Tuesday, May 3, 2011

Mini-Z Visit to a Virtual Wind Tunnel

Over the past week I have been playing with a CFD - Computational Fluid Dynamics software package trying to model the aerodynamics and estimate the drag and down forces on a typical Kyosho Mini-Z.

After struggling with the software itself and having to (re-)learn the basic concepts of fluid dynamics, I am starting to get results that are at least in the order of magnitude of what should be expected.

As can be seen from the picture above, in order to get the simulation to work I had to sacrifice on the 3D model geometry. It may be possible to add features gradually to the current model and see if and how the results change.

So far, for a speed of 10 m/s, the results indicate a drag force of 0.084 N and a down force of 0.1 N.

If I am not mistaken, this is the equivalent of masses of 8.6 g and 10 g.

That is, the horizontal resistance offered by the body at this speed (drag) is equivalent to carrying an "extra weight" of 8.6 g.

At the same time, the total down force generated by the body is equivalent to an "extra weight" of 10g. This is the total down force, not only the portion generated by the rear wing.

The numbers seem a bit high, higer than I expected at least, but are at least in an order of magnitude that is comparable to the car weight.

I'll play a bit more with the model, for example by changing speeds and increasing the rear wing angle, and post the results.

For complete results of the Mini-Z MR-03 CFD "virtual wind tunnel" simulation click here.

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