I had a few of the more experienced members in our program take a look at/advise this build (we have some individuals who have had years of launching rockets, even before university, L3s, etc). The rocket did fly successfully once before this event on smaller scale models to validate the system and stability (so there was a engineering validation process of sorts).
We have found that a lot of the college L2 fliers have two flight, their L1 cert flight and L2 cert flights. It's great that you have more experience mentors. Did your smaller scale rocket fly successfully on smaller motors and successfully recover? That is usually something you would want to do before risking the full up model. Did your full up model fly on smaller motors to lower altitudes and successfully recover?
I understand exactly what the sim is saying and doing. Of course, dynamic stability is one where the math is often less helpful than experience (I don't have an accurate matrix of stability derivatives for this rocket), which is why I brought it here to get more feedback on acceptable ranges. I was looking more for that "practical experience with rocketry" to go with the sim. (on a side note, those practical experiences have yielded answers online anywhere between .5 to 3 to "I've launched my rocket up to 10 cal and it was fine!" to even "overstability is overrated," paraphrasing of course. It's so system dependent!)
I hear where you are going. You didn't quite trust the results of your sim so you came here for clarification and didn't get any. The responses were all over the board, from it's great to it's bad. It sounds like you never got a good answer to your question, from here or anyone on your team. That probably should have been a red flag.
At least on our team, often the professors aren't making the go-no-go calls. Rather, it's the experienced students in the program, program leads, and the FAR guys.
Did you ever have an actual Flight Readiness Review of the rocket, all of it's systems, procedures, launch site requirement, etc. where there was one decision authority that said Go-NoGo for the launch? Or was it kind of a group thing where everyone put in an opinion and the majority decided to just go ahead? When individuals want to launch large rockets, it's pretty much up to them, with RSO approval. That can work for a college teams too, sometimes, but if you really want to learn what commercial engineering is about, you should do the mile stone gates with the entry and exit criteria and that includes a flight readiness review with a competent and knowledgeable decision authority.
Out of curiosity, and personal learning, why should I have not flown the rocket? At least from my perspective, it was a rocket that had flown before, was simulated to be stable, and was checked off my multiple people more experienced than I. In the pursuit of developing my own go-no-go conditions, what would people have improved knowing before calling "go" on this launch?
Unless I mis-understand, the full up rocket had never flown before (The rocket did fly successfully once before this event on smaller scale models) , only a scale model. You were asking here about stability, so what was simulated as stable? You weren't sure? From what I understood, it was the stability of the sustainer that was questionable. Was there a difference between the smaller scale model and the full scale model? My opinion is that if you were not sure of the stability of the whole rocket, the booster and the sustainer, then it shouldn't have been flown.
My opinion is that if your team had included the system engineering processes in the whole building and flying of this rocket, many things, including the stability questions would have been brought forward and solved well before the flight had take place.
Have you had a post-flight review? Has everyone gotten together and determined a cause of the flight failure?
I'm sure you'll have many more successful flights.
