propeller redesign

[sbar]

Hi guys!!

I have this problem:

I have the results of a self propulsion test for a stock propeller..

I have a software that calculate the optimum propeller using the lifting line model..

Can I compare the results of the test with the results of the software??

thanks a lot!!

[daiquiri]

Any two things can be compared, and the result of the comparison will show the degree of difference between them.

That said, what exactly is your goal?

[gonzo]

Unless the software is based on the same physical test they used on the propeller, comparisons may not be accurate.

[daiquiri]

Gonzo, one can also compare apples to bricks, or to Beethoven's music - if that is what one wants.

Fact is, Sbar should elaborate a bit more his question, because it is not clear what is the purpose of the comparison and what characteristics are to be compared...

[sbar]

Thanks for the answers..

The goal is to optimize the stock propeller in terms of officiency..

[sbar]

sorry..

efficiency..

[daiquiri]

Ok, let's try to make it look more neat and organized...
1) What kind of self propulsion data do you have and for what type of propeller?
2) What software do you intend to use?
3) Are you trying to find a new, more efficient, stock propeller as a replacement for the existing one, or
4) are you trying to re-pitch the existing one?
You will have to give as much info as you can about your boat, in order to get some help from forum members. It means (at least) type or model name, dimensions, weight, number of engines and their type, power and max rpm, boat's cruise and max speed (actual and desired) etc.
Cheers

[sbar]

parli italiano daiqiri?

[daiquiri]

Yes, but only in private.
We are all trying to use English in the public forum.

[sbar]

How can I write you in private?
I can't send you mail..

[Submarine Tom]

Left click on his name and send a "private message".

How do you propose to change your propeller or are you going to replace it?

Commercial props are a huge compromise and usually pretty well suited to the job even though not very efficiently. I don't mean to discourage you but you may end up with an impractical, although more efficient, prop. On the bright side, you will have learned a lot and, if you pass that on, so will we...

-Tom