UPM is a fast mid-fidelity tool for rotorcraft aerodynamics. It is based on an unsteady 3D panel method with a "free-wake" method or a particle method for modeling the wake of wings and rotors.

And she was pale. She had been tired, the patient told her, and she was feeling unsteady on her feet. She noticed that she felt out of breath just walking with her dogs. There had been several ...