Swap Trutrak autopilot for Dynon?

[okent]

I'm going to add an IFR navigator to my 2013 CTLSi to train and will be upgrading my Trutrak to allow altitude preselect and a level button. 

I believe the math is close enough that it works out to add the equipment in my own plane instead of renting. (50 hours @ 120$/hr=6k with no residual value in aircraft)  If I spend 10K or less on the upgrade and retain even half the value I'm ahead.  I get to build time in my own plane on my schedule instead of trying to get in line for a rental.

I was wondering if its even possible to swap out the Trutrak for a Dynon and if so is there any benefit or increased capability comparing the two.

Has anyone done either of these and what the cost was?

Also, has anyone upgraded their Skyview Classic to touch screen?

 

Thanks

 

p.s.  I have no plans of flying in IMC, just get my IFR.

[Ed Cesnalis]

I'm doing similar but with the CT pilot (trutrak) to Dynon D100a.

You already have trutrak servos and the Dynon AP in your EFIS right.  The trutrak servos can work and they are better servos but not as smart.  The electronic connection to the servos is not the same.  There are 2  AP controllers you can install to have simpler input than through your skyview.

I think

[Ed Cesnalis]

I guess this is the IFR/VFR version

 

[Ed Cesnalis]

The remaining question that I have is about the dumber but better tru trak servos already installed.  I know the cost is $1,500 for both servos but I don't know what feature is given up by using the dumber but better tru trak servos?

[Garrett Gee]

I don't think (though I could be wrong) that the TruTrak will work with the Dynon directly.  You would have to interface the Dynon with the TruTrak Vizion controller (xCruz now I think), which does work well from what I have heard.  I replaced my TruTrak with Dynon after Trutrak was bought out by Bendix, and Bendix went back on what TruTrak and I had been working on to upgrade my IIVS to the Vizion, and then basically told me to upgrade, I had to pay the full price, rather than the upgrade quote from TruTrak.

 

The Dynon servos are a direct replacement for the TruTrak (fit wise), but the wiring is differrent.  I used the existing wiring, and made an "adapter harness" to go from the TruTrak autopilot head to the Dynon Skyview Network.  The elevator servo under the pilot seat was an exact fit, but the aileron servo in the back required a slight adjustment to make work.  I ended up moving the existing bracket back a couple of inches and fabricating a small bracket to the aileron control fork in the back out of .125 aluminum bar.  I honestly don't remember why I had to do this though.  Everything said and done, I think I was about 8 hours of labor into the whole upgrade, plus test flying and tuning.

 

The benefit to the upgrade is that you get truly coupled approaches if you have the Dynon ARINC-429 module tied to the IFR navigator, plus several other modes if that kind of thing interests you.  You get altitude capture, airspeed hold, vnav, wing leveler, and very tight integration between all the Dynon components.  I think you can also get most of that just by upgrading to the Vizion (xCruz) though.  Depending on which TruTrak you have, the easiest (and probably cheapest) upgrade path would be to replace the TruTrak head unit with a more capable one, and tie it into the Dynon's using an available RS-232 link.  This was the path I was originally going to take.

[Garrett Gee]

22 minutes ago, Ed Cesnalis said:

The remaining question that I have is about the dumber but better tru trak servos already installed.  I know the cost is $1,500 for both servos but I don't know what feature is given up by using the dumber but better tru trak servos?

I don't think you really give up or gain anything.  The TruTrak servos from my understanding are driven directly from the TruTrak head unit, whereas the Dynon have a microcontroller that receives input from the Dynons, and then the microcontroller on the servo commands the servo what to do.  One thing with the Skyview Network is that it does have 2 sets of data lines though, so if one of sets chaffed, got cut, etc., you could still have the autopilot.  In terms of features, I think it really just boils down to the software in the head unit (TruTrak) or the EFIS (Dynon).

 

For example, I was going to upgrade from the TruTrak Digiflight II to the Vizion.  The Vizion has VNAV and approach capabilities, as well as altitude capture.  All I was going to have to do was change the head unit.  The servos did not have to be changed, yet I would have gotten much more in terms of capabilities.

[andyb]

1 hour ago, garrettgee2001 said:

I don't think (though I could be wrong) that the TruTrak will work with the Dynon directly.  You would have to interface the Dynon with the TruTrak Vizion controller (xCruz now I think), which does work well from what I have heard.  I replaced my TruTrak with Dynon after Trutrak was bought out by Bendix, and Bendix went back on what TruTrak and I had been working on to upgrade my IIVS to the Vizion, and then basically told me to upgrade, I had to pay the full price, rather than the upgrade quote from TruTrak.

 

The Dynon servos are a direct replacement for the TruTrak (fit wise), but the wiring is differrent.  I used the existing wiring, and made an "adapter harness" to go from the TruTrak autopilot head to the Dynon Skyview Network.  The elevator servo under the pilot seat was an exact fit, but the aileron servo in the back required a slight adjustment to make work.  I ended up moving the existing bracket back a couple of inches and fabricating a small bracket to the aileron control fork in the back out of .125 aluminum bar.  I honestly don't remember why I had to do this though.  Everything said and done, I think I was about 8 hours of labor into the whole upgrade, plus test flying and tuning.

 

The benefit to the upgrade is that you get truly coupled approaches if you have the Dynon ARINC-429 module tied to the IFR navigator, plus several other modes if that kind of thing interests you.  You get altitude capture, airspeed hold, vnav, wing leveler, and very tight integration between all the Dynon components.  I think you can also get most of that just by upgrading to the Vizion (xCruz) though.  Depending on which TruTrak you have, the easiest (and probably cheapest) upgrade path would be to replace the TruTrak head unit with a more capable one, and tie it into the Dynon's using an available RS-232 link.  This was the path I was originally going to take.

I upgraded to the Vizion.  Overall, I've been happy with it.  When you use the "Dynon" mode, it automatically responds to the altitude capture and vertical speed selected, and if (in my case) I have the HSI tracking off the Dynon or 796 input, it will intercept and track that route.  As such, if I load an approach into the 796, it will track it laterally.  However, unless there's a way that I haven't discovered, it won't track a GPS approach glideslope.  Further, it will not track a radio generated ILS, laterally or vertically, nor will it track a radio generated VOR.  If I use the radio source for the HSI, it just follows the heading bug and altitude preselect.

Having flown lots of truly coupled approaches on the Cirrus, this is nowhere near the capability of the DFC90 or STEC.  At the same time, for VFR flying, it's more than capable enough.

I have found the Vizion to be very stable and reliable.  That said, the interface is much more clunky than if I had the Dynon autopilot.

Andy

[okent]

I have the TruTrak autopilot head so I was going to change to the Vision.  Andy,  from what I understand if I add an IFR nagivator it can couple with the Vision and fly both the track and the glideslope.  That's what I'm going for.

I haven't fidgeted with changing the input source since I've got a 796 right now.  I just fly my autopiloted tracks through the 796/TruTrak and use the Skyview for everything else.   I will learn both going forward.

If you don't mind me asking, what was the cost of the Vision upgrade?

 

Tom

[andyb]

My recollection was that the Vizion upgrade was about $1,000.  I had it installed when I had my condition inspection, and I don't think it added much to the labor cost.

In my case, I have three different sources for the PFD CDI, which in turn drives the autopilot: Garmin 706, Dynon, and my Garmin Nav/Com radio.  The Nav/Com does in fact generate an official ILS  localizer and glideslope, which I believe would be IFR capable.  But, unless I'm missing something, the Vizion autopilot won't track either the localizer or glideslope; in that mode, it follows the heading bug for lateral guidance, and descends according to the vertical speed and altitude preselect from the Dynon PFD.

Maybe it's my setup, and maybe different Nav/Com would be different, and I certainly could be missing something, but I don't believe so.  When I initially looked into it, the way it worked was consistent with what was in the manual for the Vizion (note #2C below).

Andy 

 

From Vizion Manual:

Mode Operation
Operation of the autopilot in SkyView mode is also very simple. Pressing the MODE button on the autopilot will put it in
the SkyView mode, as long as the signal is present. Once in the SkyView mode, all commands are driven from the
SkyView and not the autopilot. For operation of the autopilot independent of the Dynon SkyView, please refer to the
Vizion 380/385 Operating Handbook. SkyView mode operation is outlined below.
BE SURE TO SYNC THE ALTIMETER ON THE AUTOPILOT TO THE SKYVIEW ALTIMETER!!!!!!
1) Press MODE on the autopilot to enter SkyView mode. (Fig 1)
Note: The autopilot will enter the SkyView mode from the AP OFF screen (powered but not engaged) or with
the Vizion engaged.
2) SkyView CDI SRC determines lateral actions of autopilot.
a. No selection will have the autopilot follow the heading bug of the SkyView. (Fig 2)
b. Selecting SKYVIEW or the external device (EXAMPLE: GNS430) will follow the flight plan programmed
either internally or on the external device. (Fig 3)
c. Selecting LOC/VOR/ILS will have the autopilot follow the heading bug.
3) For vertical mode control, an altitude bug AND a vertical speed bug must be set on the SkyView. Be sure to
select an appropriate vertical speed for the selected altitude. Once the autopilot gets to the selected altitude
the display will display ALT HOLD. (Fig 4) If an altitude bug is not set on the SkyView, the autopilot will follow
any changes to the vertical speed bug.
Note: The autopilot will follow the vertical speed bug any time the altitude bug is adjusted from the current
altitude!
4) Press MODE on the autopilot to exit SkyView mode and synchronize to both current track and vertical speed.
(Fig 5)

[okent]

Andy, I will confirm this but the word I got from Airtime Aviation is that the only way to load and fly IFR approaches with autopilot vertical guidance is to manage everything through the Garmin navigator.   By that I mean the autopilot is only receiving IFR info from the Garmin, making the Dynon just a monitor. This makes sense because Dynon isn't a certified IFR navigator so I shouldn't be able to create an IFR plan through it. 

I'm coming from a D100 and 696 so learning the Skyview.  On the old system everything was created and loaded through the 696.  Trying to figure out what I can and can't control on the autopilot through the Skyview while VFR and IFR.  Can I create a VFR flight plan and fly it with autopilot through Skyview only?

[andyb]

When I purchased my CTLSi, from Airtime (good experience, by the way), I considered having a Garmin 430W installed.  There was actually a picture of one on the Flightdesign web site, but I was told by Airtime that it couldn't be done.  Could be that their POV has changed on that.

If you can get it to work, all the better.

In terms of your IFR training, bear in mind that most of it, or all of it, will be done without the autopilot.  When I got my IFR rating in 1998, my plane didn't have an autopilot.  As you know, even in the best case, you plane won't be legal for IFR flying, which as you also know isn't a barrier to your training.  As such, you can do non-precision approaches (no glideslope) off the 796 if you're in VFR conditions, and you can fly a full ILS precision approach through the Dynons with a Garmin nav/com.  But, you won't be able to fly coupled ILS approaches, and you won't be able to fly in actual IFR conditions, neither of which will be necessary in your training or your checkride.

Andy

[okent]

Thanks Andy.  My thinking was to build as complete an IFR setup as possible to train in as cost effective as possible.  The new plane is such a joy to fly it's hard to rent a tin can to fly around in.  

I know of one CTLS on the field here with a 430 that Airtime sold a few years ago so they are out there.  Definitely not common.

 

Tom

[Garrett Gee]

I believe that to have the Vizion track a Glideslope (GPS or ILS) you would have to link the Vizion directly to the source (GPS or Radio) via the ARINC inputs on the Vizion and the ARINC outputs on the  Source.  Dynon does the same thing.  You have to have the ARINC-429 module, which then translates the ARINC into the dynon network language.

What I am not sure of, and the manual does not make 100% clear is, do you have to have the ARINC module linked to the Dynon for the Vizion to fly coupled approaches.  Some sources will generate a glideslope on the RS-232 interface, but most autopilots will not follow it unless it is an ARINC-429 source.  Most (IFR) units will output both, but it depends on how it was installed originally.

My guess though, is that the IFR Navigator would have to output the ARINC-429 directly to the autopilot to be able to fly coupled approaches.  You could also have it output to the Dynon as well, but I doubt the Vizion will track the Glideslope unless it directly connects to the IFR navigator.

[Duane Jefts]

Not sure of the modules and the connections but my vision auto pilot does fly a LPV GPS Approach right on down to minimums. Trutrac hooked to two G-5s and GTN650. I do need an AIRINC switch to get The autopilot to fly the ILS glide slope. That will be the next install.

[okent]

On 12/21/2020 at 2:23 PM, garrettgee2001 said:

I believe that to have the Vizion track a Glideslope (GPS or ILS) you would have to link the Vizion directly to the source (GPS or Radio) via the ARINC inputs on the Vizion and the ARINC outputs on the  Source.  Dynon does the same thing.  You have to have the ARINC-429 module, which then translates the ARINC into the dynon network language.

What I am not sure of, and the manual does not make 100% clear is, do you have to have the ARINC module linked to the Dynon for the Vizion to fly coupled approaches.  Some sources will generate a glideslope on the RS-232 interface, but most autopilots will not follow it unless it is an ARINC-429 source.  Most (IFR) units will output both, but it depends on how it was installed originally.

My guess though, is that the IFR Navigator would have to output the ARINC-429 directly to the autopilot to be able to fly coupled approaches.  You could also have it output to the Dynon as well, but I doubt the Vizion will track the Glideslope unless it directly connects to the IFR navigator.

That last bit is what I understand to be true.  Have to connect the IFR navigator to the autopilot.  My thinking is that once the approach is loaded and coupled, the plane follows the vertical/lateral guidance until told otherwise.  At that point the approach is cancelled and then all can be managed with either the IFR navigator or the Vision(or Skyview input I guess).  Then it's basically only lateral guidance like VFR.