dewayne6243

Is there a way to measure a prop to determine the rake?

bbladesprops

What style of propeller?

Tartilla

Older post...but I've been trying to measure the rake on my Rolla 5 blade Surface props.

17x25 surface cleavers.

green lightning

You can go to Home Depot or similar and get a angle finder and set it on the trailing edge of the prop to get the angle for the rake number .

green lightning

bbladesprops

Measured in degrees, and increasing in degrees as the blade tips get further away from the transom.
Initially common rake was about 15 degrees.
Our MRI machine measures rake. But, once you look at a few knowing the rake you can get close just visually.

Tartilla

Green Lightning: Thank you for the Herring visual. It's the best so far.
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Brett, thank you for chiming in. Looks lIke I only have about 10-11 ° rake on the Rolla 17×25 5 blade cleavers.

I measured the angle of the rear blade flat, squared off to the hub. These props are from 1992.
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​​​​​​These are on a 30ft Cobalt project (Carrera SS9M) 26° hull with Arneson ASD6s. Currently setup to turn in.

I'm certainly low on the rake, department. As Brett always says, I gotta 'em to get some data. Original Owner never used the 280 tabs to get on plane, even when the hull came with TSRs. BBCs are shoehorned into the front firewall, so weight is forward for sure.

Looks lIke 19 spline to 25 and/or 26 will be part of my hardware soon....lol.

bbladesprops

Rolla propellers were consistently low in rake.

Brett

Brad Christy

GreenLightning,

Not to nit-pic, and I know we all know what prop pitch actually means, but the depiction of pitch is not correct. It shows one end of the dimension line at the tail of the prop and the other at the head of the prop. You can use one or the other, but to show the actual pitch of the prop, it must be the same point on the prop from starting position to ending position.

Carry on.

Thanks. Brad.

Tartilla

Brad,

Good eye. Seems Herring messed that one up. We now live in a world that gets so complex that things like this will creep through more and more.

They still have the best visual for prop rake.

Art