Over on the "other" forum Alan15578 and I were discussing the 13MM B motors: the MPC/AVI Mini-Jet B3M, and the Centuri B4M.

https://www.rocketryforum.com/threa...50/post-2119066

If anybody has any history they would like to share, pics,engine flyers,etc please do.

Some additional info I was able to dredge up was that the paper casings were spiral-wound paper tubes like body tubes, not the traditional convolute/parallel wound body tubes.
Centuri discontinued them based on a "hi-performance paper shortage" and manufacturing problems by summer 74.


IF anybody has an original copy of the 1973 Estes Model Rocktery catalog and would scan page D frm the front.....TIA

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"Old Rocketeer's don't die; they just go OOP".....unless you 3D print them.