AP with skyview ground test

[jselesi1]

Hello!
AP calibration and AP Test OK.
On the ground with engine off, I tried to engage AP with disengage button in CWS mode (button function set to, hold to engage YES, enable broken line detect NO and CWS mode HOLD HDG/ALT).
The result was AP servos goes to maximum turn and produce very hard sound.
I expect the servos do nearly nothing because of HOLD HDG/ALT?!
Why its happening?

 

[swatson999]

I had the same thing...a loud "thump" at the end of travel? Figured it was because there's no actual aircraft response and the servo just keeps trying to climb or descent but the plane is doing nothing in response on the ground.

That was only for the pitch servo, roll servo not installed yet...but convinced me to not do any more "testing" until everything is in and we're flying.

 

[dynonsupport]

Normal. When engaged on the ground, the AP basically tries to "fly" the airplane, and never gets to where it wants to go (even if it's syncing on engage, it's trying to make small corrections, which it can't make). So it just keeps adding "a little more" stick, and eventually hits the control stops. At that point, the servo "slips", which, when you don't have engine noise masking it, can be loud in some installations, as it gets to use the whole aircraft as a big sub-woofer.

 

[swatson999]

Good to know. Startled me when I heard it.

Follow-up question...is there any recommended ground test of the a/p on a Skyview? I'm correlating the process to a sort of typical Cessna or Piper checklist, which would have you engage the autopilot and then command a left and right roll with the bug on the DG and ensure you can overcome it, then hit A/P D/C. Come to think of it, I've never had a checklist that had you check pitch a/p control

What are most people doing, or what does Dynon recommend for a pre-takeoff a/p check, using Skyview? How would you test it during run-up to make sure it's nominal?

 

[jselesi1]

even if it's syncing on engage, it's trying to make small corrections, which it can't make

Where is a 'Sync on Engage' in Setup Menu?

As Steve W. sad about ground test, I know only the 'AP test' provided in AP setup menu. Is there something else?

 

[dynonsupport]

"Sync on Engage" means that the bugs will be snapped to approximately the current heading/alt when you engage the ap. From page 8-31 of the FlightDEK-D180 manual:

..."ON ENGAGE: The HDG and ALT bugs are synchronized to the heading and altitude values each time the AP is engaged (via the AP button on the AP74 or in the EFIS AP menu). This is the default setting....."

There's an option SETUP > AP > SERVO TEST option in our D10/D100 series products.

 

[swatson999]

There's an option SETUP > AP > SERVO TEST option in our D10/D100 series products.

And on SV?

 

[jselesi1]

"Sync on Engage" means that the bugs will be snapped to approximately the current heading/alt when you engage the ap. From page 8-31 of the FlightDEK-D180 manual:

..."ON ENGAGE: The HDG and ALT bugs are synchronized to the heading and altitude values each time the AP is engaged (via the AP button on the AP74 or in the EFIS AP menu). This is the default setting....."

There's an option SETUP > AP > SERVO TEST option in our D10/D100 series products.

     I am new on Forum and sorry if I post on wrong place. I started the topic with name 'AP with skyview ground test'.
In you reply you talk on D180, D10/D100 but no about Skyview.
Please tell me:
I need to be sure that after starting AP over CWS mode (with disngage butto hold more than 2sec and release it) it will maintain the current course and the altitude (I have servo on both axis) regardless the position of Bugs.
For that I set disengage button function to, hold to engage YES, enable broken line detect NO and CWS mode HOLD HDG/ALT.
It is enough or not (or I must set something like "Sync on Engage")?

 

[dynonsupport]

Ah, OK. In that case:

The setting HOLD HDG/ALT means that when CWS is used (when the autopilot is ADLREADY engaged) that the AP, after the CWS/disengage button is released after holding it to use CWS mode, keeps holding the heading/altitude that you've manually steered to during the manual steering you performed while in CWS mode.

What determines whether the bugs are synchronized to the current bugs upon INITIAL engagement is the state of the SYNC button which is under each axis' menu in the regular AP menu.

Again, on the ground, even when the bugs looked perfectly synced, internally, the autopilot is trying to make small corrections (which it can't, because it cant change heading or altitude on the ground), and so even when everything is seemingly synchronized, the stick may be moved to the control stops by the autopilot. This is normal on the ground.

 

[jselesi1]

It is perfectly clear.
Thank you Dynon Support.