I think they went to the longer motor tube when Estes changed to the plastic nose cone during the 1970s. That version still had two pieces of 1/8" balsa that you had to trace the fin pattern on the balsa and then cut them out yourself. I believe that die cut fins first appeared in 1986 when the catalog number was changed to 1948.

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'Til next time,

Mike Toelle

NAR 31692 L1

SAM 0373

I checked my ~1970 Bertha yesterday. It has an 18" airframe (can't recall if they all did) and the long balsa nosecone. Inside, the motor tube is ~8.5" long.

Doug

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YORF member #11

cool.