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.
With the Dynon system, the integrity check for the attitude data comes from GPS.
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?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.
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?
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.
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.JonathanCook said:Could one of the GRT EFIS pilots elaborate more on how they use the flight path marker?
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.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.
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.I think you are simplifying the entire AHRS situation too much.
Quote:
I think you are simplifying the entire AHRS situation too much.
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.
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.Sam Buchanan said:It seems I was definitely incorrect in stating that you were simplifying the EFIS application.
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
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
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.
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!!