Sampo and all,
First thank you so much for the enjoyment that you have provided to this born again rocketeer. My son was working on his space exploration merit badge for boy scouts and I was telling him how we used to design and build rockets by attaching a string to find CG, making a cardboard template to find CP and swinging it on the string over our heads to test for stability. That got me to thinking, "There must be a better way now," and a quick Google search led me to OpenRocket. I was even happier when I discovered the price because, just to goof around with, I would never have shelled out the money for RocSim.
I do have a question though. As I got back into rocketry, I found what I thought was a really cool Design of the Month on the Estes website. It is a spin stabilized, 2 stage rocket called the Tao. I decided that would be the first rocket that I was going to build since coming back into the hobby. After it was built, I found several threads on TRF saying that it is a potentially unstable design.:cry: In fact one even claimed that the designer was never able to get it to fly, but submitted the design anyway. So I never flew it; however, when I found out OR could simulate spin stabilization I decided to try it out to see what it said.
I modeled it in OR12.09.1(1). Since I could not accurately model the "dog-legged" fins, I decided to try canting the entire fin to introduce the rotation. When I got the cant to around 6 degrees it showed the design as stable with a predicted altitude of 1428ft! I was ecstatic, there might be hope for this rocket yet. However, now with the release of OR13.05 this rocket remains unstable no matter how far I cant the fins. I have attached the Tao model. Can someone please explain what happened?
PS. Now that OR13 has the ability to model booster stage recovery, I will have to add that to the model
Thank You!:clap: