I have a three blade McCauley Prop #D3A36C435 on my 182A under McCauley STC# SA00819CH and I am wondering if anyone has got a Field Approval to use this prop on a PPONK 0-470-50 engine? They approve a McCauley D3A34C401 on them and I have a call into McCauley to find out the difference between the C435 and the C401. Just hoping someone has had this done already. thanks!

I’d think if you can verify the counterweight arrangement for that prop and engine combination it wouldn’t be difficult to get an approval. Then the question is: Do you have the correct counterweight bushings and pins or do you need to install them?


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I think a field approval for a prop is gonna be much harder to get than for lets say larger tires.
The 2 blade C203 is a popular prop, esp in the 88" size--
people have tried to get a field approval to put one on a Ponk,
yet I don't think I've ever heard of anyone getting one.
And that prop is approved via the C180 TCDS for the 470K,
which has the same counterweight arrangement (four 6th order dampers) as the Ponk.

hotrod180 wrote:I think a field approval for a prop is gonna be much harder to get than for lets say larger tires.
The 2 blade C203 is a popular prop, esp in the 88" size--
people have tried to get a field approval to put one on a Ponk,
yet I don't think I've ever heard of anyone getting one.
And that prop is approved via the C180 TCDS for the 470K,
which has the same counterweight arrangement (four 6th order dampers) as the Ponk.

The big issue that I ran in to, when talking with the FAA about approving the C203 on the -59 was the horsepower limit. Not sure that’s the case with the three blade, but I wouldn’t expect a slam dunk if it hasn’t been done before.

thank you for your input!

for the 470K,
which has the same counterweight arrangement (four 6th order dampers) as the Ponk.

I'm pretty sure when my 470K was converted to the Pponk, two of the counterweights were changed. I now have two 6th, one 5th and one 4th and think that is what the 470U also has. I can tell you that it is a smoother engine changing from four 6th orders.

180Marty wrote:

for the 470K,
which has the same counterweight arrangement (four 6th order dampers) as the Ponk.

I'm pretty sure when my 470K was converted to the Pponk, two of the counterweights were changed. I now have two 6th, one 5th and one 4th and think that is what the 470U also has. I can tell you that it is a smoother engine changing from four 6th orders.

All the North Point website sez is 4 crankshaft dampers.

From the O470 TCDS:
"NOTE 4. Crankshaft damper configuration: O-470-A, S/N 41000 and up, and -E, -J, -R, -S, and -T engines are
equipped with one 5th and one 6th order damper.
O-470-B, -H, and -N have two 6-½ order dampers.
O-470-K, -L, -M, -P and IO-470-A and -C have four 6th order dampers.
O-470-G has one 6-½ and one 9th order damper.
O-470-A, S/N 40001 through 40655, and -P, have two 6th order dampers.
O-470-U has two 6th, one 5th, and one 4½ order dampers."

From the IO470 TCDS:
"NOTE 5. Models IO-470-D, -E, -F, -G, -H, -M, -N, -R, and -S incorporate crankshaft with four sixth order dampers.
Models IO-470-J and -K incorporate a crankshaft with one fifth and one sixth order damper.
Models IO-470-L and -LO incorporate crankshaft with two fifth and two sixth order dampers.
Models IO-470-P, -T and LIO-470-A incorporate crankshaft with two sixth and one-half order dampers.
Models IO-470-U, -V, and -VO incorporate crankshaft with two sixth, and one fifth one fourth and a half
order dampers."

And from the IO520 TCDS:
"NOTE 5. Models IO-520-A, -B, -C, -D, -E, -F, -J, -K, -L, -M & -N incorporate crankshaft with one 4th and one 5th
and two 6th order dampers. Model IO-520-BA, -N has a crankshaft with one 4th and three 6th order
dampers. Models IO-520-BB, -CB, -MB, -NB have crankshaft with one 4th, one 5th and two 6th order
dampers. Models IO-520-P and LIO-520-P have crankshaft with one 5th and one 6th order damper."

Can anyone provide the exact wording from the 470-51 / XP470 STC re required crankshaft dampers?

Ok smart prop guys. It is possible to field approve a McCauley C50 prop (82” 2 blade) on a Pponk 520?

If not and I can’t afford a brand new prop, what is the best 2 blade option? My priority is more cruise speed over climb.

Thanks.

180driver wrote:Ok smart prop guys. It is possible to field approve a McCauley C50 prop (82” 2 blade) on a Pponk 520?

If not and I can’t afford a brand new prop, what is the best 2 blade option? My priority is more cruise speed over climb.

Thanks.

A C58, or C66. Which are essentially the same prop with different indexing. But good luck finding one with good blades.
And good luck finding anyone who works on them that will agree with that. Of course, when they recite the rhetoric about obsolescence, just ask them if they have flown the combination . But again, if you can't find a good example, it's pretty much a moot point.

Tale care, Rob.

A buddy of mine has an 86" C66 on a ponked 54 model.
Field approved, with engineering data provided by Knopp.
I can provide scans of the paperwork if you find a C66 & need it.

hotrod180 wrote:A buddy of mine has an 86" C66 on a ponked 54 model.
Field approved, with engineering data provided by Knopp.
I can provide scans of the paperwork if you find a C66 & need it.

and if you need / want multiples, I have the same (which also includes the C58) on a 53

Also an issue for the Norland IO470 and C203 Mac. It was difficult many years ago to work with the engineering office for a field approval using the C203.

C180_guy wrote:Also an issue for the Norland IO470 and C203 Mac. It was difficult many years ago to work with the engineering office for a field approval using the C203.

Scolopax wrote:The big issue that I ran in to, when talking with the FAA about approving the C203 on the -59 was the horsepower limit. Not sure that’s the case with the three blade, but I wouldn’t expect a slam dunk if it hasn’t been done before.

The horsepower limitation scolopax is referring to is in the C203 TCDS, page 9:
"Continental O-470 series (up to 230hp @ 2600 rpm)"

P.9 of P3EA shows 230 referring back to the engine, but p.2 has max. 285 hp continuous, 300 hp for takeoff.

C180_guy wrote:Also an issue for the Norland IO470 and C203 Mac. It was difficult many years ago to work with the engineering office for a field approval using the C203.

C180_guy wrote:P.9 of P3EA shows 230 referring back to the engine, but p.2 has max. 285 hp continuous, 300 hp for takeoff.

So you were successful in getting that field approval?
Apparently the horsepower issue was a show-stopper for scolopax's FA efforts.