I am extremely frustrated with my new Dynon Auto Pilot system not working properly. I installed it this past spring and religiously followed the set up instructions. In the air, it simply will NOT work properly when it comes to capturing and holding heading. I have the "old school D-100 with software version 5.4 installed. Altitude hold works perfectly...maintains altitude rock solid. Increase and decrease altitude without issues levelling off and capturing the new altitude rock solid but the system simply will NOT capture and hold a heading. Here is a summary of my very frustrating flight this past Saturday June 4thy (6 weeks now since I first started flying with the AP74 system) And before you ask, I did a compass calibration at the same time the aircraft compass was swung in early May.
AP74 and 2 servos powered up on initial startup. Takeoff and climb on a northwesterly heading of 310 Degrees. Levelled of at 5,000 ASL in very smooth, ripple free air. Trimmed the aircraft for straight and level flight and flew virtually hands free for several minutes. Pushed the HDG and ALT buttons on the AP74 and flew several more minutes straight and level. Swallowed hard and engaged the autopilot by pushing the A/P button on the AP74. The altitude did not budge BUT the airplane wallowed in shallow left and right turns about 5 degrees each side of the heading I was flying. Then after 2 or 3 seconds, the plane rolled into a 30 degree left turn ! I let it go and the plane did a complete 360 D turn left, and went right past the original heading I was flying. Altitude never varied. I then pushed the value knob and turned it to the right to get an easterly heading. The plane rolled right and flew past the new heading of 90 D by about 25 Degrees, then rolled left, again past 90 by 20 degrees, then left, then right..until I pushed the "disconnect" button on my control stick. I want to also note here, that the control wheel steering also Does Not Work...I'll get to this a little later. I turned the airplane north again, but as I was running out of land to fly over (Lake Huron) I turned south on a heading of 190 Degrees. I engaged the AP once again but this time I held !! After several minutes I pushed the value knob and dialed a new heading 20 degrees to the west. The plane hesitated for a few seconds, then rolled and captured the new heading but not before flying past it about 5 degrees, then left, then right in slowing increments. I dialed in a 30 degree westerly heading and the same thing happened. OK, now what! I pushed the AP button for the 180 degree emergency turn and the plane rolled left but not smoothly..a roll of 30 degrees or so, then level, then another 30 degree roll, then level and so on for a 180 degree reversal of course...not a smooth turn by any means !
I tried CWS once again..no joy there...it just turned off the AP..So I resumed control, turned south and tried again..this time the plane flew level for a short time but always seemed to be hunting for a heading..rolling left and right in quick succession. Enough of this...I disengaged the HDG but maintained altitude with the AP, using it to descend to my airports pattern height of 2200 ASL., I then landed and taxied back to the hangar. At the hangar, with the engine still running, I engaged the AP and it seemed to hold heading just fine, a few ticks of the roll servo, none from the pitch servo and the CWS worked when I held the disengage switch down on the control stick ...something it would NOT do in the air !
So...what is wrong? How can I fix it? :'(
AP74 and 2 servos powered up on initial startup. Takeoff and climb on a northwesterly heading of 310 Degrees. Levelled of at 5,000 ASL in very smooth, ripple free air. Trimmed the aircraft for straight and level flight and flew virtually hands free for several minutes. Pushed the HDG and ALT buttons on the AP74 and flew several more minutes straight and level. Swallowed hard and engaged the autopilot by pushing the A/P button on the AP74. The altitude did not budge BUT the airplane wallowed in shallow left and right turns about 5 degrees each side of the heading I was flying. Then after 2 or 3 seconds, the plane rolled into a 30 degree left turn ! I let it go and the plane did a complete 360 D turn left, and went right past the original heading I was flying. Altitude never varied. I then pushed the value knob and turned it to the right to get an easterly heading. The plane rolled right and flew past the new heading of 90 D by about 25 Degrees, then rolled left, again past 90 by 20 degrees, then left, then right..until I pushed the "disconnect" button on my control stick. I want to also note here, that the control wheel steering also Does Not Work...I'll get to this a little later. I turned the airplane north again, but as I was running out of land to fly over (Lake Huron) I turned south on a heading of 190 Degrees. I engaged the AP once again but this time I held !! After several minutes I pushed the value knob and dialed a new heading 20 degrees to the west. The plane hesitated for a few seconds, then rolled and captured the new heading but not before flying past it about 5 degrees, then left, then right in slowing increments. I dialed in a 30 degree westerly heading and the same thing happened. OK, now what! I pushed the AP button for the 180 degree emergency turn and the plane rolled left but not smoothly..a roll of 30 degrees or so, then level, then another 30 degree roll, then level and so on for a 180 degree reversal of course...not a smooth turn by any means !
I tried CWS once again..no joy there...it just turned off the AP..So I resumed control, turned south and tried again..this time the plane flew level for a short time but always seemed to be hunting for a heading..rolling left and right in quick succession. Enough of this...I disengaged the HDG but maintained altitude with the AP, using it to descend to my airports pattern height of 2200 ASL., I then landed and taxied back to the hangar. At the hangar, with the engine still running, I engaged the AP and it seemed to hold heading just fine, a few ticks of the roll servo, none from the pitch servo and the CWS worked when I held the disengage switch down on the control stick ...something it would NOT do in the air !
So...what is wrong? How can I fix it? :'(