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Autopilot evaluation and experiences


ctfarmer

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Happy new year to all from Australia,

 

I am new to flying having just a few hours up my sleeve and new to CT ownership having just purchased a new but old CTLS which, apart from the factory test in Dec 2009, is yet to be flown as i am awaiting final registration approval. Long story but it sat in dealer storage in Italy for close to 3 years.

 

Anyway, it has the new "steam" instrumentation in Dynon D100/120 and a Garmin 695.

 

My question relates to installing an AP and what if any good or bad experiences members have with respect to an aftermarket installation of either Dynon or TT. I expect they are my two main options.

 

So i would be grateful for any response relating to flight characteristics, features, safety aspects, operation or installation issues/problems or whatever relevant matters to assist in my decision as to which way i go.

 

I have searched here and found some relevant posts. I note the latest Dynon firmware upgrade (5.5) relates mainly to AP fix's. I have had a couple of first hand responses here in Australia saying, go TT as the Dynon AP did not work as well but they are not recent experiences.

 

cheers peter

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Peter,

 

I did an after market installation of a TruTrak autopilot in my 2005 CTSW during the summer of 2012. It required a "major repair authorization (MRA form) from Flight Design.

 

I was upgrading the rest of my panel at the time and one important feature in the choice for me at the time was that TruTrak was offering the "autopilot level" feature that worked with their EFIS. After my CFI had me do the "unusual attitudes" during my recurrent safety training, I was able to show him that my aircraft could recover at the push of a button. The FD service center that I was working with at the time recommended the TruTrak based on other customers experience. Trutrak no longer makes the EFIS that I have, but their Vizion series does offer the emergency AP level feature.

 

The fuselage needs to reinforced under the pilot seat for the pitch servo if you go for a two-axis autopilot.

 

I am still learning the stupid autopilot tricks... Like do not use rudder pressure to port fuel from one wing to the other while the autopilot is on.

 

I have no experience with other autopilots. Others will have to offer you a comparison with other products.

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Peter,

 

I've flown with the TT AP III for over a year now and found it performs very well. No complaints.

Follows the 796 flight plan flawlessly and responds very nicely to the heading bug. Preset altitudes are captured accurately.

Rate of accent and descent with the twist of the knob.

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Peter, grab a coffee and take some time to look at the many postings in this forum regarding auto pilot. For TT A/P, there are 10 to 12 attributes that can be "tweaked" and I know I've posted the settings which worked best for my CTSW. These may help you set up yours if you find it not responding as you want it to. There is also a TruTrak forum:

http://trutrakap.com/forum/index.php

 

Just about any topic you are wondering about has been discussed right here on our forum.

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Hi Peter,

 

I have used the Tru Track and Dynon autopilots in the CT and they both perform very well even in moderate turbulence. If you are planning for lots of cross country flying having an autopilot is a great asset. The Tru Track has less features then the Dynon as it is not tied into the Dynon EFIS, but it is very easy to use, accurate and reliable. The Dynon is equally as accurate and reliable and has more integrated features like altitude preselect, airspeed hold climb, etc. Given you have a CTLS it should not be difficult to install either one in your aircraft.

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The autopilot installation in the CTLS doesn't require the modification the the belly of the airplane,like the SW. There are 2 different installations for the CTLS, if you have first generation aileron controls the servo mounts on the rear cabin wall and drives the controls with a long rod, and no torque enhancer. The second generation mounts on the center tunnel just like the SW, with a torque enhancer. The pitch servo is mounted under the seat forwad of the ledge and out of site. There is already an inspection cover there, but there are 2 different sizes of openings. The early CTLS's had a bigger opening.

 

As for TruTrak compared to Dynon I think they are both good, but getting the servo mounts for the Dynon may be a problem. You can get the mounts and wiring for the TruTrak already made up ready to install.

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Thank you to all. I was comfortable the TT system work fine as thousands of them do. The Dynon option for the CTLS i was less certain.

 

I will be doing a lot of cross country flying.

 

Chris and Tom - your comparison is perfect to assist me in making a decision on which way to go. In summary, they will both work equally well and both be a simple fitment to the CTLS (brackets aside) and i would get a few additional features from the Dynon.

Another advantage is certainly purchase price as well as a little bit of weight both in favor of the Dynon servos from what i can determine. On that basis, i am leaning toward Dynon as a first step.

 

Tom, would a Dec 2009 build date be the early type and do installers normally make up the control rods to suit or are they likely to be available. I will follow up on the Dynon forum as well.

 

Again, many thanks peter

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A Decenber 2009 will be second generation control system. You may be able to get brackets and servos from Flight Design, since they started offering the Dynon autopilot around that time. If you can get the brackets and hardware for the Dynon install it should be much easier, with no cutting the panel and splicing pitot and static lines.

 

The Trutrak's that I have installed came with all the hardware and mechanical connections. The wiring harnes can also be bought ready made. If you buy the autopilot kit and wiring harness, then all you need is the fittings and line to connect the pitot and static lines.

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The Dynon autopilot should NEVER be on if you want to pull on the stick yourself (you can steer the plane using the HSI function if you dont want to entirely disengage and make a course adjustment off the flight plan).. But just yanking on the stick direcly will damage the servos. The manual is pretty clear on this point.

 

Could you please provide the reference in the manual for this? I have a Dynon 2 axis autopilot and the pilot needs to be able to override the servos by brute force if necessary. I beleive that is why they can be adjusted down from 100% if necessary, but stand ready to be corrected.

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There is also a shear pin that allows the pilot to remove the AP from the control surfaces. I would posit that any force less than that necessary to break the shear pin will not harm the servo and, of course, any force greater than that removes the servos from the control. I also read in the Dynon forums where a pilot had put 100-150lbs of force on the servo arm to demonstrate that the shear pin would break.

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I'm with Dan.

 

It should be possible to overpower any autopilot - I believe there are standards for that, and friction clutches are installed for just that ability.

 

It may be poor practice to continually overpower an autopilot, and could eventually cause premature wear on the clutches.

 

If overpowering the autopilot causes immediate damage to the control servos, I'd call that a design defect - a pilot will almost certainly on occasion have to rein in an autopilot that's misbehaving.

 

But I, too, would like to see that warning from the manual.

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Don't make the mistake, if you have the choice, of not putting in the Dynon integrated autopilot. Especially if you have or will have the Garmin 796 or 696, and the Dynon skyview. These toys are MADE to work together. FD has designed the aircraft to use the Dynon and Garmin.

 

The Dynon setup is sweet indeed. I have flown three xcountry trips using it and it works like a dream. To fly the flight plan in either the Dynon or the Garmin is a big deal. The Dynon autopilot has so many features its impossible to list them all. Make sure you talk to FD before kludging on some aftermarket solution

 

You might regret it.

 

The Trutrak autopilot is not some aftermarket solution, it is a Flight Design factory option. It is available on the CTLSi, and it will couple with the Garmin GPS to fly a route. The latest version has most of the same features offered by the Dynon. With the Dynon autopliot being intigrated and offered as a factory option many of the distributors have chose it over the Trutrak, mostly because of cost.

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From that link...

 

"Next, Dynon autopilot servos are also designed so that a pilot can manually overpower them without damage to the servos or the aircraft, and without the need for a failure-prone mechanical clutch in the system."

 

So, no clutches per se, but what sounds like equivalent "slippage" ability built in.

 

CTLSi, you might want to seek out whoever told you otherwise and bring this to their attention.

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Back tracking a little to approved AP systems.

 

Does an LOA exist for any aftermarket AP fitment as i can find none listed at all on the LOA page.

 

I have emailed FD to find out what fitments are approved for the CTLS if any and as yet no reply.

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What is the upside to toying with the AP playing chicken with servos and shear pins? None. Just press the button when you want to take the stick back.

 

When I see my windshield fill up with another airplane, I'm not worried about that little button. I'm pushing the stick to get out of the way.

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Why not get a TruTrak EFIS that comes with an auto pilot?

 

http://www.starkavio...utrak_efis.html

 

EFIS_FM_copy_ezg_1.jpg

 

That is what I did for my 2005 CTSW. My FlyDat died for the third time in the airplane's lifetime. I wanted the autopilot at the same time. So, in the summer of 2012, I bought the whole EFIS GP, EMS and autopilot package from TruTrak. The wiring harness was provided by SteinAir in MN.

 

A little more than a year later, TruTrak is no longer selling either of their two EFIS products. I already have a "legacy" panel.

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