Modifying a standard aliminium prop?

Suzuki 30hp standard prop (3x10 - 1/4 x 13) seeing that I have 3 of these props, I thought I'll take one and play with it .... how can I change or modify the cup etc. to give the motor more speed, anyone tried this? Any info will be appreciated ...

Re: Modifying a standard aliminium prop?

I think I've tried about everything on aluminum...
You can add some cup to the trailing edge by starting deeper in the blade than stock...this about takes an English wheel to do it right(without pitch blocks, that is).
You can also add cup to the tip with the right tooling hammer and the correct shaped anvil(sp?).
Another good place to play is the leading edge from about 1" from the hub, draw a straight line to the point the tip curve really starts...FWD of this line, a slight curve built into the blade that makes the very leading edge look as though it is almost parallel to the direction of travel, and it doesn't take much here...infact, the inner half should have more than the outer portion.
Alum props don't like to be bent much without cracking, so try a little at a time and use a template where you can, or build a jig of some sort and after changing 1 blade, make the other 2 match as close as you can get.

Re: Modifying a standard aliminium prop?

Thanx man, I appreciate it .... i'll give it a go ....

Re: Modifying a standard aliminium prop?

walleyehed said:

I think I've tried about everything on aluminum...

Another good place to play is the leading edge from about 1" from the hub, draw a straight line to the point the tip curve really starts...FWD of this line, a slight curve built into the blade that makes the very leading edge look as though it is almost parallel to the direction of travel, and it doesn't take much here...infact, the inner half should have more than the outer portion.

Click to expand...

Hello Walleyhed,

I would like more info on your suggested leading edge modifications.

Is the leading edge bending to increase or decrease the effective pitch?

What are the benefits and problems with this modification?

Is there any more detailed article which I can read to get more information.

Thanks,

Nev

Re: Modifying a standard aliminium prop?

What I'm describing there, is the additon of parabolic Rake...a "scoop" if you will.
It only works when all areas are sufficiently cupped to allow this to work.
The best examples I've seen are the Raker and an RE 3 Mazco. Most of the higher quality SS props have this but at different levels. The Turbo TXP and Lightning have the same feature.
It doesn't really change pitch, it affects Rake more than anything.
I'll see if I can find some written info to post on this...

Re: Modifying a standard aliminium prop?

I have a 14x13 prop and a 13.75x15 prop for my 90HP Tohatsu TLDI motor on a 20' skiff. The 13" prop sets off the over-rev alarm unless I have a really large load, and the 15" prop barley gets into the operating range with a medium load. I can't find anyone who sells a 14" pitch prop for it.

Which prop would be better to start tweaking?