I have been checking our 9 CAP Virginia Wing aircraft RPM's against the Tach as I have a Prop Tach. Found most were within 100- 150 rpm. Checked an Archer I flew and it was almost 200 rpm off. Prop was actually turning 200 rpm faster than what was indicated on TACH. Checked my Coupe and it was right on from 1000 to max. I have a wooden climb prop.
Just for your info. Jim N3439H FDK
