What propeller turns your crank?

Nathan K. Hammond · Post by **Nathan K. Hammond** » Sat Oct 15, 2005 03:50

I had a long discussion with a prop shop in Florida this afternoon. After jumping though hurtles on the McCauley prop, we started talking about other options. One was a wood prop, but I’m not too keen on that idea. Nothing against wood, but I like the performance of metal. The other option was a metal Sensenich. The tech said without bias, the Sensenich usually performs better when compared to the McCauley. Something about the airfoil they use is better, BUT it could be a dog on a Champ, he had no first hand knowledge. Keep in mind, this is for a C85.

So here’s what I’m asking: What kind of prop are you running, and what kind of performance are you getting? Anybody tried both manufactures?

nkh

Ron Babos · Post by **Ron Babos** » Sat Oct 15, 2005 18:24

Nathan: The L-16a in the hanger with me has a Senenich prop. I have a McCauley 74/43 . The L-16a really seems to work well. The only way to know for sure is to try both. Had wood and composite props and much prefer the metal. Doesn't care about sun, rain, or what position it stops in and stays for days on end. Don't know what it is about the metal polished prop, but with the wood or composite , people would always turn it out of the position I put it in. The aluminum prop seems to scare people or something. Any shrinks in the group?

Ron

Jim Catalano · Post by **Jim Catalano** » Sun Oct 16, 2005 12:00

Hey Nathan!
I've been happily flying behind a McCauley 71-48/C-85 combo for 3 decades. This is an L-3B which cruises around 92 @ 2400 with the cylinders hanging out in the breeze. Take off is good considering I first flew this old plane out of a 2000 foot strip on 65 HP. The basic Champ is lighter and with that stroker engine your building, you should have more than enough power to stroke your ego! From a purely aesthetic point of view, I prefer the Sensenich with its round hub and tips which reiterates the many curved lines of these wonderful old airplanes. It use to be that there were more 71" props on the market given damaged 74s were routinely cut down in the prop accident/ food chain. If your not in a hurry and your 74 is in excellent condition, look around before you have it cut. Jim

jim pacquin · Post by **jim pacquin** » Sun Oct 16, 2005 17:06

I recently purchased an 85hp champ that has a recently purchased mccauley prop. it is a 1B90/CM7148. It was a cruise prop as the former owner was operating out of 7000 foot runways. My airport has 2700 feet of grass. It was very slow on take off. Leavens Prop Service of Toronto tweeked it to 44 which vastly improved the take off and didn't seem to damage the cruise that much. (your gonna go slow in an aeronca anyway so why worry.) Knowing little about props, I inquired about the prop and was told it WAS VASTLY superior to a sensich and to stay away from them. This was from an aircraft rebuilder of many years and two AI's. All looked at my prop and liked it. Hope this may help.

Paul Agaliotis · Post by **Paul Agaliotis** » Sun Oct 16, 2005 17:43

Nathan,
My L16 has a McCauley 1B90 70/38 it performs well. I feel that if you limit your lenght to no more than 72in. and the pitch from 38in to 44in the prop will suit your needs.
I have only used the Sensenich metal props on the Citabrias. I didnt see much difference between the two. Be careful if you plan on buying one to actually measure the blade length. I had a Sensenich prop that was stamped as one length but was 1in short. When I called the factory they explained the numbering system to me. There was a dash number following the length and pitch numbers that identifies the length, in inches, under stock length.
I just installed a Sensenich wood prop on a A75 powered Champ, it was a 71GK41. The GK series has a different blade design and should be a good prop for the C85. I think the new CUB uses them on the O-200.
Paul

Jon B. · Post by **Jon B.** » Thu Oct 20, 2005 10:17

On my 7FC/EC I have a Sensenich 74x44 which seems to work well.

Static rpm is within the limits but in straight & level flight, even wide-open throttle will barely reach 2500 rpm. Max is 2625 for a 5-minute period; cruise max is 2475. I have only 45 hours on a fresh engine and it seems to be improving as it accumulates time.

With bare gear legs, uncovered 7.00 tires and this prop, max cruise might touch 90 mph. Economy cruise - 2250 rpm - is in the mid-80s.

Take-off performance is very good, climb is OK. I've been into and out of 1800 foot strips (1100' elevation) with 60-foot trees on the departure end and not had any concerns about getting out (solo, 15 gallons of gas).

Jon B.

Jon B. · Post by **Jon B.** » Thu Oct 20, 2005 10:18

I should mention that the prop was new at overhaul - 45 hours ago.

Jon B.

mike newall · Post by **mike newall** » Sun Oct 23, 2005 18:16

Pin back your lugholes and listen !

A-65, the best prop I have ever had was a McCauley 74/43. It gave great short field performance and a steady 90mph cruise on a very tired A-65.

I then changed my motor to a C-85 - very good move !

I figured that I could use the same prop as it needed to turn faster to create the extra horsepower.

McCauley said NO !

They will not allow a 74" prop on a C-85 due to harmonic vibration, the maximum prop size on the C-85 is 71 "

Woe, woe and thrice woe said I !

Never mind, a local prop shop/Rabbi snipped my prop down to 71", gave me the tips back, rebalanced it for $60 !

The new prop/engine combo was fantastic. I operate out of 1200' of indifferent grass, it leaps off the ground, cruises great and lands fine.

So, there it is, I have had a Sensennich club - crap - I have had a UK made wooden prop (Chris Lodge) - very good, but the McCauley was the best.

Ron Babos · Post by **Ron Babos** » Sun Oct 23, 2005 19:08

mike newall: I also have the 74/43 on my Champ with a 65. Why is the 85 prone to harmonics. I constantly cruise the 65 at 2250-2300 rpm. It is smooth there and all the way up to 2500 flat out. The only place I don't like to fly it is the recomended 2150 rpm. It is not as smooth there. That's telling me something, like don't run me here. Did McCauley ever say what causes the harmonics with the 85/74/43 combo?
Ron

Nathan K. Hammond · Post by **Nathan K. Hammond** » Sun Oct 23, 2005 20:54

Sounds like the McCauley is the club to swing. Mike, did you keep the pitch at 43? Ron, funny you mention that about cruising at 2150, my A65 74/44 did the same thing. 2050 and 2250 were smooth, but 2150 was rough like my covering job! I got like you and wouldn't run it there.

I've missed buying 4 different props from various websites, now i'm thinking of just eating the cost and buying a new one. What ever happens, it will go to a shop for overhaul and certification first. So I'm wondering about the pitch. I don't need super short field performance, most of my work is off of 1800 feet and better. I figured a 46 inch pitch would give me good results taking off and still a high cruise. Nothing less than a 44. Any thoughts?

nkh

Thanks for the input guys!!!!!

zero.one.victor · Post by **zero.one.victor** » Sun Oct 23, 2005 23:07

What I seem to gather is that when it comes to metal propellers,generally speaking the Sensenich's are better for faster airplanes (like Swifts & the like) while the McCauley's are better for STOL types (Champ, Cub,etc).

Eric

Nathan K. Hammond · Post by **Nathan K. Hammond** » Sun Oct 23, 2005 23:13

And for what it's worth.....now don't laugh.....I preffer the look of the McCauley. Something about the square tips just looks good, as compaired to the round sensenich.

Where's that shrink?

nkh

Paul Agaliotis · Post by **Paul Agaliotis** » Sun Oct 23, 2005 23:54

Eric,
The only face to face comparison that I have done is on the Citabria. And the results were the same. I did not see any improvements in the performance of the aircraft when the propellers were changed. I,ve never seen any performance data to support this other than my experience,s in the field.
The Sensenich seems to dominate the wood prop arena, while McCauley leads the fixed pitch metal prop segment. I would venture to say in a head to head test you would not see much difference in the metal props.
Mike Newall said he had a problem with his Sensenich metal prop and chose a McCauley. I would be interested to know the specifications of his prop, so I too could avoid any propeller related problems.
Paul

Jim Catalano · Post by **Jim Catalano** » Mon Oct 24, 2005 08:26

There is one advantage to the square tips.... extra material available for repairs. You can dress out nicks or have the tips rounded and still maintain diameter.

mike newall · Post by **mike newall** » Mon Oct 31, 2005 18:27

Sorry for the late reply, I've been evacuating passengers from Cancun - boy, the place is trashed !

I kept the pitch at 43" and it ran swet through the range on the C-85. Previously it ran fine on the A-65, I used to cruise at 2200 so I would agree with earlier posts regarding smoothness.

I spoke at length with the chaps on the McCauley stand at Sun n Fun, they said the 71" restriction was to do with harmonics at the normal cruising rpm. I asked about the variable rpm's for cruising and they said it was to do with a bigger bang per cylinder at similar rpm - lets face it guys, the A-65 doesn't have a reputation for being a high compression engine !!!!!!

I stand by what I said, get a McCauley, it will give you very good performance throughout the whole envelope

We are stuck with mediocre performance, but that only enhances the fun of Champing !

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What propeller turns your crank?

What propeller turns your crank?

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