What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Dynon or GRT EFIS

N

Norman CYYJ

Well Known Member
I am thinking about installing a EFIS and engine monitor in my new plane. What are your experiences with GRT or Dynon. I would like to hear about the good, the bad and the ugly times you have had with this equipment.
 
Check the archives. There are dozens and dozens of comments on these products. I have a Dynon EFIS and am very pleased with the reliability and value.
 
I've flown behind both... and they're both fine IMHO. I have a dual GRT Sport and friend has dual Dynon.. bottom line I wouldn't have minded having either... There's a little bit of difference in user interface and features.. I still suggest putting down a comparative list of features, and see which one makes more sense for you. Eg, if you want a moving map.. it'll be GRT since Dynon doesn't have it (yet) etc.. or maybe that's not a big deal.. and other things matter more.. It seems that they more or less both have "must have features" and they differ some in "need to have" features. Not sure you'd go wrong with either setup.
 
RE: Dynon D10

Norman,
I have the D10 in my -4. The artificial horizon is very good, but I think the size of the screen is a little small and all the 'goodies' get lost. I find I ignore the Airspeed and Altitude and look at my (backup) steam guages because they are so much easier to read quickly. I am looking seriously at the new offering from TruTrak.
YMMV,
Ron
N8ZD
 
Something to be aware of is the way the AHRS components for each work. The GRT systems have the added advantage of redundant inertial guidance data being used in the calculation of aircraft attitude, rather than GPS. With the Dynon system, the integrity check for the attitude data comes from GPS. What this means in practice is that the GRT system is designed with a higher level of redundancy in the case of a failed critical AHRS data source. In my opinion this makes the GRT system more suitable for hard IFR and less likely to suffer a failure that causes the system to lose reliable attitude information.

Dave
 
Last edited:
With the Dynon system, the integrity check for the attitude data comes from GPS.
Click to expand...

This is incorrect. The Dynon EFIS devices do not use GPS in the AHRS solution. They do, however, incorporate pitot info in their AHRS calculations. Hundreds of D10's have been flying for several years without any input from GPS and my D10A only uses GPS for winds aloft and HSI displays.
 
Definitely search the archives Norman - the Glass Cockpit section of the forum will give you hours of good reading! No one system is going to be right for everyone, and the selection process is highly dependent on your particular mission.

Paul
 
If you can, hold off on your decision until this summer. Dynon is working on a mod (sales guy let this slip at Puyallup last month; confirmed by a phone call to Dynon where the guy said "he wasn't supposed to tell you that") that might be ready for Arlington, but maybe not until Oshkosh.

Richard Scott
RV-9A Wings
 
I don't know how to put this without telling more than I should.

If you can, hold off on your decision until this summer. Dynon is working on a mod (sales guy let this slip at Puyallup last month; confirmed by a phone call to Dynon where the guy said "he wasn't supposed to tell you that") that might be ready for Arlington, but maybe not until Oshkosh.

Richard Scott
RV-9A Wings
 
Sam Buchanan said:
This is incorrect. The Dynon EFIS devices do not use GPS in the AHRS solution. They do, however, incorporate pitot info in their AHRS calculations. Hundreds of D10's have been flying for several years without any input from GPS and my D10A only uses GPS for winds aloft and HSI displays.
Click to expand...
Sorry, I should have been more clear. As far as I am aware, the GRT system has 2 internal inertial sources for attitude data (plus pitot-static, of course) that are continuously cross checked. The GPS data is used only to break a tie between the 2 sources in the event of a disagreement. It's my understanding that the Dynon has a single inertial source and the GPS is (or can be) used as the cross check. The results are that the GRT system is more error tolerant and less likely to display incorrect attitude information. Is my understanding incorrect?

Dave
 
Last edited:
It's my understanding that the Dynon has a single inertial source and the GPS is (or can be) used as the cross check. The results are that the GRT system is more error tolerant and less likely to display incorrect attitude information. Is my understanding incorrect?
Click to expand...

No, GPS is not used in any way in the Dynon AHRS system. You may be referring to the pilot checking a standalone GPS for a reality check but GPS isn't part of the internal workings of a Dynon AHRS platform.

I think you are simplifying the entire AHRS situation too much. The Dynon uses a combination of several inputs (airspeed, climb rate, accellerometers, etc) to increase the integrity of the AHRS. Even though there is a "single" AHRS platform in a Dynon (of course if you have more than one Dynon in the panel, I guess that would be considered multiple platforms), several factors are in play to keep the system working properly. Both Dynon and GRT have excellent field histories but there have been isolated instances of failure in both systems (check the archives). That is why a complete panel has more than one way to make sure the plane stays right-side-up.

I am not personally experienced with the GRT system in my plane, but I think it would be a jump to make a blanket statement about any one system being more failure tolerant than another. There are just too many variables in any modern glass panel to come to a conclusion that applies to all situations.

The GRT may very well be the best system for your panel but I doubt it will be because it is superior in reliability to other systems. Your final decision would best be based on total system integration with everything else you intend to install in your plane and a consideration of the type of missions you intend for your plane.

Have fun window shopping! :)
 
now or later

Your choice may be dependent on when you need/want/whatever a system. Dynon allegedly has product on the shelf ready to ship. GRT is several months behind--was 6 as of 3 months ago. TT is probably a year from shipping---a likely guess anyway.
 
cawmd82 said:
Your choice may be dependent on when you need/want/whatever a system. Dynon allegedly has product on the shelf ready to ship. GRT is several months behind--was 6 as of 3 months ago. TT is probably a year from shipping---a likely guess anyway.
Click to expand...

Things seem to have reversed: Currently (a week ago or so) GRT sport was pretty much of the shelf and Dynon quoted me 8+ weeks...
 
Not surprising......

My info is 3 months old, but had been consitant for awhile. YRMV but the timing/availability message remains the same.

CAW
 
GRT EFIS has the Flight Path Marker and Runways displayed

Grand Rapids and Dynon are both offering great customer support and very good products.

My choice for my EFIS and EIS is Grand Rapids partly because of two features that Dynon does not have. First is the flight path marker. Second is runways are displayed on the GRT EFIS.

The flight path marker totally changes the capabilities of the attitude indicator. An attitude indicator displays the pitch and roll of the airplane, but does not indicate what the airplane is doing as far as climbing or decending or drifting due to wind. The flight path marker allows the pilot to instanly see and grasp this information. If the airplane is in a pitch up attitude and the flight path marker is below the horizion then the airplane is decending. In an other example if the flight path marker is off center then wind is pushing the airplane to follow a different heading then that is shown on the heading indicator. Note: The flight path marker is an inertial instrument. Therefore, GPS is not used or needed to display flight path marker information.

Could one of the GRT EFIS pilots elaborate more on how they use the flight path marker?

The GRT EFIS does use GPS information to display runways inside the attitude indicator display.

When you combine runways with flight path marker display you have a complete picture. For people that have not flown with a flight path marker imagine that you are flying an IFR approach. You can see the runway and the flight path marker informs you if you are going to land on that runway. (It is not necessary to pipe in and say all the ways to fly an IFR approach)

Lastly, GRT offers a sport version of there EFIS that has simular costs to the dynon. This version is upgradeable by trade-in.
 
JonathanCook said:
Could one of the GRT EFIS pilots elaborate more on how they use the flight path marker?
Click to expand...
The Flight Path Indicator (or Velocity Vector, as I usually refer to it from other systems I use) is really a great tool for the reasons that Jonathan mentions. It tell you instantaneously where the aircraft is going not necessarily where it is pointed.

It is really great for little things, like making a perfect level-off at a new altitude - you put the center pixel on the horizon while you let the airplane accelerate, and you fiddle with power, and your altitude won't vary an inch. Not that any good pilot can't do that without a VV, but this makes it easy for anyone.

The other place the VV really shines is when using the Highway in the Sky display to fly an ILS or Synthetic Approach. Put the VV in the box, and you are going to be lead right to the touchdown zone - no if's, and's, or but's....it works every time!

Great tool!

Paul
 
Thanks Paul.


Can any one else give experiences with the flight path marker (indicator) or velocity vector? It has been hard for me to find a good definition of this instrument on the web.
 
No, GPS is not used in any way in the Dynon AHRS system. You may be referring to the pilot checking a standalone GPS for a reality check but GPS isn't part of the internal workings of a Dynon AHRS platform.
Click to expand...
Yes, my understanding was incorrect so thank you for providing accurate information. A good friend who is a EE and designs satellite sub-assemblies for space is the one who explained the reasons for the greater redundancy built into the GRT system, and I have apparently remembered the details incorrectly. I have a call into him this morning and will report back with a more accurate clarification after we link up. Thanks again for pointing out my error.

I think you are simplifying the entire AHRS situation too much.
Click to expand...
Sorry Sam, but I have to disagree with you on this point, as I am trying to do precisely the opposite. I think it is critical for any builder planning on doing any hard IFR to fully understand the redundancies and potential failure points of their chosen EFIS. While I would agree with your overarching point that field history matters tremendously, I would not agree that it is the final word. It's a hair splitting point in this case, but assuming that failure is a possibility in any EFIS system, understanding clearly how the units use each input and what the behavior will be when any individual components or inputs fail is critical. If one system has more desirable behavior than another in the event of the most common component failures, it is important to know that too and factor it into the buying decision.

Again, thank you for correcting my error. I will post back when I have the details.

Cheers,
Dave
 
Last edited:
I posted this line:

Quote:
I think you are simplifying the entire AHRS situation too much.
Click to expand...

To which David replied:

Sorry Sam, but I have to disagree with you on this point, as I am trying to do precisely the opposite. I think it is critical for any builder planning on doing any hard IFR to fully understand the redundancies and potential failure points of their chosen EFIS. While I would agree with your overarching point that field history matters tremendously, I would not agree that it is the final word. It's a hair splitting point in this case, but assuming that failure is a possibility in any EFIS system, understanding clearly how the units use each input and what the behavior will be when any individual components or inputs fail is critical. If one system has more desirable behavior than another in the event of the most common component failures, it is important to know that too and factor it into the buying decision.
Click to expand...

It seems I was definitely incorrect in stating that you were simplifying the EFIS application. :D
 
Sam Buchanan said:
It seems I was definitely incorrect in stating that you were simplifying the EFIS application. :D
Click to expand...
LOL. I'm all about experimental aviation, but there are limits to how much I am willing to "experiment"...particularly with primary instrumentation for hard IFR. ;)
 
As has been pointed out in this thread, the Dynon AHRS does not use GPS in any way. Our "assist" comes from pitot. We didn't even interface with GPS until last October, and our AHRS units were working fine for four years before that.

While I am not an expert on other products, I believe the "assist" in the Grand Rapids solution comes from the magnetometer. They don't use GPS at all for the AHRS solution either.

In either case, if the "assist" goes away, the whole AHRS solution goes away. We all use inexpensive gyros which drift, and we need something to help us cancel out this drift. This assist is not there in case something fails, it's a requirement for a good AHRS solution at all.

I do not believe GRT has any more internal sensor redundancy than Dynon. I think what you may be remembering is that you can purchase two GRT AHRS units with their Horizon system and network them together, so that if one fails, you have the other still available. This is also something that we plan on supporting at Dynon at some point.

As I say, I'm not a final expert on the competition's units, so please don't make a purchase decision based on what I have said.

If you're planning on flying hard IFR with any instrument, glass or not, it's a very good thing that you are thinking about possible failures. They can happen with any system.
 
Dynon or GRT EFIS? MGL!

Hi guys.

Between Dynon and GRT EFIS? I would go with the Enigma from MGL Avionics...

;-)

But that is me!!

Cheers,
Nicol.

PS: I have to agree with Dynonsupport: low cost gyros drift... See comment in another thread in response to questions regarding SP4 from MGL Avionics.
 
Last edited:
Nicol

nicolcarstens said:
Hi guys.

Between Dynon and GRT? I would go with the Enigma from MGL Avionics...

QUOTE]


Nicol,

Since you seem to be popping up on most all the EFIS threads, I'll ask the question again. Any chance you're an engineer working for MGL Avionics?

Tony
Click to expand...
 
Hi Tony,

Tony Spicer said:
Nicol,

Since you seem to be popping up on most all the EFIS threads, I'll ask the question again. Any chance you're an engineer working for MGL Avionics?

Tony
Click to expand...

Yes, I am. Although I am not represening MGL, I have updated my profile to clearly reflect this information.

I stumbled across the group and decided to take some time to post some replies... This is my first visit to the group. I posted a response where I believed the information was required...

I have to be honest: I have never had contact with the Dynon and GRT guys... I had a look at the Dynon posts, and I loved them! Honest and to the point. Not offensive towards anyone. I would like to do the same, but I do not feel comfortable being labeled "MGL Tech Support". I did not create Enigma... but like my profile said from the moment I joined: I love it!!

Hope to hear from you again soon! And that you are not upset??

Regards,
Nicol.
 
Last edited:
MGL Avionics

Nicol,

I'm not upset in the least. I just think it would have been proper etiquette for you to have identified yourself as an employee of MGL Avionics before, during, or after touting their products as strongly as you did. But then I'm sure no Miss Manners, so maybe I'm all wet.

Tony
 
I have to be honest: I have never had contact with the Dynon and GRT guys... and my intension is not to start a war, but to provide information! I had a look at the Dynon posts, and I loved them! Honest and to the point. Not offensive towards anyone. My intension is to do the same.
Click to expand...

I have had contact with both Dynon and GRT techs and have read many of their posts on this forum. I agree, their posts are honest and to the point.

Where I think you are going to get some resistance to your posts is your seemingly unabashed advertising of your product:

Between Dynon and GRT? I would go with the Enigma from MGL Avionics...

Full engine monitoring, AHRS, moving maps (raster and vector), WAAS GPS, HITS, ILS (NAV/COM radio interface), GLS, Autopilot interface, Terrain awareness, USB interfaces, free databases (airport, terrain, vector maps), multiple units, good price, excellent sunlight readability, fully customizable screen layouts, more than 8 years of digital avionics design experience ... All of that in ONE unit!!
Click to expand...

In my opinion, that is not a simple reply to a customer's technical question but a seventy word advertisement. I don't recall seeing any reps from Dynon, GRT, etc transitioning from a technical reply to a question into an unrelated broadcast of their product's advantages over the competition. A simple link in your signature to your company website might be more appropriate and appreciated. :)

Post as you wish, and your enthusiasm for your product is evident, but I don't think you are enhancing the penetration of your product into the RV market with this type post.
 
Last edited:
Hi Sam,

If you look at the original question from Norman, he wanted to know why Dynon or GRT EFIS? I made an alternative suggestion, and gave him some good reasons why he should have a look at Enigma... Hardly an "unrelated broadcast ", not so?

And with regards to your comment "I don't recall seeing any reps from Dynon, GRT, etc transitioning from a technical reply.." ... that is not entirely true in my opinion either...

But I understand your objection... And I am willing to extend an apology, to all who might feel sensitive about my light-hearted post. ;)

Regards,
Nicol
Engineer with MGL Avionics.
 
Last edited:
Nicol, I don't see any need for you to remove your posts as long you think they are productive for your company. It is your call.

If Doug thinks the posts have crossed the line into unpaid advertising on his forum he will make whatever adjustments are needed.

Best wishes with the further development of your products; it looks like you are bringing some interesting stuff to market. :)
 
Personally, I think Nichol is welcome to provide us information, as long as she clearly identifies her affiliation.

MGL has (in my opinion) been undersupported in North America, so it's nice to see Nichol is monitoring this forum and hopefully providing support.

I bit the bullet and purchased an MGL TC-3 12-channel engine monitor for my RV-9A, which I have not yet installed. I will provide a complete pictorial essay on my web site, along with a critical review when done. I made the purchase despite some choppy support from the factory on several documentation questions. Certainly not to the level of support that Dynon provides, which I consider "Best in Class". On the other hand, a 4 to 6 cylinder engine temperature monitor for $265 is pretty attractive.

Vern Little
 
Another update to my profile...

Hi Vern,

Thanks for the kind (and harsh) words... I will send you a private email, and we can further discuss the matter.

Just one more correction (and the profile does not make provision for this one as far as I can see): the sex is male! Yes: my parents had a lot of options, but they decided to "abbreviate" one of the family names, Nicolaas, into Nicol. A real pain!!

Food for thought: pity we don't all carry a label that "clearly identifies (her) affiliation" ... :rolleyes:

Kind Regards,
Nicol.
Engineer with MGL.
 
Last edited:
OK folks, here's the update on the MGL TC-3.

Some may have built their airplanes before the whiz-bang glass panel engine monitors were available.

Some may like separate instruments for failure redundency as opposed to all-in one 'god-boxes'.

Personally, I like to have separate instruments with limited functionality. Now if a instrument goes TU or a breaker pops, I'm not totally blinded.

Having said all of this, I added an MGL TC-3 to my RV-9A panel. Previously, I had a manual selector switch for EGT/CHT feeding a Rocky Mountain uMonitor.

Since I like leaning in cruise, I found it annoying managing the selector switch, and decided to put the TC-3 EGT/CHT scanner into a blank 3" hole in my panel. Installation was easy and the instrument works flawlessly.

I needed a bit of support from the Sport Flying Shop, which sold me the unit. The documentation does not indicate which inputs are EGT, which are CHT and how to wire up the channels.

I rewired the old EGT/CHT selector switch into an RS-232 selector switch so that I can data log from various instruments with my laptop in flight.

Bottom line: for $265+shipping, this was a great upgrade. The instrument is cheaper than 4 sets of probes!

Support was good from Sport Flying Shop, too.
 
FWIW, I saw the updated Dynon screen symbology yesterday at the CT Fly-in. Thumbs up. The new HS34 module works well too. Simple, easy to use and will take multiple inputs, including ARINC 429.
 
Glad to hear...

Hi Vern,

Glad we could sort out your little issue.

Now watch out for Odyssey!

;)

Kind Regards,
Nicol,
Engineer with MGL Avionics.
 
Last edited:
You must log in or register to reply here.
Back
Top