Dynon D-1 Pocket AHRS/Smart Phone Apps Pireps

[dcrogers11]

Has anyone used the Dynon D-1 pocket AHRS and if so, how close did it follow your actual attitudes, etc.  My thoughts are that it would be a nice inexpensive alternative backup to my aging steam guages.  Although not approved for "permanant" installation in certiified aircraft, there are no laws that say it can't be placed on my upcoming panel upgrade in a space that could be left for it to be semi-permanantly (industrial velcro) attached. 

 

I wish that the FAA could wise up and allow the use of their D-6 or D-10 to occupy a place permanantly in the panel as long as it did not replace the certified guages.

 

As far as smart phone apps, what are some that are out there that have had good reviews. 

 

Don 

[gsengle]

The D1 is pretty close to the same thing if you dock it...  I love mine as a backup, and I have it docked in the panel as a backup...

 

I wouldnt trust a smart phone app without an external attitude reference system.  An iPhone doesnt have a gyro, it just has accelerometers...  Those apps that just rely on the iPhone hardware don't work.

 

g

[dcrogers11]

When you say that you have better luck with it docked, are you referring to the 3 1/8" hole adapter that comes with it and mounted in the panel?  Have you had to use the external antenna?  Thanks.

[gsengle]

I find my cockpit too tight to use any of the mounts for it, and I like it close to my instrument scan...  Here is a picture.  I've found it works great with no need for the external antenna...

 

g

 

 

[gsengle]

I find my cockpit too tight to use any of the mounts for it, and I like it close to my instrument scan...  Here is a picture.  I've found it works great with no need for the external antenna...

 

g

 

I mean any of the ram mounts...  the panel dock works great if you have the space - see pic...

[AndyFromCB]

Actually, IPhone 4 on has 3 mems gyros, probably at $2 a part more accurate than what Garmin or Aspen puts in their gear ;-) We use them in tractors with GPS and a starting point with a sub inch accuracy. Yes, sub inch. Down to a millimeter. They detect movement down to milemeters.

[FloridaMan]

I wouldn't trust anything, even as a backup, that used the iPhone's sensors, GPS or as a display (not that the sensors are bad, but as an iOS developer, I have seen it report data very inaccurately at times, which may be software related). 

 

I have a Dynon D1 as a backup and it occasionally reports mildly incorrect attitude information. I'm working with Dynon at the moment attempting to diagnose the issue. 

[carusoam]

Great customer feedback Antares!

Does the iPhone5 use waas? My iPad 1 needs an external antenna for waas accuracy.

Mike a I ran an experiment.... My iPad had us running next to the runway. Not a very good demonstration of my toys...

Best regards,

-a-

[FloridaMan]

I have an iPhone 4S and have collected some data samples while flying with it. I have seen it report that it has good accuracy and, at the same time, be continuously more than 1000 ft off in altitude. Its altitude almost always lags when coming in to land, and when it would be most critical, such as it often reports altitudes 1000 feet higher than actual when you arrive in the pattern after flying at higher altitude. It appears accurate in flight, but during the phases where altitude accuracy would be most critical, you're usually more focused on flying the airplane than you are verifying the altitude's accuracy of your device and might not have noticed it. 

 

As for the app-based backup indicators, they may appear to work fine while dicking around with them on the ground. Go do some steep turns and then fly straight and level and then see where the phone shows your attitude. 

[aviatoreb]

I have an iPhone 4S and have collected some data samples while flying with it. I have seen it report that it has good accuracy and, at the same time, be continuously more than 1000 ft off in altitude. Its altitude almost always lags when coming in to land, and when it would be most critical, such as it often reports altitudes 1000 feet higher than actual when you arrive in the pattern after flying at higher altitude. It appears accurate in flight, but during the phases where altitude accuracy would be most critical, you're usually more focused on flying the airplane than you are verifying the altitude's accuracy of your device and might not have noticed it. 

 

As for the app-based backup indicators, they may appear to work fine while dicking around with them on the ground. Go do some steep turns and then fly straight and level and then see where the phone shows your attitude. 

 

It is well known that the built in GPS are lower quality than an aviation GPS.  With an external GPS - I use the bad elf, then I am confident that the gps signal is as of high quality. The accelerometers are mems devices etched into a chip. I do not know, but I am presuming that the quality control behind this process used by Apple is no different that the quality control of the device used by Dynon.

 

As far as iphone as a display device - it can be argued that a device that is mass produced with an operating system that is well known and tested is to be trusted as much or more than a in-shop operating system like that on the Dynon.

 

The software chosen is important, and I am quite confident in the company that produces Xavion, which is Laminar Research (creators of X-Plane).

 

I am not saying that Dynon's handheld is excellent, and I am sure it is and I would be happy to use it, but I am also sufficiently confident in the iphone with external gps running xavion specifically.

[FloridaMan]

From the Xavion website: http://www.x-avionics.com/xavion/development-and-testing/ 

 

 

 

The iPad has its own (solid state!) gyros, accelerometers, and (in some models) GPS receiver. We have found that the above internal sensors on the iPad are just barely good enough for emergency or experimental use. The gyros and accelerometers are good enough to track pitch and roll in flight to within about 5 degrees if your maneuvers are smooth and the bank angle is kept to within about 60 degrees or so. If you maneuver more aggressively or exceed 60 degrees in bank, you may see larger errors in pitch and roll display. In non-metal airplanes such as the Columbia-400, the internal GPS on the iPad has been shown to be adequate to receive signal the vast majority of the time, but in metal airplanes such as the Cessna 172, an external GPS of some sort is really needed to get a reliable GPS signal to the iPad.

 

 

My point is not in the quality of the sensors, or that of the software in itself. The complexity of what's going on within the iPhone is significantly greater and it was designed with goal of performance and versatility. Even Xavion's website suggests using an external sensor such as the Levil AHRS module. How long does it take Xavion to launch on your iPad? And how long does it take to reboot your iPad if it locks up? Your confidence in the company is your confidence in one guy, Austin Meyer, the guy who wrote the product. There was an article about him in Popular Science years ago. He came home drunk one night and accidentally posted the source code to X-Plane. While there's a little ad-hominem in that argument of mine, and I'll be the first in line to defend a product developed by a single person or a small, highly talented group, but I would not want it to be anything but something that can enhance my own situational awareness. 

[aviatoreb]

From the Xavion website: http://www.x-avionics.com/xavion/development-and-testing/ 

 

 

My point is not in the quality of the sensors, or that of the software in itself. The complexity of what's going on within the iPhone is significantly greater and it was designed with goal of performance and versatility. Even Xavion's website suggests using an external sensor such as the Levil AHRS module. How long does it take Xavion to launch on your iPad? And how long does it take to reboot your iPad if it locks up? Your confidence in the company is your confidence in one guy, Austin Meyer, the guy who wrote the product. There was an article about him in Popular Science years ago. He came home drunk one night and accidentally posted the source code to X-Plane. While there's a little ad-hominem in that argument of mine, and I'll be the first in line to defend a product developed by a single person or a small, highly talented group, but I would not want it to be anything but something that can enhance my own situational awareness. 

 

Antares, are we disagreeing?

 

Please see my opinion on backup instruments on a parallel thread:

http://mooneyspace.com/topic/2806-turn-coordinator-or-second-attitude-indicator/page-3

I have two certified attitude indicators, with different kinds of power sources.  For me xavion is a third level backup if that is what it is.  But rather I am describing it as synthetic vision for situational awareness.  That is different from a primary attitude device.  Dynon is not a synthetic vision device.  It is an attitude device.  But there is overlap in function.

 

But to your main point, let me say I have a great deal of software engineering experience from many consulting jobs over the years.  This is not a huge job like building a windows operating system that requires dozens or hundreds of software engineers.  A job that can be done by one person is sometimes done worse by many people.  This is my experience in the realm of software engineering.  

 

But not to say that Dynon is going to be more stable because it comes from a company.  I don't know much about that company, but I can say that I have had my garmin 396 freeze.  I have heard from my hangar neighbor that his aspen has had a software freeze.  I have heard tail of Garmin G1000 software errors causing big red x's over critical "instrument" displays.  Even big faceless companies with lots of software engineers make big errors.

 

 

Actually, I was really surprised at first to learn how sometimes even big companies have teams of software engineers but critical components are worked by one guy - when I was a grad student as an intern at the phone company, US West, I ended up writing a very large piece of code used in operations at the phone company.  It replaced a piece of code that was legacy and had been modified and modified for like a decade and no one really knew what it did.  Several of us were supposed to do the job but we weren't very organized on how to distribute the job and so I ended up doing the full thing.  In other consulting jobs, I have learned this happens a lot.  

 

I don't take the fyi about accelerometrs and built in gps to the ipad as a warning not to use their product and to go by dynon because it is better and more stable and more accurate.  Far from it.  I take the warning as honest, and a warning to carefully choose the sensors depending on what is the mission it is intended to satisfy.  For situational awareness (svt view) I am happy with built in accelerometers and external gps.  If I did not have redundant mechanical certified attitude indicators, I would a) get a second certified attitude indicator, but at least get a iLevil.  That said, I am sure Dynon is a fine instrument.  But I am more confident in the stability of the iPhone for now - on principle - and I am quite convinced it is up to the computational task, easily, but I say that fully admitting I have never touched a Dynon, but just my experience with garmin.

[FloridaMan]

I don't think we're disagreeing at all; I was, umm, elaborating on things a bit to highlight shortcomings and using your post as a prompt. As I said, I've seen my Dynon do strange things and I'm working with them at the moment in trying to diagnose the cause. Even with certified instruments, I've had two vacuum pumps fail in the past couple years. 

 

I wonder if that CFIT video of the Bonanza where the guy was flying with the 696 was the result of bad GPS data. 

 

This one: http://www.flight.org/blog/2009/09/30/bonanza-cfit-video/

[aviatoreb]

I don't think we're disagreeing at all; I was, umm, elaborating on things a bit to highlight shortcomings and using your post as a prompt. As I said, I've seen my Dynon do strange things and I'm working with them at the moment in trying to diagnose the cause. Even with certified instruments, I've had two vacuum pumps fail in the past couple years. 

 

I wonder if that CFIT video of the Bonanza where the guy was flying with the 696 was the result of bad GPS data. 

 

This one: http://www.flight.org/blog/2009/09/30/bonanza-cfit-video/

 

I think we are agreeing.  If that (almost) CFIT in the video is a result of anything it is a result of the decision to scud run in the mountains and if there was bad gps data, then that is only supporting circumstances.

 

Your new avatar picture is funny - who is it?  Can you see my avatar picture?  My own picture is not viewing to me.

[carusoam]

EB,

Your avatar went MIA.

-a-

[danb35]

Your new avatar picture is funny - who is it?

 Looks like He-Man to me...

[aviatoreb]

 Looks like He-Man to me...

 

I like your avatar better danb35

[Bennett]

Back around September or so last year I posted a PIREP about the Dynon D-1.  Now that I've had it for almost six months I can say that I find it stable, and the horizon is always in agreement with my AIs.  The GPS (ground) speed, not surprisingly, is in agreement with with my other GPS boxes, as is the Heading (really GPS track), and the VSI tape is in good agreement with my steam gauge VSI.  The altitude is GPS derived, and is not in perfect agreement with the other GPS altitudes, but not that much different. Of course, you cannot set a barometric figure into the D-1.  Nevertheless, having glanced at it all these months, I would definitely use it in an emergency to descend through a layer, giving a good deal of latitude to the altitude shown.  Provided that the pitot static instruments still worked - airspeed, altitude, and VSI, plus a compass, the D-1 could prove to be highly valuable for its display of the horizon and for its slip indicator.  I had the Dynon SkyvIew glass panels in my former LSA, and they were really good instruments - sort of a poor man's G1000, but better in a few ways. Dynon, as a company, was always helpful, and responsive to my questions and suggestions.  There is little wonder that they are so dominant in the LSA and experimental communities.  For abut $10,000 you can buy two 7" glass screens, (10" available as an option), each with their own AHRS, and each can act as a MFD, EFIS, or combination device.  That price would even include Synthetic Vision, and an integrated two axis autopilot, and at least one backup battery.  I understand that they are now working towards building radios, and the capability to add ADS-B features.  I like my Garmin boxes, but the expense delta is staggering. The D-1 is very much like their smallest panel EFIS (D-6) which is plumbed in the pitot static system). Too bad the feds would never allow this unit to be put into our panels.

 

Also the Dynon Skyview system includes an AOA indicator (but you have to add their AOA/Pitot tube option).  Worked great.

[fantom]

That is a great LSA panel, Bennett. Better than most GA certified planes, most likely.

[Marauder]

Back around September or so last year I posted a PIREP about the Dynon D-1. Now that I've had it for almost six months I can say that I find it stable, and the horizon is always in agreement with my AIs. The GPS (ground) speed, not surprisingly, is in agreement with with my other GPS boxes, as is the Heading (really GPS track), and the VSI tape is in good agreement with my steam gauge VSI. The altitude is GPS derived, and is not in perfect agreement with the other GPS altitudes, but not that much different. Of course, you cannot set a barometric figure into the D-1. Nevertheless, having glanced at it all these months, I would definitely use it in an emergency to descend through a layer, giving a good deal of latitude to the altitude shown. Provided that the pitot static instruments still worked - airspeed, altitude, and VSI, plus a compass, the D-1 could prove to be highly valuable for its display of the horizon and for its slip indicator. I had the Dynon SkyvIew glass panels in my former LSA, and they were really good instruments - sort of a poor man's G1000, but better in a few ways. Dynon, as a company, was always helpful, and responsive to my questions and suggestions. There is little wonder that they are so dominant in the LSA and experimental communities. For abut $10,000 you can buy two 7" glass screens, (10" available as an option), each with their own AHRS, and each can act as a MFD, EFIS, or combination device. That price would even include Synthetic Vision, and an integrated two axis autopilot, and at least one backup battery. I understand that they are now working towards building radios, and the capability to add ADS-B features. I like my Garmin boxes, but the expense delta is staggering. The D-1 is very much like their smallest panel EFIS (D-6) which is plumbed in the pitot static system). Too bad the feds would never allow this unit to be put into our panels. Also the Dynon Skyview system includes an AOA indicator (but you have to add their AOA/Pitot tube option). Worked great.

Bennett -- will you adopt me? I'm housebroken and promise I will never ask for the car keys (only the airplane ones). I love the stuff you have done to your planes!

[FloridaMan]

Bennett, 

 

Have you ever experienced this? Watch start from the 0:40 to the 1:00 mark:

 

[Bennett]

Interesting video - 40 to 100 seconds.  No, I have not seen anything of this magnitude.  Occasionally, I have seen a small, 3-5 degrees or less, horizon tilt, but it has only lasted a couple of seconds, and not more than once a flight, if that. The "tilting" was gradual, as was the recovery, and at this magnitude, should not pose a problem for a descent through clouds in an emergency.  The pitch indication has been rock steady. The slip indicator is sometimes in minor disagreement with the Mid-Continent "Lifesaver": electric AI ball, but never by very much. To me, the D-1 is a back-up type instrument, and for the price, I would not expect it to be as reliable and steady as the "Lifesaver" (or Trilogy, if I could afford it).  The Dynon Skyview screens were, however, really steady and I think they make great primary instrumentation. 

 

I assume you are using the external GPS antenna with the panel mount.  I don't know why, but I have not had great luck with the external GPS antennas, and I do not use them for my 796 or D-1.  In my applications they work just fine without them, and I hate the clutter on the glareshield.  I have even stopped using the Bluetooth antenna for my iPad Mini (3G model), as for my purposes, that unit works OK without the external antenna. 

[Bennett]

Thanks for the kind words about the LSA panel.  Creating that panel was more fun than flying the LSA.  Nicely built airplane, but too light for me. Landing it in strong crosswinds was far more difficult than doing so in my old Cessna 120, and it was not a machine for cross country travel in most weather conditions. Nothing like a Mooney, and I'm glad I'm back in the fold.