Which one is more desirable on a 180 and why?
I like long prop performance. That said, for a 470 I'd choose an 88" 2-blade. For a 520 I prefer an 86" 3-blade. And given the choice I prefer a 520!
They had higher compression -U engine that allowed for the same hp at lower rpm, fyi.Another consideration besides 2 or 3 blade is the shape and dimensions of the blades. By varying the blades characteristics an argument can be made to favor either choice. There are many choices today as opposed to 20 years ago. The later 180s starting in 1977 (as I recall, maybe 1979) had a lower maximum rpm along with a longer 2 blade prop. This was quieter than the previous model.
Yup, thanks. It is a 90" prop isn't it? As I recall the performance was good even though it "sounded" like it wasn't putting out the power.They had higher compression -U engine that allowed for the same hp at lower rpm, fyi.
Rob,
I am looking at a PPonk 180 with an 86” 2 blade Mac on it.
Makes sense, because the 88” prop @ 2600 rpm is going about .887 Mach, whereas the 86” @ 2700 rpm is going about .90 Mach. However, many people perceive the 3-blade prop noise to be “less bothersome” than the 2-blade’s prop noise.IMHO a C180 with a stock 230hp 470 and 88" 2-blade prop at 2600 rpm is quieter than a Ponked C180 with a 86"(??) 3-blade at 2700.
I just read that and realized I made a confusing statement. For clarification, there are no 2 blades props on Pponks STC for C180's. Flight Resources does have an STC to put a 2 blade MT on a -50 powered C180. I owned one for ~1year. It did not fit my mission profile well.
Take care, Rob
Johnny, my thoughts, having heard an MT takeoff yesterday, are that its not so much quiter, but a different sound.
Yes, it seems "softer". Not a "CRACKLE", made by the McCaulley. More like a "ZING"??!!??
Sorry Eddie
I am in a very Internet challenged area. Short answer, Yes, there are no 2 blades on the Pponk C180 STC. There ARE on the 182 STC, and there have been many FA'd to the 180.
The 2 blades I mentioned above are both Mac's. They both settle in with a much nicer CG than the 3 blade metal props, but as a general rule, the only reason we hang a more powerful engine on a propeller driven airplane is to drive more propellor.
Light the 2 blade will fly much nicer. After that the 3 blade does everything better.
Alternatively you can replace it with an MT 3 blade. It weighs about the same as a Mac 2 blade, and pulls about the same as a Mac 3 blade. I can not recommend this prop for every mission, but where it fits, it fits very well.
Take care, Rob
Hi JohnnyR,
I would guess that 85%, maybe a bit more, of the time on my 180 (which is very similarly powered to yours) is backcountry style camping. This means the back of the extended baggage stuffed with bags, tents, etc, the baggage plumb full with gear, guns. rods etc, frequently including a 17' Pakboat and a very active dog. This usually means somewhere with no road access, or we would have drove a truck, Jeep, Ranger, or quad. Most of the time there is some semblance of an airstrip, but often times there is not.
In other words, MY mission is to extract as close to a supercub performance as possible, while being able to be a legitimate 2 Pax camping vehicle, and still be able to travel from the southern most tip of the western states to it's northern most point in a reasonable block of time. It means selecting the lightest components, which still provide as close to the same performance as a heavier one. Yes, we've all heard people say 'they didn't fly a Skywagon to fly around light'... guess what? Mine is virtually never light, in fact being an early model it is pretty much always testing the limits of it's GW . But starting out lighter just means I can cram more stuff in, and not have to skimp quite as much. So... for the last 8 or 9 years the MT 3 blade has been about as good as I can get.
Something like this;
View attachment 41114
It probably would have been easier to suggest where I wouldn't prefer it...
Having said all that, and on a bit of a tangent, but somewhat related, I will add this;
Last weekend I got a call from RCC regarding a distress signal originating about 6.7 miles northwest of my strip. As it was, I had just pushed my cub in the barn, so it was probably less than a few minutes from the call until I was parked along side a gorgeous CC FX3 that had suffered an unfortunate mechanical failure. The pilot was unhurt, and his landing area was good, but just a tad short for what he had left. Just the way the chips fell...The end of his roll out put him through a small but sharp washout which nosed the airplane over.
That airplane was wearing the Hartzell Trailblazer (also composite), and while it was scuffed, scratched and bruised, it was most certainly flyable. Because it most certainly had contacted the ground, I have no doubt that had it been an MT it would have been splinters. I am not aware of anyone flying one of those on a 180, but sure would like to know more about them.
Take care, Rob