Unlike fixed wing aircraft which are modeled as a rigid body for many engineering analyses, rotorcraft are often modeled as a multibody system where, for instance, each rotor blade is modeled as a separate body. The Mono Tiltrotor demands a multibody treatment not only because it is a rotorcraft, but also because the suspended cargo pod must be treated as a body apart from the rest of the aircraft.
A challenge in modeling a new kind of multibody system like the Mono Tiltrotor is that the available engineering tools may need modification to adequately represent the system, and the kinds of modifications required may only be known after investing resources in the development of a model. Furthermore, any modification to an engineering tool must be validated to assure it produces useful results.In order to cost effectively develop a multibody model of the Mono Tiltrotor, the open source engineering tool MBDyn was selected. All modifications to MBDyn are developed and published by the open source community, and this same community provides for validation of the MBDyn code. Since the source code is available to anyone, modifications to the code are relatively easy to accomplish. In addition to contributing source code for MBDyn, Baldwin Technology has also delivered to the MBDyn community a graphical pre- and post- processor by integrating MBDyn with the Blender 3D rendering environment.