Prop tuning

[Ivan Kozyakov]

Hi guys!

I'm preparing my propellers for next season and need some advice on some confusing questions.

All ABC propellers have this flat area (marked with arrows). Is this just a characteristic of the metal casting, and should I round it off? Or should it remain flat?

photo_2025-12-15_18-54-47.jpg

If I want to reduce the diameter of a three-blade prop, I simply cut off part of the blade (marked in white), right?

photo_2025-12-15_18-56-01.jpg

Thanks in advance for your answers.

[lohring]

Do not touch the flat area! It provides a lot of the blade's strength. This site won't allow my prop article to be posted. The new ABC props are already changed to provide a lot of the modifications that were done in the past. The high rake, low blade area series have a lot of the changes that a lot of testing showed worked.

Lohring Miller

[fweasel]

That flat area needs to remain flat, with sharp edges to release the water. Same principal with blueprinting the bottom of a hull, sharp edges on the steps and transom .

[Ivan Kozyakov]

I'll ask again because I'm not sure I understood correctly. This isn't my first prop, and I know that the top edge 1 remains flat with sharp edges. My question is about the strange surface 2. Does it look like a simple casting defect? Or is it?

1.jpg

[Ivan Kozyakov]

Do not touch the flat area! It provides a lot of the blade's strength. This site won't allow my prop article to be posted. The new ABC props are already changed to provide a lot of the modifications that were done in the past. The high rake, low blade area series have a lot of the changes that a lot of testing showed worked.

Lohring Miller

I saw an excellent old post on this forum (I don’t know if it’s yours) and the picture from there helped me understand the essence of sharpening the prop. And it doesn't have any additional edges like my prop.

image_80462.jpg

[lohring]

It wasn't my post, but that's the idea. Be careful of too much thinning at the tip. That's where the most thrust is developed and the tips can curl. Send me your email address by PM and I'll send you the whole props series of articles. You probably only want the last article, buy may find the others interesting.

Lohring Miller

[lohring]

It wasn't my post, but that's the idea. Be careful of too much thinning at the tip. That's where the most thrust is developed and the tips can curl. Send me your email address by PM and I'll send you the whole props series of articles. You probably only want the last article, buy may find the others interesting.

Lohring Miller

[vvviivvv]

Hi Lohring,

Could i also send you my email for the articles?

[lohring]

Sure