I'm not sure but I think that some of the Estes tube length length codes just sort of "happened". If you think that the J designation for a 2.75" tube was interesting. What about the BT-5T and BT-20AE? Both tubes are 1.5" long. There were some tubes that had some pattern to their length code (i.e. BT-5BJ (2.0"), BT-20DJ (4.0"), BT-63CJ (3.0"), BT-50EE (5.5")), and then there were some that had codes specific to a particular kit (i.e. 1298 X-Wing Fighter used an XW length code, but the LL-1, BT-3, BT-5, and BT-20 tubes were all different lengths).

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'Til next time,

Mike Toelle

NAR 31692 L1

SAM 0373