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Old 12-08-2015, 08:45 AM
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tbzep tbzep is offline
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Join Date: Mar 2005
Location: TN
Posts: 11,610
Default Mega Red Max RocSim

Background: I'd like to use the Mega Red Max for a school demo rocket, but the smallest recommended motor (F50-6T) puts it over 500 ft. That almost guarantees that I won't be able to get it down inside the small playground. Therefore, I'm looking at clustering to get about 1/2 the altitude and still get similar or better peak thrust for liftoff safety.

The Estes/AT F60-6T specs:

76.83 N-s total impulse
79.50 N peak thrust
53.73 N average thrust
1.43 second burn time
6.05 second measured delay

3 D12-3 cluster

50.52 N-s total impulse (66%)
89.19 N peak thrust (112%)
30.63 N average thrust (76%)
1.65 second burn time
2.39 second measured delay

As you can see, I'm looking at 112% peak thrust compared to the single composite motor while total impulse is only 66%. That should theoretically get me around 1/2 the altitude or a little less and still get a decent velocity off the rod. However, I'm worried about the ramp-up time and quick drop-off of the D12 thrust compared to the near instant and consistent peak thrust of the F50. There's not much time spent at max thrust.

Could somebody with RocSim model these two motor configurations for me? Maybe model a 4 motor D12-3 cluster too? If the sim shows any promise at all, I plan to do a test flight with the cluster config this spring to compare RocSim results and to make sure it will work in the real world before flying it in public.
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