Problems with cl and cd results in propeller analysis

Hugo Dubourg

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Jun 30, 2025, 12:07:40 AM6/30/25

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Hello, I have a question.

I am currently working with AeroVSP to evaluate the performance of a propeller and I am having some problems with the results. The thrust and torque correspond to the other results I have obtained, but the cd and cl are very different from what I should be getting. In addition, I notice a Reynolds number in the results that does not correspond at all to what I have set in AeroVSP.

Is there something I am doing wrong?

Thank you in advance.

Hugo

adv.png

over.png

prop.png

cl.png

all.png

cd.png

Rob McDonald

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Jun 30, 2025, 11:22:37 AM6/30/25

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The cl and cd of the rotating blade are not useful -- they are in the vehicle frame, not the frame of the blade. Instead, what you want to do is click on the 'Blade' button on the load distribution graphs. This will present the blade loads in the conventions used for blade load distributions.

Rob

Hugo Dubourg

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Jun 30, 2025, 12:03:57 PM6/30/25

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Okay, thank you, I'll take a look at that, but does the Reynolds number of 4.8e-270 not matter?

Rob McDonald

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Jun 30, 2025, 12:11:29 PM6/30/25

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Yes, the results on that page are independent of Re and it shouldn't even be displayed.

There is a recent bug (fixed in my dev version) that made this screen display Re erroneously. I even bet if you refresh it multiple times, the value of Re will jump around...

Rob

Hugo Dubourg

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Jul 16, 2025, 8:04:25 PM7/16/25

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In the end, I used cx and cz to calculate the coefficients cl and cd and transposed them into the plane I was interested in, obtaining very satisfactory results. Thank you very much for your answers.

Hugo

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