great candidates for fitting an autopilots, most manufacturers will supply an RV specific mounting kit.

Hope this helps, Pete

Gil, feel free to pop in. I'll be happy to show you the components of an autopilot. I'll be out of the office for three weeks starting this Friday, but Zach or John can help you as well. Thanks!

Dummy speaks

When we built our RV-6A I said I don't need no stinking autopilot. I had flown our Piper Archer coast to coast and beyond the borders for 22 years IFR with an autopilot that I never used. Jim Younkin personally tried to convince me that I should install one (I think he works for Tru Trak). I flew for a year without one but I was concerned with flying perfectly straight lines in cross country air races (less distance actually flown = higher race speed). I have no modern class stuff in our airplane. Jim convinced me to replace my turn coordinator with a Pictorial Pilot for directional control and an Altrak for altitude hold. They probably don't even sell them anymore but for me they were the perfect combination. Pictorial pilot and its servo require power and a GPS serial data input (I get mine from an SL-60) and the Altrak just requires power and a static input. The Altrak consists of a annunciator/switch to turn it on or off, another switch to control the annunciator light intensity and a pitch servo. The difference was absolutely amazing. I'm not too savy on the finer points but if you fly an RV the quality of your flying life on long cross countries and in racing precision goes way up with an autopilot.

Bob Axsom

Sorry for my late response, I've been in Houston for the last few days buried in the muck of work.

Thank you everyone for your most excellent suggestions. Sam that .pdf is a great resource and has already answered some of the questions I had. Your comment about features is sort of what spurred this request. I suddenly realized that I dont know enough about these systems to understand what features are nice to haves and got to haves.

Pete thanks for that input, I wasn't aware that there were already some OEM products already implemented in EFIS's today.

Lucas, I'll contact you in a few weeks. I'm going to be traveling quite a bit for awhile. When I get some time during the day (or when my son needs to go play hockey) I'll give you a call.

Autopilot Requirements

I briefly debated whether to install an autopilot in my -8A. Quickly decided to go the TruTrak route, then decided on a dual access ADI II to provide some back up attitude reference.

No regrets - can't imagine a cross country - or even high task local flight without it. And as stated previously, the folks at TruTrak offer superb customer service.