On Monday, November 14, 2016 at 2:03:03 PM UTC-5, wrote:
We will be purchasing an additional PA25 for our club, and like many other facilities noise is becoming a bigger issue. Our current Pawnee has a 235 HP motor which has had the 250 HP STC (domed pistons) with a fixed pitch prop. The STC has performed well with far better climb performance when towing heavy glass 2-seaters. My question is whether a 260 HP Pawnee with a constant speed prop is louder that the 235 fixed pitch prop? I have heard this rumor, but have never been able to verify it.

Any and all input is welcome.

Skip Guimond

The constant speed prop will allow a higher RPM which gets you more horse power and also better acceleration due to low pitch. The higher RPM means higher tip speed on the prop which is where the big noise comes from.
UH