AeroDyn: RElm produces ill-conditioned DR


I´m trying to run a multi-body-simulation, which is using AeroDyn V13, but i can´t start it because of an error with my AeroDyn input file.
First of all, i found two different versions of input files, one defining the blade elements by RElm and DR, while the other one used the terms RNodes and DRNodes.
Are there any differences between these two Versions?
When using the following Numbers, i get an error massage saying “RElm(2) produces ill-conditioned DR(:)”. I already read the FAQ about Nodes ( and the AeroDyn Documentation, but i can´t figure out what´s wrong with these Numbers. the Hub-Radius of my model is 1.565m.

2.565	2
3.865	0.6
5.165	2
6.365	0.4
7.665	2.2
...		...

thanks in advance!

Dear Timo,

If I recall correctly for these old versions of FAST and AeroDyn, the FAST documentation used RNodes and DRNodes and the AeroDyn documentation used RElm and. Regardless, they are equivalent.

If you hub radius is really set to 1.565 m, I don’t see any problem with your RElm or DR data for these first five nodes. Could the problem be in one or more of the more outboard nodes?

Best regards,

Dear Mr. Jonkman,

thank you for your quick answer. The Numbers of RElm and DR were indeed correct, i found the problem in the multi-body-simulation program, which is using AeroDyn.

Best regards,