Hi all

can you please explain to me how WT_perf calculates the flapwise bending moment in the .oup file?

I wrote an own code and compared two blades to validate my own program with WT_perf.

All outcomes of the .bed file are the same for both blades.

The first blade I implemented in my own code had almost the same outcomes in the .oup file up to a difference of 1-2%.

For the second wing all outcomes (.oup file) were in the 1-2% range too. But the flapwise bending moment had a difference of 38%

I tried to find a bug in my program but could not find one.

Than I tried to take the thrust force / length from the .bed file and calculate the flapwise bending moment with my numerical algorithm but I got bad values with a difference of about 38% again.

Is there something I am missing. My bending force is always ~38% higher than the WT_perf one. The second wing is rotating a lot of faster than the first one but friction should be of no importance for the flapwise bending moment. Than the Torque should have an even bigger difference.

I assumed a linear function between the forces calculated at each node. What kind of numerical integration is used in WT_perf?

Thank you for the help

Andreas