in the late 90's i finished an rv-4 and used a prop from a different supplier that is no longer in bussiness. it was way under pitched as i could turn over 3100 rpms and the noise was unacceptable. I lived with it for 500 hours and only used 2350 rpms because this was the most comfortable rpm for the noise and smoothness of opperation.It is a 130 knot airplane.I needed a new leading edge and he was not available so i sent it to jeff at props inc. He asked about how it performed and said he would see what he could do with changing the pitch. I didn't expect much as i thought there was not much anyone could do (in the 90's the original supply didn't offer to do anything when i told him how it worked) I flew it this past week and what a difference at 2350 rpms i'm seeing over ten knots faster and when i raised the rpms there was no noise at all the top rpms were 2700 and the noise and vibrations were gone! the airplane is faster but what i really like is the quietness. jeff said he thought it was not an out of balance situation but a change in the airflow around the cowling. the airplane is not only faster at any given rpm but because of the new smoothness i will run at higher rpms. I thought the noise was a design and building situation not the prop. So again i am very happy with props inc.
