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Thread: 3 Blade Versus 2 Blade

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    Eddie Foy's Avatar
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    3 Blade Versus 2 Blade

    Which one is more desirable on a 180 and why?
    "Put out my hand and touched the face of God!"

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    cubdriver2's Avatar
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    Quote Originally Posted by Eddie Foy View Post
    Which one is more desirable on a 180 and why?
    Your such a propeller racist, what about this https://youtu.be/py7AX4eTyIk

    Glenn
    "Optimism is going after Moby Dick in a rowboat and taking the tartar sauce with you!"
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    Depends. Floats? Wheels? Skiis? Off airport or on airport? Want a supersonic (loud) tip of the prop or a more quiet prop on TO? What you think looks sexier? And what the checkbook/wife will allow?

    I like the 3 blade for being not as loud on TO and so do my neighbors. I like the 3 blade for further distance from the ground/water.
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    skywagon8a's Avatar
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    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.
    N1PA

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    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!
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  6. #6
    Eddie Foy's Avatar
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    Quote Originally Posted by stewartb View Post
    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!
    What about a Dash Fifty P-Ponk.
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    I have one, and a Mac C401-86" is bolted to it! I had a 470 with an 88" 2-blade prior to the Pponk. Mo' power, mo' thrust, mo' smooth, mo' better.
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    For what it's worth, find the best airframe you can find. The prop shouldn't be a deciding factor that outweighs the airplane itself. Personally I wouldn't walk away from a good airplane with a 470. A 520 would be my preference but a pristine airplane with a 470 would be better than an average airplane with a 520. 2 vs 3 blades trails behind that.
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    Rob's Avatar
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    For me the airframe / engine / prop choices always gets best answered by addressing the mission, but in this case, since you specified a -50 (not just any O-520) and a C180 (STC's are different for the 182) this choice gets pretty slim, and pretty easy, pretty quick. On a -50 powered 180 the only STC'd 2 blade I can think of is the MT. While this is a great prop on a 470, you will be leaving horsepower on the table with the Pponk. In my experience, it's just not enough prop. There are many field approvals out there for C66 / C58's. I got mine FA'd with ease as a back up, and it does OK. In 86"-88" they are a good match, still leaving a little bit of power on the table, but not as much as the MT. Trouble with these is that they are older than the hills, and good full meat blades are getting tough to come by. In recent years there have been a few C203's FA'd to the Pponk. I have never flown one of those, I expect they should perform almost identical to the C66's since the blades are very similar. I remember Steve having trouble getting these on the STC because of a vibration issue, I'd talk to him about that before I went too far down this path. Conversely there are at least three good 3 blade choices for the -50. The one SB is by far the most popular, and with good reason. I fly overweight pigs for work, so I elected to choose the one that didn't add weight to the nose over the previous 2 blade (MT). Each of these shines in different areas, but overlap quite a bit in the most important stuff. The Hartzell is no slouch, and if the new one gets approved on the -50, I suspect it will knock the MT out of it's current popularity. Take care, Rob
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  10. #10
    Eddie Foy's Avatar
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    Rob,
    I am looking at a PPonk 180 with an 86” 2 blade Mac on it.
    "Put out my hand and touched the face of God!"

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    behindpropellers's Avatar
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    Quote Originally Posted by skywagon8a View Post
    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.
    They had higher compression -U engine that allowed for the same hp at lower rpm, fyi.

  12. #12
    skywagon8a's Avatar
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    Quote Originally Posted by behindpropellers View Post
    They had higher compression -U engine that allowed for the same hp at lower rpm, fyi.
    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.
    N1PA

  13. #13
    Eddie Foy's Avatar
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    Quote Originally Posted by Eddie Foy View Post
    Rob,
    I am looking at a PPonk 180 with an 86” 2 blade Mac on it.
    Does this mean that it has to have a field approval or is illegal?
    "Put out my hand and touched the face of God!"

  14. #14
    Rob's Avatar
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    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
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    Rob's Avatar
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    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
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    2-blades are approved on IO-520 powered 185s. That should be good data for a field approval. I know a few Pponk'd 180s with 2-blades but never gave prop approval any thought. When I did mine Pponk offered a 2-blade installation (probably by FA) but the prop hub I had didn't qualify. What do the logs say about the engine and prop installation?
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  17. #17
    texmex's Avatar
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    Eddie, I've got a 88" Seaplane Prop on my C180 with an O-470 R engine. Yesterday my friend went for a fly in it from my strip behind my house. I walked inside to find my wife sheltering in the lounge room saying it's too loud. No repetive circuits from the home strip. Going outside I could see her point.

    We live in one of those trendy rural area of small farm lots about an hour from a major city.

    I can't afford it at the moment but I can see a three blader going on in the future.

  18. #18
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    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.
    Cessna Skywagon-- accept no substitute!

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    Quote Originally Posted by hotrod180 View Post
    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.
    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.

    [Edited to add this comment] Most of the recommendations I've seen suggest keeping the prop tip speed below .88 Mach, to the prop isn't in the "transonic" mode, where things get really loud. But that is a "being a good neighbor" recommendation, as opposed to a "getting the most out of your engine" recommendation. Most of the 170s and 180s I've seen (and heard) take off appear to have long enough props that they are in that transonic range - which translates to VERY loud.
    Last edited by JimParker256; 11-03-2017 at 09:37 AM.

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    Noise isn't an indicator of thrust. The difference in giddy-yup between a 470 with an 88" 2-blade and a 520 with an 86" 3-blade is impressive.
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    We had our 180 based at a major airport in a tropical climate for a while, operating on wheels, and had to "rev up" a 470-J with a 2-blade prop to 1500RPM in many cases of prolonged takeoff clearance waits just to get enough cooling while sitting on the ground. Moved to a 3-blade, and didn't have a cooling issue anymore at normal idle/taxi RPM. If you are in a similar area, I would recommend a 3-blade for that reason alone.

    Props can cause a great deal of consternation. They certainly did for me with a recent p-ponk installation. I spent hours pouring over forums and thrust calculators, comparing them against new price sheets and used props for sale, but ultimately decided to go for a field approval to keep the same 3-blade that has been on there for years (PHC-C3YF-1RF/F7691). It's in good shape, I know every hour that it has flown, and I already own it. I expect that it will not generate the performance numbers of the newer or bigger props, but I won't know the difference and am confident it will do everything I need for the way I use the airplane. At the point it needs to be replaced, I will be looking at new 3-blades.

  22. #22
    Dave Calkins's Avatar
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    I am a caveman and do not subscribe to all that "thrustcalculator" stuff. If they do not have direct testing, I dont believe them. Interoplation is NOT testing.

    dojo, I plan to stay with a 2-blade (!) for the same reason you are keeping your 3 blade. Also, I will enjoy a lighter weight and 1 less chance for a rock ding to put me outta order.

    However, having flown the 401 hub with big blades on several different 206's and 185's, there is no question they get great traction if you have HP ($!) to turn them.

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    Quote Originally Posted by Rob View Post
    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
    Glad you clarified that, Rob. I was going to write in and then saw the above.
    The MT props are surely the quietest ones out there right now, are they not? The 2-blade MT prop on our 470R has made a dramatic difference in noise, even coming from a 3-bladed Mac prior. Being mindful of care for the prop, a 3-blade MT on the PPonk seems like a good combination for performance and lower noise.
    J

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    Dave Calkins's Avatar
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    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"??!!??

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    Whooshing "zing!"


    Quote Originally Posted by Dave Calkins View Post
    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"??!!??

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    Dave Calkins's Avatar
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    Yes!! that is the sound.

    I was gonna call it a "Whiff"-"Zing". But "whiff" has a negative conotation from my baseball days.

    Whatever, it is not a displeasing and painful sound

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    Rob,

    Re: the below, for what mission would you recommend the 3-blade MT?

    I am waiting on LyCon to deliver our PPonk engine with 8.5:1 pistons and intake work, which should dyno close to 300. Assumption is that the engine should drive a 3-blade just fine at 2,700 (or "x" rpm's).
    Hot, high, heavy and short are typical operating conditions for our 180.
    Thanks,
    Johnny


    Quote Originally Posted by Rob View Post
    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
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  28. #28
    Rob's Avatar
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    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;
    Camp Tebay with Mike.jpg

    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
    Last edited by Rob; 01-25-2019 at 09:24 AM.
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  29. #29
    jrussl's Avatar
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    Quote Originally Posted by Rob View Post
    Something like this;
    Camp Tebay with Mike.jpg

    Take care, Rob
    Absolutely a beautiful place Rob. I sure enjoyed my visit there.

    Thank you!

    Jeff


    Sent from my iPad using SuperCub.Org mobile app
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  30. #30

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    Rob-
    Thanks for the informative post! We fly similarly. I'm typically at or above 3,000lbs.

    Re: the prop strike part of your post, it'd have to be a serious emergency to get me to take off again with a known ground strike on my prop, e.g. I have someone that needs to get to a cardiac center right now.

    The readings of prop durability, MT's splintering saving engine internals, pros and cons, etc. - well, I rarely find myself in a place where a satphone call can't get me home that evening. If I can't get home, I always have my overnight gear and chow for 2-weeks. Hopefully some whiskey, too...

    Thanks again for updating on the MT. Sounds like I'm making the right choice by upgrading from the 2-blade that's currently on it to the 3-blade. I'll have a few weeks to test the PPonk w/ 2-blade before switching, so will report in to the group on the differences.



    Quote Originally Posted by Rob View Post
    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;
    Camp Tebay with Mike.jpg

    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

  31. #31
    Charlie Longley's Avatar
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    I liked the O470R, Leading Edge Exhaust and 88” McCauley combination on my 180. Good combination of power and fuel burn.

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    Quote Originally Posted by Rob View Post
    Hi JohnnyR,

    ;
    Camp Tebay with Mike.jpg



    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
    I've a 180J with a PPONK and a long 2 blade. For neighborly reasons while keeping the weight down and the performance up I'm looking into composite 3 blades. At the Alaska show, after talking to the MT guys I asked the Hartzell guys about a trailblazer for my ride. They told me the company owner recently got a Skywagon and wants a trailblazer for his plane. So if I'm not in a hurry, give them about a year...

    Kevin

    p.s. Both MT and Hartzell said I'll give up a bit of top speed switching to a 3 blade.

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    Link to video test with 3 blade props on p ponk 182. In the video it sounds like the MT makes less noise. My 185 with floats and skis I run 3 blade MT. Maybe a different plane than mine but I won't run anything but composite prop. 8 years and no signs of wear or erosion.

    https://www.youtube.com/watch?v=Lumj1RV5gV8
    Last edited by LUCIFER; 05-19-2019 at 08:18 AM.

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    I spent a little time fixing rock chips this week in my very low time composite prop. When I look closely at my 86" 3 blade aluminum prop on the Cessna I can detect lots and lots of rock ticks on the back of the blades and none needs attention. Composite props have some strengths but they aren't perfect for everyone. If Whirl Wind would extend the nickel leading edge across the rear of the blade? I'd pay extra for that!
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  35. #35
    G44's Avatar
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    3 blade props can be a pain to get to and from the prop shop if you are not close to one and even then can be a hassle. I went thru this recently, no fun, expensive. Just a little something to think about.

    Kurt
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