D180 Attitude

[rngaines]

I have D180 in my RV12. The attitude moves in a motion that I can only call a wobble or looks like a dutch roll. Pitch and roll happening at the same time. This happens mostly at 4600 rpm up to 5000 rpm when the airplane is in straight and level flight. Above 5000 I get a little and by 5100 it is just fine. I have an AP74 and you can imagine what the ride is like when it is one. At 4800 it really moves around.

About a year ago Dynon swapped it out with a different unit and it is still the same. As far as I know mine is the only -12 that behaves this way. I have tried to see if voltage input or something is causing it. Doesn't seem to. A friend suggested maybe the EDC-10A. I am really out of ideas. I reality like the D180 other than that.

Richard

 

[Dynon]

If it's attitude, and it's tied to RPM, and it's doing the same thing on multiple units, it's almost definitely vibration. As a first test, does applying some pressure to the bezel/panel area around it (just to damp or change the vibration characteristics slightly) change anything?

 

[rngaines]

Is that vibration to the D180 or the EDC-10? I will try the damping of vibration on the D180. The Rotax engine does not have much vibration since it is a geared engine and turning fast. I will check today.

Richard

 

[Dynon]

The D180 itself.

 

[rngaines]

I tried to check it today but it was very bumpy with a front going though the west coast. I will check it the wx gets better. Thanks.

Richard

 

[rngaines]

I did check it. It reduced the "wobble". Now I guess I get to track down vibrations. Thanks.

Richard

 

[jakej]

maybe a dynamic prop balance check is worthwhile ?

Jake J

 

[rngaines]

Thanks. I am to get it dynamically balanced. Other -12 builders have had good results with balancing prop. It is ground adjustable and I thought it could not be balanced. I will find out soon.

Richard

 

[Jetguy]

I have this exact same problem in my RV12. Speed seems to have the biggest effect. Above 100 kts and it works great. Around 90 kts and it wobbles all over the place. Prop was balanced at max Static RPM on ground. Any ideas from other RV12 guys on how to dampen this effect. Are we sure it not the ahars in the tail? Thks