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Old 11-11-2009, 11:42 AM
stefanj stefanj is offline
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Originally Posted by Mark II
Exactly. 1968 was when Estes changed over from using English units to metric units for their motor designations. The motor chart in the 1968 Estes catalog cross-references their motors bearing the new metric designations with their previous English equivalents. I'm not sure when NAR S&T began using metric units for motor designations, but I believe it was a couple of years before that and that Estes took awhile to change over.


My working theory is that they waited until the motor redesign / new Mabel to introduce the Metric-themed motor codes.

I remember having a few A5 motors back in the day, but don't remember them being "different." I might have just not noticed. They (and B4 motors) were specialty items, in that you didn't see them in the hobby shops and variety stores that my friends and I bought motors from.
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Old 11-11-2009, 04:14 PM
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blackshire blackshire is offline
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I remember the A5-2, which was one of the recommended motors for the Estes Falcon boost-glider. Is the B4 you're referring to the plugged static test motor B4-0(P) that was listed in their catalogs up until about 1969 or 1970?
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Old 11-11-2009, 06:14 PM
stefanj stefanj is offline
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I'm speaking B4 generically. B4-2, B4-4, etc. There was even a B4-0 at one point.

The B4-x probably started out as a relabeled B.8-x, and the A5-x as a relabeled A.8-x. Old motor technology items.

Eventually the B4-x was redesigned to use the newer motor technology, and the A5 dropped.
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Old 04-05-2019, 09:13 AM
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Gus Gus is offline
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Reviving this old thread to ask a new question.

MMI also produced “Super B6” Rock-A-Chute motors, as well as separately labeled and distinctly colored booster and sustainer motors. All of these were produced by Vern.

Does anyone have any idea how these were packaged? I’ve never seen any packaging other than the original green label box for the Brown Manufacturing motors or the colorful box for the A4 motors that appears at the beginning of this thread?


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