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Blade definition w/o defined polars
Please allow a blade to be defined geometrically by airfoils without assigned polars.
There is an obvious workflow to use QBlade to find an optimized blade, and then export that blade geometry to CAD software for manufacture. But, CAD software doesn’t like exported geometry files with an open trailing edge. This leaves us with two paths:
A: Quickly generate standard airfoil sections, calculate polars, find the optimum blade, replace standard airfoil sections with closed airfoil sections for manufacture, export geometry to CAD.
B: Start with standard airfoil sections, create closed airfoil sections, calculate polars for closed airfoil sections, find optimum blade, export geometry to CAD.
Path A wastes time by generating a ton of polars for closed airfoil sections which are never used for anything. Path B forces the creation of closed airfoil sections which might not be used, and the calculation and use of polars for closed airfoil sections which are not numerically optimal. All of these issues would be solved if we split the workflow into two parts. The first part is doing all the theoretical work with nominal airfoil sections and polars. The second part is converting from the theoretically ideal geometry to geometry for fabrication. This is quite easy if we are able to simply replace theoretical airfoil sections with more fabrication friendly ones in the blade definition section.
In lieu of allowing use of airfoil sections without defined polars in blade definition, a way to quickly copy polars from one section to another, or even the ability to select a default placeholder polar for geometry definition would be appreciated.
Hi Todd,
generally the STL file should be closed at the trailing edge. Maybe this is not working in your case since your geometry is very small and the threshold to detect whether a TE is open is too large to detect this. I have reduced this threshold so in the future it should work. Also, at the moment someone is working on the implementation of a STEP export function, and I hope to have that integrated in the near future.
Best,
David
