09-26-2016, 04:54 PM
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Contest, Sport, it's all good......
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Join Date: Jul 2008
Location: West of Minneapolis, MN
Posts: 760
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Some images from old Estes catalog scans on http://www.ninfinger.org
1970 catalog, pages 92-93, engine chart. Note the burn time of the B14 as .35 second.
1969 catalog, page 76, comparison of B6 and B14. with some dimensions. Notably the throat diameter:
1968 catalog , page 52. The drawing shows a deeper drilled core than the one above, and IIRC that was more inline with other info I’d seen. Also, given the thrust curve shape, how it drops to zero SO fast, the core would need to be so deep as in the drawing below, that there would be little to no propellant left to burn forward of the core, once the flame front reached the sides (A tiny bit of an arc of unburned propellant near the casing sides and bottom of the time delay being consumed during the steep drop-off).
So, what is really needed for this thread is for someone with a very old Estes B14 from 1970 or before, to measure the core depth. .75 inches from the casing bottom seems WAY shallow for the original “real B14” thrust curve..
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