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Hope this is the right forum, I am looking for an applied approach!

I am interested in modelling the behaviour of CO2 powered rocket cars. These small models are powered by releasing pressurised carbon dioxide from a “sparklet” cylinder. The model cars race along 24 metre long tracks. A typical time to cover 20 metres is about 1 second for a 55 gram car (mass not including mass of CO2 or cylinder) The cars are guided by a nylon line stretched tightly along the length of the track. The cars are launched by pricking the diaphragm that seals the rear of the sparklet cylinder.

We use computational flow dynamics to test the aerodynamics of the designs and this produces data about the aerodynamic forces acting on the car at a specified velocity as well as estimates of coefficients of drag.

There are lots of things we would like to understand about our designs, for example: How do the forces predicted by the CFD work relate to times on the track? The cylinder seems (visual observations) to run out about half way along the track so how do we factor in the coasting period as well as the acceleration phase. Since the cars are not accelerating all the way is there any difference between simple mass of the car versus rotating mass in the wheels. I suspect there is something important going on here as in some races a car that is well ahead in the first section of the race is overtaken in the second section.

Is the optimum mass of the car always going to be the minimum allowed (assuming structural integrity is maintained)?

Being practically minded, I would rather have graphical or spread sheet type models rather than have to go too deeply into differential calculus.

Bob