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Old Oct 11, 2012, 12:51 PM
jackerbes is offline
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USA, ME, Ellsworth
Joined May 2008
18,107 Posts
Thrust generated by a prop in flight is really hard to measure realistically. And we are often using props that, regardless of what the markings on them may say, often have measured pitches that are quite different from the markings.

Not sure if it is helpful to you or not but I like to go to the prop database at and look up a prop by brand and model name or markings. Then I can see a graph of the static thrust obtained in test by various prop testers who voluntarily feed the motor and prop databases there.

That also leads me to a list of the motors that thrust data was obtained with and that is useful information. And if I'm contemplating a prop choice for a plane it gives me a potential thrust to weight ratio to consider and also a theoretical pitch speed.

I don't consider any of it to be empirical but it is certainly enough to get me in the ballpark as far as what might be good to try for props and motors.

Another thing I like about the data there is that the RPM readings for a given prop are all safe or practical to use numbers. They don't report readings that are in excess of safe RPM limits or that caused the motor temperatures to become excessive.

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