YawDyn Tilt & Pitch Moment Output

Hi everybody,
since the purpose of the forum is also the posting of request for enhancements, I will herewith suggest the following idea:

YawDyn should be able to output a channel with the “tilt moment” on the nacelle. I realize that I can compute it with the vector sum of the out of plane moments of the blades, and then projecting it on the horizontal axis (Y). But since all the other forces and moments on the top of the tower are available (channels: 25,27,29 forces; and 17,21 moments), the tilt moment would also be handy to have as an output channel.

Then I have a question/suggestion about the pitching moment: it is my understanding that the channels 36-38 or 46-48 provide the pitching moment around the 0.25*chord axis, computed using the CM provided in the Aerodyn files. If this is correct, I would appreciate the possibility of having an additional input, say “Axis offset between chord/4 and pitch axis”, in order to get directly the real pitch moment around any axis of rotation, not necessarily coincident with the chord/4.

Thanks a lot & best regards from Italy!



We haven’t done any enhancements to YawDyn in quite a while. As a matter of fact, we are debating whether or not to modify YawDyn to work with the overhauled version of AeroDyn we plan to start working on this June. I’m torn between being able to keep a simple, first-check program such as YawDyn and having to face the reality that we have very limited staff and budget for code development.

If you need features YawDyn cannot supply, I suggest you consider using FAST instead.

Thanks for the suggestions,


here are my 2 cents (do you say so? :slight_smile: )

A simple, first-check code is very useful. FAST can do everything, but requires so many inputs that most of them would need to be invented, at an early stage of design. At least for the type of work that I am requested to do at my present company, where sometimes I have to explore quick and dirty hypotesis, without a lot of deepening, I appreciate a lot the simplicity and speed of model construction provided by YawDyn. So, at least, keep it “as it is”!

Thanks for your quick answers.

I say “here are my two cents worth.” Sometimes I type it as “here are my $.02 worth.” :slight_smile:

Thanks for the feedback, Claudio. We will keep it in mind when we discuss the AeroDyn overhaul. My original plan was to get it working first with YawDyn because it would be the simplest test.