Brad Christy

Tartilla,

The trailing edge of the working face is all that matters. Anything "behind" that is simply there to materially support the working face.

For what it's worth, adding rake just enables additional rendering of thrust from the water as its being forced rearward and slung outward, where it would just be cast off without it. Essentially, you're just adding blade where there's water to wring thrust from. It consumes additional energy to do so, and also changes the lift characteristics of the blade, as well, so it's not always a feasible feature to implement.

Thanks. Brad.

Wildman_grafix

If all the blades are the same, you would hope on these expensive of props they would be.

On bravo style props everyone I have ever had worked on the blades have never been the same.

Brad Christy

Wildman,

I don't disagree at all, but, as a MFR, it's not a shocker to me at all. A Bravo is $800. A Herring is $8000. We can buy six or eight labbed, matched blade Bravos for the cost of ONE Herring. Bravos are cast and hand finished. There's GONNA be variances. What would guys like Brett do with their time otherwise, right?

Thanks. Brad.

Wildman_grafix

Exactly, at least you would hope. Since I am not a buyer of 8K props I do not know, lol.

Twin O/B Sonic

I get that and wasn’t really even considering that.

My point/question is, based on descriptions above, if I cut/change the angle of the trailing edge of the blades, this should change rake correct?

On variability of “as delivered” wheels, always depends on where from.

I went w/a buddy to pick up his, as delivered 30” Cleavers from his trusted prop shop.

According to his guy, I was front and center, there was +/- 3” in pitch.

These we’re from a west coast guy w/a known name and validated what we all thought.

Brad Christy

Gary,

Changing the angle isn’t really what you’re after. It’s blade area in the right place. Think of rake as an extension of the working face of the prop blade, in the area the water will be headed to as it is forced rearward and slung outward.

Without welding material back on, you will only be able to reduce effective rake. If you remove material from the trailing edge toward the tips, that will reduce rake. But if you remove material from the trailing edge toward the hub, it won’t really increase the rake, as it won’t extend the distance the water will stay engaged with the working face of the blade. It will make the prop easier to turn, though, but at the sacrifice of lift (if memory serves correctly).

Thanks. Brad.

Twin O/B Sonic

Thx Brad.

You did a great job of explaining it and is what I was thinking but couldn’t explain.

Which is different than orig posts.

At least my understanding of them.

If they’re determining rake by putting a protractor on the trailing edge of A blade, that means if I manipulate that edge, I change rake.

Which I did not agree with.

ICDEDPPL

Rake is easy to see.

15* rake :

ICDEDPPL

18* Rake
You can see the "bend" where the blade is further from the shaft

ICDEDPPL

On my heavy straight bottom 15* rake is slower than 18* rake ...it grabs harder at idle during a shift, rpm drop is significantly more than an 18*

18* carries the bow better I`m told and that makes sense , less boat out of the water .(3mph faster) Doesnt drop rpm at shifts, that part is really nice .