Switched a cylinder prop plane to a turbo prop plane. All works well, but when I'm in a level cruise and my speed has stablized, the RMP needles go wonky. They twitch rapidly from over what I've set to under what I've set. Any one else had this trouble with any model? Might give me a clue where to poke it next... :)

My immediate "first try" would be a different RPM gauge, just in case it's a coding issue in the gauge you're using, but I've no experience with turboprops per-se, so this is just a guess.Good luck.

I did, but no good.The gauge I am using is from the King Air, so it's a default gauge...

Look at prop_tc and prop_moi.Try prop_tc values between 0.002 and 0.005. Adjust Prop MOI based on the simplistic formula:Prop MOI = (0.6/386) * prop weight (lbs) * Prop Diam (ft) ^ 2