The Age old question.

Hi,Looking at a panel upgrade , narrowed it down to Garmin G3X or Dynon Skyview HDX , which has the best autopilot ?

Python said:

Hi,Looking at a panel upgrade , narrowed it down to Garmin G3X or Dynon Skyview HDX , which has the best autopilot ?

Click to expand...

As everybody pops their popcorn, I'll just say that I really like my HDX, particularly the:
networked design;
screen and menus' layout;
ability to customize info and displays;
the importation of ADS-B traffic, weather, PiReps, and TFRs;
the autopilot interface;
how it communicates seamlessly with my Garmin GTN650xi through the ARINC module for IFR flight;
and tech support from Dynon.

It's a very personal preference, but I keenly prefer the HDX screen layout over the Garmin's.

Have the Dynon servos changed lately? That is one important consideration in evaluating an autopilot. I'm running Dynon servos off my D180 (and HS34) and despite upgrading to the biggest servo available, it still will not keep the nose of my Rocket on the horizon in a 180 degree turn. No matter what setting I use, it just does not have the muscle to maintain altitude. Also, the Dynon servo's geartrain is always engaged, so there is always the drag of the servo even without the AP engaged. Another Rocket buddy had the same problems with his Dynon setup and switched to G5 based Garmin AP and the performance issues went completely away. Night and day improvement, he reports.

I'm less concerned with the user interface than I am about the system making the airplane go where its supposed to.

I'm switching to Garmin.

Only used Dynon AP for the first 200 hours on my 6 and it seemed to perform very similar to the GRT that replaced it. It was several years ago, so memory could be hazy. One plane now has a GRT AP (similar servo design as Dynon) and the other Garmin. THe Garmin SW does a MUCH NICER job than the GRT in all areas, especially coupled approaches, and I like that the garmin servo has 0 resistance when not engaged.

Larry

To add one data point, the HDX system in my -7 has been flying for 225 hours and works as advertised. The "drag" on the stick is imperceptible in flight and the system will only display a servo slip annunciation is moderate turbulence Adding an AP to an existing HDX costs less than $2K (Garmin might be a little more ... ) A sheared torque pin costs about $0 to replace if you ask nice. Dynon customer service is solid.

Michael, if your servo can't cut the mustard in you application, and assuming your geometry is correct, you may have the wrong one installed. The SV-32 servo I use is rated at 36in/lb or torque, and the "big" one tops out at 72! There's another one in the middle, seems like one would solve the problem.

Not associated with Dynon, just sayin'

Cheers

My old buddy has Dynon AP with legacy Skyview in the Cozy MKIV we built. Despite hours in the air fooling with the settings, the thing overshoots a turn every time and can not follow a heading even close and hunts up and down for altitude. Not much help from Dynon. They suggested replacing the elevator servo with their more powerful one. Did that and still hunts up and down.

I started out with a pair of the SV-32 servos and Dynon recommended the biggest one for the pitch. Going big helped the issue but still delivered unacceptable performance in a prolonged turn. And like 9GT's experience, it is constantly hunting for altitude. In dead calm air it will settle down to +\- 100 feet, but still annoying. I attributed this to the long abandoned development of the legacy series AP programming, but maybe not.

9GT said:

My old buddy has Dynon AP with legacy Skyview in the Cozy MKIV we built. Despite hours in the air fooling with the settings, the thing overshoots a turn every time and can not follow a heading even close and hunts up and down for altitude. Not much help from Dynon. They suggested replacing the elevator servo with their more powerful one. Did that and still hunts up and down.

Click to expand...

same experience here. Not annoying, but noticeable. Absolutely none of that with the garmin. The garmin servo has infinite resolution on the servo and the Dynon and GRT are stepper motors with a number of finite positions that can be set. This leads to hunting as it goes back and forth between two finite positions. You can actually observe the stick going back and forth between the steps. Kudos to Garmin for creating a better designed servo. WIth the stepper motors, you can go to the lowest hole on the arm to reduce the effect, but this also reduces the travel.

Larry

Maybe I just got lucky with my install... pure luck

Toobuilder said:

Have the Dynon servos changed lately? That is one important consideration in evaluating an autopilot. I'm running Dynon servos off my D180 (and HS34) and despite upgrading to the biggest servo available, it still will not keep the nose of my Rocket on the horizon in a 180 degree turn. No matter what setting I use, it just does not have the muscle to maintain altitude. Also, the Dynon servo's geartrain is always engaged, so there is always the drag of the servo even without the AP engaged. Another Rocket buddy had the same problems with his Dynon setup and switched to G5 based Garmin AP and the performance issues went completely away. Night and day improvement, he reports.

I'm less concerned with the user interface than I am about the system making the airplane go where its supposed to.

I'm switching to Garmin.

Click to expand...

Hmm. My Rocket uses the SV-32's (the lowest torque available) and has no problem keeping level in turns. Since virtually all Rockets are 'custom built', it may just because of control geometry in your aircraft.

One thing I have is autotrim (my own design, but it applies to autotrim in general), so it continuously tries to neutralize the servo torque. That may be the difference.

Vern

I have an RV-8 (1292 Hobbs hours) with a SkyView Touch and Dynon's autopilot with SV32 servos. It works well and I am quite happy with it.

Dynon continues to improve it's A/P, as seen in the HDX's SW release notes here:


Dynon has also improved the ability to tune the autopilot with this updated autopilot tuning guide for the latest SW version:


Although you can control the autopilot via the HDX screen, install the Autopilot control panel. The autopilot control panel is also a full featured dual-axis trim controller. It can control your electric pitch and/or roll trim motors, replacing the relay decks normally used.

The autopilot control panel also provides autopilot Auto-Trim. The SV-AP-PANEL can keep the the aircraft in trim while under autopilot control. This eliminates the need for the pilot to manually actuate their trim to follow the autopilot’s built-in trim advice.


I have found Dynon's support to be very good. Several years ago my pitch servo shear screw failed. Dynon introduced a new design (stronger) shear screw that was available late in the 1st quarter of 2017. It was a redesign due to premature fatigue failures of the old design screw during normal use. Dynon sent out a shear screw replacement kit with the new screw gratis. No problems with the new shear screw since.

I did have one problem with my SkyView Touch screen, and even though it was out of warranty Dynon repaired it quickly and at no charge. I live near Dynon's facility and I was able to drive it down on a Monday and pick it up on Thursday. No problems with it since.

Dynon is rock solid for approaches

Hey Michael,

You would do well to add the Dynon Linear actuator as used in the RV-10's

https://shop.dynon.com/products/rv-...nting-kit-package?_pos=1&_sid=10a04ef09&_ss=r

With the amazing amounts of fine adjustments available with the gain settings there will be no problems adjusting out any hunting.

I have used this set up on all the RV-10's and RV-14's I work with.

This set-up is so stable at all speeds or approaches.

Just for fun I was doing coupled approaches at 737 approach speeds, this included a hold and missed, and you could have sipped tea from a teacup it was so smooth.

I fly and work with G3X systems often but really like the user interface of the Dynon.
I will say that the Garmin Autopilot head is my favorite and wish Dynon would make a rack mounted AP Knob panel. I made my own hybrid to fit my panel but would rather a factory unit.

Best Autopilot

The original question was "Which has the best autopilot"

Thinking about the responses, there are those who have no issues with their Dynon and those that have some gripes and the observation of the stepper motors having only discrete positions. On the other hand, there are none that complain about their Garmins. That said, my Garmin's performance is nothing short of stunning - no hunting, exceptional accuracy and totally smooth operation regardless of speed or altitude. Watching a transition from intercept to flying an approach is a delight. And no, I don't work for Garmin!

Very happy with the Skyview autopilot. Servos work fine. Working in my -7 in IFR and VFR for many hours over the last ten years or so.

Did the OP mean to restrict himself to efis-based autopilots? e.g. I use a GRT Hx to control/drive a Trio Pro (with autotrim), and I cannot imagine any better performance, from just after takeoff to just prior to touchdown. Yes, it costs about $1K more than an efis based unit. But, it can also fly the airplane, including an LPV approach, following a complete EFIS failure.

1200 hours and counting on my Dynon, the autopilot is flawless. It does need some tweaking with the settings to get it right, but once you dial it in (use the Dynon AP tuning guide) it should fly like it's on rails. Mine is good enough that I am happy to use it flying IMC approaches to minimums, it's that tight.

Not too long ago Martin Pauley on youtube did a very well thought out report comparing AP's and what he chose. Might be useful as food for thought

WHich AP

Blw2 said:

Not too long ago Martin Pauley on youtube did a very well thought out report comparing AP's and what he chose. Might be useful as food for thought

Click to expand...

This is a very nice video, and focused on a certified installation. That said, the certified Garmin G500 components are the same stuff we get to pay half for in our experimentals. And yes, look at the controller layout for the Garmin - it is so well partitioned and so intuitive. And yes, there is the built in automatic trim function, which works great.

Finally, if you go this route, consider the Yaw dampener. I started out without it, and after a ride in a friend's -10, I had to have it and added it. Makes a big difference in turbulence!