Prop selection

Airboat propeller discussion.
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Cmcintosh721
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Prop selection

Post by Cmcintosh721 » Sun Aug 09, 2015 7:01 pm

I have a 406 525hp with a stinger 2.68 and not happy with the prop I have looking for a little lower cruise rpm and most all low end push. It's on 14x8 Alumitech

Scarecrow
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Re: Prop selection

Post by Scarecrow » Sun Aug 09, 2015 7:30 pm

Is the prop you have on there now a secret? :roll: :rebel: :rebel:

Cmcintosh721
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Re: Prop selection

Post by Cmcintosh721 » Sun Aug 09, 2015 8:04 pm

No sir I have a water walker Maximus just seeing what options are out there is there anyone that will demo props before you buy them

Scarecrow
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Re: Prop selection

Post by Scarecrow » Sun Aug 09, 2015 8:18 pm

I'm sure the 3 major makers will be glad to help you. Get in touch with Danny Sauls, PTR, or Plumcrazy they are all on SA. :thumbleft: :rebel:

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DAGWOOD0520
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Re: Prop selection

Post by DAGWOOD0520 » Tue Aug 11, 2015 10:58 am

What RPM are running the engine up to static at wide open throttle?

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WhirlWind Propellers
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Re: Prop selection

Post by WhirlWind Propellers » Tue Aug 11, 2015 5:46 pm

Agreed, we need a little more information.

What RPM does your 406 need to turn to make the 525 HP?

What WOT RPM do you turn on your current set up? And are you running a 2 or 3 blade, and what diameter?

Sincerely,
Patti
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plumcrazy
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Re: Prop selection

Post by plumcrazy » Tue Aug 11, 2015 6:14 pm

your gear selection is off for the max .. a four blade falcon would be my choice for the 268and your hp

Cmcintosh721
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Re: Prop selection

Post by Cmcintosh721 » Tue Aug 11, 2015 7:07 pm

Running a 3blade I'm turning the motor 5600 static 5850 on the water and it makes 527 at 6600

airboat83
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Re: Prop selection

Post by airboat83 » Tue Aug 11, 2015 7:11 pm

3 blade r works great for me. Would recommend it..80 inch or so..

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WhirlWind Propellers
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Re: Prop selection

Post by WhirlWind Propellers » Wed Aug 12, 2015 4:25 pm

OK, thanks for the info. I looked up the HP curves for a few high performance 406's putting out 525 HP in the mid 6000 RPM range. Around 5000 to 5600 RPM they were putting out about 500 HP. Torque peaked around 4800 RPM, but the engine continued to make power with RPM up to 6200 for the ones a I saw on the actual dyno. Every motor's a little different.

If I assume you are producing about 500 HP at 5600 RPM, with your 2.68 reduction the prop is turning between 2000 and 2100 RPM.

For this type of set-up and slower turning RPM, you would benefit from a longer diameter. Can you fit a larger diameter? I would recommend our 3-blade Whisper Tip SW 82 or 84" (15" wide) or you might consider a 4-blade in our Whisper Tip EX 79.5" (13" wide).

Sincerely,
Patti
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Deano
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Re: Prop selection

Post by Deano » Wed Aug 12, 2015 10:05 pm

Having a 2.68 gear and a cam that has you turning 6600 rpms does not make for
the best combo if the intent/desire is to attain a low rpm cruise and low end push.

Unlike what has been surmised, if you are making 527 @ 6600 rpm, I don't think you are
making 500 hp at 5600 rpm. If you were, your boat would be a tractor with the current prop.

It would seem very unlikely that 1,000 rpms would only net you an additional 27 hp. (~ 5%)

As Plum pointed out, Falcon blades (@2450 vs 2200) are better suited to your gear and cam.
"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."
- Carl Sagan

Cmcintosh721
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Re: Prop selection

Post by Cmcintosh721 » Wed Aug 12, 2015 10:28 pm

I think I'm going with the proven sensenich R what's the difference in the R and the NGR

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Re: Prop selection

Post by pgalmiche » Wed Aug 12, 2015 11:30 pm

I would go with the 3 blade 80" sensenich S . I have 5 airboat with motors from 450 hp to 600 hp and 2.31 belt drives . I find the super wide 3 blade has more low end push than the 3 and 4 blade r series.

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