Propeller Pitch Recommendations

[8434]

Hi Folks,

I have a C90 with CM7152 on it. There is a CM7147 for sale nearby and I'm considering buying it to have two props, one for cruising and one for playing in the backcountry. My Static RPM with the 7152 is ~2050 and I have checked it with an optical tach. I have concluded that elevation I do the test at doesn't matter as the decrease in engine power is close to proportional to the decrease in drag on the propeller.

Does anyone have experience swapping to a climb prop they would like to share? What static did you start with and end with? What pitch to what pitch?

Marshall

[6898]

Flew from Chicago to Tucson was afraid our C-90 wouldn't have enough to clear the mountains so removed our 71-50 and borrowed a 71-46 lost a good 8mph but performance was great did have to keep a close watch on the tach. that prop was easy to pass redline. Can no recall all our static numbers but I assure you it will make a huge difference from your 52. Good Luck

[6643]

7150 is considered a climb prop for the C90 on a 140. At 46 pitch I'm surprised you use full throttle on your takeoff run without exceeding redline!

[8434]

Hmm, interesting. Ideally I was looking for a 48 or 50. But a 47 is awfully close to what I am looking for. I don't have any clue what difference 1,2 or 5 inches will make to my RPM or takeoff performance. Like I said I'm on the low end of my Static RPM so I have some room to move, just how much is what I'm trying to figure out.

Anyway thanks for the input.

[6643]

Can you borrow it?

Don't forget, you need to meet the static limits in the Aircraft Specifications. A 46" may not. For the McCauley, not over 2350, not under 2050.