A friend of mine was checking out the STC for the Ponked engine in his C182 to make sure the prop he wanted to install (Mac C58) was listed as approved. It was-- in fact, the Mac C58, C66, and C90 2-bladers were listed, as was the C401 3-blader.

I recalled hearing that only the 3-blader was listed on the Ponk STC for the C180, since the 2-bladers were approved for the C182 that didn't seem to make sense so I decided to look it up.
I checked under Pponk in the FAA's STC library, nothing listed.
Then I checked under Knopp, and found several STC's.
Surprise!! -- all of them were for the C182, nothing for the C180.

Who can provide the STC number for the Ponk engine conversion on the C180?

Try:

STC SA02278AK
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/2a6df9c31273c1f786257560007e09c2/$FILE/SA02278AK.pdf

and

AML SA02278AK
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/2a6df9c31273c1f786257560007e09c2/$FILE/AML%20SA02278AK.pdf

Fly safely,
Pat

A lot of the prop STC combos had to do with what they were testing / had available at the time (their words). Several people have field-approved alternative prop combos in cases where it exists on another approved airframe, so that may be an option too if you're only out-of-STC by the airframe itself. Of course, that's between you and your FSDO.

iPat wrote:Try:
STC SA02278AK
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/2a6df9c31273c1f786257560007e09c2/$FILE/SA02278AK.pdf
and
AML SA02278AK
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/2a6df9c31273c1f786257560007e09c2/$FILE/AML%20SA02278AK.pdf

THat was the one STC lI found listed that I didn't click on, but to my untrained eye it looks like it is to install Hartzell prop(s) on a C180 and C182.
It does NOT appear to be for installation of a Ponk 470-50 engine on either airframe.
The STC I'm interested in would be to install the 470-50 on a C180 airframe, and includes approval for a Mac C401 or 403 3-blade prop...
but (from my understanding) none of the 2-blade props.

Field approval is needed for a C58 2-blade on the C180 P-Ponk; it took me 6 months and was orchestrated by Lawson Aviation of Michigan. I couldn't get it done in Oklahoma.

What's the STC number for the Pponk 470-50 engine on a C180?

SA00468WI

Here's the STC's for the Ponk 470-50 engine on the C182 through 182G, 182H through P, and 182Q & R.
(interesting that they're broken down that way by specific sub-models, instead of all being one the same STC)
They list the C58, C66, C90 2-blade and C401 three-blade props as approved.

http://rgl.faa.gov/Regulatory_and_Guida ... enDocument
http://rgl.faa.gov/Regulatory_and_Guida ... 5664NM.pdf
http://rgl.faa.gov/Regulatory_and_Guida ... 5966NM.pdf

Here's the STC for the Ponk 470-50 on the C180 through C180K.
For some reason, it only lists the C401 3 blade prop.
Some people have gotten field approvals for the 2 blade props as listed on the C182 STC,
I'm kinda curious why Knopp didn't include them as part of the STC.

http://rgl.faa.gov/Regulatory_and_Guida ... 0468WI.pdf

Steve Knopp told me it was a time/money issue. Of course, back then getting a FA for a 182 approved prop on a 180 was pretty much a nonissue.

New (Part 36) Noise regs that must be complied with will not allow approval of any prop or accessory that increases the noise level compared to existing approved engine/props. The MT 2 and 3 blades 83" at 2700 RPM just made it by a 'hair' 10 years ago. No way anything longer will ever be approved these days.
John