Anyone using McCauley Prop greater than 81"

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amyandgary
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Anyone using McCauley Prop greater than 81"

Post by amyandgary »

I have an M-5-235C that I am changing the engine on, installing an O-540-B4B5, and am wanting to put a larger
prop on it. Both Hartzell and McCauley have 81 inch props that are in the TCDS, but I am wanting to put the 86"
Mac on it, or even cutting that down to an 84"...The airplane has 29 Alaska Bushwheels on it, so clearance is
not an issue...

Has anyone done this mod? And if so, was there an STC that you used? Which one?

I am trying to track down STC SA2728SO, but so far no luck...

Any hints or help would be greatly appreciated!

Cheers,

Gary Haass

Dale Smith
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Re: Anyone using McCauley Prop greater than 81"

Post by Dale Smith »

My new 86" Mac just showed up last week. I will be pulling the 78" Hartzell hopefully later this week to do the swap. The 86" originally had an approval letter to use, now it is on the equipment list. You do need larger than 8.50 tire or extended gear to run the 86". I will hopefully be able to give some more info once I get the props changed. If you search the form hard enough, there was someone that did it years ago. If I remember correctly it took a couple hundred off his take of roll and a added almost 10 MPH in cruise.

If you email me I can send you a copy of the equipment list.
Dale@RCX-Inc.com
No great story started with a good idea...

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FARMAULE
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Re: Anyone using McCauley Prop greater than 81"

Post by FARMAULE »

Dale thanks for the data. Am I reading it correctly that the 86” prop is only approved on Float equipped aircraft? I hope not because this seams like a great option

Dale Smith
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Re: Anyone using McCauley Prop greater than 81"

Post by Dale Smith »

It is a little bit of a grey area. There is an Approval Letter from McCauley about running it on wheel gear to make it completely legal. I have it somewhere but will have to dig it up. You have to have larger that 8.50 tires or extended gear for clearance with one main wheel flat per regs. Jeremy and a I believe Eric did the testing in the late 90's if I remember correctly. There is an older post where there was a performance comparison when someone did the swap. I have talked to others that are running it.
Jeremy has a post that also lists the prop options in order of performance. I believe the 86" just edges out the MT on the J-series motors due to the lower RPM.

I skipped right over the motor swap on the original post. The 86" mac is only approved on the J-Series motor, lower RPM, noise regulations.

On a side note to that... there are a lot of 180's out there that go on and off floats, and that 88" Seaplane prop just magically gets smaller when the wheel gear goes back on.....
No great story started with a good idea...

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Andy Young
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Re: Anyone using McCauley Prop greater than 81"

Post by Andy Young »

I’m running the 86” McCauley on my M-6-235, which has an IO-540-W1A5D. Note that the W also has a 2400 rpm redline, so this prop is approved on these as well as the J motors. Paperwork basis is STC #SA2728SO, which I got from Jeremy. The STC does require extended gear, or tires larger than 8.50s. I have the extended gear, so it works with my 8.50s when I’m on those, and, of course, works with the 31” Bushwheels that I use in the summer.

Dale Smith
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Re: Anyone using McCauley Prop greater than 81"

Post by Dale Smith »

Alright, I dug through paper work and made some calls. I believe you are correct about being approved on floats, though I have not called Maule. There is an STC for the installation. Jeremy is the holder of the STC. I got the STC from him. He will sell a prop with the paper work, or you can buy the STC alone from him. I will let people deal with Jeremy direct on pricing if they are interested.

Sorry for the confusion...
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FARMAULE
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Re: Anyone using McCauley Prop greater than 81"

Post by FARMAULE »

Thanks for all of the information gents.

amyandgary
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Re: Anyone using McCauley Prop greater than 81"

Post by amyandgary »

Thanks for all the good info...Since we are going with the B4B5 engine, 2575 RPM version, the 86" won't work out. Decided to go with
the 81" McCauley, as it was recommended by some as to having more pull than the same size Hartzell...
Again, thanks for all the input, and good luck to those who are going with the 86!!
gary haass

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