16.4 Update Feedback

[CRW]

Any feedback from the installation of his update?
I have been waiting for this and plan to install it tomorrow but I am very interested in hearing from someone who has done the install and what you have experienced. Hopefully no new "bugs" will show themselves with this update.

Best regards,
Chuck

 

[RV8JD]

I have not loaded or flown v16.4.0, but I am flying a "Release Candidate", v16.4.RC0.9553 (for the Classic models) awhile back. Some problems fixed and no new problems noted. It included the fix for the aggressive autopilot roll behavior and the fix for the Tach time issue when the ignition sources used different pulse/revolution settings. See this post for what I found:

https://forum.flydynon.com/threads/...-like-a-fighter-pilot.14071/page-4#post-83737

 

[jsalak]

Did the 16.4.0 upgrade today and will test fly it tomorrow. Looking forward to not hearing "BANK ANGLE" anymore. Hopefully I can get a better AP tune with the new guide, the altitude hunting in any kind turbulence is getting old (hysteresis in pretty bad). Not sure why the AP allows such large VSI numbers that contribute to the overshooting in both directions.

 

[Marc_J._Zeitlin]

...Hopefully I can get a better AP tune with the new guide, the altitude hunting in any kind turbulence is getting old (hysteresis in pretty bad). Not sure why the AP allows such large VSI numbers that contribute to the overshooting in both directions.

THIS. I was very pleased to see that there's now a way to take the play in the system into account, although I don't know that the hysteresis is a function of my pitch control system (there's very little play) or a software issue. I've played with the VSI gain to no avail. It'll hold altitude great when smooth - within 5 ft - but in turbulence (and it doesn't have to be bad turbulence - just light chop) I can hand fly within 20 ft., while the AP will oscillate a few hundred ft. No safety issue, but very annoying, and can be nausea producing. Here's hoping...

 

[jsalak]

Went out and flew for a couple of hours today to check out the 16.4 SW. No improvement in the pitch control with a light chop, I was seeing 700-800 FPM in the VSI and speed changes of 10-15 knots with the pitch up and down hunting around the altitude bug. I tried some of the adjustments suggested in the AP tuning guide with no apparent improvement. Maybe it's time to reset to the defaults numbers and start over on the tuning. Flew a coupled approach (LP+V) with the IDF540 and did not see any issues with VNAV holding the glideslope.

 

[Solana]

Went out and flew for a couple of hours today to check out the 16.4 SW. No improvement in the pitch control with a light chop, I was seeing 700-800 FPM in the VSI and speed changes of 10-15 knots with the pitch up and down hunting around the altitude bug. I tried some of the adjustments suggested in the AP tuning guide with no apparent improvement. Maybe it's time to reset to the defaults numbers and start over on the tuning. Flew a coupled approach (LP+V) with the IDF540 and did not see any issues with VNAV holding the glideslope.

Are you sure you don’t have a broken shear pin? Or maybe a cracked capstan in the pitch servo? You can put your autopilot on altitude hold (in the hangar) and see how much play you have when you push the elevator up and down.

 

[jsalak]

Are you sure you don’t have a broken shear pin? Or maybe a cracked capstan in the pitch servo? You can put your autopilot on altitude hold (in the hangar) and see how much play you have when you push the elevator up and down.

I went out today in smooth air to try some more adjustments, the Lost Motion Compensation was interesting setting it to 2 resulted in a short period pitch oscillation, 1 reduced it some, and zero stopped it. I already reduced the G-Error-Limit and G-Error-Gain with not much of an observable change in some light bumps. Perhaps a better approach would be to start near the minimum on the sensitivity for gains other than the glideslope related items. The stabilator on my RV-12 is very sensitive to minor inputs and it appears the AP reaction to minor turbulence is just over controlling it, somewhat similar to a PIO. The new AP Tuning Guide is a lot more useful than the previous version in defining what the coefficients are.

 

[jsalak]

A follow-up on various AP pitch settings, I set all of the non-glideslope pitch values to something close to the minimums and flew in some light chop to see the effects. Still doing a bit of altitude hunting with over and under shoots, however the VSI did not show any numbers higher than 300-400 FPM, airspeed was also more stable within a +/- 5 knot range. The only odd item I noted was being 20 ft above the altitude bug and the AP pitched up and climbed 60 ft before starting back down to the set altitude. I am not sure what the realistic limit is for AP pitch / altitude holding in light to moderate chop, but it is a change in the right direction.

 

[campipilot]

Did the 16.4.0 upgrade today and will test fly it tomorrow. Looking forward to not hearing "BANK ANGLE" anymore. Hopefully I can get a better AP tune with the new guide, the altitude hunting in any kind turbulence is getting old (hysteresis in pretty bad). Not sure why the AP allows such large VSI numbers that contribute to the overshooting in both directions.

Is it true it will get rid of bank angle alerts? I’ve been looking in the system menus for a way to turn those off to no avail….what a pain and distraction in our sporty planes that can fly aero.

 

[RV8JD]

Is it true it will get rid of bank angle alerts? I’ve been looking in the system menus for a way to turn those off to no avail….what a pain and distraction in our sporty planes that can fly aero.

Yes, v16.4.0 removed the bank angle alert.

The bank angle alert started with v16.3, as of May 2022.

"Bank Angle - The autopilot is engaged, and the bank angle of the aircraft is greater or equal to set Bank Angle Limit plus 5 degrees. The alert is cleared when the autopilot is disconnected, or the bank angle is less than the set Bank Angle Limit. The audio alert repeats every 5 seconds until cleared."

If still flying the older firmware versions, press the AP disconnect button twice within one second, to turn off the FD and the alerts (including bank angle) that go with it.

From the User Guide:

"Disengaging the Autopilot
When engaged:

• Press the autopilot disconnect switch once to disengage the servos while leaving the flight director active with all active and armed modes unchanged. Press the autopilot disconnect again within 1 second to turn the flight director off (regardless whether the autopilot was engaged).