i also want to konw how to get these data, why the authors of xflr5 don't provide a detailed tutorial about stability and control analysis topic,many people encount these ralative problem.
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The stability and control derivatives are calculated by forward differentiation, i.e. adding a little increment to the stabilized state, and then making the difference.
AVL uses automatic differentiation.
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first of all xflr5 is a great program! It helps me a lot to understand the design process of an aircraft.
btw: is it possible to implement central differentiation insted forward differentiation, this would incrase the accuracy. But there is no free lunch, it would cost twice the calculating ressouces.
This would be an improvement, but it's considerable work and I'm not sure what would be the benefit given the other approximations made in the calculation of derivatives. More likely I will at some point implement auto-differentiation but this is not a priority.
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hello, how XFLR5 calculates the control derivative?
i also want to konw how to get these data, why the authors of xflr5 don't provide a detailed tutorial about stability and control analysis topic,many people encount these ralative problem.
The stability and control derivatives are calculated by forward differentiation, i.e. adding a little increment to the stabilized state, and then making the difference.
AVL uses automatic differentiation.
Hello André,
first of all xflr5 is a great program! It helps me a lot to understand the design process of an aircraft.
btw: is it possible to implement central differentiation insted forward differentiation, this would incrase the accuracy. But there is no free lunch, it would cost twice the calculating ressouces.
Last edit: Marko J. 2017-02-10
This would be an improvement, but it's considerable work and I'm not sure what would be the benefit given the other approximations made in the calculation of derivatives. More likely I will at some point implement auto-differentiation but this is not a priority.