Just curious
Thanks
Gary

Last year when I was hunting an 88" C203 I was told (numerous times) that it wasn't approved for "when you get your engine ponked". FWIW I ended up with a C201 which isn't approved either. I was told Knopp had vibration issues with the C203 on the 520 conversions, that's why it's not on the STC. I have seen two blade props on Ponked engines, but I believe they have all been the older threaded design props like the C58(?) or C66(?).

Gary:

Sounds like you scored a 180!!

Pictures, we need pictures!!!

L

Thanks Hotrod.
I did run the 88" C66 on my other and was happy with that.

Larry
Patience

Gary

Not a approval on P.Ponk but there is provisions to use -203 on Kenmore Air harbor STC to use -203 ,I believe it also exist on Texas Skyways $$$$$$ STC for 520 on Carb.Airplanes(Kansas) has a STC to make it Fuel Injected 520-550 but it's $$$$$ . The only 2 blade props on the P.Ponk stc is -58 or -66 McCalley .

Pponk has a 337 for the C230 2-blade; however, it took me 3 months to get a field approval for a C58 with 3 previous 337's including one with a completed field approval checklist.

Looks like conflicting information-- JRC says a field approval is required for the C58, and Bill Reid says it's on the STC. I seem to recall hearing somewhere that the 182 Ponk STC included 2 blade pro(s), but not the 180 STC. Can anyone clear that up?

hotrod180 wrote:Looks like conflicting information-- JRC says a field approval is required for the C58, and Bill Reid says it's on the STC. I seem to recall hearing somewhere that the 182 Ponk STC included 2 blade pro(s), but not the 180 STC. Can anyone clear that up?

C58: I can't comment.

C66: Straight from Norma's mouth as told to me over the phone, the C66 is only on the STC for the 182, not the 180. Have a 82" C66 collecting dust for that reason and ultimately an MT on the plane. Several field approvals have been obtained, however for the 180, including those shared here as well as others.

Having flown with a Pponked 180 with the 82" C66, It's a rocket ship with the go knob pushed in. Definitely faster than mine with a 3 blade MT, same year, similarly configured.

Flynengr

182 STOL driver wrote:Not a approval on P.Ponk but there is provisions to use -203 on Kenmore Air harbor STC to use -203 ,I believe it also exist on Texas Skyways $$$$$$ STC for 520 on Carb.Airplanes(Kansas) has a STC to make it Fuel Injected 520-550 but it's $$$$$ . The only 2 blade props on the P.Ponk stc is -58 or -66 McCalley .

The MT 83" 2-blade prop is approved for installation on all PPonk or any other 180/182/185 with any version of the -470, -520 or -550 engine. PPonks own tip speed calculator shows why 83" at 2700 is best for propeller efficiency. If you don't believe that, find a digital strain gauge. Hook it up to your long prop plane, go to full power and rpm. Then keep power at full and reduce RPM and observe the thrust increase. If your prop is making a bunch of noise, it is not operating at peak efficiency.

John

As someone has pointed out before, pull tests are not necessarily the whole story when it comes to propeller performance. Unfortunately it is one of the few ways we can compare props, other than empirical data which usually compares actual flight performance between different props mounted on different airplanes or obtained on different days under different conditions.

As far as pull results, here's a page off Ponk's site showing their test results using 80,82,86, & 88" props. Don't know about 2700 rpm, but the longer props definitely delivered more thrust at 2600 according to these results.
http://www.pponk.com/HTML%20PAGES/propellers.html
The online tip speed calculator on Ponk's website doesn't wanna work for me, but here's the long-hand version:

To determine propeller tip speed: Prop Diameter X Pi / 12 X RPM X 60 / 5280 = Tip Speed in MPH
Example: 86" prop turning at 2800 RPM 86 X 3.1416 / 12 X 2800 X 60 / 5280 = 716.4 MPH
To determine the speed of sound: Square Root (absolute temp + ambient temp) X 33.4 = Speed of Sound
Example: 59 degree F. day Square root (460+59) X 33.4 = 760.9 MPH (speed of sound)
To determine propeller tip mach speed: Tip Speed / Speed of Sound = Tip Mach Speed
716.4 / 760.9 = .942 MACH (to fast)

Ponk says .88 to .92 mach is the sweet spot.
An 83" prop at 2700 is .87 mach, just easing up into that sweet spot.
An 86 incher @ 2700 is .907, still well within it.
If you accept Ponk's .88-.92 bracket, I don't understand why an 83" @ 2700 making .87 mach is "best for propeller efficiency". I do agree that it will be much more audio-friendly than the longer props.
Even an 88" @ 2700 is .928 mach, just barely above it.

flynengr wrote:Having flown with a Pponked 180 with the 82" C66, It's a rocket ship with the go knob pushed in. Definitely faster than mine with a 3 blade MT, same year, similarly configured.

Flynengr

A rocket in cruise or a rocket in climb-out?

soyAnarchisto wrote:

flynengr wrote:Having flown with a Pponked 180 with the 82" C66, It's a rocket ship with the go knob pushed in. Definitely faster than mine with a 3 blade MT, same year, similarly configured.

Flynengr

A rocket in cruise or a rocket in climb-out?

Cruise. The Pponk and 3 bladed MT is pretty much the gold standard for climb performance. Haven't run across anything yet that will climb as fast in the 180/182/185 category.

Flynengr

The C180 is only approved for a 3-blade:

http://rgl.faa.gov/Regulatory_and_Guida ... t=o-470-50

C182 with C58 & C66:

http://rgl.faa.gov/Regulatory_and_Guida ... t=o-470-50

HTH

There are several 180's that have gotten field approvals for the C66. I had one.
Gary

jrc111 wrote:....C182 with C58 & C66:
http://rgl.faa.gov/Regulatory_and_Guida ... t=o-470-50

I see the C182 is approved only for the 82" version.
Understandable for a standard nosewheel airplane, but lots of guys with big nosegear or a tailwheel conversion might want the 88-incher.
Ditto for C180 guys who might want to use the 182 STC data as basis for a field approval for the C58 or C66.

I'm curious what the rpm limit is for the Ponk 470-50?