Tuesday, September 27, 2011

Simulating square rockets

In Apogee Newsletter #296, Bruce Levinson begins to explore how to simulate square bodied rockets, such as those offered by New Way Space Models.  He starts with a standard round rocket with the same frontal area.  This gives a 'best case' in terms of performance because it doesn't account for the affects the square edges have when zipping through the airflow.  In his day job, Bruce works with scientists who model the structure of complex bio-molecules.  So he is inclined to search for a more accurate representation.  Well, his rocket background probably equally accounts for his motivation.  He proceeds to describe and compare 5 other approximations.  If you are interested in simulating odd designs in RockSim, whether square or not, you will find this issue very interesting.  The bad news is that he doesn't come up with a firm answer as to which one is 'best'.  He points out that wind tunnel or altimeter data would be required to determine which one is most accurate.  On a final note, when I make 'what if' models in RockSim, I usually run several versions and then pick the worst case.

For now he's planning to simulate 3-sided models in his next installement in this series. Maybe he'll also fly an altimeter one in one of his New Way models and report back.