Centering Ray Allen Trim Annunciators

RV7ator · #1 04-15-2011, 10:39 PM

Is there any way to cause the annunciator LEDs that accompany the Ray Allen trim servos to track servo position accurately, or skew their center indication even if the servo is nowheres near center?

Out of the box, these things are very non-linear, and the center indication could find the servo considerable distance either side of center. Also, I know that on RV-7s (perhaps others) that far more elevator trim tab down deflection (nose up) is needed than up deflection. Thus I'd like to set the servo's mechanical position so that most of it's stroke, say 75%, is dedicated to down deflection with the annunciator LED next nearest one end of the display lit when the tab is in trail.

Any possibilities?

John Siebold

MCA · #2 04-17-2011, 10:25 PM

John, I don't know if this is any help to you, but on most EFIS units and Vertical Power units you can set the indicator limits digitally in the setup menus to accomplish exactly what you want to do. So, if you are using any of these units, you might consider running the trim indicator through that.

Rosie · #3 08-31-2014, 06:17 PM

Resurrecting an old thread....can anyone tell me how to center the LED Ray Allen indicators? Do I run the indicator to 'Center' then readjust the pushrod to neutral? I don't remember how I did mine and now doing one for a friend, Rosie

pczar3 · #4 08-31-2014, 07:04 PM

Hi Rosie,
the Ray Allen units use a special led driver chip that has internal voltage comparators. Run the servo until the center led is lit then adjust the linkage.

Paul