Sure can. The AT E15 and E30, and the RMS 24/40 are size compatible with the D12. Most rockets that will fly on a D12 will fly fine on the E15 or E18 reload, although the reload casing will slightly affect the CG, so it might need a tad nose weight.
I haven't seent he announcement, but I'd guess that The Big Daddy E is modified for the longer motor mount. IMHO the rather heavy Big Daddy is a poor choice for the E9, but flies great with the D12 or the AT WL and BT alternatives.
Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle: http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org
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