My son built his SEMROC version with a removable mount. It's flown on single D12-3's, 4 B6's, and 3 C6's. We didn't fly on 4 C6's because of our limited recovery area. You know the chances of landing in a tree grows exponentially with the amount of time spent building and finishing a model!

IIRC, it flew great on our combination of 2 B6-2's and 2B-64's. The delay was about right and you didn't have four charges kicking the crap out of the NC. Three C6-3's were about perfect also. It might go a little long on the B6/C6-5 combo. (His was a little heavy with the removable mount and plenty of priming and sanding to get a slick finish.)

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I love sanding.