From two to three blade on a 0540

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FROGMOSS
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From two to three blade on a 0540

Postby FROGMOSS » Fri Dec 16, 2016 12:39 pm

I have a Signature Series 72" two blade from Water Walker on a 0540 angle valve, the two blades are in good shape and only about 2 years old. To go to a three blade, could I get another 72" Signature Series blade with the same tip weight and a three blade hub? Or should I bite the bullet and go with a new three blade prop? Thanks.

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Deano
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Re: From two to three blade on a 0540

Postby Deano » Fri Dec 16, 2016 1:47 pm

Yes, a three blade hub and additional, balanced blade. :thumbleft:
There is no reason of which I am aware, that a new prop would be necessary.

I would however, take the two existing blades to Andrew so he can balance all three at the same time.
Last edited by Deano on Fri Dec 16, 2016 1:57 pm, edited 1 time in total.
"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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AirRanger
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Re: From two to three blade on a 0540

Postby AirRanger » Fri Dec 16, 2016 1:49 pm

You may want to contact Water Walker. Unless you are over spinning (RPM) the two blades now at an optimal pitch setting, you may have to consider three narrower style blades that can be properly pitched to get the most from the prop. What you don't want to do is under pitch three wider blades to achieve the prime RPM. I am certain others will comment on this as you have a very popular prop and engine.
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Deano
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Re: From two to three blade on a 0540

Postby Deano » Fri Dec 16, 2016 2:01 pm

The initial thrust tests were done with a 72" 3 blade Signature on an angle valve O-540, IIRC.

I thought I could find that, but it must have been on my last computer that puked.
That is were the initial 4 lbs thrust / per HP benchmark came from. As far as I remember,
I think it pulled 1200 ft/lbs thrust with the 300hp angle valve o540 they were using.

The only thing I've seen comparable with those blades, is I have a friend that runs a long two blade hub (74") with the blades over pitched to allow for spraying it with a 100 hp (I think) shot. The beauty of that arrangement is that when running extra pitch, it is very fuel efficient w/o the button, but if he needs it, it becomes an animal when sprayed.

The ability to do that with that arrangement, has changed my mind about the value of installing nitrous on a DD airboat. If you are spraying yours, it is a thought. If not, the 72" three blade is probably the best bet if you are making the power you should be with a healthy av o540.
"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


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