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  #11  
Old 06-17-2017, 02:10 PM
todehnal todehnal is offline
 
Join Date: Jan 2005
Location: Kentucky Lakes area in KY
Posts: 887
Default Post Test Flight Update

OK, a post test flight update. First of all, it was not the best day for a comfortable test flight so I cut it short, but I was able to do a little. The shutter flutter is not there at idle, in fact, anything below 5000 rpm and the screen is on solid. At about 5000 rpm and above it become subtly visible, but it never is particularly annoying, or distracting. I would just like to identify the cause. I couldn't tell if there was any shutter frequency difference between 5000, and 5500. On my next flight I will pull the 5 amp Skyview fuse, and see what happens. I didn't do it on this last flight because I wasn't sure if the fuse also interrupted the battery backup, or not. I first want to check the schematic to verify before doing that. I don't like experimenting without having a reasonable expectation. I do find the RPM sensitivity to be interesting, albeit not real informative to this novice. But with my tenacity, and tapping into the vast talent in the group, I am confident in a positive cause and fix outcome

More to come.........Tom
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2013- RV12, Kit #119. N123M First flight Nov21. It's a keeper!
1998- RV-9 tail kit, built and sold
1989- RV-6 tail kit, built and sold
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  #12  
Old 06-21-2017, 10:32 AM
todehnal todehnal is offline
 
Join Date: Jan 2005
Location: Kentucky Lakes area in KY
Posts: 887
Default 2nd Update

Today's flight was a great time to pull the EFIS fuse, and to take note of any changes in my screen shutter flutter. The screen dimmed slightly, as would be expected while running on the backup battery. My little girl gave me a warning call, but the shutter effect continued. Not sure what that rules out, but anything over 5000 RPM still produces a slight screen shutter effect, with a frequency of somewhere around 5 cycles per second. Any other ideas would be greatly appreciated...............Tom
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2013- RV12, Kit #119. N123M First flight Nov21. It's a keeper!
1998- RV-9 tail kit, built and sold
1989- RV-6 tail kit, built and sold
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  #13  
Old 06-21-2017, 11:13 AM
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Jetguy Jetguy is offline
 
Join Date: Aug 2008
Location: Texas, Fort Worth
Posts: 1,216
Default

Take a 10 second as clear as possible video with your phone and email it to Dynon tech support. See what they think. You may have to send it back. Do you have the latest software update installed?
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  #14  
Old 06-21-2017, 11:35 AM
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DaleB DaleB is offline
 
Join Date: Sep 2012
Location: Omaha, NE (KMLE)
Posts: 1,720
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I still would suspect a beat between the prop blades modulating sunlight, and LCD backlight.

At 5000 to 5500 engine RPM your prop is turning at 2057-ish to about 2263 RPM, or about 68 to 75 blades per second passing in front of your field of view. I think that's probably within the range required to create a strobe effect with the dimmer for an LCD screen backlight - depending on exactly how the engine is running and the dimmer switching rate. I don't know for sure what the Dynon display uses, but a few CCFL driver data sheets I looked at typically showed PWM rates in the 250 - 350 Hz range, depending on the model. LEDs I'm not sure, I've seen numbers like 400 Hz but I'm sure that's not carved in stone.

It would be interesting to check it at a low sun angle to see if flying into, away from, or perpendicular to the sun makes a difference. It would also be interesting to see if changing the screen brightness made the flicker more or less pronounced. Another test would be to very slowly reduce throttle and see if the strobe effect slows and stops.
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  #15  
Old 06-22-2017, 01:39 AM
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Gagarin737 Gagarin737 is offline
 
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Location: Netherlands
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I have also seen this effect on some of my flights. When I notice it next time I'll try to write down some parameters.
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  #16  
Old 08-06-2017, 10:44 AM
todehnal todehnal is offline
 
Join Date: Jan 2005
Location: Kentucky Lakes area in KY
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While at Oshkosh I had the opportunity to chat with one pf the Dynon tech gurus about the slight screen flutter at high RPM. He was very specific in stating the there was nothing in the Skyview that could cause this condition. He said that the condition as stated was most likely being generated by the tach signal and that the filtering was done in the EMS. His suspicion was a bad filter capacitor in the EMS box. So, I will be sending it in for rework. Thanks for all of your thoughts..........Tom
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2013- RV12, Kit #119. N123M First flight Nov21. It's a keeper!
1998- RV-9 tail kit, built and sold
1989- RV-6 tail kit, built and sold
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  #17  
Old 08-06-2017, 11:30 AM
E. D. Eliot E. D. Eliot is offline
 
Join Date: Dec 2005
Location: San Pedro
Posts: 843
Default VR

I suspect the VR whenever weird things begin to happen. Have you purchased a replacement VR to carry with you just in case? We seem to have an airframe good for many years, an engine good for 2000 hrs and a VR set up good for?
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  #18  
Old 08-06-2017, 01:38 PM
todehnal todehnal is offline
 
Join Date: Jan 2005
Location: Kentucky Lakes area in KY
Posts: 887
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I still have the original regulator, and my voltage has not varied. From day one I get 13.8 volts which shows up slightly above idle. Also, I just completed another backup battery test and passed. The Dynon tech was pretty certain about the source of the interference coming from the tach input to the EMS module, which makes sense if you consider that it only shows above 5000 rpm. Also, lets not forget that even when I pulled the fuse, which isolated the charging circuit and ran it strictly on the back up battery, the condition did not change.
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2013- RV12, Kit #119. N123M First flight Nov21. It's a keeper!
1998- RV-9 tail kit, built and sold
1989- RV-6 tail kit, built and sold

Last edited by todehnal : 08-06-2017 at 01:41 PM.
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