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Old 03-19-2010, 06:38 PM
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CPMcGraw CPMcGraw is offline
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Join Date: Mar 2005
Location: Mobile, Alabama
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Jay,

First thing I notice is that the rocket is still travelling upward at deployment, so that lets you know the delay values are short, and as Mark said, the optimal value is a moving target. However, it does give you a target range to work toward.

Notice that the A8-3 and C6-5 values are close to perfect. They are still moving upward, but they're closer to the right Dv than the B4-4 and B6-4. What you want to do is shift the A8-3 and C6-5 flights until the model is heading downward before they deploy. Since you cannot adjust the delay times, you have to adjust the Dv.

How? Shifting the Dv is also a product of how much drag the model has. Increase the drag slightly, and the model will begin to arc over sooner. What you want to achieve is to have the A and C engines deploy just after apogee, and the two B engines just before.

Scale up the fins a couple of percent and try running the simulation again. See my attached image for the simulation runs I got. I tried to bump the scale up slowly until I came into range, and the resulting scale factor was 25%. YMMV...


A8-3......220'......Dv 3 FPS
B4-4......517'......Dv 14 FPS
B6-4......525'......Dv 19 FPS
C6-5......816'......Dv 10 FPS
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