Fearoflightning
Well-Known Member
- Joined
- Jul 22, 2015
- Messages
- 92
- Reaction score
- 0
Hello,
I am currently designing a 6" diameter all-fiberglass rocket very similar to the ultimate wildman. The biggest motor that I will ever fly it on is the N5800, which, according to openrocket, pushes it to just over mach 2, so it will be designed to have a static stability margin of 1.5 (with that motor) to account for CP shift forward.
Now this brings me to my question(s):
Should I use four smaller fins, or three fins that have a slightly longer span to equal the same stability margin?
Every missile that I have ever seen has four fins, Why is that? Is there some advantage over three in their cases? Is it just due to the fact that they use active guidance?
To clarify, I am not interested in any aesthetic factor that number of fins provide, and I'm fully aware of the slightly increased weight that goes along with having four fins. I am only interested in any aerodynamic differences. Especially those that work toward my advantage. (i.e. speed, height, both...)
Thanks in advance! I'm sure this will be interesting.....
I am currently designing a 6" diameter all-fiberglass rocket very similar to the ultimate wildman. The biggest motor that I will ever fly it on is the N5800, which, according to openrocket, pushes it to just over mach 2, so it will be designed to have a static stability margin of 1.5 (with that motor) to account for CP shift forward.
Now this brings me to my question(s):
Should I use four smaller fins, or three fins that have a slightly longer span to equal the same stability margin?
Every missile that I have ever seen has four fins, Why is that? Is there some advantage over three in their cases? Is it just due to the fact that they use active guidance?
To clarify, I am not interested in any aesthetic factor that number of fins provide, and I'm fully aware of the slightly increased weight that goes along with having four fins. I am only interested in any aerodynamic differences. Especially those that work toward my advantage. (i.e. speed, height, both...)
Thanks in advance! I'm sure this will be interesting.....
Last edited: