Yellow band from 2000 to 2250 rpm

[dahugo]

My RV9A has an IO320/Hartzel combo from Van's. Upon installation i dutifully told the 180 it was hooked to a lycoming 4 cylinder engine. Is that the parameter which placed the yellow band on my tach? Whats the purpose of that yellow band?

 

[Battson]

The yellow band is just a setting the alarm ranges, in the tacho settings, under sensors. You can configure it to whatever you want, or get rid of it by setting it to the same value (top of yellow and bottom of yellow).
The purpose of it, as I understand it, is for aircraft which has a resonant freequency in a certain RPM range, which should be avoided.

 

[Dynon]

There's a band there by default to show that you can have a caution range like some engines have with particular prop combinations. But, the red/yellow/green lines on our products need to be set manually - they're ballpark in the right area for Lycoming/Continental motors out of the box, but there are lots of engines out there with lots of different precise limits, and so you should make sure you affirmatively set EVERY range on the EMS to your exact engine specs.