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Navalav8tor
01-01-2021, 11:39 PM
Looking for recommendations on metal Prop combinations on a PA-11 C85-12, thanks in advance.

cubdriver2
01-02-2021, 12:23 AM
Welcome, climb? Cruise? Midrange? What are you trying to improve?

Glenn

cubman
01-02-2021, 08:45 AM
I have a McCauley CM7146 on my PA11/C-85. It is a cruise prop and I typically fly at pressure altitudes between 900-3000 feet. Static RPM is about 2500 - a little below redline. Hope this data point helps.

supercrow
01-02-2021, 09:40 AM
If your tach is accurate, you are doing a really good job with that prop.

cubman
01-02-2021, 09:59 AM
I misspoke. Static RPM is ~2200. Full throttle is 2500.

Navalav8tor
01-02-2021, 08:36 PM
Glenn, mostly climb. Hopefully that will allow me to continue to fly during our summer months in Texas...
Thanks

cubdriver2
01-02-2021, 10:54 PM
Glenn, mostly climb. Hopefully that will allow me to continue to fly during our summer months in Texas...
Thanks

What prop are you flying now?

Glenn

Navalav8tor
01-02-2021, 11:25 PM
Glenn,
Currently do not have one is why I'm soliciting the information, then I'll be faced with finding one...
I bought the PA-11 as a project and am ready to assemble the engine and install the wings, then ready for a prop. Thanks

Andy Meyer
01-03-2021, 07:42 AM
Iím a new owner of a PA-18-95 that has a C90-12 and came with two props. One is a Mac 71-46 cruise prop and the other is a Sen 76-2-42 climb prop. The Sen is new with only 100hrs. The Mac is fresh overhauled. Iím going to be flying a bit with both of them to decide which I prefer and then will likely part with one or the other. PM me or text me at 641-529-0420 if any interest.

Douten
01-03-2021, 08:43 AM
Are you stroking the engine? that will make a huge difference in your performance.

mam90
01-03-2021, 08:49 AM
Are you stroking the engine? that will make a huge difference in your performance.

I do wipe the oil off occasionally, but..........

Dan Gervae
01-03-2021, 05:56 PM
C85 best climb prop in my experience (if stock) is Mac 71-42

Hardtailjohn
01-03-2021, 09:29 PM
I had 46 on my Tcraft and it was great for cruise, but I couldn't get off the ground with 2 people on skis, so had it repitched to 42 and it's awesome! Lost a few mph in cruise, but it was a whole different animal on takeoff.
John

Dan M
02-09-2021, 01:55 PM
Might be apples and oranges C85 to a stock O-200 but.

I am in a PA11 with a O-200 and I have friends that let me try a couple of props so I tried 3 different McCauley props. Noting it's a cub so I not worried about cruse speed at this point just overall engine RPM's. Working from memory here is what I got, cruse is strait & level in a long downwind pattern except for the last one that I am sticking with for now.
47 Pitch gave me about 1950 Static and 2300 Cruse, a little low for my liking at full throttle.
44 Pitch gave me about 2050 Static and 2450 so in cruse again full throttle.
42 Pitch (the one I am using now) gave is giving me 2350 Static, 2550 initially in clime out, then I have the throttle back to about 3/4 or less as soon as my airspeed passes about 70 or 80 indicated, at 2500 RPM I am settling in at about 90 Miles an hour indicated 6500' MSL, flying out of Broomfield CO. Just north of Denver, Field Elevation is about 5675 MSL. I like this one because it does give me more in the climb if I need it. I expect it would easily pass redline full throttle in any decent but haven't had the need to check that out yet.

Dan M

mvivion
02-09-2021, 02:55 PM
I’m a new owner of a PA-18-95 that has a C90-12 and came with two props. One is a Mac 71-46 cruise prop and the other is a Sen 76-2-42 climb prop. The Sen is new with only 100hrs. The Mac is fresh overhauled. I’m going to be flying a bit with both of them to decide which I prefer and then will likely part with one or the other. PM me or text me at 641-529-0420 if any interest.




What basis are you going to use to install the 76 inch prop? Or are you experimental?

MTV

BC12D-4-85
02-09-2021, 04:01 PM
Hey Mike it's ok...Sen 76AK-2-** = 74" diameter. It's on Piper's 1A2 TCDS under Item 1(d) for C-90 engines. Also approved under TCDS 1P2 vibrationwise by Sen for the C-90 for 90 hp @ 2475 or less.

Gary (-40F this morning so bored at the keys)

cubdriver2
02-09-2021, 07:14 PM
What basis are you going to use to install the 76 inch prop? Or are you experimental?

MTV

-2 means it was cut 2" shorter after being factory made

Glenn

BC12D-4-85
02-09-2021, 07:52 PM
Sometimes 2" longer makes all the difference......I'm still looking for a 76AK-0-**

Gary

mvivion
02-09-2021, 08:39 PM
-2 means it was cut 2" shorter after being factory made

Glenn

Yup, duh!

MTV

skywagon8a
02-10-2021, 06:31 AM
-2 means it was cut 2" shorter after being factory made

Glenn
Almost, It was the factory which made it a 74. The 76 is the basic length of the design. The dash number is the amount the factory reduces the diameter from the basic design.

Dan Gervae
02-10-2021, 08:15 AM
I once put a tape on my 76AK-2-40 prop on my C90 and it measured almost exactly 75” rounded tip to rounded tip. I also once swapped that prop onto my stock C-85-8 (removing the 71-42 mc ) it wouldn’t turn past 2100 rpm. Too much prop for a stock 85. It only had 200 hrs smoh so it wasn’t a tired motor. That 76AK IS “The” prop on the C90 though. Results may vary I guess, but the 71-42 was the sweet spot for my C-85

DavePA11
02-11-2021, 01:39 AM
Dan, I had same experience with 76AK-2-42 Sensenich prop on C-85., but worked great on C-90.

Andy, I don’t think you will find the -42 a climb prop on the c-90. -40 might be better for climb or at least that is what I experienced.

Brandsman
02-11-2021, 10:14 PM
I run the 76AK-2-42 on my J-3 which has an ex PA-18 C-90. The airfield I fly from is at 5440 amsl and it seems like the perfect prop although you have to be careful in any descent as it easily reaches red line


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