# How to calculate Propeller Power Curve

Hi All,

I’m trying to find a formula to calculate propeller power versus propeller speed. I have searched online and could not find any formula that I can use.
Any help would be appreciated.

Best Regards,
Mike Yilmaz

You might need to be more specific. Do you mean thrust vs rotational speed? Or power required to rotate the propeller at various speeds? I would definitely include the term “thrust” in your google search for formulae. You’re going to need dimensional info including pitch obviously.

Take a look through this paper, particularly page 12 might help some.

Also this one just for interest more related to azimuth props. Adding a nozzle at the appropriate angle, as seen on drillships, certainly makes a difference in the power consumption curve, though that may not be what you are looking for. There’s certainly more out there on this topic due to research related to Dynamic Positioning system optimization, where available thrust and power are keenly studied.

http://www.marinepropulsors.com/proceedings/MA3-2-Minchev%20-%20Ducted%20Propeller%20Design%20and%20Verification%20for%20Contempor.pdf

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You might have better luck using the terms torque and thrust.

From Wikipedia

https://en.wikipedia.org/wiki/Propeller#Thrust_and_torque

#### Thrust and torque

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In my part of the world, when there are questions about prop’s the go to is
Michigan Wheel.

They used to have a program called, “Prop it Right”. They would ask a number of questions and offer a list of hull shapes in the work sheets that they would send you so you could mark the one most similar to your own… Then the temperature of the water
you would likely be operating in. Then questions about the outboard or engine that would drive the prop.

On my runabout I was informed my prop was a 10x10 when a 10x12 or 10x13 would be more optimal. (with less cavitation) It was like I was stuck in mule gear before and burning fuel much too quickly. .I bought a 10x12 from them and life was sweeter after that as I could get on plane much quicker and without cavitating. The savings in fuel offset the cost of the prop in a couple of seasons…

Michigan Wheel

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They helped me with my 25’ Grady. No complaints. These boys are talking a much bigger scale.

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