Imagining a LEGO Technic Aero Hawk helicopter taking flight

Oct 23, 2020 | FloEFD

Simcenter FLOEFD can make the seemingly impossible come true

Executive summary

The subject of this white paper, Simcenter™ FLOEFD™ for NX™ software, was selected as the tool to analyze the possibility of the LEGO® Technic Aero Hawk helicopter taking flight. Using the new sliding mesh technology of Simcenter FLOEFD to simulate the main rotor’s rotation, this study serves as a good test to see how Siemens Digital Industries Software’s computational fluid dynamics (CFD) simulation tool would handle the rotation of more complex geometry

Karl du Plessis Technical Specialist

Siemens Digital Industries Software

Simcenter FLOEFD is a highly sophisticated CFD tool. Its main objective is to enable engineers to make design decisions as quickly and simply as possible, without having to perform the thermal-fluid analyses that traditionally require extensive expertise and patience. Simcenter FLOEFD transcends the inherent obstacles of traditional CFD through innovative and ingenious technologies.It is not impossible to believe that someone has looked at their LEGO Technic Aero Hawk helicopter and thought about what it would take to make it fly. It is also not impossible to believe that person was likely an engineer. So, how could a LEGO Technic Aero Hawk helicopter take flight? With the help of Siemens’ Simcenter FLOEFD software’s CFD tool, perhaps anything is possible, even making a plastic helicopter fly. 
Figure 1: The CAD model of the LEGO Technic Aero Hawk helicopter. (
The next step is to load the model into NX as-is, with only an additional rotating region part (simple cylindrical component) modeled to represent the rotation region, that encapsulates the main rotor at a rotor speed of 300 rotations per minute (rpm). Then, set the computational domain size and make use of a relatively coarse base mesh as a start with local mesh refinements to control the level of mesh resolution in the rotating region and on the helicopter. A satisfactory mesh resolution generates approximately one million cells. Surprisingly, Simcenter FLOEFD had no trouble creating the mesh, even with all of the small geometric features and unnecessary narrow channels between the stacked LEGO blocks.
This is obviously wasteful, and some time would need to be spent cleaning up the CAD model. Nevertheless, there is curiosity as to how Simcenter FLOEFD will respond, leaving the model as-is in order to test the solver stability.

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Computational Fluid Dinamics

Simcenter FLOEFD is the only fluid dynamics simulation software which is really embedded into CAD.
It is powerful, accurate and simple to use.
FLOEFD is distributed in Italy by BSim Engineering.