Originally Posted by Royatl

Yes, they were both owned by Damon since late 1970. For whatever reason, Centuri didn't announce it or put "a DAMON company" on their logo. It was *mentioned* in Model Rocketry Magazine, but nothing else after that. I wonder if the deal was structured differently in Centuri's case? (more like a majority investment rather than the "purchase with stock and employment contracts" that the Estes' did).

Centuri invested in their own machines in 1970 because Estes was at capacity and was having trouble filling both their own needs and Centuri's. Once the slow down took hold, Estes could handle both again, and Damon had decided to slowly consolidate.

Two ways you can differentiate Estes and Centuri motors from this era. Centuri used modern printing technology on their casings... they were sharper and could do "white on black". When Estes resumed making their motors, they returned to black on white, because their ink ran. ("black" being whatever ink was used and "white" being no ink)

Centuri continued making small bore motors (0.408 id) like the original 1/2A6-2 and A5-2. The nozzles for these had a flat exit plane, where Estes motors have always been slightly bezeled. I don't *think* the large bore (0.5" id) had a flat exit plane, but I don't have any to look at. For Estes, small bore corresponded to motors still made on the original Mabel, while the Mabel G2 machines (to borrow Bill Stine's recent nomenclature) were large bore.

As to the mention of spiral casings above; I'm pretty sure that was pre-release hopefulness, and that none made it on the market (at least intentionally).