ChrisAttebery
Well-Known Member
- Joined
- Feb 15, 2014
- Messages
- 2,454
- Reaction score
- 90
Since becoming a REBAR last year I've been flying low and slow. I plan on making the trip to Black Rock for the first time in 15 years this year. I'd like to build something worthy of the trip. I can't afford to build an L3 project so it's going to have to be a minimum diameter 54mm rocket to fly at the extreme edge of the envelope. My personal altitude record is 8500' on an L850 in a 5" 35lb rocket. I'd like to break into the 25k region this time around. That should be reasonable with the motors and materials available now.
I plan to use the new thin wall fiberglass and an injection molded nose cone from Wildman. I've been tinkering with the design in OpenRocket and I've got it all worked out except the for the fins. The design I have now has just over 1 caliber of stability with the K300 loaded. All other motors will need ballast in the nose cone or forward body tube to be stabile. Since I won't be shooting for a record I don't see that as a problem. I'll probably just figure out what the absolute worst case is and make a removable ballast weight to suit.
The design I have now uses 3 small fins with a span of 2". According to OpenRocket there is ~1.1 calibers of stability. So the question is, how small of fin can you really get away with? Are there any better simulation tools for the mach 2+ region?
View attachment Attebery 54mm Minimum Diameter 3 Fin.ork
I plan to use the new thin wall fiberglass and an injection molded nose cone from Wildman. I've been tinkering with the design in OpenRocket and I've got it all worked out except the for the fins. The design I have now has just over 1 caliber of stability with the K300 loaded. All other motors will need ballast in the nose cone or forward body tube to be stabile. Since I won't be shooting for a record I don't see that as a problem. I'll probably just figure out what the absolute worst case is and make a removable ballast weight to suit.
The design I have now uses 3 small fins with a span of 2". According to OpenRocket there is ~1.1 calibers of stability. So the question is, how small of fin can you really get away with? Are there any better simulation tools for the mach 2+ region?
View attachment Attebery 54mm Minimum Diameter 3 Fin.ork