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View Full Version : Autopilot Decision Time: Trio or TruTrak


Don
08-04-2007, 10:44 AM
I'm nearing a very convenient time to install the servos for a two axis autopilot. I have been looking hard at the TruTrak ADI Pilot II and the Trio EZ Pilot combined with an EZ-3 Altitude hold. I've already purchased the GRT Series I EFIS (dual) and I'm planning to put a GNS 430 in the 9A I'm building. I want to interface the components and get the maximum flexibility out of them that I can.

I was leaning toward the Trio system until I read elsewhere in a thread in this section that Stein believes the TruTak autopilot will do more with the GRT EFIS than the Trio system. I've read what he says and I respect his opinion (and hope he comments) but it appears to me that he was comparing the two axis Trutrak with the EZ-altitude hold. If the two axis Trio will do what the TruTrak will do, then I'm inclined to go with the Trio because it's lighter and I like some of the safety features built into it. The cost difference between the two is not significant. Weight, safety, and functionality are significant. Any and all comments on the decision making process are welcome.

Radomir
08-04-2007, 10:49 AM
Does Trio have ARINC connection? If not, then yes, GRT + Trutrak will do more...

tacaruth
08-04-2007, 11:23 AM
Hi Don,

When I was looking to purchase my autopilot, the key difference that was explained to me was that the Trio system was two separate components and the Trutrak was a single system. This would allow for the Trutrak to sense a bank, anticipate the loss of altitude and begin pitch correction at an early point. In the Trio system, the bank would not be sensed by the altitude hold system and would have to wait for the loss of altitude to react. I ended up going with a Digiflight IIVS for that reason. The Digiflight system also leaves open the options of upgrading to a unit with GPS steering and other advanced options in the future. I don't believe that either the ADI Pilot II system or the Trio system have this upgrade path.

Good Luck,

Tom

JohnInReno
08-04-2007, 12:10 PM
Both autopilots are good but I chose the Trio because I liked the servo clutch better. The Trio does read all sorts of GPS signals including ARINC. The manual states that the handheld GPS has a slower refresh rate than the panel mounted systems that use ARINC. It is not supposed to be noticeable but I can't confirm... not flying yet.

SteinAir
08-04-2007, 03:26 PM
Both Autopilots are great....both companies are great. But, in your case there is only really one good decision based on the equipment you're installing.

Buy a Trutrak Digiflight IIVSG or better and you'll be able to fly coupled approaches from the 430/GRT. Even better, you can put in a source select switch, and if you have the newere 430W, the TruTrak can be coupled directly to the 430 for WAAS GPS approaches.

With the GRT (+ the 430) and it's functionality, the only real choice here is the Digiflight (or better) AP. If you didn't have the GRT or a 430, then your decision would be a wash IMHO.

Like I said, both systems are great and both companies are great - but with a GRT/Chelton/Garmin/OP (and soon to be AFS) EFIS, to utilize all the functionality available from the ARINC stream, the Digiflight is the only way to go.

Cheers,
Stein.

SteinAir
08-04-2007, 03:30 PM
Both autopilots are good but I chose the Trio because I liked the servo clutch better. The Trio does read all sorts of GPS signals including ARINC. The manual states that the handheld GPS has a slower refresh rate than the panel mounted systems that use ARINC. It is not supposed to be noticeable but I can't confirm... not flying yet.

That's news to me....we build their harnesses and have never put in a set of ARINC lines yet- that I'm aware of. What pins are you using to run ARINC into your EZpilot? As far as I know, the Trio only accepts RS-232 GPS/NMEA.

Also, are you referring to the Baud Rate when you say "refresh rates"? I only ask because if so, then your statement isn't necessarily true. Baud rates can be adjusted in most of the equipment and autopilots.

No flames intended, just trying to keep the facts in line.

Cheers,
Stein.

newtech
08-04-2007, 07:13 PM
Like I said, both systems are great and both companies are great - but with a GRT/Chelton/Garmin/OP (and soon to be AFS) EFIS, to utilize all the functionality available from the ARINC stream, the Digiflight is the only way to go.

Cheers,
Stein.
Are there any plans at GRT to provide more than a single axis autopilot output from the new GRT EFIS Sport? I have been leaning toward the single axis Trio with separate altitude hold because the GRT Sport only supported a single axis output.

Steve Eberhart
RV-7A, engine mounted, starting on the panel.

Don
08-05-2007, 01:13 PM
I really appreciate the information everyone provided. It looks like the DigiFlight is the way to go. My question though is, when I looked at the Trio at OSH the gentleman was quick to point out a bunch of safety factors - how their clutch mechanism disengages and the drive mechanism can be over come by the pilot and the 180 degree turn at the push of a button (for recovering from accidental VFR into IFR). How much of this really adds to safety how much is either sales hype, foofoo dust, or just a minor feature, compared to the TruTrak?

Don

Ironflight
08-05-2007, 02:06 PM
Don,

I have no problem whatsoever overpowerign my TruTrak if I want - I can even fly fairly precisely by hand with it engaged and fighting me (tested this in Phase 1). The automatic 180? My Pictorial Pilot shows current heading, and you can twist the knob to command it to any other heading, so I guess you have to do a little arithmetic, but once you twist th knob, it will take you wherever you want to go.

I think they are both fine autopilots from everything I have read. I believe that the Tru Traks integrate well with the GRT because the GRT folks and the Tru Trak folks worked together to make that happen.

Paul

briand
08-06-2007, 12:37 PM
Don, this is a must read for anyone considering an AP to go with their GRT EFIS.

http://www.grtavionics.com/Impressions.htm

Don
08-08-2007, 11:10 AM
Gentlemen,

Your knowledge, suggestions, and advice have been a great help. I'm now replanning my panel to include the TruTrak VSG. It's one thing to make a good decision and another to make an informed decision that leads you to understand why it's the right decision for you - it's been said before and I'll repeat it again - this board is a great resource of information!

MNRVFlyer
08-09-2007, 09:18 AM
[QUOTE=newtech]Are there any plans at GRT to provide more than a single axis autopilot output from the new GRT EFIS Sport? I have been leaning toward the single axis Trio with separate altitude hold because the GRT Sport only supported a single axis output.

Steve,

I don't think so, although I'm not sure. It's one of the only differences between GRT's 2 EFIS systems... and if they included that (V guidance) there would be almost no reason to buy the more expensive system

Mike S
08-09-2007, 09:56 AM
Gentlemen,

Your knowledge, suggestions, and advice have been a great help. I'm now replanning my panel to include the TruTrak VSG. It's one thing to make a good decision and another to make an informed decision that leads you to understand why it's the right decision for you - it's been said before and I'll repeat it again - this board is a great resource of information!

Yep, a great source. I call it the VAF data base.

Just one thing to add to your decision process----------are you aware that the Tru Track control head is available in a "Flat Pack" configuration-----I had to use this to fit above the GRT screens-----------you can see it here, second post has the link.

http://www.vansairforce.com/community/showthread.php?t=18921

The "Flat Pack" gives you a bit more options vs the round.

Good luck,

dlg
11-23-2010, 08:10 AM
The posts about these autopilots are fairly old. I would like to know if there are any new thoughts, pro's and con's,etc. I would be connecting the autopilot to a KMD150.

Brantel
11-23-2010, 08:17 AM
These post are very outdated for what is out there today. Much has changed....there are way more offerings and features available now.

I must warn you that King does their own thing on allot of their stuff and that box may or may not talk/play well with the current experimental AP's on the market. You really should investigate carefully to make sure that it (the complete system) will do what you expect it will before selecting an AP. Talk to the manufacturers directly about this otherwise you may get bad advice and be disappointed.

SteinAir
11-23-2010, 10:01 AM
The posts about these autopilots are fairly old. I would like to know if there are any new thoughts, pro's and con's,etc. I would be connecting the autopilot to a KMD150.

Brian is right regarding new features and such, but when it comes to an answer to your specific question, the KMD-150 nothing has changed in regards to how any of them will work with it. There really isnt' a need to rehash another "which a/p" should I choose thread, because the archives are literrally littered with them. A quick search will turn up many recent heated debates on A/P's.

In the end your KMD-150 will feed any of the A/P's on the market in exactly the same way with exactly the same functionality. The King KMD and Skyforce will send a RS-232 GPS feed sufficienent for a simple course hold...works the same with any of them (as they all will accept an RS-232 GPS input).

No need to restart another "which one is better thread", because in regards to your specific question the answer is any of them will do the job the same way and do a good job of it at that.

My 2 cents as usual!

Cheers,
Stein

Brantel
11-23-2010, 11:45 AM
Stein is right of course... I am not familiar with that KMD box, he most likely is so his would be good advice....just make sure your not expecting more than what a NMEA stream can give you.

Bavafa
11-23-2010, 12:27 PM
From a user perspective, I can vouch for all Stein said. The combination of TT VSGV, GRT and 430 makes flying an approach so much easier and precise and long distance flying a breeze.

breister
11-23-2010, 12:52 PM
I really appreciate the information everyone provided. It looks like the DigiFlight is the way to go. My question though is, when I looked at the Trio at OSH the gentleman was quick to point out a bunch of safety factors - how their clutch mechanism disengages and the drive mechanism can be over come by the pilot and the 180 degree turn at the push of a button (for recovering from accidental VFR into IFR). How much of this really adds to safety how much is either sales hype, foofoo dust, or just a minor feature, compared to the TruTrak?

Don

Hi Don,

TT also has an autopilot disengage function that you can wire to a button on the stick ("Control Wheel Disengage" or some such nomenclature). As for a clutch, if properly installed the stepper motors can easily be overcome with stick pressure in an emergency and you can simply pull the CB to disable the AP completely - thus, a clutch is somewhat irrelevant. While there is no dedicated "180" feature in the TT, you can dial in a course to fly for the same effect and punch in a vertical speed (or altitude hold) to literally "fly the airplane using the AP."

While I have no experience with the Trio, I hear only good things about it. On the other hand, it sounds like those "features" you were told about are really just different ways of accomplishing the same goals (e.g. marketing-speak).

Edit - should have looked at the date of this post! Well, the answer is still the same. :)

dlg
11-23-2010, 01:21 PM
Thanks for all the information on the discussion about auto pilots and that I just need to be aware that the KMD 150 is somewhat limited as a GPS, at least compared to a 430W or equivalent. Those Garmin GPS's are great but I can't afford them right now so I have to use what I have. As mentioned in my original question, I asked this question because most all the discussions I could find were at least 3 years old. I'm new to the site so I just thought it was appropriate to ask the question.

SteinAir
11-23-2010, 04:46 PM
Thanks for all the information on the discussion about auto pilots and that I just need to be aware that the KMD 150 is somewhat limited as a GPS, at least compared to a 430W or equivalent. Those Garmin GPS's are great but I can't afford them right now so I have to use what I have. As mentioned in my original question, I asked this question because most all the discussions I could find were at least 3 years old. I'm new to the site so I just thought it was appropriate to ask the question.

First of all Dana, welcome to the VAF community! This site is full of a great bunch of folks that are very passionate about RV's and a wealth of knowledge.

Next, don't be ashamed of owning a KMD-150. I flew behind one for many years until it died and loved that thing. It and the Skyforce are still one of the best designed user interfaces out there and a joy to fly behind. Sure it's not like the new fancy stuff, but it is what it is and it does a darned good job of doing a moving map made simple very well. It's too bad that Bendix/King has almost entirely abandoned GA because that product (kept refreshed) could have been competitive.

Anyway, it'll work plenty well for you no matter which a/p you use, including some of the certified ones.

Have a good holiday and again, welcome aboard!

Cheers,
Stein.

woodmanrog
11-25-2010, 05:40 AM
I have had 2 planes with Bendix Kings gps's . One with a KMD150 and my present plane with the less expensive version. Both planes came with Navaid autopilots that I changed out for Trio units. Easy to install and work flawlessly. I am adding a Trio Alt. hold this Dec. to compliment the original unit because I don't see any point in investing in a combined unit at more expense. When I did have a connection issue, I called Trio and was immediatly taken care of. I forgot to put in a setting on the GPS.
Woodman