going to a lower pitch: yes, no, maybe so?

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FP1201
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going to a lower pitch: yes, no, maybe so?

Post by FP1201 » Sun Dec 28, 2014 10:01 pm

PE90 came with an Air Props 66lxl34 paddle prop. Now it turned it without perceivable issue, but never really got above about 2500rpm. (Holly 2300 2V, headers w/o mufflers, reconditioned Bendix mag.)
Tried an old Kirkland 66x36 and it turned maybe 2600rpm.
I see a 66lml32 in the classified for $250.
Now what I have works/worked alright, but this is a heavy boat subjected to ice, snow and deep (>1' to 6') water.
The paddle prop has tip damage and I'd expect it to cost at least a couple hundred to have the leading edge/tip replaced and round trip shipping.
Years ago I asked Tom Jeffords if he had any idea why the engine just wouldn't turn up and he said some of those engines had cam shafts that just wouldn't allow the engine to get into the 2,800rpm range...course there's really no way to know without pulling the camshaft.
Questions: Go ahead and spend the money on having the paddle prop repaired?
Buy the 66x32 thinking it'll pull a little harder and the engine will turn a higher rpm?
Just stick with the 66x36 that doesn't have as much thrust as the 66x34 made with relatively the same engine speed?
AFTER it's back in the water and back in use, then I might go the weedeater or carbon fiber route, but unless it's too good a deal to pass up, I don't want to put "another thousand" into it.
Mother Nature plays to win, and if she doesn't get you, her bitch of a daughter Krama will.

Gary S
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Re: going to a lower pitch: yes, no, maybe so?

Post by Gary S » Mon Dec 29, 2014 6:08 am

If you have a wood prop with tip damage your running on borrowed time. If you can't get a composite prop I think I would spend the 250 and try it. If it doesn't work out you could try and resell or hang on to it for a spare.

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Deano
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Re: going to a lower pitch: yes, no, maybe so?

Post by Deano » Mon Dec 29, 2014 9:15 am

I certainly can understand the 'not gonna put another grand into it' sentiment.
However, putting a carbon fiber prop (a real one) is the best answer from every standpoint except the financial one.

Having been faced with the same reality a few times in the past, I've opted for the new(er) CF prop every time and have not regretted that decision yet. Part of the justification for doing that is that (provided you buy it right) you can always sell it and recoup your money, or use it on another boat.

If I were you, I'd call or PM Plumcrazy on here and see if by chance Water Walker either has some used or demo Cypress blades that you could acquire for a reasonable amount. You could very well end up surprised just how well that little guy is capable of running with a good prop tuned to his capabilities.
"The suppression of uncomfortable ideas may be common in religion and politics,
but it is not the path to knowledge; it has no place in the endeavor of science."
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FP1201
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Re: going to a lower pitch: yes, no, maybe so?

Post by FP1201 » Mon Dec 29, 2014 2:53 pm

Gary S wrote:If you have a wood prop with tip damage your running on borrowed time. If you can't get a composite prop I think I would spend the 250 and try it. If it doesn't work out you could try and resell or hang on to it for a spare.
I took the 66x34 paddle prop off as soon as I got it home. The 66x36 was a "spare" and while it has more pitch, it was a standard/narrow width.

My though was the lesser pitch 66x32 wouldn't go as fast, but would puch harder by allowing the engine to get into the higher rpm's or am I over thinking it.....I would thinnk the 66x34 paddle would move a whole lot more air, but maybe it's too much for the engine (unless the engine isn't capable of turning more than 2600rpm.) :?
Mother Nature plays to win, and if she doesn't get you, her bitch of a daughter Krama will.

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WhirlWind Propellers
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Re: going to a lower pitch: yes, no, maybe so?

Post by WhirlWind Propellers » Tue Dec 30, 2014 12:25 am

You could take the guess work out of which exact fixed-pitch prop would be the best match for your PE-90, and take advantage of all the improvements you would get with an adjustable pitch composite propeller. The beauty of adjustable pitch is being able to tune your propeller to your engine's exact power output and RPM, and gain peak performance.

And, as the general benefits of composite vs. wood have been discussed often here on SA:
http://www.southernairboat.com/phpBB3/v ... 33&t=64407

Your conditions of moisture and ice are not friendly to your wood propellers. Wood retains moisture which can severely affect balance, longevity, and safety. I would say that you would benefit more than some in spending a few extra dollars on a composite propeller.

For a PE90, if yours is a 4 Cyl 150 HP, I'd recommend a 2-blade Whisper Tip 66" diameter for $1590. If you find anything used like this, I would be happy to help evaluate it.

Sincerely,
Patti
:proud:

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grey owl
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Re: going to a lower pitch: yes, no, maybe so?

Post by grey owl » Tue Dec 30, 2014 9:20 am

You mentioned that you are running on ice and snow, are you running the shoulder seasons during freeze-up and thaw? I don't have any suggestions for what pitch prop to run but do want to comment on composite vs. wood.
I want to predicate my thought by saying that I run primarily during freeze-up and thaw, once the ice is in I'm on to snowmobiles fairly quickly. Composite props are by far the better performer relative to thrust but in my conditions they don't last as long as a cared for wood prop. we have had a lot of people in my area try composite props and where everyone has loved the thrust performance they have mostly all gone back to wood as the composite props aren't taking the abuse of the environment with ice going through the prop. The leading edge seams to be fine but the body of the composite props aren't holding up compared to the wood props with wire tips.
Im not trying to start an argument, this is my personal experience and is based on my specific environment running mostly thin or broken ice. if you are running mostly well frozen lakes I don't expect you to notice this issue.

Another thought is paddle vs. stick. I run a 540 on a 16ft fiberglass boat and have both paddle and stick props. On very sticky days with slush you may enjoy having a paddle prop but with the snow you can't beat the performance of a good old stick prop. There is very little friction from snow on a good day so it makes it easy to throttle up getting speed up then backing down to 1200 rpm while holding a good speed (70mph ish). The paddle prop will lend itself to higher fuel burn, higher engine heat and a much lower top end as the paddle prop will create quite a bit of drag when you back off the throttle.

Not knowing your exact conditions I want to reiterate that this is my experience in my area. we also rarely run during the summer as there is too much boat traffic and no need to run a scoot, what we call are boats as they are different from the average airboat.
cheers
Will

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WhirlWind Propellers
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Re: going to a lower pitch: yes, no, maybe so?

Post by WhirlWind Propellers » Tue Dec 30, 2014 1:33 pm

Will, I appreciate your comments. We have hundreds of propellers operating in extreme ice and cold environments, and we rarely see blades needing repair. People using our blades in ice boat applications cannot afford to have propeller durability concerns while operating in isolated extreme environments. We use an electro-formed nickel leading edge protection shield, the same as used by commercial passenger turbo propeller aircraft. There is nothing more durable than the electro-formed nickel for propeller blade leading edge protection. Your comments might be referring to the smaller composite propellers such as Ivo and Warp that don't have very good leading edge protection. Our composite blades with the electro-formed nickel will be far more durable than wood, and if you do take large pieces of ice through the propeller, composite will not shatter like wood.

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FP1201
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Re: going to a lower pitch: yes, no, maybe so?

Post by FP1201 » Tue Dec 30, 2014 8:49 pm

Thanks guys! I live on the Eastern Shore of Lake Ontario where it's very much like the ocean and inter-coastal waterway. The man I bought it from ran the St. Lawrence out of Clayton NY. He used it exclusively as an Ice-boat to travel to/from the Islands.
First off I haven't run the boat in at least two years, but when I did, I ran it year round (except the bitter cold) the hull is aluminum and has a 3/8" polymer bottom. I've run it across snow covered corn fields, thawing/just freezing ice, as well as foot thick ice, creeks, streams, cat-tails, pretty much anywhere there's water. It's too heavy to run dry; it will for a little while IF you make a running start at it.
I want to try ice fishing this year and with the warm weather it'll be February before the Lake is frozen over. In the summer I stay on the edge of the lake, and in the marshes, and bad ju-ju as it is, the water is usually too deep for ground effect. I suppose I'm going to have to run it while taking notes on speed, RPM, oil temp/pressure, etc.
I'd like a Whirl-wind, but at this moment it's out of the question.
Biggest thing is when I need to climb up, it'll do it...sliding backwards into the water can make for a very bad day.
Mother Nature plays to win, and if she doesn't get you, her bitch of a daughter Krama will.

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