The Cessna 120-140 Association Forum

I have a macauley prop 71/48 and know this is considered a cruise prop.... I know a climb prop would be less than 48... what is a reasonably pitch for a climb prop???

thing73 wrote: ↑Mon Oct 25, 2021 7:52 am I have a macauley prop 71/48 and know this is considered a cruise prop....

7148 is considered a "normal" prop for the C85. 7146 would be a climb prop. To optimize climb, find the pitch that gives you the maximum allowed static RPM.

6183 wrote: ↑Mon Oct 25, 2021 9:23 am https://mccauley.txtav.com/?PropType=fi ... 2F%20(TCM)

Interesting... It looks like Textron has reinstated the "Avoid continuous operation between 1950 and 2170 rpm" limitation!

6643 wrote: ↑Mon Oct 25, 2021 10:25 am

6183 wrote: ↑Mon Oct 25, 2021 9:23 am https://mccauley.txtav.com/?PropType=fi ... 2F%20(TCM)

Interesting... It looks like Textron has reinstated the "Avoid continuous operation between 1950 and 2170 rpm" limitation!

If you select the C-90 engine it doesn’t have the restriction.

6339 wrote: ↑Tue Oct 26, 2021 9:03 am If you select the C-90 engine it doesn’t have the restriction.

It never did. McCauley rescinded the restriction in a service bulletin in 1949. I think Textron has just republished obsolete information.

I asked McC this question and the response was "where did you see this??. The TCDS has no restriction and there is no restriction". I responded "heard it on your website" and haven't gotten a response yet. So John is right, unless you want to trust the web-master over tech support.

Thank you John for posting a definitive answer to the placard question.

Rick