@neil_w
I encountered minor coning with the model in my avatar which led me to look further into the graphical analysis tools available in OR. Specifically, the Stability vs Time and Angle of Attack and Orientation vs Time graphs show a likelihood of oscillation and/or coning. I'm trying to avoid the "jumpy" blue line and the "squiggly" yellow line. These are from the model above without the trap-fins. The screenshots below them are from the model with the trap-fins. Then again, I may be overthinking it way too much!
But yeah, the trap-fins are definitely not scale-like but they DO look cool! I have the Estes Nike kit and some good details from the LOC Zeus kit (2-1/4"). I took detailed measurements and scaled them in AutoCAD to come up with my design. Like I said, my model's CP is exactly where LOC's CP is (proportionally). The difference is I built it with a 38mm motor tube and 1.5mm FG fins. I made a 38-29mm adapter that weighs next to nothing, but all of the weight adds up when modeling 29mm motors.
Back to the CP: Adding the trap-fins moved the CP aft a touch over an inch.
Without the trap-fins:
With the trap-fins:
I encountered minor coning with the model in my avatar which led me to look further into the graphical analysis tools available in OR. Specifically, the Stability vs Time and Angle of Attack and Orientation vs Time graphs show a likelihood of oscillation and/or coning. I'm trying to avoid the "jumpy" blue line and the "squiggly" yellow line. These are from the model above without the trap-fins. The screenshots below them are from the model with the trap-fins. Then again, I may be overthinking it way too much!
But yeah, the trap-fins are definitely not scale-like but they DO look cool! I have the Estes Nike kit and some good details from the LOC Zeus kit (2-1/4"). I took detailed measurements and scaled them in AutoCAD to come up with my design. Like I said, my model's CP is exactly where LOC's CP is (proportionally). The difference is I built it with a 38mm motor tube and 1.5mm FG fins. I made a 38-29mm adapter that weighs next to nothing, but all of the weight adds up when modeling 29mm motors.
Back to the CP: Adding the trap-fins moved the CP aft a touch over an inch.
Without the trap-fins:
With the trap-fins:
