C-85 Props
Posted: Wed Mar 04, 2026 7:05 pm
Is anyone using a 1B90 CM pitched at 44 inches for a land based airplane?
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C-85 Props
https://www.cessna120140.com/Forum2018/viewtopic.php?f=7&t=2740
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Re: C-85 Props
Posted: Wed Mar 04, 2026 7:59 pm
Not I, but, I would be surprised if it met the static RPM requirements.
Re: C-85 Props
Posted: Wed Mar 04, 2026 8:26 pm
I have a 1B90 CM 71"x42" pitch on my 0-200, static maximum 2400 static minimum 2100, from an approval from Witchita. Climbs like crazy but have to watch redline when I level out. I call it the seaplane pitched prop. I think a previous owner, when coverting to the 0-200, didn't want to spend the $$ to get a 69x-- prop as per the Lucas STC so he somehow got an approval back in 1987. Yeah, I know, kinda different but I've learned to work with it for over 30 years...
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Re: C-85 Props
Posted: Wed Mar 04, 2026 9:37 pm
According to my logbooks, I am. Static is around 2250. I’ve never had the prop measured though, so can’t confirm it personally. I’m guessing @flybuoy already knows that about my airplane though. 
Re: C-85 Props
Posted: Thu Mar 05, 2026 12:44 pm
I want to see the prop that meets those limits! (And the person who measured it!)Diameter
- not over 71 inches
- not under 71 inches