Ye Olde Rocket Forum - View Single Post - My fairly expensive, COTS motor test stand

Quote:

Originally Posted by Royatl

I just measured the core depth of a 1975 Estes B14 and a 1990 B8 and found them to be within a hundreth of an inch of each other (0.68" from the casing edge, not the nozzle exit, though they appeared to be the same). The throat diameter of the B14 was 0.17" vs the B8's 0.145", so they were already de-tuning the B14 at that time.

I see that the one you tested was a Centuri one from 1973.

That may have been one that was actually manufactured at Centuri. I don't know when they shut down their machines (which had only been running two or three years), but I bet they didn't want to do the post-process drilling that Estes did, and that's what led to the development of the deep-pintle motors that Estes eventually adopted.

By the way. I haven't completely confirmed this, but I think you can usually tell Centuri manufactured motors by their labels. they had crisp printing and the motor designation was in reverse on a dark band. On later Estes manufactured Centuri motors, the motor designation band was just normal printing within a couple of borders, and the general look of the printing was a bit smudgier (is that a word?). The problem I still have with this is that the mini motors were printed the second way, and they were definitely not made on Estes machines (they had the longer casings and the partial graphite clay).