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A/P Opinion request

Pounder

Well Known Member
Hello,

I am looking at a panel upgrade to my RV8 with the goal of a solid IFR platform.

I may be choosing between GRT and Dynon for primary display.

I'm somewhat interested in opinions with regard to comparing these two EFIS systems, but for now what I am most curious about are their auto pilots, GRT vs Dynon.

Nav will likely be Avidyne.

Does anyone have a experience with both, enough that you might articulate a comparison or contrast?



Thanks,

Bryan
 
Hello,

I am looking at a panel upgrade to my RV8 with the goal of a solid IFR platform.

I may be choosing between GRT and Dynon for primary display.

I'm somewhat interested in opinions with regard to comparing these two EFIS systems, but for now what I am most curious about are their auto pilots, GRT vs Dynon.

Nav will likely be Avidyne.

Does anyone have a experience with both, enough that you might articulate a comparison or contrast?



Thanks,

Bryan

I just removed my Trutrak Vizion and servos from my RV-10 and replaced with Dynon servos. This probably makes a bit biased.

The Dynon servos are attached to the EFIS via the SV-Network. The nice thing about the SV-Network is that you can change the master if an EFIS should fail. The Dynon servos work with both Dynon HDX and Advanced Flight 5000 amd 6600 series EFIS. I have the AF-6600s.

I also like the Dynon SV-EMS over the Grt engine sensor module.

My personal opinion is that GRT hasn’t kept up with the innovation that Dynon, Advanced Flight, and Garmin have delivered. I can also share from personal experience that GRT doesn’t provide the same level of support that either Dynon or AFS does.
 
Caveat #1. My avionics are a dozen years old, so my comments are somewhat out of date. I have a pair of GRT Hx’s (primary) and a Dynon D6 (backup). Also a Trio Pro autopilot with autotrim. The D6 will lose its attitude reference if you lose both airspeed (pitot data) and gps data. The Hx will not. Not likely to have a dual failure, but never say never. The Hx-Trio perform wonderfully, as if on railroad tracks, from just after lift off to just before flaring for landing. If you are serious about IFR don’t overlook the advisability of backups. If the EFIS quits, one flip of a switch puts the autopilot in stand-alone mode, and, connected directly to the 420W gps, will navigate to the destination and shoot any available gps approach. Yes, the self contained autopilots are $1K cheaper, but a stand-alone is priceless if the chips are down. It is true that GRT is a smaller company, less handholding, and their documentation is written in engineer-speak. But, as a sample size of one, I designed and wired my panel myself, never had to call GRT, everything worked on day one.
 
I don't have any experience with GRT but my 8 has a Dynon HDX paired with an Avidyne IFD-440. I'm very happy with the autopilot performance. It tracks steady in all modes including following guidance (lateral and vertical) from the IFD.
 
GRT EFIS, EIS and A/P servos are quality components - but that’s where it ends! Their documentation is scattered and confusing at best. Tech support can be difficult but is usually helpful as long as you’re willing to ask and receive it via email. IMHO they are a small company and desire to stay that way which makes implementing any improvements and long term sustainability questionable.

Remember, when you’re spending significant money on an avionics system you need to consider quality, longevity, documentation, technical support and finally price. There’s an old saying in business, “either grow or die.” Most people want their aviation systems to be reliable and serviceable. I frankly don’t know many avionics shops willing to work on aircraft with GRT equipment installed since company support to them is limited to non-existent.

My two cents.
 
Separate A/P Option

I recently upgraded from a TruTrak ADI Pilot II to the Bendix King xCruze 110 (formerly TruTrak Gemini). It has ARINC connections for GPSS, and will fly LPV approaches from my GNS480.

I have a Dynon Skyview system, which has the A/P software already built into the box, but I don't like to have all my eggs in one basket. The xCruze 110 has an artificial horizon, airspeed indicator and altimeter, so it is my backup system if the Dynon system craps out. I will say that I haven't been able to completely dampen out "porpoising" when it makes 90-degree turns, like the T-patterns on RNAV approaches. I'm also not a fan of the Bendix King big-industry attitude.

Another option for you to consider.
 
My personal opinion is that GRT hasn’t kept up with the innovation that Dynon, Advanced Flight, and Garmin have delivered. I can also share from personal experience that GRT doesn’t provide the same level of support that either Dynon or AFS does.

I have GRT HXr and a mini in my 6 and a G3X and G5 in my 10. Many 100's of hours using both. I can only think of a couple insignificant features that my G3X has that isn't on the GRT and there are a few capabilities, more important to me, on the GRT that do not exist on th G3X. User Interfaces are different, but difficult to say which is better, as it is pure personal preference.

Based upon my experience, I believe it is unfair to say GRT is outdated. Given the OP request, I will say that the AP software on the G3X is much more stable than the GRT. They both work fine, just that the G3X is rock solid. GRT is just not as smooth, but then again no worse than the D100 based dynon that it replaced.
 
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Five years ago I settled on dual HDX, dual Dynon ADAHRS, Dynon autopilot, GPS175, GNC255, GTR200 (second radio), Dynon autopilot control panel, dual alternators, single battery, backup batteries for both HDX’s.
The Dynon autopilot works well in Expert mode, but has some mode menus that cause me go into “what is this thing up to now “ mode. The connect and disconnect sequences, what is engaged and what is not seem particularly unique to Dynon. Compared to the quality of Garmin documentation, Dynon documentation is definitely written to a lower standard.

Another consideration is charts, software support, developing and loading flight plans.

HDX only supports Seattle Avionics charts, so I need an annual subscription for SA charts. For the GPS 175 I need a separate subscription for charts and approaches because Garmin does not support SA charts. For flight plan preparation I had been using FlyQ on an IPad which works well for the HDX but doesn’t work for the GPS175 so I use Garmin Pilot for loading the GPS175 flight plan - yet another subscription.
I wish it all worked seamlessly ,but it doesn’t, not with my configuration.

If I were going to start over with a new design and planning on a fully capable IFR aircraft I would probably go with dual G3 and a Garmin autopilot. I did single pilot IFR in a Cardinal for many years - I wouldn’t consider doing IFR in an RV without a working autopilot that had a high probability of being available and doing what I wanted for the whole flight. I consider myself a very average pilot getting on in years so my tolerance for high workload and stress is much lower than it once was.

Going through the motions of planning a flight, arm chair executing the flight, considering all the likely failures and how you will deal with them is a good start to getting to the configuration you will be happy with.

Keith Turner
 
I recently upgraded from a TruTrak ADI Pilot II to the Bendix King xCruze 110 (formerly TruTrak Gemini). It has ARINC connections for GPSS, and will fly LPV approaches from my GNS480.

I have a Dynon Skyview system, which has the A/P software already built into the box, but I don't like to have all my eggs in one basket. The xCruze 110 has an artificial horizon, airspeed indicator and altimeter, so it is my backup system if the Dynon system craps out. I will say that I haven't been able to completely dampen out "porpoising" when it makes 90-degree turns, like the T-patterns on RNAV approaches. I'm also not a fan of the Bendix King big-industry attitude.

Another option for you to consider.

I also upgraded from the TruTrak ADI Pilot II to the Gemini and have it talking to my D100 and the GNX375, it all works pretty well together however it would be nice to have a "heading mode" and I am not sure I have experienced the "porpoising" mentioned so would be interested in more info on that. It also is my backup ADI in the event of a D100 failure and can be driven from my Aera 760 portable in lateral nav mode if I lose the 375.
Figs
 
AFS, etc

Bob,

I'm getting things narrowed down to, probably AFS for EFIS (FS 6600) Avidyne IFD 540, and the sister Dynon stuff: Com 2, A/P, EMS..

Any chance you might have a picture of your panel?

VR/
Bryan

I just removed my Trutrak Vizion and servos from my RV-10 and replaced with Dynon servos. This probably makes a bit biased.

The Dynon servos are attached to the EFIS via the SV-Network. The nice thing about the SV-Network is that you can change the master if an EFIS should fail. The Dynon servos work with both Dynon HDX and Advanced Flight 5000 amd 6600 series EFIS. I have the AF-6600s.

I also like the Dynon SV-EMS over the Grt engine sensor module.

My personal opinion is that GRT hasn’t kept up with the innovation that Dynon, Advanced Flight, and Garmin have delivered. I can also share from personal experience that GRT doesn’t provide the same level of support that either Dynon or AFS does.
 
Love the Dynon autopilot, and fly an Avidyne 440 through it. I fly a lot of actual IMC and it handles like it's on rails.
 

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Our Glasair Sportsman features triple GRT EFIS devices; HX, Sport EX and Mini-X. The autopilot is a TruTrak Vizion 385, predecessor to the XCRUZE110 with the flat pack control head. Nav sources are GNS480 and SL30.

I've had some troubles with altitude scalloping with the autopilot in basic altitude hold mode. This was resolved through a very brief flight in which I made minor adjustments to one of the autopilot programming variables. It was very easy to do and has tamed the scalloping in rough air down to +/-20 feet - far better than I could hand-fly the airplane in those conditions.

Navigation via autopilot is simple; mode selection defaults to GPSS when the GPS is programmed to navigate to a waypoint or via a flight plan. I have installed the recommended switch which allows this same functionality to be executed via the HX EFIS; I rarely use this mode but it's there in case the GNS480 should go belly up.

Approaches are truly "like it's on rails". It's very, very impressive, and a joy to fly when all I have to do is manage engine power and make radio calls.

All of the products you are considering are terrific products and light years ahead of anything available even a couple of decades ago. These truly are the "good old days" of experimental avionics.
 
I have two Dynon 11" HDX displays with the Dynon Autopilot with the Dynon auto pilot knob panel. It is interfaced with an Avidyne IFD540. I just love the way it communicates flawlessly with each other. This set up allows the autopilot perform the auto-trim feature flawlessly. I also like how the autopilot is easy to fine tune and that Dynon frequently provides software updates to constantly improve things.

This makes my RV-7A a very nice IFR platform. I fly coupled approaches frequently with ease (it is almost cheating).
 
I have two Dynon 11" HDX displays with the Dynon Autopilot with the Dynon auto pilot knob panel.

I should have mentioned in my post above that one of the reasons I appreciate having a stand-alone autopilot controller is because it has dedicated knob and button functionality and dedicated mode annunciation.

If installing an autopilot, having access to autopilot control functionality through a dedicated control head such as the Dynon AP panel or Garmin GMC507 makes autopilot operation so much faster and easier and much more intuitive.

I know all the EFIS manufacturers have some degree of autopilot control built into their primary EFIS functionality. That's great and I'm really glad they offer this most basic means of accessing autopilot functions. Still, the added cost and space of a dedicated autopilot controller are far outweighed by the improvement in ease of use of the autopilot and, most importantly, by the improvement in situational awareness.

One of the worst feelings is to be in the clag on autopilot and having to ask oneself, "what's it doing now?" The dedicated controller takes a lot of that guesswork off the table and thus is a huge safety enhancement.
 
I have two Dynon 11" HDX displays with the Dynon Autopilot with the Dynon auto pilot knob panel. It is interfaced with an Avidyne IFD540. I just love the way it communicates flawlessly with each other. This set up allows the autopilot perform the auto-trim feature flawlessly. I also like how the autopilot is easy to fine tune and that Dynon frequently provides software updates to constantly improve things.

This makes my RV-7A a very nice IFR platform. I fly coupled approaches frequently with ease (it is almost cheating).

Thank you everyone for your inputs..

Thanks Bill for this,
It's looking like I will have a similar set-up, HDX + IFD540, though only room for single PFD. The IFD was a significant $ commitment. Your testimonial along with others is reassuring.
 
[
One of the worst feelings is to be in the clag on autopilot and having to ask oneself, "what's it doing now?" The dedicated controller takes a lot of that guesswork off the table and thus is a huge safety enhancement.[/QUOTE]

I hate that "what's it doing now" feeling. Had that in a prior life with some auto flight systems..
 
I have a Dynon Skyview system, which has the A/P software already built into the box, but I don't like to have all my eggs in one basket. .

I have an Advanced Flight 5400 on a Skyview network and legacy Advanced Flight (TruTrak) autopilot. Navigator is an IFD440. I have a simple switch that let's me select autopilot source as either the 5400 EFIS or the IFD440.
 
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