D180 lag in roll

[rvg8tor]

My D180 lags when I do an aileron roll, someone asked me if this is normal and I said yes since it has done this since I first flew back in December.  I had never actually looked at my D10A at the same time it is usually up on the HSI page, well the other day I did a roll and the D10A rolls just like one would expect an attitude indicator to work no jittery lag.

I started checking this because I had some recent issues on a long cross country where first thing in the morning my D180 has a slight list to it, disconcerting to say the least as you fly up into a low overcast deck, it seems to work itself back to a normal attitude with a few minutes of lever flight but I am loosing my confidence to fly actual instruments with it.

So what is the answer, might I have something wrong with my D180?  My auto pilot flies a GPS approach just fine but cant' seem to keep the course on and ILS or VOR, the compass is calibrated but wonder if the two issues are interconnected.

This video shows what is does, this was one of my first flights. 

http://www.youtube.com/watch?v=kRVExBMlSYk

Cheers
Mike

 

[dynonsupport]

Mike,
The Dynon products have a max specified roll rate of 150 degrees a second. In timing your video, you are right up against that with the quick roll rate of the RV-8. The reality is that because each EFIS has different calibrations, some can handle a bit faster than that, so that may be why the D10A is OK.

It would be interesting to do a slower roll and see if the D180 keeps up, or if it has an issue no matter what.

Your experience with the D10A of course is what we expect, assuming that you don't go faster than 150 degrees a second at any point.

The lean in the morning is something to be concerned about. Since you have a D10A, you should check the two against one another before flight, early in the flight, and a bit later. Check the roll, pitch, and ball. If you really feel the D180 is out, then we should take a look at it here.

If the roll and pitch are close, then they shouldn't affect VOR/ILS tracking much. The compass will make a huge difference however, so you do need to make sure you have the compass dead on.

Since you have a D10A and a D180, you actually could use the D10A as the AP controller if you really wanted to test if it did a better job on a VOR.

 

[rgrigson]

I installed the Dynon AP servos & AP-74 in my RV-8 three week ago (it has a D180 already installed).

Today I noticed that the EFIS is significantly lagging during maneuvers. I have never noticed this lag before in the previous 4 years of flying. Very noticeable on aileron rolls as the post above has alluded to. It looks like the refresh rate within the box has decreased significantly.

Are there any settings that I should look at? The box has the latest software.

Thanks,
Robert




Are there

 

[Dynon]

It could be one of a couple of things, but likely it's a hardware issue with the D180 that we'll need to address here. One thing to look at: is the clock on the D180 running slow? Look at the seconds.