which propeller for a c85

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dfcpac
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which propeller for a c85

Post by dfcpac » Sat May 12, 2012 14:05

i just converted my 1971 americian champ from a a65 to a c85-12, one of the props recommended was a sensenich wood 72gk44. static run up is 2400, climb out it 2400 at 60 mph and flat out it will go over red line. cruise at 2200 rpm about 85 90 mph.

what would be the correct prop for me? it does climb better with the 85 but i still think it might not be the best prop for it.
is was told to try a mcCauley metal prop they will out proform wood. what model number should i get for climb out

thank you
dan carley

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Nathan K. Hammond
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Re: which propeller for a c85

Post by Nathan K. Hammond » Sat May 12, 2012 14:25

The GK is a hot prop if you want to go wood. CaptKelley has one on his Super-85.

You will gain a little performance all around if you go with a Metal Mac, but you might feel a very slight increase in vibration. One nice attribute of wood is it acts as a dampener. A Mac CM71/42 would be a real good climb prop, probably turn close to 2500rpm on takeoff roll, and go over red line if wide open throttle and level. A CM71/44 is considered the combination prop, and a CM71/46 is a cruise prop.

CM or CF will work (M=square tips, F=round tips)

Anybody near by that you can swap props with for a day? That helped me decide which I liked the best.

nkh
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Captgrumps
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Re: which propeller for a c85

Post by Captgrumps » Sat May 12, 2012 17:54

I have got both props and happy. Nae where have you been?..Still in Danville?

Doug
Keep the pointed end forward--
The dirty side down.....
And the blue skies on top....

dfcpac
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Re: which propeller for a c85

Post by dfcpac » Sat May 12, 2012 17:58

no there is no one around ithat i could try one. is there anyone on the list that might have a cm 71-44 that would like to sell it? either cm or cf mcCauley?

mike newall
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Re: which propeller for a c85

Post by mike newall » Sat May 12, 2012 19:03

My last Champ had an A-65 with a McCauley 1B90/CM 73" X 43"

I then converted it to a C-85 and the only change was to visit the local Rabbi to take an inch of each tip :shock:

It then became a 71" to avoid harmonic issues.

Anyhow - the best prop I ever had - smoooooth, speedy, good take off - would highly recommend.

Sensenich wood props are great for air boats, or for chocks... :mrgreen:

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Nathan K. Hammond
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Re: which propeller for a c85

Post by Nathan K. Hammond » Sun May 13, 2012 01:18

Still in Danville. Haven't made it back much; usually a night or two, so no time to make the (R)ounds. Plan to be there in a couple weeks though! Peachstate, June 2nd, Vintage days; you be there?

Thanks for asking.

nkh
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Re: which propeller for a c85

Post by Senior » Wed May 16, 2012 08:48

mike newall wrote:
It then became a 71" to avoid harmonic issues.

Anyhow - the best prop I ever had - smoooooth, speedy, good take off - would highly recommend.

Sensenich wood props are great for air boats, or for chocks... :mrgreen:
If I'm not mistaken, floatplanes with a 85hp are ok with 74" props,
Do floats tend to dampen the harmonics :shock: :lol:


Curiously enough I just happened onto Sensy site which lists a 74" as FAA Certified on a 85hp.
http://www.sensenich.com/products/item/37
and
FAA Certified 76" on a 85hp.
http://www.sensenich.com/products/item/13
46 Chief Serial #11AC-80
originally N86275 now C-GQHP
46 Taylorcarft in rebuild

Paul Agaliotis
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Re: which propeller for a c85

Post by Paul Agaliotis » Wed May 16, 2012 16:17

Senior,
That 76" Sensenich is a 74" prop. The -2 indicates a 76" blank that is 2" shorter. Just put on the 1A105 SCM McCauley, it's got a good blade design and a 71" with 44-48" of pitch will do. It all kind of depends what type of flying you do.
Paul
Mailing Adress : Paul Agaliotis 2060 E. San Martin, San Martin,Calif. 95046

jc pacquin
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Re: which propeller for a c85

Post by jc pacquin » Wed May 16, 2012 20:17

I had a McCauley climb prop on my 85hp 7BCM Champ. It worked VERY well. It did not vibrate.. of course it will NOT climb out like a Citibra 150 hp, but it gets out better verses a wooden prop. Most old timers I've spoken with always say wooden props are for over fireplaces. Less efficient than metal props. Randy, manager at East Coast propeller, (Lancaster, Penna.) sells both Sensich and or McCauley. He will tell you quickly what model you want for what you want to do. ( I wanted to climb.) A metal prop also made a large difference on my T-Craft BC12D when I traded Randy my wooden prop. He was recommended by Bill Pancake. I was very satisfied. East Coast always advertises in Trade a Plane. JP

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Re: which propeller for a c85

Post by Senior » Thu May 17, 2012 08:10

Paul Agaliotis wrote:Senior,
That 76" Sensenich is a 74" prop. The -2 indicates a 76" blank that is 2" shorter. Just put on the 1A105 SCM McCauley, it's got a good blade design and a 71" with 44-48" of pitch will do. It all kind of depends what type of flying you do.
Paul
Yes, reading to fast to notice the -2
Stupid way to designate length anyway. :roll:
Why not just call a 74" a 74"!
46 Chief Serial #11AC-80
originally N86275 now C-GQHP
46 Taylorcarft in rebuild

Paul Agaliotis
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Re: which propeller for a c85

Post by Paul Agaliotis » Thu May 17, 2012 16:17

It is pretty confusing. The props pitch is taken at the 75% length, So if you use a 76" blank the pitch is measured and manufactured at a station further out. A lot of black art in props.
Paul
Mailing Adress : Paul Agaliotis 2060 E. San Martin, San Martin,Calif. 95046

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