I've been on the hunt for an 88" McCauley seaplane prop for my 180. It has a grease-filled 82" C203 prop now. The C203 has a good rep, so I'd like one of those. It's not approved for a Ponk'd engine but I have no plans to go that route so that's OK. I thought I might be able to have mine fitted with 88" blades, but after talking to the prop shop it turns out that it's not cost effective to do so-- in between new blades and updating the hub to oil-filled, it would cost less to just buy a complete new prop, including spinner!

Next thought was a C66 which is listed on the C180 TCDS. I believe it's an old "threaded" design, but it's approved for the Ponk engine so must be a good prop. A guy at my airport replaced his 82" C66 with a new Mac C203. The blades on his old prop are beat up but I believe the hub is good, and I'm sure I could get it pretty cheap. It's already oil-filled so I wouldn't have to do that, but I'm afraid that re-blading this hub might not be cost-effective either. I need to talk to the prop shop again to be sure.

I just came across an ad for a 180 seaplane prop, and it turns out it's a 2A34C50 which I've never even heard of. Can anyone tell me about this model?

There is some info on the TCDS but not a lot.

hotrod180 wrote:
I just came across an ad for a 180 seaplane prop, and it turns out it's a 2A34C50 which I've never even heard of. Can anyone tell me about this model?

Possibly a D2A34C58 ???

If so it will fit a 185 205, 206, 207

TangoFox wrote:

hotrod180 wrote:
I just came across an ad for a 180 seaplane prop, and it turns out it's a 2A34C50 which I've never even heard of. Can anyone tell me about this model?

Possibly a D2A34C58 ???

If so it will fit a 185 205, 206, 207

No, it and the C49 are the predecessors to the C58 and C66. They use the 90A blades rather than the 90AT blades of the later prop. I have never ran one, but I'd speculate performance wise it would be at least as good as a C203/204 (which is not quite as good as C58/66). It isn't on the Pponk STC either, but as you noted, that's irrelevant to you.
Looking at the manuals one thing interesting I see is that the balde angle at fine pitch is quite a bit coarser on the 49/50 than on the 58/66, coincidentally it is also coarser on the 203/204 series blades as well.

Try looking at Kenmore Air Harbor 520 STC for 180. More Props

nice

I've got a 2A34C50-NP on my airplane.. C-180A, O-470R. What's to tell, it works fine, lasts a long time.

gunny

Rob wrote:..... They use the 90A blades rather than the 90AT blades of the later prop. I have never ran one, but I'd speculate performance wise it would be at least as good as a C203/204 (which is not quite as good as C58/66).....

Curious as to why performance of the C203/204 props is "not quite as good as the C58/66"?
Blade width? Pitch setting? ??

Consider one of these for best performance in a 46 pound package!
http://www.flight-resource.com/Datasheets/Cessna180.pdf

Best regards,
John

Your MT prop looks like a real performer, but my budget can't take the hit.
Can't hardly take the hit for a new Mac either, that's why I'm looking for a good used one.

hotrod180 wrote:Your MT prop looks like a real performer, but my budget can't take the hit.
Can't hardly take the hit for a new Mac either, that's why I'm looking for a good used one.

I priced a new Mac C203 for a IO520 and it was $11,000. For that price I'd be buying a MT. I'm in the same boat as you though; whichever engine I end up with I'll likely be looking for a used prop.

And is the reason for the sea plane prop for the extra noise Good for our rep in the backcountry

Tim

qmdv wrote:And is the reason for the sea plane prop for the extra noise Good for our rep in the backcountry

Tim

I got a quote for $8200 not long ago for a new 88" C203 Mac.
John (Flight Resource) quoted me $12,950 + crate & freight for an 83" scimitar MT.
And yes, of course the longer prop is just for the noise. I'm sure there's no performance increase, and I wouldn't want it even if there was.

hotrod180 wrote:

qmdv wrote:And is the reason for the sea plane prop for the extra noise Good for our rep in the backcountry

Tim

I got a quote for $8200 not long ago for a new 88" C203 Mac.
John (Flight Resource) quoted me $12,950 + crate & freight for an 83" scimitar MT.
And yes, of course the longer prop is just for the noise. I'm sure there's no performance increase, and I wouldn't want it even if there was.

Oops, forgot the

Who quoted you the Mac price? That ain't bad.

Per the 5A6 C180 TDCS, here is the pitch stops for the 88" seaplane prop/C66 hub. I believe the 8° low pitch is the reason why it is such a good preformer. I'm curious as to what the other props mentioned in this thread are for low pitch (C58/C203/MT).

9. McCauley constant speed propeller
(a) Hub 2A34C66, blades 90AT-2
Diameter: not over 88 in., not under 86 in.
Pitch settings at 36 in. sta.:
Low 8°, high 22°

Hi Hotrod, and Matt,

It's my purely uneducated opinion that the reason the 88" C58/66 perform so much better than the other 88" props is due to the increased cord of the 90AT blades (assuming a reasonably fresh prop, not a filed down wore out toothpick) they are a big fat blade, and the flatter blade angle spec'd for the long C58/66 series.

It is also my opinion that props are pure black magic. I have seen identically spec'd props perform tremendously different (back to back) on several occasions, most recently on a -34 Pratte/ Hartzel combination. Consequently it's not hard to imagine different props that share only length as a common denominator would perform different.

Matt,
Per McCauley,

The earlier hubs (C1, C18, C29, C50, C58, and C66) all have low blade angles in the 8.5° to 10°.5. The longer the blades, the lower the angle.

The later hubs (C201/203/204) all have low blade angles at 10.5° to 13°. With the exception that the modern 3 blade hubs which are flatter when long.
Again the lowest angles corresponding to the longest blades. Notice that even the longest blades of the modern props are only as flat as the shortest of the older props.

Matt, thanks for bringing up the 180 TCDS. I see that the Hartzell props all seem to have a low setting of 12 degrees. Here's the mac breakdown from the C180 TCDS::
Cessna 180 (A J & K engines)
36C-- 82": 10.5 degrees low & 22 degrees high 88" : 8 & 22
34C-- 82" 10.5 & 22 88" 10.5 & 22
(BTW when I asked Dick Jacobs at NW Prop about the 2A34C50 prop, he told me it was considered a 2A34C as per the TCDS)
C66-- 82" 10.5 & 22 88" 8 & 22
Cessna 180G & H
C201 -- 82" 13 & 24.5 88" 10.5 & 24.5
C203-- 82" 12.5 & 25 88" 10 & 24.5

I agree with Rob that props are more a black art than science.

whee wrote:Who quoted you the Mac price? That ain't bad.

AC Prop in Seattle.

As far as more performance vs just making more noise, check this page off Ponk's site.

http://www.pponk.com/HTML%20PAGES/propellers.html

It shows 940 lbs thrust for the 82" C58 prop at 2600 rpm vs 1016 for the 88" version, an increase of just over 8% -- a significant (but not huge) amount. It shows an even bigger difference between the 80" and 86 / 88" 3-bladers.