I am developing a free program for finding the drag on rockets based on flight data, and I need your help! I need data from as many rockets as I can get in order to make sure my program is accurate. If you already have the information I need (below) from a previous launch, send it my way! If you have a rocket and a recording altimeter, bring it to the next launch and gather some data! Use your own recording altimeter, or borrow my G-Wiz MC2 and send it along for the ride. Contact me (leave a comment) with any data or questions you may have, or to make arrangements to borrow my altimeter.
Here’s what I need:
- Rocket weight on the pad
- Frontal area (or largest diameter)
- Rocket motor used (allows me to look up the thrust curve on ThrustCurve.org, for finding drag during boost phase — EX motor without a known thrust curve? That’s ok, I just won’t have accurate data for the boost phase)
- Altimeter data (accelerometer AND barometric data would be perfect, accelerometer is the next best, but I’ll take just baro if that’s all you have!)
About my program, DragFinder: The goal is to find real-world drag information by launching real rockets. Programs like RockSim can try to estimate the drag, but when ballpark guesstimates aren’t accurate enough, DragFinder will offer the solution. The program will be freely available for download by anyone, and it will allow you to find the drag coefficient for your rocket as it varies with altitude, Mach number (taking altitude into account), and time. It will tell you the aerodynamic force on your rocket, and even Reynolds numbers (in case you are doing scale models and want to be able to compare flows).
Why would you want to help? Because when I’m done with it, I’m going to release it for free on my website. But why would you want to USE the program? Because it’s almost like having a wind tunnel. For one thing, it can help improve your future simulations. Maybe you have a crazy-shaped rocket that RockSim doesn’t know how to handle — this can help you model it. Maybe you’re planning on launching something really big/high/fast/wacky — this can help you understand the aerodynamic forces better on a scale model first, and help you model it more accurately.
I would also like to make the flight data I receive (along with descriptions and pictures if possible, maybe even RockSim files) freely available on my website. This way others that need similar information won’t have to replicate all this effort to experiment with writing their own rocket software. If you have data but do not want me to include your name on the website, just let me know.
