09-02-2010, 10:23 PM
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When Pigs Fly!
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Join Date: Sep 2005
Location: Orlando, FL
Posts: 1,102
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The changeover first showed up in the 1972 catalog.
http://www.ninfinger.org/rockets/no...a/72est038.html
Estes did sell 5/20 adapters for some of the older models that used 18mm S engines.
I went and looked through that catalog.
I'd forgotten about the "Series" engine designations.
Series I were standard 18mm x 2 3/4" engines
Sereis II were the B14
Series III were the shorter 18mm x 1 3/4" long S engines
Series IV were the D engines.
The "S" stood for short engines
I guess the "T" designation (13mm) is for tiny.
Hope this helps! |